Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Some effects of slashburning clearcutting and skidroads on the physical-hydrologic properties of coarse… Willington, R. P. 1968

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1969_A6_7 W55.pdf [ 14.86MB ]
Metadata
JSON: 831-1.0103990.json
JSON-LD: 831-1.0103990-ld.json
RDF/XML (Pretty): 831-1.0103990-rdf.xml
RDF/JSON: 831-1.0103990-rdf.json
Turtle: 831-1.0103990-turtle.txt
N-Triples: 831-1.0103990-rdf-ntriples.txt
Original Record: 831-1.0103990-source.json
Full Text
831-1.0103990-fulltext.txt
Citation
831-1.0103990.ris

Full Text

SOME EFFECTS OF SLASHBURNING, CLEARCUTTING AND SHIDROADS ON THE PHYSICAL-HYDROLOGIC PROPERTIES OF COARSE GLACIAL SOILS IN COASTAL BRITISH COLUMBIA by R.P. Willing-ton B.S.F., U n i v e r s i t y of B r i t i s h Columbia, 1967 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n the Faculty of FORESTRY We accept t h i s t h e s i s as conforming to the requi r e d standard THE UNIVERSITY OF BRITISH COLUMBIA December, 19GB In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r an a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and S t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r . e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e Head o f my D e p a r t m e n t o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . D e p a r t m e n t o f Forestry  The U n i v e r s i t y o f B r i t i s h C o l u m b i a V a n c o u v e r 8, Canada D a t e December 2 5 , 1!968 Abstract This study was i n i t i a t e d to determine the impact of c lear-cu t t i ng , slashburning and skidroads on deep (>3 feet ) coarse g l a c i a l s o i l s at low elevat ions (<1000 f t . above sea l e ve l ) of coasta l B r i t i s h Columbia. I n f i l t r a t i o n capaci ty , as measured with double-r i n g , constant-head i n f i l t r ome te r s , was the main measure of phys ica l-hydrologic s o i l cond i t ion . The re la t ionsh ips between i n f i l t r a t i o n capacity and s o i l va r iab les , inc luding aerat ion poros i ty , t o t a l poros i t y , bulk density , texture , organic matter content and antece-dent s o i l water content, werB examined. The average i n f i l t r a t i o n rates of the undisturbed, forested areas were 17.92 inches/hour on well-drained ac id brown wooded s o i l and 25.99 inches/hour on well-drained degraded ac id brown wooded s o i l . Skidroads caused d ras t i c reductions i n i n f i l t r a t i o n . Aver-age i n f i l t r a t i o n over a three hour period was 3.66 inches/hour on well-drained ac id brown wooded s o i l three years af ter moderate sk id-road use, 12.36 inches/hour on well drained degraded ac id brown wooded s o i l three years a f t e r l i g h t skidroad use and 5.33 inches/ h o u r on moderately well-drained or th i c podsol s o i l ten years a f te r heavy skidroad use. Slashburning s i g n i f i c a n t l y reduced i n f i l t r a t i o n , although not to the l e ve l s of skidroads. Two years a f ter burning, average i n f i l t r a t i o n over a three hour period was 13.42 inches/hour on wel l-drained ac id brown uooded s o i l and 17.87 inches/hour on well-drained degraded ac id brown wooded. C learcut t ing did not s i g n i f i c a n t l y a l t e r i n f i l t r a t i o n . Av-erage i n f i l t r a t i o n over a three hour period was 2D.51 inches/hour on well-drained degraded ac id brown wooded s o i l and 20.17 inches/hour on moderately well-drained or th i c podsol s o i l . Some of the var ia t ions in i n f i l t r a t i o n by treatment and s o i l type are explained with the a id of mult ip le regression t ech -niques. Acknowledgements Without the help and advice of c e r t a i n people and agencies, t h i s t h e s i s would not have been p o s s i b l e . S p e c i a l thanks are due Dr. w.U. J e f f r e y , Associate Professor ,of Forest Hydrology, Faculty of F o r e s t r y , U.B.C., who gave valuable guidance at a l l stages of the study and who arranged a l l the required f i n a n c i n g (!\IRC grant A - 3 6 4 0 ) . Thanks are a l s o extended to Dr. J . de V r i e s , A s s i s t a n t Professor of S o i l P h ysics, Department of S o i l Science, .11.B.C., who provided help, advice, space and equipment during the laboratory phases of the study, and to Mr. J . Walters, D i r e c t o r , U.B.C. Research Forest, f o r help regarding equipment and f a c i l i t i e s during the f i e l d phases. The w r i t e r a l s o acknowledges the r e c e i p t of the help pro-vided by Dr. A. Kozak, Associate Professor of S t a t i s t i c s , Faculty of For e s t r y , U.B.C, i n the s t a t i s t i c a l analyses using the e l e c t r o n i c computer. To Dr. T. Singh, Canada Department of F i s h e r i e s and Fore s t -r y , Calgary, A l b e r t a , go thanks f o r h i s advice and recommendations during the planning stages of the study. A v i s i t to see him and the double-ring i n f i l t r o m e t e r , developed f o r h i s own research on the e f f e c t s of the conversion of aspen f o r e s t to grassland on i n f i l t r a -t i o n , provided an opportunity to discover the l i m i t a t i o n s of the i n -f i l t r o m e t e r and to examine the pr e l i m i n a r y analyses c a r r i e d out by Dr. Singh. A l a r g e part of the success of t h i s study r e s u l t s from an experimental program i n i t i a t e d i n the summer of 1 9 6 7 by Dr. W.U. Je f f rey whereby an . undergraduate fores t ry student, se lected for h is academic and potent ia l research a b i l i t y , i s given the opportun-i t y to work on a research project with a graduate student and to write up his resu l t s in h is graduating thes i s . As a consequence of th i s program, which to date has been extremely success fu l , the wr i ter extends thanks to Mr. T. Lewis and Mr. D.S. Jamieson for the i r help during the summers of 1967 and 1968 respec t i ve l y . To my wife Georgina, I extend my deepest appreciat ion f o r , without her constant patience and encouragement, no aspect of the project or thes is could have been completed. Table of Contents Page Introduction 1 Survey of L i terature 5 1. I n f i l t r a t i o n 5 A. Relat ion of i n f i l t r a t i o n to hydrologic cyc l e . 6 B. The i n f i l t r a t i o n process 6 C. Factors in f luenc ing i n f i l t r a t i o n 12 2. C learcut t ing 24 A. As a harvesting method.. . 2k B. E f fec t on s o i l p r o p e r t i e s . . . . . 2k 3. Slashburning 27 A. . As a regulat ion 27 B. E f fec t on s o i l propert ies 27 C. E f fec t on i n f i l t r a t i o n 33 k. Skidroads 34 A. Purposes and construct ion 3k B. E f fec t on i n f i l t r a t i o n 36 The Study Area 37 1. Location and general d e s c r i p t i o n . . . . . 37 2. Spec i f i c areas studied 36 A. Block A. 38 B. Block B . . . 3 9 C. Block C 41 Experimental Design 43 Data Co l l ec t ion 45 1. I n f i l t r a t i o n as a basic measure of treatment e f fec ts 45 A. L imitat ions of double-ring i n f i l t r o m e t e r s . . . 4 8 2. So i l data 51 A. Bulk density and porosi ty cha r a c t e r i s t i c s . . . 52 B. Pa r t i c l e s ize d i s t r i b u t i o n . 56 C. Organic matter ^content determination 57 D. Derived var iables 57 Page A n a l y s i s of Data .59 1. Scattergram a n a l y s i s 59 2. M u l t i p l e regression a n a l y s i s 60 Results and Discussion 63 I. EFFECTS OF CLEARCUTTING AND SLASHBURNING ON INFILTRATION. 63 1. O v e r a l l e f f e c t s . 63 2. Mechanisms of treatment e f f e c t s . . . . . . . . . . . ••r73;a A. S o i l p o r o s i t y 74 B. Other s o i l v a r i a b l e s 81 a. Bulk density 64 b. . T o t a l p o r o s i t y 86 c. Incorporated organic matter 87 d. L i t t e r cover 91 e. Depth of fermented and humus l a y e r s 91 f. Macro-vegetation cover 94 3. I n f i l t r a t i o n p r e d i c t i o n equations, Blocks A and B...96 I I . EFFECTS OF SKIDROADS; ON INFILTRATION 100 1. O v e r a l l e f f e c t s 100 2. Mechanisms of treatment e f f e c t s 107 A. S o i l p o r o s i t y . ..108 B. Cither s o i l v a r i a b l e s 113 a. Bulk density .....116 b. T o t a l p o r o s i t y 117 c. S o i l t e x t u r e . . . . . . . . . . 118 d. Organic matter content 120 e. L i t t e r cover .122 f. Vegetation cover 123 3. E f f e c t s of skidroads on a r t i f i c i a l regeneration response 124 4. I n f i l t r a t i o n p r e d i c t i o n equations, Block C 126 Summary 129 1. Control or uncut .129 2. Clearcut 129 Page 3. Slashburned 133 k. Skidroads 136 5. Regeneration response 138 Conclusion 139 L i t e r a t u r e C i t e d 142 Appendix I Forest Regions of the Vancouver Forest D i s t r i c t i Appendix I I S o i l P r o f i l e D e s criptions . . . . . i i Appendix I I I Vegetation C h a r a c t e r i s t i c s of Experimental Units i i i Appendix IV Photographic D e s c r i p t i o n s of Experimental Units i v Appendix V P r a c t i c a l AspEcts of Ring I n f i l t r o m e t e r Use.. v Appendix VI Key to V a r i a b l e s . . . . . . v i Appendix VII Variable C h a r a c t e r i s t i c s by Experimental Unit . . . v i i L i s t of Tables Table Page 1 Three equational estimates of i n f i l t r a t i o n compared to measured i n f i l t r a t i o n 11 2 So i l disturbance fo l lowing logging in the U.S. P a c i f i c Northwest 25 3 Charac te r i s t i cs of f i r s t-hour i n f i l t r a t i o n mult ip le regression equation used in covariance analys is 64 4 Mean values of f i r s t-hour i n f i l t r a t i o n covariance var iables by experimental uni ts 65 5 Covariance analys is of f i r s t-hour i n f i l t r a t i o n rate (Y1) 67 6 Measured and adjusted means of f i r s t-hour i n f i l t r a t i o n (Y1) by experimental unit 67 7 Results of Duncan's New Mult ip le Range test on adjusted Y1 experimental unit means 68 8 Charac te r i s t i cs of third-hour i n f i l t r a t i o n mult ip le regression equation used i n covariance analys is 69 9 Mean values of the third-hour i n f i l t r a t i o n covariance var iables by experimental uni ts 70 10 Covariance analys is of third-hour i n f i l t r a t i o n rate (Y3) 71 11 Measured and adjusted means of third-hour i n f i l t r a t i o n (Y3) by experimental unit 71 12^  Results of Duncan's New Mult ip le Range test on adjusted Y3 experimental unit means 72 13 F i r s t and third-hour i n f i l t r a t i o n means by experimental unit corrected fo r r e f i l l error 73 14 Simple regression equations re l a t ing f i r s t-hour i n f i l t r a t i o n (Y1) to the aerat ion poros i t i es of the 0 - 3 , and 4 - 7 inch mineral s o i l layers 75 15 Simple regression equations r e l a t i ng third-hour i n f i l t r a t i o n (Y3) to the aerat ion poros i t i es of the 0 - 3 , and 4 - 7 inch mineral s o i l layers 80 L i s t of Tables (continued) Table Page 16 Mult ip le regression equation r e l a t i ng cer ta in s o i l var iables to the logarithm of the aerat ion porosi ty of the D - 3 inch s o i l layer ...82? 17 Mult ip le regression equation r e l a t i ng cer ta in s o i l var iables to the aeration porosity of the Q - 3 inch s o i l layer 83 18 Mult ip le regression equation r e l a t i ng cer ta in s o i l var iables to the logarithm of the aerat ion porosi ty of the 4 - 7 inch layer 84 19 Mult ip le regression equations r e l a t i ng s o i l organic matter content to f i r s t and th i rd-hour i n f i l t r a t i o n . . . . .90 20 Mean values of percent l i t t e r cover for each experimental u n i t . . . . .92 21 Funct ional pred ic t ion equations of f i r s t (Y1) and third-hour (Y3) i n f i l t r a t i o n r a t e s . . . 98 22 Charac te r i s t i cs of f i r s t-hour i n f i l t r a t i o n (Y1) mult ip le regression equation used in covariance analys is . . . . . . . 1 0 1 23 Mean values of f i r s t-hour i n f i l t r a t i o n (YD covariance var iables by experimental unit 102 24 Covariance analys is of f i r s t-hour i n f i l t r a t i o n rate (Y1) 103 25 Measured and adjusted means of f i r s t-hour i n f i l t r a t i o n (Y1) by experimental unit . . . . 104 26 Charac te r i s t i cs of third-hour i n f i l t r a t i o n (Y3) mult iple regression equation used in covariance a n a l y s i s . . . . 105 27 Covariance analys is of third-hour i n f i l t r a t i o n rate (Y3). ..105 28 Measured and adjusted means of third-hour i n f i l t r a t i o n (Y3) by experimental u n i t . . 106 29 Simple regression equations r e l a t i ng f i r s t-hour i n f i l t r a t i o n (Yl) to the aerat ion poros i t i es of the 0 - 3 , and 4 - 7 inch s o i l l a ye r s ; 109 L i s t of Tables (continued) Table Page 30 Simple re g r e s s i o n equations r e l a t i n g third-hour i n f i l t r a t i o n (Y3) to the aer a t i o n p o r o s i t i e s of the 0 - 3 , and 4 - 7 inch s o i l l a y e r s . . . . . 111 31 Aeration p o r o s i t i e s of the 0 - 3 and 4 - 7 inch l a y e r s of the skidroad and c o n t r o l u n i t s of Blocks A and B 112 32 M u l t i p l e regression equation r e l a t i n g the a e r a t i o n p o r o s i t y of the 0 - 3 inch s o i l l a y e r (XS) to other s o i l v a r i a b l e s 114 33 M u l t i p l e r e g r e s s i o n equation r e l a t i n g the a e r a t i o n p o r o s i t y of the 4 - 7 inch l a y e r (X7) to other s o i l v a r i a b l e s .......115 34 Mean values of percent l i t t e r cover (X51) by experimental u n i t . ....122 35 Mean values f o r percent macro (X55) and micro (X56) vegetation cover by experimental u n i t 123 36 Simple regression equations r e l a t i n g f i r s t -(Y1) and third-hour (Y3) i n f i l t r a t i o n r a t e s to average Dbh (X59) and height (X60) of a r t i f i c i a l regeneration 125 37 Mean values of a r t i f i c i a l regeneration Dbh and height by experimental u n i t ...125 -38 M u l t i p l e regression equations f o r the p r e d i c t i o n of f i r s t and third-hour i n f i l t r a t i o n . . . . . 127 39 Mean values of the aeration p o r o s i t y of the l i m i t i n g l a y e r (X57) by experimental u n i t 128 L i s t of Figures Figure Page 1 Water content vs. depth f o r two times during i n f i l t r a t i o n . . . 7 2 A t y p i c a l i n f i l t r a t i o n curve 8 3 Factors a f f e c t i n g i n f i l t r a t i o n i n t o s o i l . ...13 4 Schematic e f f e c t of antecedent s o i l water content on i n f i l t r a t i o n rate 21 5 Area of i n f l u e n c e of slashburning on various components of an open system 28 6 The general area included i n Block A 40 7 The general area included i n Block B 41 8 The general area included i n Block C 42 9 D e t a i l of so u b l e - r i n g , f l o o d i n g type i n f i l t r o m e t e r with constant head r e g u l a t i o n tube.... .46 10 Schematic e f f e c t of p o t e n t i a l l a t e r a l flow l a y e r ( a ) , and the l i m i t i n g l a y e r (b) on i n f i l t r a t i o n .58 11 Aeration p o r o s i t y d i s t r i b u t i o n i n the average s o i l p r o f i l e of each experimental u n i t i n d i c a t -ing high v a r i a t i o n which tends to o b l i t e r a t e treatment e f f e c t s 66 12 Means and ranges of aeration p o r o s i t i e s of the 0 - 3 and 4 - 7 inch s o i l l a y e r s and f i r s t and third-hour i n f i l t r a t i o n r ates of experimental u n i t 77 13 Bulk density and ae r a t i o n p o r o s i t y f o r the 0 - 3 inch mineral s o i l l a y e r by e x p e r i -mental u n i t 85 14. T o t a l and a e r a t i o n p o r o s i t i e s of the 0 - 3 inch l a y e r of mineral s o i l by experimental u n i t 86 15 Percent s o i l content of > 2 mm. (X49), < 2 mm. (X53) and t o t a l organic matter (X57) of the 0 - 3 inch l a y e r by experimental u n i t .........87 L i s t of Figures (continued) Figure Page 16 Means and ranges of fermented and humus layer depths by experimental unit 93 17 Mean values and ranges of macro-vegetation cover (X65) by experimental unit 95 18 F i r s t and third-hour i n f i l t r a t i o n and 0 - 3 and k - 7 inch aeration porosi ty means by experimental unit 110 19 Ve r t i c a l d i s t r i bu t i on of aerat ion porosity in the average s o i l pedon of each expe r i -mental; unit showing the increas ing var ia t ion with increas ing depth 113 20 Var ia t ion of bulk density of the 0 - 3 inch s o i l layer between experimental uni ts . . . . 1 1 6 21 Var ia t ion in the t o t a l porosi ty of the 0 - 3 (X11), and U - 7 (X12) inch s o i l layers between experimental uni ts . . . . . . . 1 1 8 22 Mean values of percent sand ( 0 - 3 inch layer ) and percent s i l t plus clay ( 0 - 3 and l« - 7 inch layers ) by experimental unit 119 23 Mean values of coarse organic matter of the 0 - 3 (X36) and U - 7 (X37) inch layers and f ine organic matter of the 0 - 3 inch layer (X41) by experimental unit 120 2k I n f i l t r a t i o n curves for Block A .130 25 I n f i l t r a t i o n curves fo r Block B..... 131 26 I n f i l t r a t i o n curves for Block C 132 SOME EFFECTS OF SLASHBURNING, CLEARCUTTING AND SKIDROADS ON THE PHYSICAL-HYDROLOGIC PROPERTIES OF COARSE GLACIAL SOILS IN COASTAL BRITISH COLUMBIA Intr o d u c t i o n The logging of nearly 100,000 acres annually i n the Vancou ver Forest D i s t r i c t represents a major disturbance of the f o r e s t s and s o i l s of c o a s t a l B r i t i s h Columbia. The hydrologic i m p l i c a t i o n s of t h i s s c a l e of disturbance, although o c c a s s i o n a l l y s u b j e c t i v e l y noted by f o r e s t workers, have not been adequately appraised q u a n t i -t a t i v e l y f o r t h i s r e gion. The importance of t h i s l a t t e r point i s emphasized by the steep topography and high p r e c i p i t a t i o n character i s t i c of the region, which tend to make erosion and a l l of i t s ram-i f i c a t i o n s suspect i n a region which i s experiencing a booming i n -crease i n population with attendant demands f o r goods and s e r v i c e s of acceptable q u a l i t y from the land. - 2 -Of the two main logging methods employed on c o a s t a l B r i t i s h Columbia, highlead and t r a c t o r , the former i s the most popular, with the l a t t e r r e s t r i c t e d to more a c c e s s i b l e areas amounting to l e s s than 1 0 % of the f o r e s t area of the c o a s t a l r e g i o n . Although research i s continuing on other logging systems ( s k y l i n e and balloon) the dom-inant r o l e of highlead l o g g i n g , a method w e l l - s u i t e d to timber ex-t r a c t i o n i n rugged t e r r a i n , w i l l l i k e l y remain f o r a long time to come. The logging operation c o n s i s t s of s e v e r a l i d e n t i f i a b l e stages of disturbance. One of these stages i s road c o n s t r u c t i o n , the hydrologic e f f e c t s of which are f a i r l y obvious and as such have been documented e x t e n s i v e l y . Following road c o n s t r u c t i o n , s e t t i n g s of 2 0 acres or more are c l e a r - f e l l e d , i n i t i a t i n g a major change i n the microclimate of the area c l e a r e d . The f u l l impact of t h i s change i s yet to be appraised i n t h i s region i n the context of hydrology, •nee the area has been f e l l e d , the merchantable logs are yarded, e i t h e r by a cable system or t r a c t o r system, to a landing where they can be loaded on a truck f o r hauling to t h e i r d e s t i n a t i o n . The a c t i o n of a l o g s l i d i n g and bouncing over the s o i l represents a major source of disturbance to the s a i l surface and as such i s of import-ance h y d r o l o g i c a l l y (Dyrness, 1967). Skidroads constructed f o r t r a c -t o r logging represent extensive zones of s o i l disturbance and t h e i r place as a p o t e n t i a l source of runoff and erosion i s not to be under-r a t e d , even on the B.C. coast where t h i s logging system has l i m i t e d a p p l i c a t i o n . Slash d i s p o s a l f o l l o w i n g the yarding operation i s c a r r i e d out p r i m a r i l y f o r f i r e hazard abatement. Broadcast burning of the 3-logging debris i s the most common method of s l a s h d i s p o s a l on the B.C. coast and data on t h i s operation, as employed i n the United States P a c i f i c Northwest, i n d i c a t e s the p o s s i b i l i t y of surface s o i l damage accruing from the burning (Austin and B a i s i n g e r , 1955; Dyr-ness, 1967). I t has been st r e s s e d that a research program i n t o the hydrolagic e f f e c t s of slashburning r e q u i r e s high p r i o r i t y ( J e f f r e y , 1968), due to the present l a c k of knowledge p e r t a i n i n g to s l a s h -burning on c o a s t a l B.C. As a r e s u l t of the r e a d i l y i d e n t i f i a b l e lack of information on the h y d r o l o g i c a l aspects of f o r e s t harvesting on c o a s t a l B.C., an i n i t i a l p r o j e c t was e s t a b l i s h e d to study those areas i d e n t i f i e d . S p e c i f i c research o b j e c t i v e s were to assess the e f f e c t s of c l e a r -c u t t i n g , slashburning and skidroads on i n f i l t r a t i o n (a hydrologic measure s e n s i t i v e to ecosystem a l t e r a t i o n ) and to e x p l a i n some of the mechanisms of the i n f i l t r a t i o n process. F i e l d work was c a r r i e d out during the summers of 1967 and 1968 on three low e l e v a t i o n , coarse g l a c i a l s o i l s on thB U n i v e r s i t y of B r i t i s h Columbia Research Forest near Haney, B.C. I n f i l t r a t i o n measurements were obtained using double-ring, constant head i n f i l t r o m e t e r s . A n a l y s i s of data was c a r r i e d out using m u l t i p l e r e g r e s s i o n and covariance techniques. The e f f e c t of skidroads on i n f i l t r a t i o n on two s o i l types was w r i t t e n as an undergraduate t h e s i s by Mr. T. Lewis i n 1968 (Lewis, 1968). His f i n d i n g s are summarized i n t h i s t h e s i s . The study of the hydrologic i m p l i c a t i o n s of c l e a r c u t t i n g and slashburn-i i n g on two s o i l types and skidroads on another type c o n s t i t u t e s the main part of t h i s t h e s i s . - i t -I t i s important to note that the new information presented i n t h i s t h e s i s , on the h y d r o l o g i c a l e f f e c t s of f o r e s t harvesting on the coast of B.C., i s f a r from complete and a great deal more r e -search i s r e q u i r e d . Wherever p o s s i b l e , throughout the t h e s i s , the author has attempted to i d e n t i f y areas where f u r t h e r research e f f o r t s should be d i r e c t e d . However, i t i s also necessary to emphasize t h a t , i n the case of determining and recommending a l t e r n a t i v e f o r e s t man-agement techniques f o r the p r o t e c t i o n of the land phases of the hydrologic c y c l e , i t w i l l take not only research, but a l s o profe-s s i o n a l awareness on the part of management f o r e s t e r s . -5-Survey of L i t e r a t u r e 1. I n f i l t r a t i o n I n f i l t r a t i o n i s described as the entry of water i n the l i q -u i d s t a t e i n t o the s o i l , across the soil-atmosphere i n t e r f a c e . The term i n f i l t r a t i o n capacity has been used f o r a number of years by h y d r o l o g i s t s to describe "the maximum r a t e at which a given s o i l , i n a given c o n d i t i o n , can absorb r a i n as i t f a l l s " (Horton, 1940). The d e f i n i t i o n r e f e r s to r a t e r a t h e r than cap a c i t y and i n f i l t r a t i o n r a te has been brought i n t o common use among s o i l p h y s i c i s t s i n a sense synonymous with i n f i l t r a t i o n c a p a c i t y . Another term, i n f i l t r a t i o n v e l o c i t y , has been introduced by a S o i l Science Society of America Terminology Committee (Richards, 1952) to designate the instantaneous l o c a l r a t e of i n f i l t r a t i o n . Other terms commonly used i n conjunction with i n f i l t r a t i o n phenomena are p e r c o l a t i o n and p e r m e a b i l i t y . P e r c o l a t i o n i s q u a l i t a -t i v e l y used i n the same context as i n f i l t r a t i o n , but with emphasis towards downward movement of water i n s o i l s . I n f i l t r a t i o n cannot continue unimpeded unless p e r c o l a t i o n provides s u f f i c i e n t space (drained pores) i n the surface l a y e r of s o i l f o r i n f i l t e r e d water ( L i n s l e y et a l . 1949). P e r m e a b i l i t y , on the other hand, r e f e r s to the s o i l r a t h e r than to the s o i l water and q u a l i t a t i v e l y i s the c h a r a c t e r i s t i c of the s o i l r e l a t i n g to the readiness with which i t transmits water. Q u a n t i t a t i v e l y , Richards 1 (1952) committee express-ed i t as the s p e c i f i c property denoting the rate at which the s o i l t ransmits water under standard c o n d i t i o n s . A . R e l a t i o n of i n f i l t r a t i o n to hydrologic c y c l e The only way by which s o i l water and ground water may be recharged i s by i n f i l t r a t i o n of r a i n f a l l or snowmelt water. I n f i l -t r a t i o n i s v i r t u a l l y the only mechanism by which water i s made a v a i l a b l e to the t r a n s p i r a t i o n stream. The i n f i l t r a t i o n capacity of the s o i l d i v i d e s r a i n f a l l i n t o two parts which t h e r e a f t e r pursue d i f f e r e n t courses through thB hydrologic c y c l e ; one part going i n i t i a l l y i n t o the s o i l and the other t r a v e l l i n g over the s o i l sur-face (Horton, 1933). I f the supply i n t e n s i t y , I , of r a i n f a l l or snowmelt r a t e i s l e s s that the i n f i l t r a t i o n c a p a c i t y , F, the e n t i r e water input i s absorbed by the s o i l . I f , however, I>F some water accumulates on the s o i l s u r f a c e . The l a t t e r case has important i m p l i c a t i o n s i n water erosion processes. In order f o r water erosion to occur, t h i s surface water must have enough energy to detach s o i l p a r t i c l e s , t h i s energy being dependent on the quantity of flowing water and i t s r a t e of movement. I n f i l t r a t i o n plays a major r o l e i n determination of • the q u a n t i t y , Q, a v a i l a b l e f o r flow according to the approximate r e -l a t i o n s h i p Q = I - F. B. The i n f i l t r a t i o n process water reaching the s o i l surface enters the s o i l under the combined i n f l u e n c e of g r a v i t y and matric f o r c e s . Although both f a r c e s act i n the v e r t i c a l d i r e c t i o n to cause p e r c o l a t i o n downward, matric f o r c e s a l s o act l a t e r a l l y , removing water from the ae r a t i o n (Peele, 1949) pores. As the i n f i l t r a t i o n process continues, the s a i l water d i s t r i b u t i o n assumes the c h a r a c t e r i s t i c pattern i n d i c a t e d i n Figure 1 (Bodman and Coleman, 1944). Figure 1. Water content vs. depth f o r two times during i n f i l t r a t i o n . I t can be seen that the transmission zone i s a c o n t i n u a l l y lengthen-in g unsaturated zone of f a i r l y uniform water content and p o t e n t i a l . Water movement i n t h i s zone i s p r i m a r i l y by unsaturated flow which, although i t increases with s o i l water content, i s l i m i t i n g to down-ward flow of water i n the s o i l p r o f i l e . P a r t i a l l y as a consequence of the i n c r e a s i n g length of flow paths i n the transmission zone (Gray and Norum, 1967) and of i n c r e a s i n g a i r pressure ahead of the wetting f r o n t (Adrian and F r a n z i n i , 1966) a r a p i d reduction of i n -f i l t r a t i o n r a t e i n the f i r s t few hours of a storm occurs, a f t e r which the r a t e remains nearly constant f o r the remainder of the -8-storrn event. This gives r i s e to the t y p i c a l i n f i l t r a t i o n curve, i n d i c a t e d i n Figure 2. time Figure 2. A t y p i c a l i n f i l t r a t i o n curve. Hortom (1933) described the extremes of the i n f i l t r a t i o n r a t e as maximum and minimum i n f i l t r a t i o n c a p a c i t y . Several equations have been developed r e l a t i n g i n f i l t r a t i o n to measurable parameters. Most of these equations are dependent on the Richards s o i l moisture d i f f u s i o n equation (Gray and IMorum, 1967). TT = V - 1 < V £ (1) d t i n which © = the volumetric water content \ = the unsaturated c o n d u c t i v i t y , and <5 = the t o t a l s o i l water p o t e n t i a l This equation i s the c o n t i n u i t y equation f o r flow which has the f l u x , -9-V , at any paint defined by the Darcy equation. xr = - k v l > (2) •ne of the f i r s t i n f i l t r a t i o n equations was that of K o s t i a -kov (1932) who expressed i n f i l t r a t i o n capacity f , as a power func-t i o n of time, t . f = 06kt C ° ' (3) The terms OC and Tc are parameters which, because they must be con-st a n t f o r the equation to be v a l i d , unfortunately vary i n p r a c t i c e and are not independent. Also when CC>1 (which i s g e n e r a l l y the case) the value of f approaches zero as "t approaches i n f i n i t y . Horton (1940) proposed an improved equation f o r i n f i l t r a -t i o n f = fc-+(fo - f c J e _ K f t (4) where To i s the i n i t i a l value of -f ( i n f i l t r a t i o n c a p a c i t y ) and TC i s the s t a b i l i z e d or f i n a l value of -p . The value Kp i s a constant which v a r i e s with s o i l c o n d i t i o n s and may a f f e c t the time, "h , r e -quired f o r i n f i l t r a t i o n c apacity to change from T O tO "fc . The main advantage of t h i s equation i s that as "t approach-es i n f i n i t y -f does not approach zero. The main disadvantages are that i t i s incapable of adequately representing the very r a p i d de-- i n -crease of f from high values at small {, , and the need f o r three parameters. One of the most s i g n i f i c a n t c o n t r i b u t i o n s t o understanding the i n f i l t r a t i o n process uas given by P h i l i p (1957a) i n which he presented the s o l u t i o n to the d i f f u s i o n equation (equation 1) f o r one-dimensional v e r t i c a l i n f i l t r a t i o n i n t o a uniform, s e m i - i n f i n i t e medium, i n i t i a l l y at a constant moisture content. The r e s u l t i n g equation gives the distance from the s o i l surface to a point i n the p r o f i l e at which the moisture content i s Q as ± 3 xce)=^(G)t2 +J&(e)t + 7/r(9)t* (5) where the q u a n t i t i e s (JP(0), S&(&) and yf(6), as fu n c t i o n s of 9, can be evaluated from unsaturated c o n d u c t i v i t y and d l f f u s i v i t y curves. In a l a t e r paper P h i l i p (1957b) developed equation (5) i n -to a s i m p l i f i e d form, a p p l i c a b l e to s t a b l e , nonswelling s o i l s , as f - £-t~V + (Kr> + f ) - ( 6 ) where f = S = s o r p t i v i t y ; K-n = s t a b i l i z e d unsaturated c o n d u c t i v i t y and f = distance between maximum depth of s a t u r a t i o n and depth of wetting f r o n t . Equation (6) can be s i m p l i f i e d by s u b s t i t u t i n g (a parameter) f o r Kn. + / to y i e l d the equation f = i S t ~ * M . (7) -11-Although equation (7) i s advantaged by i t s s i m p l i c i t y and p h y s i c a l theory base, i t f a i l s at l a r g e since In the same paper P h i l i p (1957b) compared the accuracy of h i s equation (equation 7) f o r estimating i n f i l t r a t i o n with those of KDstiakov (equation 3) arid Horton (equation 4 ) . A l l equations were compared to values of i n f i l t r a t i o n obtained from l a b o r a t o r y e x p e r i -ment (Table 1). The f i n d i n g s i n t h i s t a b l e show that Horton's equation f a i l s badly, the Hostiakov equation f i t s moderately w e l l and P h i l i p ' s approach i s quite adequate. I t i s important to note that the l a b o r a t o r y measure of i n f i l t r a t i o n was obtained from u n i -form s o i l columns. Table 1. Three equational estimates of i n f i l t r a t i o n compared to measured i n f i l t r a t i o n . Method of Estimation t = 1D5 sec. t = 1Q6 sec. % e r r o r f % e r r o r D e t a i l e d l a b . measurement 4.477 0 18.670 • Kostiakov equation (3) 4.225 -5.6 15.395 -18 Horton equation (4) 8.174 +82 29.412 +58 P h i l i p equation (7) 4.449 0.63 17.753 -4.9 Equations have been developed to compute i n f i l t r a t i o n i n t o l a y e r e d s o i l s and s o i l s i n which the s o i l water content i s not u n i -form (Hanks and Bowers, 1962; Staple and Gupta, 1966) but t h e i r accuracy has not been c o n c l u s i v e l y determined. -12 C. Factors affecting i n f i l t r a t i o n It i s evident from equation (2) that the flux at any point in a s o i l system, including the s o i l surface, i s proportional to the unsaturated conductivity, 1< , and the total potential gradient V § (Gray and Norum, 1967). Therefore, the i n f i l t r a t i o n process mill be affected by any factor which affects either of these two quantities. Figure 3 (based on the model developed by Gray and Norum, 1967) out-lines the most pertinent of these factors within the context of for-ested ecosystems. Soil porosity exerts the greatest influence on i n f i l t r a t i o n and most of the other s o i l properties exert their influence on i n f i l -tration through pore size characteristics. The pore spaces in a s o i l consist of two sizes; pores of water retention* size through which water can pass only under tension, and aeration pores which are larger, through which water can move more or less freely under the influence of gravity. An absolute dimension for separating s o i l pores into two categories does not exist due to the continuum of the pore size distribution. Porosity determines the storage available for infiltered water and also effects resistance to flow; both of these effects are such that i n f i l t r a t i o n increases with porosity (Linsley et a l . 1949). Since aeration pores drain under the influence of gravity, a certain pore volume i s constantly made available to i n f i l t e r i h g * of a size that water i s retained at levels of matric potential less than a given level (usually -60 cm. of water) -13-INFILTRATIDN RATE GRADIENT OF TOTAL POTENTIAL MATRIC GRADIENT GRAVITATIONAL GRADIENT PRESSURE GRADIENT DEPTH TO WET FRONT POROUS MEDIUM PROPERTIES PRESSURE AT WET FRONT PRESSURE AT SOIL SURFACE FLUID PROPERTIES SOIL SURFACE CONDITIONS POROSITY CHARACTERISTICS ANTECEDENT SOIL WATER CONTENT DENSITY AND IVISC05ITY ANTECEDENT ACCUMULA" fED SOIL WATER VOLUME CONTENT INFILTERED SURFACE TENSION AND CONTACT ANGLE PRESSURE OF CONFINED AIR BAROMETER AND HYDROSTATIC PRESSURE UNINCORPOR ORGANIC MATTER EXPOSED MINERAL SOIL PARTICLE SIZE DISTRIBUTION HOMOGENEITY COLLOIDS BIOLOGICAL ACTIVITY VEGETATION (ROOTS) IN-WASHING SOIL STRUCTURE LATERAL FLOW DM CLAY FUNGI MOLDS Figure 3. Factors a f f ec t ing i n f i l t r a t i o n into Boil -14 ' water as long as groundwater drainage i s equal to or greater than 1 the i n f i l t r a t i o n r a t e . Conversely, water r e t e n t i o n p o r o s i t y e f f e c t s are e l i m i n a t e d through a d d i t i o n D f water to the s o i l pedon. water moves to the water r e t e n t i o n pores along a matric p o t e n t i a l gradient which i s gradually e l i m i n a t e d through increased water content of the same pores. Water held i n the water r e t e n t i o n pores w i l l only d r a i n i n response to a matric p o t e n t i a l gradient such as induced by evapo-t r a n s p i r a t i o n . Thus, under co n d i t i o n s of sustained water d e l i v e r y ( s i n g l e long storm event or s e r i e s of c l o s e l y spaced storm events such as occur during the f a l l on c o a s t a l B.C.) the e f f e c t of water r e t e n t i o n p o r o s i t y on i n f i l t r a t i o n becomes n e g l i g i b l e . S o i l t e x t u r e and s t r u c t u r e are primary s o i l c h a r a c t e r i s -t i c s determining t o t a l p o r o s i t y and pore s i z e d i s t r i b u t i o n . Gener-a l l y , the l a r g e r the g r a i n s i z e (primary or secondary), the l a r g e r the pores. Lutz and Learner (1939) evaluated the e f f e c t of texture and s w e l l i n g on the pore s i z e d i s t r i b u t i o n and permeabi l i t y of a s e r i e s of sand separates and on s e v e r a l s u b s o i l s . In the coarser f r a c t i o n s permeability was found to increase e x p o n e n t i a l l y with an increase i n p a r t i c l e s i z e . In the s u b s o i l s an important f a c t o r de-termining permeability was the s w e l l i n g of the c o l l o i d a l m a t e r i a l , r e s u l t i n g i n a reduction of p o r o s i t y . Free and Palmer (1940), using graded s i l i c a sand, found i n f i l t r a t i o n r a t e decreased with i n c r e a s i n g wetting f r o n t penetration u n t i l i t became constant and a f u n c t i o n of p a r t i c l e diameter. Moldenhauer and Long (1964) found that i n f i l t r a -t i o n r a t e s decreased with decreasing p a r t i c l e s i z e . Dortignac and Love (1961), i n an i n f i l t r a t i o n study on Ponderosa pine ranges of Colorado, found the percent sand content was the best i n d i c a t o r of 15-the i n f l u e n c e of texture on i n f i l t r a t i o n such that i n f i l t r a t i o n i n -creased with an increase, i n sand content. S o i l s t r u c t u r e tends to modify the e f f e c t of texture on i n -f i l t r a t i o n . Aggregation of f i n e textured s o i l s may cause a s i g n i f i -cant increase i n aer a t i o n p o r o s i t y at the expense of water r e t e n t i o n p o r o s i t y . Aggregation of coarse textured s o i l s , however, has a cor-respondingly minor e f f e c t on i n c r e a s i n g a e r a t i o n p o r o s i t y . Since the arrangement of p a r t i c l e s and aggregates i n an i n t e r m i n g l i n g s o i l as-semblage may be such as to increase or decrease ae r a t i o n p o r o s i t y , i t i s not to be expected that a high degree of aggregation w i l l i n -v a r i a b l y be associated with high r a t e s of i n f i l t r a t i o n . Vegetation i n f l u e n c e s the i n f i l t r a t i o n capacity of s o i l s . Baver (1966) described some of the more important e f f e c t s of roots on the promotion of favorable s o i l s t r u c t u r e and subsequent p o r o s i t y . Included are root growth pressure, s o i l water content changes i n the v i c i n i t y of the root system and root e x c r e t i o n s . Other i n f l u e n c e s of vegetation on i n f i l t r a t i o n i nclude organic matter generation, p r o t e c t i o n of the s o i l surface from raindrop impact and associated m i c r o b i o l o g i c a l e f f e c t s . Research f i n d i n g s on the o v e r a l l e f f e c t s of vegetation on i n f i l t r a t i o n have not been c o n c l u s i v e . Dortignac and Love (1961) pointed out that the d i f f e r e n c e s i n i n f i l t r a t i o n between vegetation cover types was a t t r i b u t a b l e to a large number of s o i l and vegeta-t i o n p r o p e r t i e s r a t h e r than vegetation alone. Johnson and IMiederhaf (1941) found that w i t h i n each of three cover types t e s t e d , plant density seemed to have no d e f i n i t e e f f e c t on surface runoff or i n --16-f i l t r a t i o n . Pear9B (1937) found that f i b r o u s - r o o t e d p l a n t s , such as grasses and mesophytic f a r b s , were approximately 2)6 times more e f f e c t i v e i n promoting absorption of surface water than were tap-rooted spec i e s . Organic matter has c o n s i s t e n t l y been recognized as being b e n e f i c i a l i n promoting high i n f i l t r a t i o n r a t e s of s o i l s (Arend, 1941; Duley, 1939). Organic m a t e r i a l i n c o l l o i d a l and p a r t i c l e form develops as a r e s u l t of extensive decomposition of organic horizons and r o o t s . I t has been noted that organic matter i s conducive to the formation of r e l a t i v e l y l a r g e r ( l a r g e r than 0.1 mm. i n diameter) water s t a b l e aggregates (Baver, 1966; Saine et a l . 1966). Pearse (1937) found that the i n f i l t r a t i o n of g r a n i t i c s o i l s was i n f l u e n c e d much more by organic matter content than by e i t h e r s o i l water con-tent or texture v a r i a t i o n s . Recent evidence i n d i c a t e s the p o s s i b i l -i t y that incorporated organic matter may not always be b e n e f i c i a l to water intake (Letey et a l . 1962). Sand p a r t i c l e s coated with a water e x t r a c t of chaparral l i t t e r were found to by hydrophobic, r e -s u l t i n g i n decreased i n f i l t r a t i o n . Water enters hydrophobic s o i l s only under the i n f l u e n c e of g r a v i t y through the ae r a t i o n pores thereby rendering i n f i l t r a t i o n a f u n c t i o n of the s i z e and continu-i t y of the ae r a t i o n pores. Unincorporated organic matter ( l i t t e r , d u ff, fermented and humus l a y e r s ) plays a s i g n i f i c a n t r o l e i n i n f i l t r a t i o n , as summariz-ed by Lowdermilk (1930): i . Forest l i t t e r g r e a t l y reduces s u r f i c i a l r unoff even a f t e r i t i s completely saturated. -17-i i . D estruction of the l i t t e r g r e a t l y increases the amount of eroded s o i l and reduces the i n f i l t r a -t i o n c a p a c i t y . i i i . Suspended p a r t i c l e s i n runoff water from bare s o i l f i l t e r s out at the surface and se a l s the pores. i v . The capacity of f o r e s t l i t t e r to absorb r a i n f a l l i s i n s i g n i f i c a n t i n comparison to i t s a b i l i t y to main-t a i n the maximum p o r o s i t y of the mineral s o i l . In a Ponderosa pine f o r e s t , Johnson (1940) found the i n -f i l t r a t i o n c a p a c i t y on p l o t s with the l i t t e r i n t a c t was 1.52 inches per hour and 0.92 incher per hour f o r p l o t s with the l i t t e r removed - a s i g n i f i c a n t d i f f e r e n c e of 0.6Q inches per hour. Dortignac and Love (1961) found a high c o r r e l a t i o n between i n f i l t r a t i o n capacity and extent of organic horizons. When the hardwood l i t t e r and f e r -mented l a y e r s were removed from four s o i l types to t e s t the d i r e c t e f f e c t s of the f o r e s t f l o o r on i n f i l t r a t i o n , the average f i n a l i n -f i l t r a t i o n r a t e was s i g n i f i c a n t l y reduced by 18% (Arend, 1941). As a negative i n f l u e n c e , P i e r c e (1967) noted t h a t , i n a wet and matted s t a t e , hardwood leaves may t i g h t l y overlap each other much l i k e s h i n g l e s on a roof (imbricated) and apparantly permit water to flow over them without much i n f i l t r a t i o n . F o r tunately, due to the pre-sence of surface rocks, down logs and branches, and a great v a r i -a t i o n i n microtopographic r e l i e f , most of t h i s overland flow t r a v e l s short d i s t a n c e s . Microtopography, as an i n f l u e n c e on i n f i l t r a t i o n , was f i r s t noted by Horton (1933). He defined surface detention storage as that p o r t i o n of d e l i v e r e d water which remains on the s o i l surface i n small pockets or depressions and e i t h e r i n f i l t r a t e s or evaporates f o l l o w i n g -18-the storm event. Although i t can be recognized that vegetation (stems, surface r o o t s , leaves etc.) and s u r f i c i a l organic l a y e r s (roughness of surface through minature b a r r i e r s , depressions etc.) c o n t r i b u t e to surface detention storage, no q u a n t i t a t i v e data are a v a i l a b l e . Although Byrnes and Kardos (1963) found i n c o n s i s t e n t r e l a t i o n s h i p s , and Weal (1938) found no r e l a t i o n s h i p , between slope and i n f i l t r a t i o n , no attempt has been made to r e l a t e slope t o sur-face detention storage. This r e l a t i o n s h i p may e x i s t such that the l a t t e r i s reduced on steep slopes (100%+, which i s not uncommon on c o a s t a l B.C.) but t h i s i s c o n j e c t u r a l and subject to v e r i f i c a t i o n by research. The p o s s i b i l i t y that surface detention storage increases i n f i l t r a t i o n due to the e x i 3 t a n c e of a p o s i t i v e head has been i n -v e s t i g a t e d p r a c t i c a l l y and t h e o r e t i c a l l y . S c h i f f (1953) reported that t e s t s on untreated s o i l s i n d i c a t e d that an increase i n i n f i l -t r a t i o n r ate was d i r e c t l y p r o p o r t i o n a l to an increase i n head used. A r o n o v i c i (1955), using heads of water of 2.5, 5.B and 11.0 c e n t i -meters, reported i n f i l t r a t i o n r a t e s of 2.0, 2.8 and 3.5 centimeters per hour, r e s p e c t i v e l y . P h i l i p (1958) developed an expression from which the i n f l u e n c e on i n f i l t r a t i o n r a t e of the depth of water over the s o i l surface can pe derived. S =[2Ko (P+HXeo-eJp ca) where >S = ( s o r p t i v i t y ) a measure of water uptake (cm/sec) K'o = f i n a l or s t a b i l i z e d i n f i l t r a t i o n r a t e (cm/sec) -19-P ss wetting f r o n t c a p i l l a r y (matric) p o t e n t i a l (cm) "h: = depth of water over the s o i l (cm) ©o = volumetric s o i l water content corresponding to 0 c a p i l l a r y (matric) p o t e n t i a l 0^ = i n i t i a l volumetric s o i l water content This leads t o an approximate method of ev a l u a t i n g the e f f e c t of water depth over the surface on S ("short-term" i n f i l t r a t i o n r a t e ) . By p u t t i n g 5^=0 f o r the value of 5 when h=o the f o l l o w i n g equation i s obtained 5 • + 4 (9) The value of P v a r i e s with texture (coarse texture - low P and v i c e versa) and water content (low water content - high P ). Using experimental data, P h i l i p found that with h= 10 cm, i n f i l t r a t i o n may be increased as much as 5%. Associated with the e f f e c t s of organic matter on i n f i l t r a -t i o n , are s o i l microorganism c o n t r i b u t i o n s to improved s o i l p o r o s i t y . Martin and Uaksman (1940) noted that the a c t i o n of s o i l microorgan-isms ( s p e c i f i c a l l y fungal mycelia) r e s u l t e d i n a marked binding and aggregation of the s o i l p a r t i c l e s , which i n turn promoted high i n -f i l t r a t i o n r a t e s . The extent of the binding depended on the organ-isms comcerned and the nature of the organic m a t e r i a l present. This evidence has been substantiated i n more recent i n v e s t i g a t i o n s (McCalla, 1950; Bond, 1964; Chesters et a l . 1957 and Gilmour et a l . 1948) but d e t a i l e d information on the b e n e f i c i a l e f f e c t s of s o i l 20-micraorganisms on i n f i l t r a t i o n remains sketchy, due to d i f f i c u l t i e s of i s o l a t i o n and d e s c r i p t i o n of i n d i v i d u a l organisms. Organic matter, as unincorporated surface l a y e r s , tends to absorb a great deal of the k i n e t i c energy possessed by f a l l i n g r a i n . Raindrop energy, when transmitted to exposed mineral s o i l can cause a breakdown D f s o i l aggregates, washing-in of f i n e p a r t i c l e s and compaction of the immediate s o i l surface which a d d i t i v e l y produce a c r u s t on the s o i l surface. Tackett arid Pearson (1965) found that c r u s t s had an extremely dense l a y e r from 1 to 3 ram t h i c k and cover-ed with a t h i n s k i n of w e l l o r i e n t e d c l a y p a r t i c l e s . The cr u s t e f f e c t i v e l y reduces i n f i l t r a t i o n since the underlying s o i l may have a pe r m e a b i l i t y 200 times that of the washed-in region of the surface c r u s t and 2000 times that of the s k i n s e a l (Mclntyre, 1958). The antecedent s o i l water content stro n g l y i n f l u e n c e s the i n f i l t r a t i o n process since an increase i n i n i t i a l s o i l water content decreases the matric p o t e n t i a l and increases the i n f l u e n c e of grav-i t y . The e f f e c t of antecedent s o i l water content on the "shape" of i n f i l t r a t i o n curves i s schematically presented i n Figure k (Gray and Norum, 1957). The l i t e r a t u r e contains considerable d i f f e r e n c e s of opinion between i n v e s t i g a t o r s as to the r e l a t i v e importance of antecedent s o i l water e f f e c t s on i n f i l t r a t i o n . Duley and K e l l y (1941), i n s p r i n k l e r i r r i g a t i o n t e s t s conducted on s i l t loam and sandy loam s o i l s , found that the c o n d i t i o n s of the s o i l surface had a marked e f f e c t on i n f i l t r a t i o n and f e l t that i t s i n f l u e n c e on the i n f i l t r a -t i o n r a t e was much greater than the i n f l u e n c e of the i n i t i a l water 21-content. On the other hand, Green (1963) considered that the ante-cedent water co n d i t i o n s of a given s o i l may i n f l u e n c e i n f i l t r a t i o n r a t e s as much as t i l l a g e , surface s e a l i n g or p r o f i l e d i f f e r e n c e s . TimB Figure k. Schsmatic e f f e c t of antecedent s o i l water content on i n f i l t r a t i o n r a t e . In a t h e o r e t i c a l v e i n , Holtan (1961) suggested an approach to define the i n f i l t r a t i o n r a te of a s o i l as a f u n c t i o n of s o i l moisture storage as f o l l o w s T V f = a ( S - M f ) + f c do) wherB f = i n f i l t r a t i o n r a t e S = p o t e n t i a l s o i l water storage volume Mr = mass i n f i l t r a t i o n •fc = f i n a l constant r a t e of i n f i l t r a t i o n through the c o n t r o l horizon, and a , n = constants f o r a p a r t i c u l a r s o i l i n a given c o n d i t i o n -22-In t h i s equation, the e f f e c t of i n c r e a s i n g the mass i n f i l t r a -t i o n , H-f , i s analogous to i n c r e a s i n g the i n i t i a l s o i l water content which w i l l cause a decrease i n the i n f i l t r a t i o n r a t e . Another feature of the equation i s that when M-f = S , the i n f i l t r a t i o n r a te i s that of the c o n t r o l l a y e r . Hanks and Bowers (1962) su b s t a n t i a t e d t h i s by concluding that i n f i l t r a t i o n was governed by the unsaturated conduc-t i v i t y (unsaturated c o n d u c t i v i t y = •£ ( s o i l water content)) of the l e a s t permeable l a y e r , once the wetting f r o n t extended i n t o that l a y e r . Gray and Worum (1967) o f f e r e d the f o l l o w i n g summary s t a t e -ments on thB i n f l u e n c e of antecedent s o i l water content on i n f i l t r a -t i o n : i . Increasing the i n i t i a l s o i l water content increases the v e l o c i t y at which the wetting f r o n t moves but decreases the i n f i l t r a t i o n r a t e . i i . The i n i t i a l water content of the s o i l a f f e c t s the shape of the water content d i s t r i b u t i o n p r o f i l e , e s p e c i a l l y at short times a f t e r w e t t i n g , i i i . For a given s o i l , the e f f e c t of a water content gradient would cause the i n f i l t r a t i o n r a t e to de-crease more r a p i d l y than i n a uniformly dry p r o f i l e . C e r t a i n other v a r i a b l e s i n f l u e n c i n g i n f i l t r a t i o n are a f u n c t i o n of season (Bertoni et a l . 1956). M O O T B (1941) found that as s o i l temperature increased between 5°and 3D°C. there was a cor-responding increase i n i n f i l t r a t i o n r a t e . Between 30° to 35° there was a r a p i d increase i n i n f i l t r a t i o n r a t e , a f t e r which a r a p i d de-crease occurred. Duley and Domingo (1944) determined that water temperatures between 4°and 44° y i e l d e d s i m i l a r i n f i l t r a t i o n r a t e s . 23-S o i l f r o s t has been recognized as having a v a r i a b l e e f f e c t on i n f i l t r a t i o n (Trimble et af. 1958). Byrnes (1951) found that concrete f r o s t i n mineral s o i l prevented p e r c o l a t i o n . Trimble et a l . , (1958) found that concrete f r o s t i n the f o r e s t and open mas imperme-able, but i n the f o r e s t i t was traversed i n places by l a r g e , unfro-zen areas that allowed water to i n f i l t r a t e . Byrnes (1951) and Trimble et a l . , (1958) both found granular f r o s t i n c e r t a i n s o i l s to be more permeable to water than unfrozen s o i l as a r e s u l t of im-proved aggregation due to f r o s t . Haupt (1967) found that s t a l a c t i t e s o i l f r o s t (needle-ice) d i d not impair i n f i l t r a t i o n where pla n t and l i t t e r cover were appreciable. Of the v a r i a b l e s i n f l u e n c i n g i n f i l t r a t i o n noted, few have, been adequately q u a n t i f i e d to generalize t h e i r i n f l u e n c e . The wide b i o l o g i c a l and p h y s i c a l v a r i a t i o n i n s o i l s commonly r e f e r r e d to i n the l i t e r a t u r e a t t e s t s to the d i f f i c u l t y of developing a f u l l y d e f i n i t i v e model of i n f i l t r a t i o n . Other c h a r a c t e r i s t i c s of n a t u r a l and a l t e r e d systems may be i d e n t i f i e d as research on i n f i l t r a t i o n continues, to complicate f u r t h e r understanding of the i n f i l t r a t i o n process. -2k-2. C l e a r c u t t i n g A. As a harvesting method The most p r a c t i c a l and widely accepted method of harvesting c o a s t a l Douglas f i r (Pseudotsuga m e n z i e s i i (Mirb.) Franco) i s c l e a r -c u t t i n g i n blocks (Hawley and Smith, 1954). These blocks vary i n s i z e from 15 to 100 acres. On the coast of B.C., most timber har-v e s t i n g i n v o l v e s one of three methods; t r a c t o r , highlead or s k y l i n e . Since t r a c t o r and highlead are the most common logging systems pre-s e n t l y employed they deserve most a t t e n t i o n . By v i r t u e of the ex-t e n s i v e changes wrought upon an ecosystem, c l e a r c u t t i n g can be i d e n t i f i e d as having p o t e n t i a l e f f e c t s on i n f i l t r a t i o n . B. E f f e c t of s o i l p r o p e r t i e s The r e s u l t s of s e v e r a l s t u d i e s on s o i l disturbance f o l l o w -in g logging i n the U.S. P a c i f i c Northwest are summarized i n Table 2. From the standpoint of i n f i l t r a t i o n , disturbance r e s u l t i n g i n the r e -moval of s u r f i c i a l organic l a y e r s r e s u l t i n g i n exposure and compac-t i o n of the mineral s o i l i s the most important. Exposure of the mineral s o i l to raindrop impact can reduce i n f i l t r a t i o n d r a s t i c a l l y . S i g n i f i c a n t increases i n the bulk density of the s l i g h t l y disturbed (10%) and deeply disturbed (30%) f o r highlead lagging have been r e -ported by Dyrness (1967). Increases i n bulk density y i e l d concomi-tant decreases i n p o r o s i t y and thus reduce i n f i l t r a t i o n . However, i t must be noted that those areas i n the deeply disturbed and com-pacted c l a s s e s generally occur as small s c a t t e r e d patches and may not c o n t r i b u t e to s i g n i f i c a n t runoff and erosion i n s p i t e of reduced -25-i n f t i t r a t i o n c a p a c i t i e s . Table 2. S o i l disturbance f o l l o w i n g logging i n the U.S. P a c i f i c Northwest. . . % T o t a l Area by Disturbance Class M ? h r i undis- s l i g h t l y ? d eeply 3 corn- Study pietnoo t u r b e d 1 disturbed disturbed pacted4 Skyl i n e 63.3 24.4 4.7 3.4 Dyrness, 1967 88.9 5.7 2.2 3.2 Uooldridge, 1960 - - 6.4 Ruth, 1967 Highlead 57.2 12.5 9.7 9.1 Dyrness, 1967 - - - 15.8 Ruth, 1967 Tractor 49.3 27.2 8.6 27.1 Dyrness, 1965 70.6 7.2 6.3 15.9 Uooldridge, 1960 1 l i t t e r s t i l l i n place and no evidence of compaction 2 l i t t e r removed and mineral s o i l exposed; or mineral s o i l and l i t t e r i n t i m a t e l y mixed; or pure mineral s o i l on top of l i t t e r and s l a s h 3 surface s o i l removed and the s u b s o i l exposed 4 obvious compaction due to passage of l o g , track or wheel Although no data are a v a i l a b l e f o r i n f i l t r a t i o n changes f o l l o w i n g c l e a r c u t t i n g on the U.S. P a c i f i c Northwest or c o a s t a l B.C., road d e n s i t i e s required f o r the three main logging methods have been st u d i e d . Uooldridge (1960) estimated that s k y l i n e logging required only 10 percent of the road area necessary f o r t r a c t o r yarding. B r i n k l e y (1965) c a l c u l a t e d that the road requirements f o r s k y l i n e yarding are only about o n e - t h i r d of those necessary f o r highlead l o g g i n g . Roads have been i d e n t i f i e d as a major source of runoff and erosion (Dyrness, 1967b) and mechanisms behind t h i s w i l l be discussed - 2 6 -i n a l a t e r s e c t i o n . On most c l e a r c u t blocks on c o a s t a l B.C. f u r t h e r treatments are c a r r i e d out a f t e r the yarding operation to abate s l a s h f i r e haz-ards and secure adequate regeneration of an acceptable tree s p e c i e s . On those blocks not subjected to f u r t h e r treatment, n a t u r a l regrouith of native vegetation occurs r a p i d l y , and gen e r a l l y a f t e r two years most of the surface s o i l on the area has been secured against erosion by vegetation regrowth. -27-3. Slashburning A. As a r e g u l a t i o n C l e a r c u t t i n g i n blocks ge n e r a l l y leaves the ground covered with accumulations of s l a s h , c o n s i s t i n g of branches, tops, debris from snags, d e f e c t i v e t r e e s , push-over and breakage. This s l a s h m a t e r i a l may amount to as much as 100 tons per acre ( D i l l and Green, 1968) and as such, c o n s t i t u t e a p o t e n t i a l f i r e hazard. Consequently, slashburning has been s t i p u l a t e d as the most acceptable method of reducing the hazard (The Forest Act. Chapter 3, Section 116, Sub-s e c t i o n k. as quoted by Haddon, 1967) with a $12.00 f i n e per acre of unburned s l a s h f o r the f a i l u r e of the f o r e s t operator to comply. Slashburning has become a h o t l y debated issue between two major groups. One group advocates burning but even t h i s group sub-d i v i d e s i n t o f a c t i o n s ; those who b e l i e v e that burning aids or i s e s s e n t i a l to regrowth of the new crop of t r e e s and those who advo-cate a scorched earth p o l i c y on the theory that a planned burn pre-vents an a c c i d e n t a l burn. The second group opposes burning on the b a s i s that i t i s harmful to the s o i l and w a s t e f u l l y expensive, i n the l i g h t D f the frequency i n which planned f i r e turns i n t o an un-planned d e s t r u c t i o n of adjacent f o r e s t s . B. E f f e c t on s o i l p r o p e r t i e s The complexity of studying the e f f e c t s of slashburning on various components of an open system i s i n d i c a t e d i n Figure 5. Two main ways of approaching the p o s s i b l e harmful e f f e c t s of slashburn-SLASHBURNING VEGETATION SOIL FRINGE RESIDUAL WATER PHYSICAL PROPERTIES CHEMICAL PROPERTIES BIOLOGICAL PROPERTIES! QUANTITY / \ t \ J INFILTRATION J QUALITY DOMESTIC WATER FLOODS, FISHERY NEW FDREST CROP STUMPAGE e t c . POPULATION GOVERNMENT ALTERNATIVES AIR QUALITY Figure 5. Area of i n f l u e n c e of slashburning on various components of an open system -29-ing i n the Vancouver Forest D i s t r i c t (Appendix I) are i d e n t i f i a b l e : economic and e c o l o g i c . In the f a l l of 1967, 62,535 acres of s l a s h were burned i n the Vancouver Forest D i s t r i c t and associated with t h i s was $846,024.00 damage to f o r e s t cover, cut products and equip-ment and property, plus $7D7,008.00 i n suppression costs (Annual Report of the Forest S e r v i c e , 1967). The e c o l o g i c a l e f f e c t s of burning t h i s same area can only be s u b j e c t i v e l y appraised since very l i t t l e , i f any, research has been c a r r i e d out. Although some r e -search f i n d i n g s are a v a i l a b l e regarding burning on r e s i d u a l s o i l s i n the U.S. P a c i f i c Northwest (Austin and B a i s i n g e r , 1955; Dyrness et a l . 1957; Tarrant, 1956; Neal et a l . 1965; and o t h e r s ) , care and caution are necessary i n e x t r a p o l a t i n g these r e s u l t s to the g l a c i a l l y modified landscape of c o a s t a l B.C. In a given c l e a r c u t block the e f f e c t of f i r e on the s o i l surface w i l l vary according to the l o c a l c o n d i t i o n s of slope, aspect, f u e l moisture, s l a s h density d i s t r i b u t i o n and weather c o n d i t i o n s (Frampton, 1968). Three c l a s s e s of burn i n t e n s i t y have been i d e n t i -f i e d (Dyrness and Youngberg, 1957): unburned areas occupying 50 per-cent of a c l e a r c u t block, l i g h t l y burned occupying 45 percent, and severely burned on the remaining 5 percent. Although the e f f e c t of slashburning on s o i l p o r o s i t y i s i n -d i r e c t , i t r e q u i r e s s p e c i a l a t t e n t i o n due to the high c o r r e l a t i o n be-tween s o i l p o r o s i t y and i n f i l t r a t i o n c a p a c i t y . Although no data are a v a i l a b l e on the e f f e c t s of f i r e on the p o r o s i t y of organic l a y e r s , some work has been c a r r i e d out regarding mineral l a y e r s . Tarrant (1956) found the aeration p o r o s i t y s i g n i f i c a n t l y decreased and the water r e t e n t i o n p o r o s i t y s i g n i f i c a n t l y increased on the surface of -30-two mineral s o i l s of l i g h t and severe burn. On the basis of the t o t a l area burned, Beaton (1959) reported a reduction i n aer a t i o n p o r o s i t y of 25 percent and an increase i n water r e t e n t i o n p o r o s i t y of 18 percent. The r e s u l t s of Isaac and Hopkins (1937) were i n agreement with these f i n d i n g s . A l l the authors explained the a l t e r -a t i o n s i n p o r o s i t y on the ba s i s of the change, by f i r e , of the other s o i l v a r i a b l e s r e l a t e d to p o r o s i t y . Data on the i n f l u e n c e of slashburning on s o i l texture and s t r u c t u r e are very sketchy. Dyrness and Youngberg (1957) found a s i g n i f i c a n t reduction i n the c l a y f r a c t i o n i n s e v e r a l s o i l s and sug-gested t h i s was a r e s u l t of high temperature f u s i o n of c l a y p a r t i c l e s i n t o s t a b l e , sand-sized, secondary p a r t i c l e s . This i s i n apparant c o n f l i c t with the p o r o s i t y f i n d i n g s , since an increase i n aeration p o r o s i t y would be expected with an increase i n sand p a r t i c l e s . The same study (Dyrness and Youngberg, 1957), however, i n d i c a t e d a r e -duction i n the percentage composition of aggregates (0.1 to 5.0 mm. diameter) i n the top two inches of severely burned s o i l s . I t was suggested that t h i s was l a r g e l y due to the removal of c o l l o i d a l o r -ganic matter by f i r e . Although the e f f e c t of slashburning on vegetation i s o b v i -ous, the e f f e c t on organic matter r e q u i r e s some e l u c i d a t i o n . Severe burning destroys a l l s u r f i c i a l organic l a y e r s , but the e f f e c t of l i g h t burning on these l a y e r s i s not f u l l y understood. Cooper (1961) noted that humus which had not been exposed to f i r e had an open, f e l t y texture whereas the organic l a y e r beneath a burned surface was more compact, darker i n colour and was d i s t i n c t l y f i n e - g r a i n e d . 31-Beaton (1959) found,that burning reduced the thickness of the sur-face organic l a y e r s by :an. average of 53.3 percent over the e n t i r e area subjected to the burn. As has been prev i o u s l y pointed out, r e -moval of s u r f i c i a l organic l a y e r s exposes the mineral s o i l to the compacting and pore plugging p o t e n t i a l of r a i n f a l l . This may b B em-phasized i n the burned c o n d i t i o n since the a l k a l i n e ash may encour-age d i s p e r s i o n of s o i l p a r t i c l e s which i n turn may be c a r r i e d i n t o the s o i l pores by raindrop a c t i o n (Beaton, 1959). Studies have shown that severe burning reduces s i g n i f i c a n t -l y the c o l l o i d a l organic matter i n the surface mineral s o i l (Austin and B a i s i n g e r , 1955 and Dyrness et a l . 1957). Beaton (1959) found t h a t burning reduced the organic matter content of the leached (Ae) horizon by 13 percent. Loss of organic matter i s a r e s u l t of the extremely high and prolonged temperatures associated with severe burning which encourages o x i d a t i o n of s u b s u r f i c i a l organic matter. The e f f e c t of microorganisms, although d i f f i c u l t to ap-p r a i s e , has received some research a t t e n t i o n . B a c t e r i a and a c t i n o -mycetes, important i n the decomposition of l i g n i n s and other forms of r e s i s t a n t organic matter, have c o n s i s t e n t l y been found i n higher l e v e l s a f t e r severe burning than l i g h t burning or no burning at a l l (Wright and Tarrant, 1957; Wright and B o l l e n , 1961; and IMeal et a l . 1965). Decreases i n l e v e l s of e c t o t r o p h i c mycorrhizea, important i n t ree growth, have been found f o l l o w i n g both l i g h t and severe burning (Wright and Tarrant, 1958). Populations of fungi are s i g n i f -i c a n t l y reduced by l i g h t and severe burning (Wright and Tarrant, 1957 and Wright and B o l l e n , 1961). -32-Fungi, e s p e c i a l l y t h e i r mycelia, are important i n maintain-ance of s o i l aggregation which i n turn f o s t e r s d e s i r a b l e p o r o s i t y c h a r a c t e r i s t i c s . LJright and Bo l l e n (1961) found that severely burned s o i l acquired complex m i c r o f l o r a about a year a f t e r being burned and i n the second year began to e x h i b i t a population character-i s t i c of unburned s o i l . D i f ferences i n antecedent s o i l water content between the un-disturbed f o r e s t c o n d i t i o n and the clea r e d u n i t are u s u a l l y a r e s u l t of the p h y s i c a l removal of the f o r e s t cover and the changes wrought upon l e s s e r vegetation and the s o i l surface by slashburning. Removal of vegetation with the attendant decrease i n t r a n s p i r a t i o n would be expected to r e s u l t i n higher s o i l water content l e v e l s . Slashburning, through i t s e f f e c t on s o i l p o r o s i t y , t e x t u r e , s t r u c t u r e and organic matter, can a l s o be expected to i n f l u e n c e s o i l water content l e v e l s . Bethlahmy (1962) discovered that s o i l water i n re c e n t l y c l e a r c u t areas i n western Oregon begins to de c l i n e only i n the l a t e summer. Weal et a l . (1965) found that the water holding capacity was decreas-ed throughout the sampling period of one year f o l l o w i n g the burn. The reduction was p r o p o r t i o n a l to the i n t e n s i t y of burn and no s i g -n i f i c a n t d i f f e r e n c e s were found between north and south slopes. Re-s u l t s of moisture equivalence determinations by Dyrness et a l . (1957) i n d i c a t e d that the a b i l i t y of the surface s o i l to r e t a i n moisture i s s i g n i f i c a n t l y reduced by exposure to intense heat. S i m i l a r f i n d i n g s have been reported by Austin and Bais i n g e r (1955) and Heyward (1939). Cooper (1961) found no s i g n i f i c a n t d i f f e r e n c e i n water holding capa-c i t y of the humus l a y e r s i n burned and unburned s o i l s . Thus, the e f f e c t of slashburning on the water r e t e n t i o n p r o p e r t i e s of the s u r --33-face s o i l has not been c o n c l u s i v e l y demonstrated. C. E f f e c t on i n f i l t r a t i o n On the t o t a l burned area b a s i s , Beaton (1959) found the average reduction i n i n f i l t r a t i o n a f t e r slashburning to be 6k per-cent, but s t r e s s e d that t h i s value was open to question owing to un-known e r r o r s . Tarrant (1956) found severe burning s i g n i f i c a n t l y r e -duced p e r c o l a t i o n but could not e x p l a i n why l i g h t burning increased p e r c o l a t i o n . Tackle (1962) found that although burning i n i t i a l l y reduced the average i n f i l t r a t i o n of the e n t i r e burned area by 37.5 percent, three years l a t e r , i n f i l t r a t i o n increased to before-burn l e v e l s . Although they d i d not measure i t , Dyrness e_t a l . (1957) suggested that i n f i l t r a t i o n capacity would seldom be surpassed i n a l l but the severely burned areas since r a i n f a l l i n the U.S. P a c i f i c Northwest u s u a l l y f a l l s at low i n t e n s i t i e s (<0.5 inches per hour). Consistent agreement i s found regarding the detrimental e f -f e c t of severe s l a s h f i r e s on i n f i l t r a t i o n , but a v a r i e t y and con-f l i c t of opinion and data e x i s t s as to the e f f e c t of l i g h t burning on i n f i l t r a t i o n . Perhaps, one way of overcoming f u t u r e disagree-ments would be to e l i m i n a t e the s u b j e c t i v e s u b d i v i s i o n of a burned area i n t o the a r b i t r a r y c l a s s e s of unburned, l i g h t l y burned and sev-e r e l y burned. By l o c a t i n g measurement s i t e s randomly over the burn-ed block, r e s u l t s can be reported f o r the e n t i r e area to obtain the net e f f e c t of slashburning. -34-4. Skidroads A. Purpose and c o n s t r u c t i o n The e x t r a c t i o n of f e l l e d and bucked timber from a c l e a r c u t block with a t r a c t o r , t r a c t o r - p l u s - a r c h or rubber t i r e d skidder, r e -quires the c o n s t r u c t i o n of skidroads. On the coast of B.C. these skidroads are gene r a l l y constructed uiith a blade-equipped crawler t r a c t o r . One of the prime r e q u i s i t e s f o r these roads i s that con-s t r u c t i o n costs be as low as p o s s i b l e and that they be constructed w e l l enough so as to requ i r e no maintenance during the yarding oper-a t i o n . I m p l i c a t i o n s of these a t t i t u d e s regarding erosion and s e d i -ment production have been w e l l documented (Dyrness, 1967a; Dyrness, 1967b; Packer, 1967; Reinhart e_t a l . 1963). The amount of a c l e a r c u t block subjected to the s o i l com-pacting e f f e c t s of yarding machinery has been found to vary between 16 percent (Wooldridge, 1960) and 26.8 percent (Dyrness, 1965) of the t o t a l area. The magnitude of^compaction on these areas v a r i e s according to those f a c t o r s a f f e c t i n g the inherent r e s i s t a n c e of the s o i l . These f a c t o r s include s o i l water content, t e x t u r e , i n i t i a l bulk d e n s i t y , s t r u c t u r e and organic matter content. L u l l (1959) noted that the greatest compaction can be achie-ved when the s o i l i s at a water content s l i g h t l y below the p l a s t i c l i m i t . The r o l e of water i n s o i l compaction i s that of a l u b r i c a n t . Ease of compaction increases as water content increases up to a c r i t i c a l point at which a maximum of the smaller p a r t i c l e s have been forced i n t o the voids between the coarse grains and the bulk of the -35-remaining pore space i s f i l l e d with water and a i r (Buchanan, 1942). Steinbrenner (1955) found that f i v e t r i p s of a t r a c t o r along a s k i d -road increased bulk density by 9 percent under "dry" c o n d i t i o n s and 22 percent under "wet" c o n d i t i o n s . Kryine (1941) found that maximum d e n s i t i e s a t t a i n a b l e with equipment used i n highway c o n s t r u c t i o n decrease as p a r t i c l e s i z e decreases. I t i s ge n e r a l l y agreed that s o i l s having the great-est range of p a r t i c l e s i z e s compact to the greatest d e n s i t i e s , f i n e r p a r t i c l e s f i l l i n g the voids between coarser p a r t i c l e s (Huberty, 1944; L u l l , 1959). C e t e r i s paribus, the degree of compaction i s a f u n c t i o n of the i n i t i a l bulk density. L u l l (1959) pointed out that the lower the i n i t i a l s o i l bulk density, the greater the opportunity f o r compaction. Since s o i l s t r u c t u r e tends to reduce bulk d e n s i t y , good s o i l s t r u c -ture increases the opportunity f o r compaction. Bulk density a l s o de-creases with i n c r e a s i n g organic matter content due to i t s low p a r t i -c l e density and i t s promotion of aggregation (Baver, 1956). However, the greater the content of organic matter, the smaller the maximum compaction and the greater the water content required f o r maximum compaction ( L u l l , 1959) since organic matter absorbs water which would otherwise c o n t r i b u t e to f i l m formation ( l u b r i c a t i o n ) between p a r t i c l e s . The importance of frequency of t r a v e l , on i n c r e a s i n g bulk d e n s i t y , i s l i m i t e d because maximum compaction i s achieved with only a few t r a c t o r t r i p s ( L u l l , 1959). L u l l (1959) also i n f e r r e d that the degree of disturbance increases d i r e c t l y with slope percent un--36-t i l the slopes become so steep as to be i n a c c e s s i b l e by t r a c t o r . These two concepts are important i n that they open up the p o s s i b i l i t y that maximum compaction could accrue during the c o n s t r u c t i o n of the skidroad p r i o r to a c t u a l yarding usage. B. E f f e c t on i n f i l t r a t i o n Compaction, by i n c r e a s i n g water r e t e n t i o n p o r o s i t y at the expense of a e r a t i o n p o r o s i t y , consequently reduces i n f i l t r a t i o n capa-c i t y . Steinbrenner (1955) observed that one t r a c t o r t r i p under "wet" c o n d i t i o n s and four t r i p s under "dry" c o n d i t i o n s reduced i n f i l t r a -t i o n by 84 and 89 percent r e s p e c t i v e l y a f t e r which f u r t h e r t r a c t o r passes had r e l a t i v e l y l i t t l e e f f e c t . Steinbrenner (1955) als o found that on s i l t y c l a y loam and c l a y loam s o i l s of southwestern Washing-ton, p ermeability of skidroads was s i x to ten percent that of the adjacent timbered areas while bulk density increased by 35 percent. Trimble and Weitzman (1953) found t h a t , three months a f t e r s k i dding operations, the time f o r a given quantity of water to enter the s o i l was 19 times longer on skidroads than on nearby timbered areas. -37-The Study Area 1. Location and general d e s c r i p t i o n This study was c a r r i e d out on the U n i v e r s i t y of B r i t i s h Columbia Research Forest during the summer and f a l l of 1967 and the sp r i n g of 1968. The Forest, a 13,000 acre t r a c t of f o r e s t e d land, l i e s w i t h i n the Southern P a c i f i c Coast Section of the Coast Forest Region (Roue, 1959); a Section which occupies a major p o r t i o n of the Vancouver Forest D i s t r i c t (Appendix I ) . The Research Forest i s lo c a t e d on the south f r i n g e of the Coast Mountains and i s bounded on the north and east by G a r i b a l d i Park and on the northwest by P i t t Lake. I t s southern boundary i s approximately four miles north of Haney, B.C. The region as a whole i s warm and dry during the summer and comparatively m i l d and wet during the winter months. P r e c i p i t a t i o n f o l l o w s the general pattern f o r the southern c o a s t a l region of B.C. - October to March i s very moist with an average monthly p r e c i p i t a -t i o n (mostly as r a i n ) of 11.24 inches,* and the other s i x months are r e l a t i v e l y dry with an average monthly p r e c i p i t a t i o n of 3.98 inches. The average annual p r e c i p i t a t i o n f o r the period 1962 to 1966 was 88.43 inches almost a l l of which f e l l as low i n t e n s i t y (<1 inch per hour) r a i n . The average f r o s t - f r e e period i s 193 days and approxi-mately 1500 hours of sunshine are received annually. a l l weather data from the Weather Records of the U n i v e r s i t y of B r i t i s h Columbia Research Forest. -38-The underlying bedrock of the Forest i s mainly quartz d i o -r i t e and g r a n o d i o r i t e with minor i n c l u s i o n s of v o l c a n i c s . The bed-rock i s o v e r l a i n by deposits of basal t i l l , a b l a t i o n t i l l , g l a c i a l outwash and glaciomarine and g l a c i o l a c u s t r i n e m a t e r i a l s of various thicknesses and extents. A physiographic s i t e map of the area has been prepared by Lacate (1955) and bias used as the b a s i s f o r the s e l e c t i o n of study s i t e s . 2. S p e c i f i c areas studied The study was c a r r i e d out on three d i f f e r e n t s i t e s or ex-perimental b l o c k s . These blocks were s e l e c t e d as being f a i r l y repre-s e n t a t i v e of low e l e v a t i o n (<1500 f e e t above sea l e v e l ) f o r e s t con-d i t i o n s i n the Vancouver Forest D i s t r i c t . The d i f f e r e n c e s between the blocks are measured i n terms of s o i l s , past management a c t i v i t i e s and present vegetation. A. Block A Block A i s l o c a t e d on Timber Sale 64B to the east of Spur U-1 on a moderately w e l l drained a c i d brown wooded* s o i l developed i n Sunnyside Beach sands over Whatcom glaciomarine (Appendix I I ) . S o i l depth i s v a r i a b l e (12 to 48 inches) but averages 44 inches to the impermeable glaciomarine. The area i s approximately 500 f e e t above sea l e v e l and has an average slope of 5 percent with f l a t r e -l i e f and a southwest aspect. * Natio nal S o i l Survey Committee of Canada. S i x t h Meeting 1965. Laval U n i v e r s i t y . 39-The primary logging of Timber Bale 64B was by means of highlead from A p r i l 23, 1964 u n t i l min-May, 1964*. Second pass l o g -ging was c a r r i e d out with a D-7E Cat from the termination of high-lead yarding u n t i l May 25, 1964. This i n v o l v e d the c o n s t r u c t i o n of approximately 1000 feet of skidroad. Approximately 1.8 inches of r a i n f e l l during the c o n s t r u c t i o n and use of the skidroad. The i n -t e n s i t y of use of the skidroad might be considered l i g h t . Since the f a l l of 1964 was extremely wet,.Timber Sale 64B was slashburned towards the end of September, 1965. Burning condi-t i o n s were considered to be optimum with a r a i n f a l l f o r September of only 1.38 inches. The burn was "spotty" but could be c l a s s i f i e d as "hot" i n those areas a c t u a l l y burned due to the high volume of stand-i n g hemlock and cedar s a p l i n g s and logging debris l y i n g on the ground (Figure 6 ) . B. Block B Block B i s l o c a t e d to the west of Spur 2GBP on a w e l l d r a i n -ed, degraded a c i d brown wooded s o i l developed i n v a r i o u s l y reworked a b l a t i o n t i l l o v e r l y i n g basal t i l l (Appendix I I ) . S o i l depth i s l e s s v a r i a b l e than i n Block A and averages 36 inches to the completely im-permeable basal t i l l . The area i s approximately 600 f e e t above sea l e v e l and has an average slope of 15 percent on a concave p r o f i l e with a southeast aspect. * Personal Communication: Jay Uee Logging Co., Haney, B.C. and McCormack Bros. Logging, Haney, B.C. -40-Figure 6. The general area included i n Block A. The primary logging of Timber Sale 2GGP was by highlead between J u l y 31, 1964 and August 20, 1964. Subsequent salvage l a g -ging and f i r e guard c o n s t r u c t i o n by a D-7E Cat took place over a s i x day period during which 0.9 inches of r a i n f e l l . The i n t e n s i t y of use of these skidroads was considered very l i g h t . As was the case f o r Block A, the slashburning of the s e t -t i n g used i n Block B was postponed u n t i l l a t e September, 1965 due to poor burning c o n d i t i o n s i n the f a l l of 1964. Although the burn was considered to be e x c e l l e n t , f i r e temperatures were low and the f i r e moved r a p i d l y . This r e s u l t e d i n heavy accumulations of l a r g e s l a s h m a t e r i a l remaining f o l l o w i n g the burn (Figure 7 ) . Figure 7. The general area included i n Block B. C. Block C Block C i s located immediately north of Road UJ on a moder-a t e l y w e l l drained, o r t h i c podzol s o i l developed i n outwash parent m a t e r i a l o v e r l y i n g Whatcom glaciomarine (Appendix I I ) . S o i l depth i s extremely v a r i a b l e but averages 36 inches to the impermeable glaciomarine. The area i s located on a r i v e r t errace approximately 500 f e e t above sea l e v e l . The r e l i e f i s f l a t with an average slope of 5 percent y i e l d i n g a southwest aspect. By 1957 the logging of the area was completed. Logging was a l l by t r a c t o r yarding r e q u i r i n g an extensive network of skidroads. The use of the main skidroad was extremely heavy and other skidroads (secondary and t e r t i a r y ) received l e s s e r use i n t e n s i t i e s . Post-logging treatments included p i l i n g and burning by hand and eventual Figure 8. The general area included i n Block C. -43-Experimental Design The three experimental areas or Blocks, as p r e v i o u s l y des-c r i b e d , mere employed i n randomized complete block designs f o r pur-poses of determinations and comparisons of various treatment e f f e c t s on the i n f i l t r a t i o n p r o p e r t i e s of the s o i l s . This p a r t i c u l a r design utas s e l e c t e d because i t was easy to l a y out i n the f i e l d , allowed the maximum number of degrees of freedom i n the e r r o r sum of squares and was one of the simplest designs to analyze. The use of the Blocks and the subsequent a n a l y s i s was dichotomous. Blocks A and B were employed at the same time f o r two stud-i e s . On each block, four treatments were employed: skidroad, c l e a r -cut, slashburned and c o n t r o l ( f o r e s t e d c o n d i t i o n ) . The v e g e t a t i o n a l c h a r a c t e r i s t i c s of both blocks by treatment are presented i n Appendix I I I and photographs t y p i f y i n g each treatment of each block are pre-sented i n Appendix IV. The skidroad and c o n t r o l treatments on both blocks c o n s t i t u t e d one study (Lewis, 1966) and the c l e a r c u t , s l a s h -burned and c o n t r o l treatments on both blocks c o n s t i t u t e d the study analyzed f o r the f i r s t time i n t h i s t h e s i s . Within each experimental u n i t (a treatment - block combin-a t i o n ) measurements of i n f i l t r a t i o n and associated s o i l v a r i a b l e s were taken at each of f i f t e e n randomly l o c a t e d s i t e s . A c e r t a i n amount of sampling bias was i n c u r r e d since only those s i t e s f r e e of l a r g e stones, r o o t s , stumps or r o t t e n logs were acceptable due to the p h y s i c a l l i m i t a t i o n s of the technique of i n f i l t r a t i o n measurement (covered i n a l a t e r s e c t i o n ) . Slopes over 5 percent were also r e -s t r i c t i v e to i n f i l t r a t i o n measurement. The t h i r d study described i n t h i s t h e s i s was c a r r i e d out on Block C, which was di v i d e d i n t o three experimental blocks each con t a i n i n g the treatments of skidroad and c l e a r c u t . Appendix I I I contains vegetation d e s c r i p t i o n s of the treatments and photographic d e s c r i p t i o n s of the experimental u n i t s are included i n Appendix II/. Within each experimental u n i t , measurements of i n f i l t r a -t i o n and associated s o i l v a r i a b l e s were taken at each of f i v e random-l y l o c a t e d s i t e s . The same sampling b i a s occurred i n the s e l e c t i o n of these s i t e s as i n Blocks A and B. -45-Data C o l l e c t i o n 1. I n f i l t r a t i o n as a basic measure of treatment e f f e c t s As has been pointed out p r e v i o u s l y , i n f i l t r a t i o n capacity i s i n f l u e n c e d by a l a r g e number of s o i l p r o p e r t i e s which i n turn are i n f l u e n c e d to varying degrees by logging and slashburning. For t h i s reason, and because of i t s important r o l e i n the hydrologic c y c l e , i n f i l t r a t i o n was s e l e c t e d as the b a s i c q u a n t i f i e d measure of treatment e f f e c t s . I n f i l t r a t i o n r a t e s were determined with double-ring, f l o o d -ing-type i n f i l t r o m e t B r s equipped with constant head r e g u l a t i o n tubes (Figure 9 ) . These were b u i l t by those inv o l v e d i n the f i e l d work with the help of a machinist, at an approximate cost of $60.00 per i n f i l t r o m e t e r . They proved to be r e l i a b l e devices and r e p a i r s were only required on the apparatus employed to drive the s t e e l r i n g s i n t o the s o i l . The a c t u a l i n s t a l l a t i o n and operation of the i n f i l t r o m e t e r s was r e l a t i v e l y simple. The two s t e e l r i n g s were d r i v e n , c o n c e n t r i -c a l l y , from 5 to 10 inches i n t o the s o i l depending on the p h y s i c a l r e s i s t a n c e of the s o i l to p e n e t r a t i o n . I n f i l t r a t i o n was measured simultaneously on as many s i t e s as p o s s i b l e depending on the manpower a v a i l a b l e , the distance to the water supply, the distance between s i t e s and the p h y s i c a l o b s t r u c t i o n s i n the sampling area. Generally, two men could operate f i v e i n f i l t r o m e t e r s at once. Immediately p r i o r to s t a r t i n g a three hour "run" of an DOUBLE RING INFILTROMETER APPARATUS CONSTANT WATER LEVEL DETAIL hi J h2 hi = h2 plastic water level regulation cylinder (I 3/4" I.D. ) rigid plastic tubing (1/4" I.D.) Concentric infiltration rings (14" long - 1/8" wall thickness) flexible plastic tubing (1/4" I.D.) calibrated plastic delivery cylinder (3" I.D.) —iron support rod rigid plastic tubing (1/4° I.D.) buffer (20"dia.)— center (12" dia.)-Figure 9. D e t a i l of double-ring, flooding-type i n f i l t r o -meter with constant head r e g u l a t i o n tube. -47-i n f i l t r o m e t e r , the l e v e l of water to be maintained over the s o i l surface i n the inner (measurement) r i n g was adjusted to between 0.5 and 1.0 inches. This wide v a r i a t i o n was due to the d i f f i c u l t y i n determining true s o i l surface r e s u l t i n g from the extremely rough microtopography of s o i l . s u r f a c e i n the inner r i n g . Once the run had s t a r t e d , the cumulative volume of water passing through the system was noted Bvery 5 minutes f o r the f i r s t 15 minutes, every 10 minutes f o r the next h a l f hour and every 15 minutes t h e r e a f t e r to the end of the run. A greater number of observations was required at the begin-ning of the run since the ra t e of change of i n f i l t r a t i o n was i n i t i a l -l y q u ite l a r g e . The water l e v e l i n the outsids or b u f f s r r i n g was maintain-ed (by hand) approximately the same as that of the inner r i n g f o r the duration of the run. The buf f e r r i n g , therefore was intended to minimize the l a t e r a l flow of water which had i n f i l t r a t e d i n t o the s o i l i n the inner r i n g . In t h i s way, i t was hoped that only the ver-t i c a l component of s o i l water movement was measured. Since the r e s e r v o i r c y l i n d e r d i d not contain s u f f i c i e n t water to l a s t the duration of the run, i t required r e f i l l i n g a num-ber of times depending on the i n f i l t r a t i o n r a t e . At each f i l l i n g , the o u t l e t had to be closed o f f to prevent r a p i d flow r e s u l t i n g from the opening of the system to atmospheric pressure. This allowed the head i n the inner r i n g to e i t h e r drop or, as was often the case, disappear while the r e s e r v o i r was being f i l l e d . When the flow r e -sumed, a p o r t i o n of the water supply (measured as i n f i l t r a t i o n ) was used i n r e b u i l d i n g the head. Although r e f i l l i n g was c a r r i e d out, as much as p o s s i b l e , a f t e r a measurement was taken, e r r o r s were i n e v i --ra-t a b l y . Since more r e f i l l s were required on areas with high i n f i l -t r a t i o n c a p a c i t y , equation (11) was developed to r e l a t e e r r o r s r e -s u l t i n g from r e f i l l i n g to the measured i n f i l t r a t i o n r a t e . r o . o s n i C f ) . . . . cr. = e - i ( H ) where £f = overestimate of i n f i l t r a t i o n ( i n . / h r . ) -f = measured i n f i l t r a t i o n r a te ( i n . / h r . ) Unfortunately, t h i s e r r o r f u n c t i o n was derived from the c o l l e c t e d data and was not accurately measured. I t i s t h e r e f o r e , somewhat h y p o t h e t i c a l , and consequently has been l a r g e l y ignored i n the sub-sequent a n a l y s i s developed i n t h i s t h e s i s . Avoidance of r e f i l l i n g e r r o r s could be ensured i n future work by using m u l t i p l e r e s e r v o i r c y l i n d e r s to maintain constant d e l i v e r y of water to the inner r i n g . A. L i m i t a t i o n s of double-ring i n f i l t r o m e t e r E r r o r s , i n a d d i t i o n to those p r e v i o u s l y noted, i n the measurement of i n f i l t r a t i o n with double-ring i n f i l t r o m e t e r s suggest se r i o u s l i m i t a t i o n s to i t s use. The v i o l e n t method of d r i v i n g the c y l i n d e r s i n t o the s o i l must cause disturbance to the n a t u r a l s t r u c -t u r a l c o n d i t i o n s of the s o i l . This disturbance may i n c l u d e s h a t t e r -i n g and compaction, as w e l l as subsurface a l t e r a t i o n caused by roots and rocks pushed ahead of the penetrating edge of the c y l i n d e r . Connected with t h i s i s the p o s s i b i l i t y that the i n t e r f a c e between the s o i l and the side of the metal r i n g may form unnatural seepage planes * assumes each r e f i l l i n g rakes 30 seconds -49-r e s u l t i n g i n abnormally high i n f i l t r a t i o n r a t e s . The r e l a t i o n be-i' tween these disturbance e f f e c t s and i n f i l t r a t i o n r a t e s mould not l i k e l y be of the same magnitude on a l l treatments. This i s exempli-f i e d by the skidroad treatment which, because of compaction, r e q u i r -ed two or three times as many blows on the c y l i n d e r s (per penetrated-inch) as on non-compacted arBas such as the c o n t r o l , A f u r t h e r l i m i t a t i o n to the use of r i n g i n f i l t r o m e t e r s i s ths problem of a i r trapped i n the s o i l column caused by the e x i s -tence of the constant head of water maintained on the s o i l surface. The e f f e c t of a i r pressure buildup on i n f i l t r a t i o n capacity has been p r e v i o u s l y noted (Adrian and F r a n z i n i , 1966). The existence of an impermeable l a y e r i n a l l the s o i l s studied (Appendix I I ) would sug-gest that a i r pressure could only be r e l i e v e d by h o r i z o n t a l movemsnt w i t h i n the s o i l p r o f i l e . The q u a n t i f i e d e f f e c t on i n f i l t r a t i o n has not been f u l l y i d e n t i f i e d although the concept has been recognized (Evans et, a l . 1950). I t has a l s o been found that a f t e r the wetting f r o n t reached the impermeable l a y e r , water movement was p r i m a r i l y h o r i z o n t a l . In studying the e f f e c t of t h i s l a t e r a l movement on i n f i l t r a t i o n , Mar-s h a l l and S t i r k (1950) employed both buffered and unbuffered r i n g s ranging from 1 to 10 fe e t i n diameter. They found that the maximum i n f i l t r a t i o n r a t e of a given s o i l decreased with i n c r e a s i n g s i z e of the r i n g . The use of b u f f e r r i n g s to minimize l a t e r a l flow i s more important i n s o i l s having a slowly permeable l a y e r than those w i t h -out ( S l a t e r , 1957). As a r e s u l t of the l a t e r a l flow phenomenon, i t has been found that the deeper the r i n g s are driven i n t o the s o i l , -50-the lower the i n f i l t r a t i o n r a te ( A r o n o v i c i , 1955; S h u l l , 1964). This l a t t e r aspect was not taken i n t o c o n s i d e r a t i o n i n t h i s study and r i n g s were driven as f a r as p o s s i b l e , up to 10 inches, depend-ing on the p h y s i c a l s o i l c o n d i t i o n s (stones, bulk d e n s i t y , roots and buried l o g s ) of the measurement s i t e . In future s t u d i e s , i t i s recommended that the r i n g s e i t h e r be driven to the same depth, r e l a t i v e to the mineral s o i l surface, on a l l study s i t e s or the depth to which they are driven be measured and recorded. Owing to the l i m i t a t i o n s o u t l i n e d above, i t i s to be ex-pected that measured i n f i l t r a t i o n r a t e s are r e l a t i v e r a t h e r than ab-s o l u t e . Horton (1940) pointed out that t h i s was not n e c e s s a r i l y the case i n that i f f ^ and f 2 are the measured i n f i l t r a t i o n c a p a c i t i e s of two s o i l s , then f ^ / f ^ i s the true r a t i o of the two i n f i l t r a -t i o n c a p a c i t i e s . However, i f e x t r a q u a n t i t i e s of water, q^ and q^, enter the s o i l because of disturbance a t t r i b u t a b l e to the occurence of stone i n the s o i l , and f r e e l a t e r a l escape of a i r , then the r a t i o f ^ + q^/ fr, + q^ would he determined by r i n g i n f i l t r o m e t e r measure-ment. I f q,j and q^ are the r e s u l t of random events, t h i s r a t i o i s not n e c e s s a r i l y equal to the true r a t i o f ^ / f ^ (Horton, 1940). This problem i s l i k e l y best circumvented by adequate r e p l i c a t i o n on each s o i l type. Other l i m i t a t i o n s to the double-ring i n f i l t r o m e t e r s are those concerning the p r a c t i c a l l i t y of t h e i r use i n rugged f i e l d con-d i t i o n s . One disadvantage of the r i n g i n f i l t r o m e t e r s was the weight and bulk which combined to make t h e i r t r a n s p o r t to the study s i t e s , awkward and arduous. The f i v e i n f i l t r o m e t e r s plus required a n c i l l -ary equipment was transported to the Blocks by truck (Appendix V, Photograph 1) and thence to the study s i t e s by hand. Another prac-i t i c a l disadvantage, p r e v i o u s l y alluded t o , was the extreme p h y s i c a l d i f f i c u l t y of d r i v i n g the s t e e l r i n g s i n t o the s o i l with minimum disturbance. One of the most f r u s t r a t i n g aspects of the r i n g i n f i l -trometers was water supply: a s i t u a t i o n aggravated by lout summer stream flows and rugged t e r r a i n . Depending on the i n f i l t r a t i o n r a t e s , as much as 800 g a l l o n s of water was required f o r a run of f i v e i n f i l t r o m e t e r s . On Block A", a l l of the required water was packed as f a r as p o s s i b l e i n 45 g a l l o n drums i n the truck and thence by hand i n 5 g a l l o n buckets to the etudy s i t e s . On Blocks B and C, a small stream was dammed o f f and water was pumped (Appendix V, Photograph 2) to 45 g a l l o n holding tanks (Appendix V/, Photograph 3) s i t u a t e d near the study s i t e s . Because these p r a c t i c a l aspects proved extremely f r u s t r a t i n g and time consuming, i t i s recommended that f o r f u t u r e studies of t h i s type, l i g h t , portable i n f i l t r o m e t e r s with low water requirements be s e r i o u s l y considered. 2. S o i l data Since one of the aims of the s t u d i e s described herein was to attempt to e x p l a i n some of the mechanisms of i n f i l t r a t i o n r a t e a l t e r a t i o n by treatment e f f e c t s , s o i l data were c o l l e c t e d f o r each study s i t e . S a i l data were derived somewhat d i f f e r e n t l y i n Blocks A' and B, than i n Block C as a r e s u l t of accumulated experience i n the two former blocks which was applied i n Block C . In Blocks A and B, the s o i l s urface, f o r sampling purposes, was taken to be the surface of the mineral s o i l which meant the p h y s i c a l p r o p e r t i e s -52-of the unincorporated organic l a y e r s i n f l u e n c i n g i n f i l t r a t i o n mere not appraised. Unfortunately, t h i s e r r o r was not r e a l i z e d u n t i l the winter f o l l o w i n g the f i e l d season, at which time i t was too l a t e to be remedied. However, i n the study of Block C, the s o i l surface f o r sampling purposes was taken to be the soil-atmosphere I n t e r f a c e , thereby i n c l u d i n g the organic l a y e r s i n the data d e s c r i b i n g the p h y s i c a l s o i l p r o p e r t i e s . Antecedent s o i l water content at each study s i t e was deter-mined by g r a v i m e t r i c sampling immediately p r i o r to the s t a r t of a run. Two samples were taken at each of the depths, 0 - 3, 4 - 7, 8 - 12, 12 - 18 and 18 - 24 inches i n the mineral s o i l from a s o i l p i t adja-cent to the b u f f e r r i n g . Water content was expressed by the oven-dry (105°C) weight b a s i s . At the end of a "run" measurements were taken to character-i z e vegetation and organic matter cover. Percent l i t t e r cover was t determined by point sampling under a wire g r i d placed over the s o i l i surface i n the inner r i n g . Percent moss cover (micro Jvegetation cover) was s i m i l a r l y determined and percent macro-vegetation cover was v i s u a l l y estimated. The depths of the l i t t e r ( L ) , fermented (F) and (H) humus l a y e r s were measured to a tenth of an inch by se v e r a l d i r e c t measurements w i t h i n the inner r i n g . A. Bulk density and p o r o s i t y c h a r a c t e r i s t i c s In order to evaluate the bulk d e n s i t y , p o r o s i t y and texture of the s o i l i n the inner r i n g of the i n f i l t r o m e t e r , "undisturbed" s o i l cores were e x t r a c t e d . Using an a g r i c u l t u r a l s o i l sampler, mod--53-i f i e d to withstand the r i g o r s of f o r e s t s o i l s , two samples were taken from the 0 - 3 inch depth and one from each of the 4 - 7, 8 -12, 12 - 18 and 18 - 2k i n c h depths. Following e x t r a c t i o n , the three by three inch c y l i n d e r cores were roughly trimmed, bagged and stored i n c o l d storage (35°F) u n t i l l a b oratory analyses were c a r r i e d out. In Blocks A and By the zero depth was taken to be the surface of the mineral s o i l whereas i n Block C, the zero depth was the s o i l -atmosphere i n t e r f a c e . With the method employed i n the e x t r a c t i o n of s o i l cores, disturbance of stones and root networks made the e x t r a c t i o n of cores of acceptable q u a l i t y , d i f f i c u l t and time consuming. When a large stone or root was encountered, the s o i l core was f r a c t u r e d or com-pacted. When t h i s was obvious enough to be detected during the sampling operation, the sample was replaced by an acceptable one. However, with proper care and patience, good q u a l i t y cores were ob-t a i n a b l e i n low density s o i l s . In securing s u i t a b l e cores from dense pedogenic horizons, massive parent m a t e r i a l s such as basal t i l l or glaciomarine ai com-pacted l a y e r s , compounded the e x t r a c t i o n problem. In these s i t u -a t i o n s , bulk density w i l l be underestimated and aer a t i o n p o r o s i t y w i l l be overestimated from the s o i l cores. This bias a r i s e s because the cores that were extracted were, of ne c e s s i t y , taken from places where i t was p h y s i c a l l y p o s s i b l e to do so. These places were con-sequently i s o l e t s of lower bulk density and higher aeration p o r o s i t y than the average f o r the horizon sampled. -54-The f e a s i b i l i t y of a l t e r n a t i v e methods of measuring both bulk density and aeration p o r o s i t y of f o r e s t e d s o i l s should be de-termined. In the l a t t e r case, gamma ray attenuation methods may prove e f f i c i e n t and accurate (de V r i e s , 1968). Any new method de-veloped should y i e l d b e t t e r r e s o l u t i o n than i s obtainable from a three inch core. In the la b o r a t o r y , the cores were c a r e f u l l y trimmed, f i t t e d w ith a gauze cap on one end, and saturated f o r a l e a s t 24 hours i n a f l o o d i n g tank. At the end of the 24 hour p e r i o d , i t was observed that many of the cores had e i t h e r not wetted or were wetted only i n patches. This s i t u a t i o n p r e v a i l e d i n approximately 3D percent of the s o i l cores t e s t e d . To overcome t h i s c o n d i t i o n of hydrophobicity, or wetting r e s i s t a n c e , some of the p r o p e r t i e s of water i n f l u e n c i n g wetting were adjusted i n accordance with the f o l l o w i n g approximation (Letey et a l . 1962): ^ _ T r T ^ p r g h + z 3" cos & ) ( 1 2 ) ^ 8 L T [ ! where Q = ra t e of flow i n volume per u n i t r =:radius of c a p i l l a r y ^ = the density of water cj = the g r a v i t y constant h = the c a p i l l a r y length plus depth of water i n f l o o d i n g tank # = surface tension 0 = the l i q u i d - s o l i d contact angle L = the c a p i l l a r y length = v i s c o s i t y of water -55-In some cases s a t u r a t i o n of the s l i g h t l y hydrophobic cores was accom-p l i s h e d by using warm water which tended to reduce v i s c o s i t y (17,). In the case of very hydrophobic s o i l s , i n c r e a s i n g the temperature was not s u f f i c i e n t to cause wetting so a small amount of detergent was added to the water. This tended to decrease the wetting angle, © , and encourage wetting. Once they were saturated, the cores were weighed and placed on a tension t a b l e where a hanging water column of 60 cm. was a p p l i e d u n t i l e q u i l i b r i u m was a t t a i n e d . The cores were then weighed, oven d r i e d at 105°C. and weighed a f i n a l time. Bulk density was c a l c u -l a t e d from the oven dry weight of the s o i l and the volume of the core (bulk density (gm./cc.) = o.d. s o i l weight / core volume). The index of ae r a t i o n p o r o s i t y was taken as the d i f f e r e n c e i n volumetric water content between s a t u r a t i o n ( s o i l water p o t e n t i a l of 0 cm. of water) and a s o i l water p o t e n t i a l of -60 cm. of water. The aera t i o n p o r o s i t y , then, was the volume of pores coarse enough to dra i n at p o t e n t i a l s greater than -60 cm. of water (Peele, 1949). The t o t a l p o r o s i t y f o r each depth, at each study s i t e , was c a l c u l a t e d from the f o l l o w i n g equation. ^ - . _ bulk densi+q , T.P=I.GO j ~ , , 3 . • (13) p a r t i c l e aenstlL) P a r t i c l e d e n s i t i e s f o r each depth, at each study s i t e , were c a l c u -l a t e d from the f o l l o w i n g equation. P.D. =(l.3gm/cOX. + (2.k5gm/cc)(f.0-X) (14) -56-where - l . 3 g m / f c c = the density of s o i l organic matter 2.1=5 gm/cc = the density of the s o i l mineral f r a c t i o n "X- = the t o t a l (%) organic matter f r a c t i o n j This l a t t e r equation was developed and used to save time i n the analyses by e l i m i n a t i n g the laboratory determination of s o i l p a r t i -c l e d e n s i t y . B. P a r t i c l e s i z e d i s t r i b u t i o n P a r t i c l e s i z e d i s t r i b u t i o n ( t e x t u r e ) was determined f o r the s o i l i n the undisturbed cores. For Blacks A and B, the oven d r i e d cores were broken and a l l the cores were pooled by the f i v e depths f o r each run of f i v e p l o t s . The composite sample was passed through a two m i l l i m e t e r seive and the percentage by weight greater than two i m i l l i m e t e r s was c a l c u l a t e d . The f i n e m a t e r i a l passing through the seive was t r e a t e d w i t h hydrogen peroxide to remove the organic mat-t e r and a 40 gram subsample was drawn at random and analyzed f o r p a r t i c l e s i z e d i s t r i b u t i o n using the hydrometer method. The percent-age composition, by weight, of sand, s i l t and clay was determined, i n t h i s way, three times f o r each s o i l depth i n each experimental u n i t . For Block C, the same basic procedure was followed with two exceptions. As a r e s u l t of the very low clay contents i n the s o i l s of Blacks A and B, the s i l t and cl a y f r a c t i o n s were combined i n t o a s i l t - p l u s - c l a y f r a c t i o n . This was j u s t i f i e d i n the l i g h t of analyses made on Blocks A and B and the f a c t that the s o i l of Block C does not vary r a d i c a l l y from the other two Blacks. By grouping the s o i l i n t o -57-composites same of the v a r i a t i o n i n t e x t u r e of the s o i l s i n Blocks A' and B mas l o s t . Consequently, no grouping was done:for the t e x t u r -a l a n a l y s i s of Block C. C. Organic matter content determination Organic matter content was determined by the l o s s on i g n i -t i o n method. For Blocks A and B, disturbed s o i l samples f o r organic matter content determinations were taken from the 0 - 3 , 3 - 6 , and 6 - 1 2 inch depths i n the mineral s o i l i n the inner i n f i l t r o m e t e r r i n g . In Block C, randomly s e l e c t e d p o r t i o n s of the s o i l from each of the undisturbed s o i l cores were used f o r organic matter content determinations. Before i g n i t i o n , the samples were segregated i n t o a coarse and a f i n e f r a c t i o n with a two m i l l i m e t e r s i e v e . This was done because i t was suspected that a s i g n i f i c a n t amount of coarse organic debris was incorporated i n t o the s o i l on skidroads during t h e i r use. Because of the p l a t y nature of t h i s m a t e r i a l , i t was f e l t i t could p o s s i b l y reduce the c r o s s - s e c t i o n a v a i l a b l e to v e r t i -c a l water flow and thereby i n f l u e n c e the i n f i l t r a t i o n c a p a c i t y . The samples were i g n i t e d i n a muffle furnace f o r a minimum of four hours at 500°C. Organic matter was c a l c u l a t e d as a percent by weight of the unburned oven dry s o i l f o r both the coarse and f i n e s o i l f r a c t i o n s . T o t a l percent organic matter content was c a l c u l a t e d as an average of the two, weighed by the percentage composition of the s o i l by the coarse and f i n e f r a c t i o n s . D. Derived v a r i a b l e s -58-In order to account for; the v a r i a t i o n in, i n f i l t r a t i o n r a t e s a t t r i b u t a b l e to the l a t e r a l flow of a i r and mater, two v a r i a b l e s were derived. I t was f e l t that the downward movement of water would be retarded by the s o i l l a y e r having the l e a s t a eration p o r o s i t y . This v a r i a b l e ( l i m i t i n g l a y e r ) was s e l e c t e d f o r each study s i t e from the a e r a t i o n p o r o s i t y data.' I f t h i s l a y e r slowed water movement r e l a t i v e to i n f i l t r a t i o n , then i t was f u r t h e r hypothesized that the greatest proportion of l a t e r a l flows of both a i r and water would take place i n a three inch l a y e r d i r e c t l y o v e r l y i n g the l i m i t i n g l a y e r . The term " p o t e n t i a l l a t e r a l flow l a y e r " was coined to des-c r i b e the a e r a t i o n p o r o s i t y of the l a y e r which o v e r l i e s the l i m i t i n g l a y e r . These two derived v a r i a b l e s schematically i l l u s t r a t e d i n Figure 10, and important only with reference to double-ring i n f i l t r o -meters, were extremely u s e f u l i n ensuing analyses. Figure 10. Schematic e f f e c t of p o t e n t i a l l a t e r a l flow l a y e r ( a ) , and the l i m i t i n g l a y e r (b) on i n f i l t r a t i o n . -59-A n a l y s i s of Data The primary o b j e c t i v e s of the s t u d i e s described i n t h i s t h e s i s , the e f f e c t s of various treatments on the i n f i l t r a t i o n of three coarse g l a c i a l s o i l s D f B.C. and the a p p r a i s a l of the mechan-isms of the treatment e f f e c t s , were l a r g e l y r e a l i z e d through the s t a t i s t i c a l a n a l y s i s of the data obtained i n the f i e l d and l a b o r a -t o r y . The o r i g i n a l data were t r a n s f e r r e d to computer cards and the analyses were executed on IBM 70kk e l e c t r o n i c computer. The analyses were e s s e n t i a l l y dichotomous with Blocks A and B handled separately from Block C. The v a r i a b l e s f o r each "set" were numbered c o n s e c u t i v e l y , the d e s c r i p t i o n s of the v a r i a b l e s by number being presented i n Appendix UI. The mean, standard d e v i a t i o n , maxi-mum and minimum values f o r each v a r i a b l e by experimental u n i t are out-l i n e d i n Appendix V I I . The lower number of s o i l v a r i a b l e s f o r Block C was a r e s u l t of the incidence of glaciomarine at an average depth of 20 inches on the skidroad. This meant that s o i l cores could not be e x t r a c t e d from the 18 - Zk inch depth at s u f f i c i e n t study s i t e s to j u s t i f y i t s i n c l u s i o n i n the data. In order to maintain c l a r i t y i n the d i s c u s s i o n of treatment e f f e c t s on i n f i l t r a t i o n , the e f f e c t s of skidroads are described sep-a r a t e l y from slashburning and c l e a r c u t t i n g e f f e c t s . The r e s u l t s of the.analyses of a l l treatments are summarized f o r purposes of compre-hension, comparison and c o n t r a s t . 1. Scattergram a n a l y s i s -60-Befare s t a t i s t i c a l a n a l y s i s could be c a r r i e d out, a basic understanding of the data had to be gained. To overcome the problem of gaining an i n s i g h t i n t o the r e l a t i o n s h i p between a great many v a r i a b l e s , scattergrams were developed f o r each i n f i l t r a t i o n v a r i -able and each other v a r i a b l e . For Blacks A and B, each scattergram contained 120 points compared to 30 points per scattergram f o r Block C. Inferences drawn from the scattergrams were of higher confidence from those with 120 points than from those with 30 points due to the greater expression of v a r i a t i o n i n the former. Two bas i c pieces of information were obtainable from the scattergrams. The degree of s c a t t e r i n g was i n d i c a t i v e of the e x i s -tence of any r e l a t i o n s h i p between any two v a r i a b l e s . As was expect-ed, the scattergrams ranged from i n d i c a t i n g no r e l a t i o n s h i p s to i n -d i c a t i n g high r e l a t i o n s h i p s between v a r i a b l e s . The former v a r i a b l e s were r e j e c t e d from f u r t h e r a n a l y s i s , but the l a t t e r were examined f o r n o n l i n e a r i t y . Some of the scattergrams, which were d e f i n i t e l y not l i n e a r r e l a t i o n s h i p s , were noted as being somewhat c u r v i l i n e a r but p o t e n t i a l l y describable by l i n e a r equations. This information was important i n f u r t h e r analyses. 2. M u l t i p l e r e g r e s s i o n a n a l y s i s The data c o l l e c t e d f o r t h i s study could have been analysed i n two basis ways: mechanistic or d e s c r i p t i v e . The mechanistic method, although being the more rigorous of the two, was the l e s s d e s i r a b l e due to the wide, p a r t i a l l y undefined v a r i a t i o n i n the v a r i a b l e * values and the high number of v a r i a b l e s measured. Thus, -61-the d e s c r i p t i v e approach i s emphasized i n t h i s t h e s i s although the mechanisms of the i n f i l t r a t i o n process have not been ignored. The most e f f e c t i v e t o o l f o r accomplishing t h i s o b j e c t i v e was s e l e c t e d as being m u l t i p l e regression a n a l y s i s . Although a d e s c r i p t i o n of the techniques involved i n m u l t i -ple r e g r e s s i o n a n a l y s i s w i l l not be attempted, i t i s important to note s e v e r a l s p e c i a l features of t h i s s t a t i s t i c a l t o o l . The assump-t i o n s underlying m u l t i p l e r e g r e s s i o n a n a l y s i s , which are frequently ignored by many users of the t o o l , are summarized as f o l l o w s ( L i , 1964): i . Each array of Y (dependent v a r i a b l e ) of the popu-l a t i o n f o l l o w s the normal d i s t r i b u t i o n . i i . The regression of Y on x^, x2,m"xm (^dependent v a r i a b l e s ) i s l i n e a r , or the regression equation i s i i i . The variances of a l l arrays of Y of the population are equal. i v . The samples are drawn at random. v. The X-values remain constant f o r a l l samples and do not change from sample to sample. These assumptions were adhered to as c l o s e l y as p o s s i b l e i n t h i s study; however, q u a n t i f i c a t i o n of the divergence of the a c t u a l from the true would be extremely d i f f i c u l t . The s e l e c t i o n of the best regression i s u s u a l l y a compro-mise between the extremes of a large number of X-values f o r ensuring optimum p r e d i c t i o n and d e s c r i p t i o n and a minimum number of X-values -62-f o r purposes of s i m p l i c i t y . In t h i s study, a l l r e g r e s s i o n equations were reduced from maximum X-values to one X-value by the backward e l i m i n a t i o n method (Draper and Smith, 1968). From the array of equa-t i o n s thus developed, the most d e s i r a b l e equation was'selected according to the f o l l o w i n g c r i t e r i a : i . The maximum m u l t i p l e c o r r e l a t i o n c o e f f i c i e n t (sum of squares of Y accounted f o r by regression) p o s s i b l e i n conjunction with i i . the minimum standard e r r o r of estimate (the e r r o r i n the estimate of Y predicted from a given set of X-values using the determined equation); compatible with i i i . s i g n i f i c a n c e of the equation according to the variance r a t i o t e s t at a given l e v e l of p r o b a b i l i t y . -63-Results and Discussion I. EFFECTS: OF CLEARCUTTING AND SLASHBURNING ON INFILTRATION 1. O v e r a l l e f f e c t s A d i r e c t comparison of measured i n f i l t r a t i o n r a t e s on d i f -f e r e n t treatments i n order to appraise c l e a r c u t t i n g and slashburn-in g e f f e c t s i s a p o t e n t i a l l y biased approach. This r e s u l t s from the v a r i a t i o n i n c e r t a i n s o i l p r o p e r t i e s , a f f e c t i n g i n f i l t r a t i o n , not a t t r i b u t a b l e to treatment e f f e c t s . In other words, some of the d i f -ferences of measured i n f i l t r a t i o n r ates between treatments i s caused by n a t u r a l l y occuring v a r i a t i o n i n the ecosystem. The adjustment of measured i n f i l t r a t i o n r a t e s of each experimental u n i t by removing nontreatment v a r i a t i o n and the subsequent a n a l y s i s of treatment e f f e c t s was accomplished by covariance a n a l y s i s . The s e l e c t i o n of v a r i a b l e s which v a r i e d from treatment to treatment and yet were not in f l u e n c e d by treatment was, to a degree, s u b j e c t i v e . This s u b j e c t i v i t y was minimized, as much as p o s s i b l e , through information i n the l i t e r a t u r e , personal observation and bas i c knowledge and understanding. Once the v a r i a b l e s had been s e l e c t e d , a m u l t i p l e r e g r e s s i o n was developed r e l a t i n g these independent v a r i -ables to i n f i l t r a t i o n r a t e . Of a l l the i n f i l t r a t i o n v a r i a b l e s c o l l -ected, only two were employed f o r the m u l t i p l e r e g r e s s i o n equations used i n the covariance a n a l y s i s : Y1, the f i r s t - h o u r i n f i l t r a t i o n r a t e and Y2, the third-hour i n f i l t r a t i o n r a t e . These were s e l e c t e d as being d i a g n o s t i c of the i n f i l t r a t i o n r a te vs. time curve. -64-The c h a r a c t e r i s t i c s of the m u l t i p l e r e g r e s s i o n equation s e l e c t e d f o r the covariance a n a l y s i s of treatment e f f e c t s on f i r s t -hour i n f i l t r a t i o n r a te are presented i n Table 3. The:inclusion of the v a r i a b l e s can be j u s t i f i e d as not.being h i g h l y i n f l u e n c e d by treatment. The changes brought about i n s o i l texture (X25, X31 and X37) by c l e a r c u t t i n g and slashburning are very l i k e l y minor compar-ed to the e x i s t i n g n a t u r a l texture v a r i a t i o n (Table 4 ) . Small de-creases (<5%) i n the clay and s i l t - p l u s - c l a y f r a c t i o n s may accrue on severely burned areas, but disturbances due to c l e a r c u t t i n g and l i g h t and medium slashburning does not produce discernable changes i n texture (Dyrness and Youngberg, 1957). Table 3. C h a r a c t e r i s t i c s of f i r s t - h o u r i n f i l t r a t i o n m u l t i p l e reg r e s s i o n equation used i n covariance a n a l y s i s . Independent V a r i a b l e X25 (0-3" % sand) X31 (0-3» % s i l t ) X37 (D-3» % c l a y ) X43 (0-3" s o i l water) X67 ( p o t e n t i a l l a t e r a l flow l a y e r ) X68 ( l i m i t i n g l a y e r ) Regression Standard Variance C o e f f i c i e n t Deviation Ratio -3.02 1.73 3.054 -3.10 1.71 3.298 -3.07 1.82 2.844 0.02 0.01 8.272 47.96 15.80 9.214 Constant term = 306.55 n = 90 Standard e r r o r of estimate = - 6.33 inches per hour M u l t i p l e c o r r e l a t i o n c o e f f i c i e n t = 0.613 M u l t i p l e c o e f f i c i e n t of determination = 37.57% -65-Table 4. Mean values of f i r s t - h o u r i n f i l t r a t i o n c o v a r i -ance v a r i a b l e s by experimental u n i t s . • Var i a b l e S l a s h -burned Block A Clearcut Control S l a s h -burned Block B Clearcut Control 1 X25 40.33 41.33 39.00 37.67 44.33 45.33 1 X31 53.33 48.33 50.67 55.00 47.00 49.00 1 X37 6.33 10.33 10.33 7.33 8.00 5.67 1 X43 93.50 218.67 171.74 54.04 58.24 41.03 2 X67^ 0.278 0.255 0.247 0.305 0.302 0.303 X6S 2 0.214 0.177 0.151 0.255 0.253 0.263 1 2 percent by weight cubic centimeters per cubic centimeter of o.d. s o i l The e f f e c t of treatment on antecedent s o i l water • content (X43) was assumed to be minor compared to the i wide range of values measured (Table 4 ) . S o i l water content has been found to vary i r i d e - ; -pendently of treatment on many areas s t u d i e s i n the U.S. P a c i f i c Northwest (Bethlahmy, 1962; H a l l i n , 1967). The f a c t that s o i l t e x t u r e , a c h a r a c t e r i s t i c s t r o n g l y i n f l u e n d i n g the water r e t e n t i o n p r o p e r t i e s of a s o i l , was not strong l y i n f l u e n c e d by treatment f u r t h e r s the j u s t i f i c a t i o n f o r the i n c l u s i o n of X43. The v a r i a b l e s of p o t e n t i a l l a t e r a l flow l a y e r (X67) and l i m i t i n g l a y e r (X68) were very l i k e l y to have been in f l u e n c e d by treatment due to t h e i r p o s i t i o n deep w i t h i n the s o i l pedon, as i n -dicat e d i n Figure 11. According to the bulk of the l i t e r a t u r e (as -66-c i t e d i n previous s e c t i o n s ) , the disturbance e f f e c t s of c l e a r c u t t i n g and slashburning are concentrated i n the surface three inches of the s o i l p r o f i l e . T h is, i n conjunction with the information presented i n Figure 11, j u s t i f i e s the i n c l u s i o n of X67 and X68 in, the regres-s i o n equation used i n the covariance a n a l y s i s . (O • 1 o c 0. 5T20-3o. i con t ro l c lecxrojt s l a S n b u r n e d _i_ 0 . 2 0 0 . 2 5 0 . 3 0 0 . 2 5 0 . 3 O a e r a . t i o n porosity (cc./ca.) B L O C K A B L O C K . B Figure 11. Aeration p o r o s i t y d i s t r i b u t i o n by depth i n the average s o i l p r o f i l e of each experimental u n i t i n d i c a t i n g high v a r i a t i o n which tends to o b l i t -erate treatment e f f e c t s . Although the r e s u l t s of the a n a l y s i s of covariance of the f i r s t - h o u r i n f i l t r a t i o n r a t e (Table 5) are r e a d i l y i n t e r p r e t e d , they do not i n d i c a t e a l l of the treatment i m p l i c a t i o n s . The hi g h l y s i g -n i f i c a n t e f f e c t of treatment on f i r s t - h o u r i n f i l t r a t i o n acts i n the -67-same way on both blocks. However, the treatment or treatments which s i g n i f i c a n t l y i n f l u e n c e f i r s t - h o u r i n f i l t r a t i o n are not defined i n t h i s a n a l y s i s . In order to compare treatment e f f e c t s , ; the measured means of each experimental u n i t were adjusted according to the m u l t i -ple r e g r e s s i o n equation used i n covariance a n a l y s i s (Table 6 ) . Table 5. Covariance a n a l y s i s of f i r s t - h o u r i n f i l t r a t i o n r a te (Y1). DSQPBBS of"* Source of v a r i a t i o n preedom S u m S c I u a r e Mean Square F Value Treatment 2 Block 1 Treatment X Block 2 E r r o r 78 962.90 94.39 7.59 2050.40 481.45 94.39 3.80 26.29, 18.32** 3.59 0.14 ** s i g n i f i c a n t at the 0.01 l e v e l of p r o b a b i l i t y Table 6. Measured and adjusted means of f i r s t - h o u r i n f i l t r a t i o n (Y1) by experimental u n i t . Treatment Measured Block A Adjusted Measured Block B Adjusted Slashburned Clearcut Control - inches per hour -16.94 17.49 20.19 19.61 24.66 24.83 29.54 27.89 21.94 24.39 29.00 28.07 -68-A Duncan's New M u l t i p l e Range t e s t was employed to appraise the d i f f e r e n c e between the adjusted mean values (Table 7 ) . The f i r s t - h o u r i n f i l t r a t i o n means f o r the slashburned treatment on Blocks A. and B were s i g n i f i c a n t l y lower than f i r s t - h o u r i n f i l t r a t i o n means f o r c l e a r c u t and c o n t r o l on both b l o c k s . I t appears,.from the exam-i n a t i o n of adjusted treatment means, that slashburned means are an expression of extended reduction i n f i r s t - h o u r i n f i l t r a t i o n r a t e s i n i t i a l l y reduced through c l e a r c u t t i n g . This i m p l i e s , i n other words, that treatment e f f e c t s on f i r s t - h o u r i n f i l t r a t i o n r a te are somewhat a d d i t i v e on both blocks. Further i m p l i c a t i o n s of t h i s w i l l be discussed i n l a t e r s e c t i o n s . Table 7. Results of Duncan's New M u l t i p l e Range t e s t on adjusted Y1 experimental u n i t means. Slashburned Clearcut Control Block A Block B Block A Block B Block A Block B - inches per hour -17.49 19.61 24.39 24.83 27.89 28.07 * * mean values underlined by the same l i n e not s i g n i f i c a n t l y d i f f e r e n t at the 0.01 l e v e l of p r o b a b i l i t y . Third-hour i n f i l t r a t i o n (Standard Deviation = - 6.74 inches per hour) i s somewhat l e s s v a r i a b l e than f i r s t - h o u r i n f i l -t r a t i o n (Standard Deviation = - 7.74 inches per hour) due to both -69-i t s more s t a b i l i z e d nature (Horton, 1933) and a l s o , as i n f i l t r a t i o n decreased i t was p h y s i c a l l y e a s i e r to operate the i n f i l t r o m e t e r e . Consequently, i t i s suspected that treatment d i f f e r e n c e s of t h i r d -hour i n f i l t r a t i o n w i l l be more r e l i a b l e than those f o r f i r s t - h o u r i n f i l t r a t i o n . Third-hour i n f i l t r a t i o n was analyzed according to the same sequence as f i r s t - h o u r i n f i l t r a t i o n . The c h a r a c t e r i s t i c s of the m u l t i p l e regression equation s e l e c t e d f o r the covariance a n a l y s i s of treatment e f f e c t s on t h i r d -hour i n f i l t r a t i o n r a te are presented i n Table Q. The l i k e l i h o o d that any of the included v a r i a b l e s were st r o n g l y a l t e r e d by t r e a t -ment e f f e c t s i s very d o u b t f u l . Table 8. C h a r a c t e r i s t i c s of third-hour i n f i l t r a t i o n m u l t i p l e regression equation used f o r covariance a n a l y s i s . Independent Va r i a b l e X19 (0-3" % > 2 mm.) X24 (average 96 > 2 mm.) X30 (average % sand) X36 (average % s i l t ) X42 (average % c l a y ) X43 (0-3" % s o i l water) X67 ( p o t e n t i a l l a t e r a l flow l a y e r ) X68 ( l i m i t i n g l a y e r ) Regression Standard Variance C o e f f i c i e n t Deviation Ratio -0.41 0.13 9.620 0.65 0.15 18.214 -5.07 2.76 3.376 -5.32 2.77 3.696 -4.86 2.73 3.168 -0.01 0.01 4.157 41.27 11.43 13.038 26,78 11.55 5.374 Constant term = 501.62 n = 90 Standard e r r o r of estimate = - 4.59 inches per hour M u l t i p l e c o r r e l a t i o n c o e f f i c i e n t = 0.761 M u l t i p l e c o e f f i c i e n t of determination = 57.92% -70-Idith i n c r e a s i n g time an attendant i n c r e a s i n g depth of wet-t i n g f r o n t penetration, i n f i l t r a t i o n p a r t i a l l y becomes a f u n c t i o n of subsurface s o i l p r o p e r t i e s . Thus, the v a r i a b l e s of average min-e r a l s o i l components i n the 0 - 2 4 inch p o r t i o n of the p r o f i l e (X24, X30, X36 and X42) are j u s t i f i a b l y included i n the equation. J u s t i f i -c a t i o n of the i n c l u s i o n of the other v a r i a b l e s (X19, X43, X67 and X68) has been described i n the context of f i r s t - h o u r i n f i l t r a t i o n . The v a r i a t i o n of each of the v a r i a b l e s used i s described i n Table 9. Table 9. Mean values of the third-hour i n f i l t r a t i o n co-variance v a r i a b l e s by experimental u n i t s . Block A Block B Var i a b l e S l a s h - _,, ~ _ , . Slash- —. „ . , , Clearcut Control . . Clearcut Control burned burned - percent by weight -X19 27.26 42.39 49.77 49.77 47.07 42.98 X24 29.22 38.49 32.49 51.36 47.36 50.28 X30 45.33 54.33 53.00 56.33 56.33 56.67 X36 45.33 36.33 42.67 38.33 36.67 36.33 X42 9.33 9.00 4.33 5.33 7.00 7.00 X43, X67, X68 - see Table 4 The r e s u l t s of covariance a n a l y s i s of third-hour i n f i l t r a -t i o n are presented i n Table 10. As f o r the s i m i l a r a n a l y s i s of f i r s t - h o u r i n f i l t r a t i o n , the hig h l y s i g n i f i c a n t e f f e c t of treatment on Y3 operates i n the same way on both blo c k s . The treatment means were adjusted according to the m u l t i p l e regression equation used i n the covariance a n a l y s i s (Table 11). Table 10. Covariance a n a l y s i s of t h i r d -hour i n f i l t r a t i o n r a te (Y3). D E O T B B S o f Source of V a r i a t i o n preedom S u m S c I u a r B Mean Square F Value Treatment 2 Block 1 Treatment X Block 2 E r r o r 76 688.18 17.19 16.25 1098.80 344.09 17.19 8.12 14.46 23.80** 1.19 0.56 c* s i g n i f i c a n t at the 0.01 l e v e l of p r o b a b i l i t y Table 11. Measured and adjusted means of third-hour i n f i l t r a t i o n (Y3) by experimental u n i t . Treatment Measured Block A Adjusted Measured Block B Adjusted Slashburned Clearcut Control - inches per hour -9.23 12.03 15.79 12.52 15.96 18.29 21.74 19.58 13.96 16.71 23.21 20.51 The s i g n i f i c a n c e of the d i f f e r e n c e s between the adjusted experimental u n i t means of third-hour i n f i l t r a t i o n was tested by Duncan's New M u l t i p l e Range Test (Table 12). The adjusted means of -72-the slashburn treatment f o r both blocks are s i g n i f i c a n t l y lower than the adjusted means of c l e a r c u t and c o n t r o l on both blocks. The a d d i t i v i t y of treatment e f f e c t s , as noted f o r f i r s t - h o u r i n f i l -t r a t i o n , i s not c l e a r l y e x i s t e n t i n the case of the third-hour i n -f i l t r a t i o n . This could be a r e s u l t of the lack of s e n s i t i v i t y of third-hour i n f i l t r a t i o n to treatments which, e s s e n t i a l l y , a l t e r only the surface three inches of s o i l . Third-hour i n f i l t r a t i o n may only be a d d i t i v e i n i t s expression of treatments i f these t r e a t -ments s i g n i f i c a n t l y reduce i n f i l t r a t i o n below the permeability of the underlying s o i l . Table 12. Results of Duncan's New M u l t i p l e Range t e s t on adjusted Y3 experimental u n i t means. Slashburned Clearcut Control Block A, Block B Block A Block B Block A Block B - inches per hour -12.03 12.52 18.29 19.58 16.72 20.51 * mean values underlined by the same l i n e not s i g n i f i c a n t l y d i f f e r e n t at the 0.01 l e v e l of p r o b a b i l i t y . By way of s p e c u l a t i o n , i f the adjusted mean values of f i r s t and third-hour i n f i l t r a t i o n by experimental u n i t are corrected ac-cording to the r e f i l l - e r r o r equation (equation 11) a more meaningful conclusion r e s u l t s . The new values (Table 13) are smaller and the -73-d i f f e r e n c e between them l e s s than was the case f o r the adjusted v a l -ues. I f the c o r r e c t i o n equation were proven c o r r e c t , the new mean values f o r Y1 and Y3 by experimental u n i t would s t i l l , y i e l d the same conclusions as were developed from the covariance-adjusted msans. Table 13. F i r s t and third - h o u r i n f i l t r a t i o n means by e x p e r i -mental u n i t corrected f o r r e f i l l e r r o r . Treatment Block Y1 A Y3 Block Y1 B Y3 Slashburned 15.79** 11.11** 17.55** 11.47** (17.49)* (12.03) (19.61) (12.52) Clearcut 21.37 16.43 21.72 17.52 (24.39) (18.29) (24.83) (19.58) Control 22.99 15.10 24.12! 18.29 (27.89) (16.71) (28.07) (20.51) ** s i g n i f i c a n t l y lower at 0.01 l e v e l of p r o b a b i l i t y * adjusted values from covariance a n a l y s i s i n brackets 2. Mechanisms of treatment e f f e c t s The covariance a n a l y s i s of f i r s t and third-hour i n f i l t r a -t i o n i n d i c a t e s trends of treatment e f f e c t s , but does not e x p l a i n ths mechanisms of these e f f e c t s . Slashburned treatments on both blocks were shown to have s i g n i f i c a n t l y lower i n f i l t r a t i o n r ates than any of the other treatments. The reasons f o r the apparant low-e r i n g of i n f i l t r a t i o n by slashburning remain to be explained, as do the p o s s i b l e a d d i t i v e e f f e c t s of c l e a r c u t t i n g . -74-M u l t i p l e regressian techniques were u t i l i z e d to bath a i d i n the explanation of p o s s i b l e mechanisms of i n f i l t r a t i o n a l t e r -a t i o n by treatment and to develop an equation which would y i e l d a reasonable p r e d i c t i o n of i n f i l t r a t i o n f o r a given ecosystem. This dichotomous approach was undertaken i n order to maximize the u t i l -i t y of the c o l l e c t e d data and to develop as much information as p o s s i b l e f o r the s o i l s studied since so l i t t l e i s known about the hydrology of coarse g l a c i a l s o i l s of c o a s t a l B.C. I t has long been recognized that s o i l p o r o s i t y exerts the greatest i n f l u e n c e on i n f i l t r a t i o n (Horton, 1933; L i n s l e y et a l . 1949; Gray and Norum, 1967) and that most of the other s o i l proper-t i e s exert t h e i r i n f l u e n c e on i n f i l t r a t i o n through pore s i z e char-a c t e r i s t i c s . As a f i r s t step i n e x p l a i n i n g the e f f e c t of c l e a r c u t -t i n g and slashburning on f i r s t and third-hour i n f i l t r a t i o n , m u l t i p l e r e g r e s s i o n equations were developed r e l a t i n g p o r o s i t y c h a r a c t e r i s t i c s to i n f i l t r a t i o n . M u l t i p l e regression equations were then developed r e l a t i n g other s o i l c h a r a c t e r i s t i c s to p o r o s i t y . A. S o i l p o r o s i t y Aeration p o r o s i t y a f f e c t s i n f i l t r a t i o n more than water r e -t e n t i o n p o r o s i t y s i n c e , i n the fo r e s t e d s o i l s i n v e s t i g a t e d , s o i l water contents r a r e l y dropped low enough to render the water r e t e n -t i o n pores empty. Simple regression equations r e l a t i n g a e r a t i o n p o r o s i t y c h a r a c t e r i s t i c s to f i r s t and third-hour i n f i l t r a t i o n r a t e s were developed. F i r s t - h o u r i n f i l t r a t i o n r a t e s were c o r r e l a t e d with the -75-a e r a t i o n p o r o s i t y ( f r a c t i o n by volume) of the 0 - 3 and 4 - 7 inch l a y e r s of the mineral s o i l (Table 14). Although ne i t h e r equation accounts f o r a large p o r t i o n of the sum of squares of| Y1 and both standard e r r o r s of the estimates are r e l a t i m e l y l a r g e , the r e l a -t i o n s h i p s described are s i g n i f i c a n t at the 0.01 l e v e l of p r o b a b i l -i t y . F i r s t - h o u r i n f i l t r a t i o n i s more hi g h l y dependent on the aera-t i o n p o r o s i t y of the surface l a y e r of mineral s o i l than the aeration p o r o s i t y of the 4 - 7 inch mineral s o i l l a y e r . Both equations des-c r i b e a p o s i t i v e c u r v i l i n e a r r e l a t i o n s h i p . Table 14. Simple regr e s s i o n equations r e l a t i n g f i r s t - h o u r i n f i l t r a t i o n (Y1) to the aeration p o r o s i t i e s of the 0 - 3 , and 4 - 7 inch mineral s o i l l a y e r s . A. Independent Var i a b l e = l o g X7 (aer a t i o n p o r o s i t y , 0 - 3 inch l a y e r ) Regression c o e f f i c i e n t = 13.799 Constant term = 41.05 n = 90 Standard e r r o r of estimate = - 6.85 i n . / h r . C o r r e l a t i o n c o e f f i c i e n t = 0.474 C o e f f i c i e n t of determination = 22.50% 8. Independent Var i a b l e =• log XB (aer a t i o n p o r o s i t y , 4 - 7 inch l a y e r ) Regression c o e f f i c i e n t = 8.296 Constant term = 34.75 n = 90 Standard e r r o r of estimate = -7.21 i n . / h r . C o r r e l a t i o n c o e f f i c i e n t =0.376 C o e f f i c i e n t of determination = 14.12% -76-A comparison of the measured f i r s t - h o u r i n f i l t r a t i o n r a t e s and 0 - 3 and k - 7 inch l a y e r a eration p o r o s i t i e s f o r each e x p e r i -mental u n i t (Figure 12) diverges i n places from the r e l a t i o n s h i p e s t a b l i s h e d by regression a n a l y s i s . In a l l but the Block A s l a s h -burned experimental u n i t , the regression r e l a t i o n s h i p i s v a l i d . However, the regression of a e r a t i o n p o r o s i t y and f i r s t - h o u r i n f i l -t r a t i o n i s more stron g l y i n f l u e n c e d by the other experimental u n i t s where i n c r e a s i n g aeration p o r o s i t y y i e l d s greater i n f i l t r a t i o n r a t e s . I t i s l i k e l y that the one divergent experimental u n i t i s a major reason f o r the high standard e r r o r of estimate and low c o r r e -l a t i o n c o e f f i c i e n t of the simple r e g r e s s i o n equations. I f the r e l a t i o n s h i p s between ae r a t i o n p o r o s i t y and i n f i l -t r a t i o n are v a l i d f o r the bulk of the experimental u n i t s , then the Block A - slashburned u n i t must contain some e r r o r . The three main p o s s i b i l i t i e s f o r e r r o r can be i d e n t i f i e d as f o l l o w s : i * E r r o r s i n a e r a t i o n p o r o s i t y determination. Since the a e r a t i o n p o r o s i t y was determined separately f o r each experimental u n i t , any f a u l t s i n the tension t a b l e or e r r o r s i n weighing would have given a poor estimate of a e r a t i o n p o r o s i t y of one, but i s not n e c e s s a r i l y a l l , experimental u n i t s . This i s h i g h l y u n l i k e l y , how-ever, due to the extreme care taken i n s e t t i n g up the tension t a b l e and c a r r y i n g out the manipulative techniques on the s o i l cores. A l s o , the a e r a t i o n p o r o s i t i e s were determined separately f o r each depth and since the c o n t i n u i t y i n a e r a t i o n p o r o s i t y between depths i s s i m i l a r f o r a l l experimental u n i t s , the p o s s i b i l i t y of major e r r o r s occuring i n aeration p o r o s i t y determination f o r Block A -slashburned i s very low. ences i i . E r r o r s i n i n f i l t r a t i o n i n measurement technique were measurement. Since no d i f f e r -employed on the Block A -u u \ u u -p •H CD • U a a. c a 1-1 -p CO u m CO ,35 .3D ,25 ,20 .15 ,10 1 I 1 .05 1 I 1 I I 1 M a x . 1 i l i P I 1 i l I 1 1 1 1 1 1 1 1 1 I I i 1 P 1 l l II 1 i 1 I 40 35 30 25 20 15 iO 5 0. X 7 X 8 VI Y 3 X 7 X 8 Y( Y 3 slashburn c l e a r c u t BLOCK A X 7 X 8 Y l Y3 c o n t r o l X7 X8 y i Y3 slashburn X7 xs yi y 3 c l e a r c u t BLOCK B X7 xs yi V3 c o n t r o l Figure 12. Means and ranges of aeration p o r o s i t i e s of the 0-3 and 4-7 inch s o i l l a y e r s and f i r s t and third-hour i n f i l t r a t i o n r ates by experimental u n i t . -78-slashburned u n i t , e r r o r s i n excess of those incurred pn a l l e x p e r i -mental u n i t s were extremely u n l i k e l y . i i i . E r r o r s through poor s o i l core r e s o l u t i o n . The determin-a t i o n of a e r a t i o n p o r o s i t y from 3 inch s o i l cores incorporates an averaging e r r o r such that the value obtained i s the average aeration p o r o s i t y f o r the e n t i r e core. Thus, i f one l a y e r of the core has a s i g n i f i c a n t l y lower a e r a t i o n p o r o s i t y than the re s t of the core, i t i s not d i s c e r n a b l e . By using a r a t i o of the mean aeration p o r o s i t y of the 0 - 3 inch l a y e r to the mean f i r s t - h o u r i n f i l t r a t i o n r a te i t i s p o s s i b l e to estimate the p o r o s i t y of the surface l a y e r of the two slashburned s o i l s . This r a t i o i s co n s i s t e n t f o r the c l e a r c u t and c o n t r o l treatments on both blocks with an average value of 1.11. The r a t i o f o r Block A - slashburned i s 1.71 and f o r Block B - s l a s h -burned i s 1.39. I f these r a t i o s were made consist e n t with those of the other experimental u n i t s , the a e r a t i o n p o r o s i t i e s would be 0.20 cc./cc. and 0.22 cc./cc. f o r the Block A - slashburned and Block B -slashburned r e s p e c t i v e l y . I t i s l o g i c a l to expect slashburning to in f l u e n c e a very t h i n surface l a y e r of s o i l and have l i t t l e e f f e c t on the subsurface s o i l . Thus, i f the aer a t i o n p o r o s i t i e s derived f o r the slashburned u n i t s described the surface 0.5 inches, the r e -mainder of the s o i l core would have an aer a t i o n p o r o s i t y of 36 cc./ cc. and 3k cc./cc. f o r Block A - slashburned and Block B - s l a s h -burned r e s p e c t i v e l y . Although the values of aer a t i o n p o r o s i t y f o r the immediate s o i l surface of the slashburned u n i t s , as explained above, are es-timated, the underlying concepts are co n s i s t e n t with data found i n the l i t e r a t u r e (as pr e v i o u s l y noted). A f t e r nine annual burns on a lo e s s s o i l , the a l t e r a t i o n of aer a t i o n p o r o s i t y was found to be r e -s t r i c t e d to the surface inch of s o i l (Moehring e_t a l . 1966). The e f f e c t of in-washing of ash by raindrops i s also known to be r e -s t r i c t e d to the surface of the s o i l (Beaton, 1959). I f the aeration -79-p o r o s i t y of the t h i n surface s o i l l a y e r i s lower than the underly-ing s o i l , i n f i l t r a t i o n becomes more a f u n c t i o n of the s o i l surface than any subsurface f r a c t i o n of; the s o i l . The simple regression of Y1 on l o g X8 (Table 14) i n d i c a t e s f i r s t - h o u r i n f i l t r a t i o n to be more h i g h l y i n f l u e n c e d by the aera-t i o n p o r o s i t y of the 0 - 3 inch s o i l l a y e r than the 4 - 7 inch s o i l l a y e r . This r e l a t i o n s h i p i s reasonably consi s t e n t i n a l l but the slashburned u n i t s (Figure 12). The r a t i o of mean aer a t i o n p o r o s i t y ( 4 - 7 inch l a y e r ) to mean f i r s t - h o u r i n f i l t r a t i o n v a r i e s between 0.96 and 1.07 f o r the c l e a r c u t and c o n t r o l treatments, but i s 1.73 f o r Block A - slashburned and 1.50 f o r Block B - slashburned e x p e r i -mental u n i t s . This increases!;the confidence i n the hypothesis that slashburning has i t s greatest reduction e f f e c t i n a e r a t i o n p o r o s i t y i n the immediate s o i l s u r f a c e . Simple regression equations were also developed r e l a t i n g the a e r a t i o n p o r o s i t y of the 0 - 3 and 4 - 7 inch s o i l l a y e r s (those most l i k e l y a l t e r e d by treatment) to the third-hour i n f i l t r a t i o n r a t e (Table 15). I t i s i n t e r e s t i n g to note that these reg r e s s i o n equa-t i o n s account f o r the same order of magnitude of the sum of squares of Y3 as the comparable equations d i d f o r Y1. In the two s o i l s stud-i e d the th i r d - h o u r , more s t a b l e , i n f i l t r a t i o n rate i s h i g h l y i n f l u -enced by the aer a t i o n p o r o s i t y of the s o i l surface. In reference to Figure 12, the r e l a t i o n s h i p s explained f o r the regressions of Y1 on aeration p o r o s i t y are equally v a l i d f o r the regressions of Y3 on aer a t i o n p o r o s i t y . The r a t i o s of aeration por-o s i t y ( 0 - 3 inch l a y e r ) to third-hour i n f i l t r a t i o n f o r the c l e a r c u t -80-and c o n t r o l u n i t s are s i m i l a r and average 1.67 whereas the same r a t i o f o r the slashburned areas are 3.25 and 1.86 f o r Blocks A and B r e s p e c t i v e l y . This f u r t h e r s u b s t a n t i a t e s the hypothesis that slashburning reduces the a e r a t i o n p o r o s i t y of a surface l a y e r too t h i n to be detected i n the approach employed. Table 15. Simple regr e s s i o n equations r e l a t i n g third-hour i n f i l t r a t i o n (Y3) to the aer a t i o n p o r o s i t i e s of the 0 - 3 , and 4 - 7 inch mineral s o i l l a y e r s . A. Independent Var i a b l e = X7 (aer a t i o n p o r o s i t y , 0 - 3 inch l a y e r ) Regression c o e f f i c i e n t = 56.307 Constant term =0.14 n =90 Standard e r r o r of estimate = - 6.01 i n . / h r . C o r r e l a t i o n c o e f f i c i e n t = 0.464 C o e f f i c i e n t of determination = 21.55% B. Independent Var i a b l e = l o g X8 (ae r a t i o n p o r o s i t y , 4 - 7 inch l a y e r ) Regression c o e f f i c i e n t = 8.063 Constant term = 27.32 n = 90 Standard e r r o r of estimate = - 6.18 i n . / h r . C o r r e l a t i o n c o e f f i c i e n t = 0.419 C o e f f i c i e n t of vdetermination =17.55% The pre d i c t e d values of the ae r a t i o n p o r o s i t y of the sur-face h a l f inch of s o i l are 0.17 cc./cc. f o r Block A - slashburned. These values d i f f e r from those pr e d i c t e d from the f i r s t - h o u r i n f i l --81-t r a t i o n - a e r a t i o n p o r o s i t y ( 0 - 3 inch l a y e r ) r e l a t i o n by only 0.03 and 0.02 cc./cc. r e s p e c t i v e l y . These are considered p r e d i c t i o n e r r o r s of a n e g l i g i b l e magnitude. [ I t i s somewhat unfortunate that the aeration p o r o s i t i e s were not determined f o r the surface h a l f inch of s o i l , although the e s t i m a t i o n of these values f o r the slashburned treatments are thought to be reasonably v a l i d . • The simple regression equations r e l a t i n g i n f i l t r a t i o n to the aeration p o r o s i t i e s of the 0 - 3 and 4 - 7 inch s o i l l a y e r s are s t a t i s t i c a l l y sound. The f a c t that both f i r s t and third-hour i n f i l t r a t i o n are more hig h l y c o r r e l a t e d to the aeration p o r o s i t y of the surface l a y e r r a t h e r than the subsurface l a y e r s t r e s s e s the hydrologic s i g n i f i c a n c e of treatments a f f e c t i n g surface a e r a t i o n p o r o s i t y . Thus, i t may be concluded that while c l e a r c u t t i n g has no e f f e c t , slashburning s i g n i f i c a n t l y reduces the aeration por-o s i t y of the immediate surface l a y e r s of the a c i d brown wooded and degraded a c i d brown wooded s o i l s s t u d i e d . B. Other s o i l v a r i a b l e s In order to appraise the i n f l u e n c e of treatments on i n f i l -t r a t i o n , m u l t i p l e regression equations were used to r e l a t e other s o i l v a r i a b l e s to the a e r a t i o n p o r o s i t y of the 0 - 3 and 4 - 7 inch s o i l l a y e r . Thus, the e f f e c t of c e r t a i n other s o i l v a r i a b l e s on i n -f i l t r a t i o n i s assumed to be i n d i r e c t through t h e i r i n f l u e n c e on a e r a t i o n p o r o s i t y . This assumption i s based on the underlying mech-anisms of the i n f i l t r a t i o n process. The a e r a t i o n p o r o s i t y of the 0 - 3 inch l a y e r ( l o g X7) has -82-been shown to be c o r r e l a t e d to f i r s t - h o u r i n f i l t r a t i o n . The r e l a -t i o n s h i p of l o g X7 to other s o i l v a r i a b l e s i s described i n Table 16. Although the high standard e r r o r of estimate i n h i b i t s the use of the equation f o r p r e d i c t i o n purposes, i t s s i g n i f i c a n c e at the 0.01 l e v e l of p r o b a b i l i t y permits i t s use i n the examination of trends of s o i l p h y s i c a l p r o p e r t y . e f f e c t s on aer a t i o n p o r o s i t y . Table 16. M u l t i p l e regression equation r e l a t i n g c e r t a i n s o i l v a r i a b l e s to the logarithm of the aera-t i o n p o r o s i t y of the 0 - 3 inch s o i l l a y e r . Independent V a r i a b l e Regression C o e f f i c i e n t Standard Deviation Variance ' Ratio X1 (Bulk d e n s i t y , 0-3 inch) -6.665 2.49 7.149 X13 ( t o t a l p o r o s i t y , 0-3 inch) -16.742 6.26 7.142 X53 (% O.M. < 2 mm. 0-3 inch) -0.D17 0.01 2.719 X61 (% l i t t e r cover) -0.001 0.01 1.296 X63 (depth of fermented) 0.003 0.01 1.024 X64 (depth of humus) -0.018 0.01 2.452 X65 (macro-vegetation) -0.001 0.01 2.017 Constant term = 15.83 n = 90 Standard e r r o r of estimate = - 0.04 cc./cc. M u l t i p l e c o r r e l a t i o n c o e f f i c i e n t = 0.451 M u l t i p l e c o e f f i c i e n t of determination = 20.31% Third-hour i n f i l t r a t i o n has been shown to be r e l a t e d to the aera t i o n p o r o s i t y of the 0 - 3 inch l a y e r (X7) which, i n tu r n , i s inf l u e n c e d by other s a i l v a r i a b l e s (Table 17). As f o r the equation -83-described i n Table 16, the p r e d i c t i o n value of t h i s equation i s re-duced by the high standard e r r o r of estimate, but i t s s i g n i f i c a n c e permits the ev a l u a t i o n of trends. ' Table 17. M u l t i p l e regression equation r e l a t i n g c e r t a i n s o i l v a r i a b l e s to the aer a t i o n p o r o s i t y of the 0 - 3 inch s o i l l a y e r . Independent Va r i a b l e „ e e . . . n . K C o e f f i c i e n t Deviation Regression Standard Variance Ratio X49 (% O.M. >2 mm. 0 - 3 inch) 0.004 0.001 9.792 X63 (depth fermented l a y e r ) 0.001 0.001 2.193 X64 (depth of humus) -0.005 0.002 3.914 X65 (macro-vegetation) -0.001 0.001 3.023 Constant term = 0.28 n = 90 Standard e r r o r of estimate = - 0.05 cc./cc. M u l t i p l e c o r r e l a t i o n c o e f f i c i e n t = 0.467 M u l t i p l e c o e f f i c i e n t of determination = 21.78% Both f i r s t and third-hour i n f i l t r a t i o n were r e l a t e d to the aer a t i o n p o r o s i t y of the 4 - 7 inch s o i l l a y e r . The m u l t i p l e r e -gression equation r e l a t i n g the logarithm of aeration p o r o s i t y ( l o g X7) to c e r t a i n p h y s i c a l s o i l p r o p e r t i e s i s described i n Table 18. Since the l i k e l i h o o d that any of the p h y s i c a l s o i l p r o p e r t i e s were s i g n i f i c a n t l y i n f l u e n c e d by any of the treatments studies i s very low, t h i s equation i s included f o r completeness rather than f o r the eva l u a t i o n of trends. -84-Table 18. M u l t i p l e regression equation r e l a t i n g c e r t a i n s o i l v a r i a b l e s to the logarithm of the aera-t i o n p o r o s i t y of the 4 - 7 inch l a y e r . Independent Variable X2D (% > 2 mm. mineral 4-7 inch) X38 (% c l a y , 4-7 inch) X54 (% O.M. <• 2 mm. 4-7 inch) X 5 8 . ( t o t a l % D.M. 4-7 inch) Regression Standard Variance C o e f f i c i e n t .Deviation Ratio 0.006 0.003 3.778 -0.016 0.016 1.011 -0.042 0.014 8.555 0.045 0.013 11.230 Constant term = -1.4 n = 90 Standard e r r o r of estimate = - 0.07 c c . / c c * M u l t i p l e c o r r e l a t i o n c o e f f i c i e n t = 0.400 M u l t i p l e c o e f f i c i e n t of determination = 15.97% * c a l c u l a t e d from formula 5E = I (YocW-Yp^icj-td) 2-E |^ degrees of freedom The independent v a r i a b l e s included i n the m u l t i p l e regres-si o n equations r e l a t i n g i n f i l t r a t i o n to the aeration p o r o s i t y of the 0 - 3 inch l a y e r require f u r t h e r e v a l u a t i o n . Some or a l l of these v a r i a b l e s were p o t e n t i a l l y a l t e r e d through the e f f e c t s of slashburn-ing and, to a l e s s e r degree, c l e a r c u t t i n g . The eval u a t i o n of these e f f e c t s i s described i n the f o l l o w i n g s e c t i o n s . a. Bulk density The e f f e c t of treatment on the bulk density of the 0 - 3 inch mineral s o i l i s not r e a d i l y d i s c e r n i b l e (Figure 13) and any -85-g e n e r a l i z a t i o n s are c o n j e c t u r a l . The reasonable agreement between X1 and X7 i n d i c a t e s the p o s s i b i l i t y that the bulk density was a l t e r -ed only i n the immediate s o i l s urface. As was the case f o r a e r a t i o n p o r o s i t y , any increase i n bulk density i n the surface h a l f inch of s o i l caused by c l e a r c u t t i n g and slashburning would not be detected using the three inch core. I t could be concluded i n the case of Block B - slashburned that the increase i n bulk density was caused by slashburning, but the data are not s u f f i c i e n t l y c o n c l u s i v e . 1.25-u 1.00-e CP 43 0.75- 1 01 S 0.50-aO.25 E Min- M«»«~t Max. •I 1 I I I p 1 1 1 1 i 1 1 I I 1 X7 X T X I s l a s h - c l e a r c o n t r o l burned cut BLOCK A. i 1 1 • 1 X> XT XI X7 XI X7 ! s l a s h - c l e a r c o n t r o l burned cut BLOCK B Figure 13. Bulk density and aer a t i o n p o r o s i t y f o r the 0 - 3 inch mineral s o i l l a y e r by experimental u n i t . In Block A, a decrease i n bulk density y i e l d s a decrease i n aera t i o n p o r o s i t y whereas i n Block B, an increase i n one y i e l d s a decrease i n the other. Thus, i t must be concluded e i t h e r that i f 86-slashburning and c l e a r c u t t i n g i n f l u e n c e bulk density, i t i s not of s u f f i c i e n t magnitude to be gen e r a l l y detectable by the core sampling methods employed or undetected d i f f e r e n c e s i n the ae r a t i o n p o r o s i t y - bulk density a s s o c i a t i o n e x i s t between the two s o i l s s t u d i e d . b. T o t a l p o r o s i t y The negative e f f e c t of t o t a l p o r o s i t y on ae r a t i o n p o r o s i t y i s l i k e l y an a s s o c i a t i v e one rather than a causal one. Figure 14 i n d i c a t e s the t o t a l p o r o s i t i e s of both slashburned u n i t s to be lower than the t o t a l p o r o s i t i e s of the other two u n i t s on the same Block. This d i f f e r e n c e i s not s i g n i f i c a n t , however, and i t s explanation on the bas i s of in-washings of ash i s purely c o n j e c t u r a l . 0.1S-, slash- Clear corthrol slash- clear . Confrol burneol cot burned Cot BLOCK A BLOCK B Figure 14. T o t a l and aera t i o n p o r o s i t i e s of the 0 - 3 in c h l a y e r of mineral s o i l by experimental u n i t . -87-c. Incorporated organic matter The e f f e c t s of organic matter on the aeration p o r o s i t y of the surface s o i l l a y e r most l i k e l y a l t e r e d by c l e a r c u t t i n g and slashburning are vague (Figure 15). Experimental u n i t trends d i f f e r widely between bloc k s , making g e n e r a l i z a t i o n s concerning the hydro-l o g i c a l r o l e of incorporated organic matter, d i f f i c u l t . 3°n 25 1 8 E /5-C iO-m W v n « a r < m a x . I 1 IJ I l 1 i l l 11 11  1 I l l 11 11 i *53 X57 X53 X57 **9 XS3 X57 slashburned cleorcufc Control BLOCK A X49 X53 V57 *53 X57 *49 *53 *S7 Sla-shburned. clearcut Con+rol ft-ock S Figure 15. Percent s o i l content of > 2 mm. (X49), < 2 mm. (X53) and t o t a l organic matter (X57) of thB 0 - 3 inch l a y e r by experimental u n i t . According to the data, a e r a t i o n p o r o s i t y v a r i e s d i r e c t l y with the content of coarse organic matter, but t h i s may not be the a c t u a l case. The m a t e r i a l most fr e q u e n t l y included i n the s o i l sam-ple acquired f o r organic matter content determinations was that -88-which could be e a s i l y removed from a small s o i l p i t . Consequently, dead, f r a c t u r e d root m a t e r i a l was favored over sound, l i v e r o o t s . Since c l e a r c u t t i n g and slashburning destroy a c e r t a i n amount of veg-e t a t i o n , a s u c c e s s i v e l y higher volume of dead root m a t e r i a l per u n i t volume of s o i l i s i n c u r r e d on c l e a r c u t and slashburned areas than on undisturbed c o n t r o l areas. In r e a l i t y , coarse organic matter e s p e c i a l l y when p l a t e - l i k e , tends to reduce aeration p o r o s i t y by reducing the c r o s s - s e c t i o n a l area a v a i l a b l e f o r water flow. In view of t h i s , and the p o t e n t i a l b ias i n c u r r e d i n sampling, any g e n e r a l i z a t i o n s regarding the i n f l u -ence of treatment on coarse organic matter content would lack v a l i d -i t y . The d i f f e r e n c e s between the average f i n e organic contents of the s o i l s on each treatment w i t h i n blocks are not s i g n i f i c a n t , but are perhaps i n d i c a t i v e of trends. C l e a r c u t t i n g has no d e f i n i t i v e e f f e c t on f i n e organic matter content, but slashburning would seem to have a s l i g h t lowering e f f e c t . The s i g n i f i c a n c e of t h i s lowering e f f e c t a r i s e s due to the lack of r e s o l u t i o n of the three inch sample c o l l e c t e d f o r the organic content determinations. , A s s i g n i f i c a n t lowering i n the f i n e organic content of the surface h a l f inch of s o i l i s masked i n a three inch sample. The lowering of f i n e organic'mat-t e r content by slashburning was p r i m a r i l y due to combustion and was l i k e l y maintained at low l e v e l s due to reduced decomposer organisms on the slashburned areas. The t o t a l organic matter content, although shown to i n f l u -ence ae r a t i o n p o r o s i t y , cannot be appraised i n terms of treatment -89-e f f e c t s . Since i t was derived from coarse and f i n e organic matter contents, t o t a l organic matter content includes the sampling bias and lack of r e s o l u t i o n encountered i n the determination of the sep-arate organic f r a c t i o n s . Organic matter, because of i t s unique p r o p e r t i e s , may exert an i n f l u e n c e on i n f i l t r a t i o n r a te d i r e c t l y by having a d i f f e r e n t a f f i n i t y f o r water than mineral s o i l p a r t i c l e s as w e l l as i n d i r e c t l y through i t s i n f l u e n c e on a e r a t i o n p o r o s i t y . M u l t i p l e regression equations developed to i n v e s t i g a t e t h i s p o s s i b i l i t y are described i n Table .19. The equation i n v o l v i n g f i r s t - h o u r i n f i l t r a t i o n , although not s i g n i f i c a n t , i n d i c a t e s that i n c r e a s i n g l e v e l s of f i n e organic matter contents may increase i n f i l t r a t i o n . I f the r e s o l u t i o n of the sampling technique had been b e t t e r , t h i s r e l a t i o n s h i p may have been s i g n i f i c a n t . The equation i n v o l v i n g third-hour i n f i l t r a t i o n , s i g n i f i c a n t at the 0.01 l e v e l of p r o b a b i l i t y , i n d i c a t e s the p o s s i b i l i t y that or-ganic matter aids i n the maintenance of high i n f i l t r a t i o n r a t e s . Since the organic matter content of the 4 - 7 inch l a y e r was not l i k e l y i n f l u e n c e d by treatments, any f u r t h e r duscussion or r e s u l t a n t i m p l i c a t i o n s i s meaningless due to lack of s u b s t a n t i a t i v e data. By way of summary, the e f f e c t s of organic matter on i n f i l -t r a t i o n are both d i r e c t and i n d i r e c t . Reductions i n coarse, f i n e and t o t a l s o i l organic matter, y i e l d concomitant reductions i n both f i r s t and third-hour i n f i l t r a t i o n . Generally, slashburning tends to reduce the organic matter content of the surface s o i l although the magnitude of the reduction reported i n t h i s study i s conservative due to the -90-Table 19. M u l t i p l e regression equations r e l a t i n g s o i l organic matter content to f i r s t and t h i r d hour i n f i l t r a t i o n . ' A. Dependent Va r i a b l e = f i r s t - h o u r i n f i l t r a t i o n r a te (Y1) _ . , ... , ., Regression Standard Variance Independent Variable C o e f f i c i e n t Deviation Ratio X53 (% O.M. < 2 mm. 0 - 3 inch) 0.209 0.181 1.330 Constant term = 20.85 n = 90 Standard e r r o r of estimate = - 7.72 i n . / h r . Simple c o r r e l a t i o n c o e f f i c i e n t = 0.122 Simple c o e f f i c i e n t of determination = 1.49% B. Dependent Va r i a b l e = third-hour i n f i l t r a t i o n r a t e (Y3) , . . . ,, . ., Regression Standard Variance Independent V a r i a b l e r „ L p . _. D_. - . . . n „ r G o e f f i c i e n t Deviation Ratio X50 (% O.M. > 2 mm. 4 - 7 inch) 0.962 0.304 10.049 X54 (% O.M. < 2 mm. 4 - 7 inch) 0.869 0.410 4.485 X58 (% t o t a l O.M. 4 - 7 inch) -1.593 0.609 6.852 Constant term = 15.67 n = 90 Standard e r r o r of estimate = - 6.48 i n . / h r . M u l t i p l e c o r r e l a t i o n c o e f f i c i e n t = 0.329 M u l t i p l e c o e f f i c i e n t of determination = 10.82% -91-poor r e s o l u t i o n of the determination method employed. The d i r e c t and i n d i r e c t (through a e r a t i o n p o r o s i t y ) e f f e c t s of s o i l are of s u f f i c i e n t s-ignificance as to make i n f i l t r a t i o n s e n s i t i v e to d i f f e r -ences i n s o i l organic matter content. d. Organic matter L i t t e r cover has been shown to have a negative e f f e c t on the aer a t i o n p o r o s i t y of the 0 - 3 inch l a y e r . This a r i s e s due to the f a c t t h a t , g e n e r a l l y , areas of exposed mineral s o i l are evenly cover-ed by a f r e s h l a y e r of l i t t e r while the l i t t e r f a l l i n g on undisturbed areas i s e i t h e r decomposed or dfcscontinuously d i s t r i b u t e d over the fermented l a y e r . An a l t e r n a t i v e explanation would be that i n s p i t e of the regre s s i o n a s s o c i a t i o n , the data of Table 20 would seem to sub s t a n t i a t e the hypothesis advanced e a r l i e r , that slashburning a f f e c t s only the immediate s o i l surface. The lower l e v e l s Df l i t t e r caver on the slashburned u n i t s i n d i c a t e s the p o s s i b i l i t y that l i t t e r was consumed by f i r e and subsequent inwashing of ash reduced surface s a i l a e r a t i o n p o r o s i t y . These causal explanations are at l e a s t as comparable as the a s s o c i a t i v e r e l a t i o n s h i p described by the m u l t i p l e r e g r e s s i o n equation. Although i n f l u e n c i n g i n f i l t r a t i o n , l i t t e r cover cannot be evaluated on i t s awn, but must be considered i n conjunction with other s o i l v a r i a b l e s and the post treatment h i s t o r y . e. Depth of fermented and humus l a y e r s Aeration p o r o s i t y of the 0 - 3 inch mineral s a i l l a y e r -92-v a r i e s d i r e c t l y with the depth of the fermented l a y e r and i n v e r s e l y with the depth of the humus l a y e r . The values of these two organic matter v a r i a b l e s (X63iand X64) are presented i n Figure 16. Because the mean values f o l l o w vague trends, g e n e r a l i z a t i o n s are d i f f i c u l t and some e x t r a p o l a t i o n of the given data i s re q u i r e d . Table 20. Mean values of percent l i t t e r cover f o r each experimental u n i t . Treatment Block A Block B Slashburned 53.67* 54.33* Clearcut 97.93 61.67 Control 92.27 75.00 * s i g n i f i c a n t l y d i f f e r e n t at the 0.05 l e v e l of p r o b a b i l i t y The r e l a t i o n s h i p described by the m u l t i p l e regression be-tween the depths of the fermented and humus l a y e r s and aeration p o r o s i t y i s more a s s o c i a t i v e than c a u s a l . This i s due to the lack of r e s o l u t i o n of the method of aeration p o r o s i t y determination and c e r t a i n i n c o n g r u i t i e s of thB data d e s c r i b i n g the unincorporated l a y e r s . The mean values i n d i c a t e d i n Figure 16 obscure some import-ant i n f o r m a t i o n . The two slashburned areas are the only e x p e r i -mental u n i t s i n which some of the study s i t e s were not covered by unincorporated organic matter. Thus, on these s i t e s , the mineral s o i l was exposed to the e f f e c t s of raindrop compaction and inwashing of f i n e m a t e r i a l s , both such e f f e c t s a c t i n g to reduce the aer a t i o n -93-p o r o s i t y of the immediate s o i l surface. This reduction, although s i g n i f i c a n t l y reducing the i n f i l t r a t i o n c a p a c i t y , would not have been detected with the method used i n aer a t i o n p o r o s i t y determin-a t i o n . Xb3 Xb4 xb3 xb4 Xfc3 Xfc4 S l a sh - clea<- Con+rot txircicA cot B L O C K : .AS xb3 xb-* x*>4 borntci cut SLOCK; S X4.3 XfaA con+rol Figure 16. Means and ranges of fermented and humus l a y e r depths by experimental u n i t . I t i s very p o s s i b l e that the r e l a t i o n s h i p between aeration p o r o s i t y and depth of fermented and humua l a y e r s i s of a threshold nature whereby reduction i n ae r a t i o n p o r o s i t y only accrue with zero depth of the s u r f i c i a l organic l a y e r s . The l a r g e mean values of fermented l a y e r depths f o r the two c l e a r c u t areas r e s u l t from a very deep fermented l a y e r (60 and 36 -94-inches) on one study s i t e on each of the c l e a r c u t areas. The occur-ence of these deep l a y e r s was by chance and not a r e s u l t of t r e a t -ment e f f e c t s since the l a y e r s mere r o t t e n and buried l o g s . This s i t u a t i o n occurred on a l l of the other experimental u n i t s and was not sampled simply because of the random number a p p r o p r i a t i o n of study s i t e s . On none of the study s i t e s on the c l e a r c u t and c o n t r o l u n i t s was the mineral s o i l exposed. The ranges of the fermented and humus layer-depths are i n -d i c a t i v e of ecosystem disturbance. The comparatively low ranges of the two c o n t r o l u n i t s denote a s t a b l e ecosystem where the a d d i t i o n of f r e s h organic m a t e r i a l i s nearly equivalent to decomposition l o s s . On the c l e a r c u t and slashburned areas, the disturbance of the f o r e s t f l o o r has r e s u l t e d i n wide ranges of depths. This disturbance of the f o r e s t f l o o r took the form of various combinations of large a d d i t i o n s of organic m a t e r i a l from the logging operation, scouring by yarded logs and comsumption by f i r e . This disturbance i s f u r t h e r aggravated through t r e a t m e n t - i n f l i c t e d a l t e r a t i o n s i n population l e v e l s of de-composer organisms and rate of organic matter a d d i t i o n s by p o s t - t r e a t -ment vegetation (Appendix I I I ) . f. Macro-vegetation cover Macro-vegetation cover ( a l l vegetation excluding moss cover) has been shown to have a negative e f f e c t on aeration p o r o s i t y of the 0 - 3 inch mineral s o i l l a y e r and, as such, complicates a d e c i s i v e explanation. The data i n Figure 17 does not i n d i c a t e the type of veg-e t a t i o n (deciduous or coniferous, herb, :shrub or t r e e ) , or the depth -95-and density of the r o o t s . Macro-vegetation would l i k e l y exert i t s greatest e f f e c t on ae r a t i o n p o r o s i t y on those areas where the min-e r a l s o i l was exposed by p r o t e c t i n g the s o i l from raindrop impact. This e f f e c t would r e s u l t from canopy i n t e r c e p t i o n of r a i n f a l l and decomposition of a p r o t e c t i v e l a y e r of l i t t e r on the exposed mineral s o i l . SI<tsW- clear con+rol Slash- ctaa<- control bor-rxd e a t b*rr>.d c u t BLOCK A SLOCK 6 Figure 17. Meen values and ranges of macro-vegeta-t i o n cover (X65) by experimental u n i t . Contrary to what might be expected, on a study s i t e b a s i s , mScro-vegetation density was frequently higher on slashburned areas -96-th an on c l e a r c u t or c o n t r o l areas. This i s based on stems / square foot whereas the data i n Figure 17 i s based on crown cover. Thus, because fireweed was the reason f o r high macro-vegetation d e n s i t i e s i an slashburned areas and i s a pioneer species, macro-vegetation may be associated with disturbance h i s t o r y and r e s u l t a n t changes i n i n -f i l t r a t i o n . Macro-vegetation cover exerted a major i n f l u e n c e on the study s i t e s e l e c t i o n such that the vegetation had to be e a s i l y r e -movable f o r e f f i c i e n t operation of the i n f i l t r o m e t e r . Study areas i n close proximity to vegetation bearing large roots were also avoid-ed because the r i n g s could not be driven through the roots without causing excessive s o i l disturbance. In s p i t e of the shortcomings of the v a r i a b l e d e s c r i b i n g macro-vegetation, i t s i n c l u s i o n i s j u s t i f i e d since the removal of a l l or part of the vegetation from an area c o n s t i t u t e s a major a l t e r -a t i o n to the ecosystem. Included i n t h i s a l t e r a t i o n are heat budget, eva p o t r a n s p i r a t i o n and b i o l o g i c a l changes which are q u a n t i t a t i v e l y accountable only with great d i f f i c u l t y . 3. I n f i l t r a t i o n p r e d i c t i o n equations, Blocks A and B On attempting to account f o r d i f f e r e n c e s i n i n f i l t r a t i o n caused by treatments, i t was necessary to subject the e s t a b l i s h e d r e l a t i o n s h i p s to a c e r t a i n amount of c o n j e c t u r a l e x t r a p o l a t i o n . A l -though the dangers of t h i s are r e a l i z e d , i t must be emphasized that the e x t r a p o l a t i o n d i d not i n v o l v e guesswork. However, to maintain the u t i l i t y of the c o l l e c t e d data, m u l t i p l e regression equations - 9 7 -were developed to enable p r e d i c t i o n of i n f i l t r a t i o n under v a r i a b l e c o n d i t i o n s of a c i d brown wooded and degraded a c i d brown wooded s o i l s . Although not f u l l y defined, the e f f e c t s of treatments are i n c o r p o r - ; ated i n t o the regression equations. Two types of p r e d i c t i o n equation were developed: one based on the p r i n c i p l e s of the i n f i l t r a t i o n process and the other based on using those v a r i a b l e s which ^i'eld an equation with the highest m u l t i -ple c o e f f i c i e n t of determination and lowest standard e r r o r of e s t i -mate p o s s i b l e . In the f i r s t type, i n t e r a c t i o n s between independent variables? have been minimized whereas i n t e r a c t i o n s were ignored i n the second type. The p r e d i c t i o n equations f o r f i r s t and third-hour i n f i l t r a -t i o n r a t e s , developed with minimum i n t e r a c t i o n and based on the i n -f i l t r a t i o n process are d e t a i l e d i n Table 21. Unfortunately,, n e i t h e r equation gives an estimate of i n f i l t r a t i o n with an e r r o r much smaller than the d i f f e r e n c e s between the measured i n f i l t r a t i o n r a t e s of each of the treatments. I t i s s i g n i f i c a n t , however, that i n conjunction with i n f i l t r a t i o n measurement with a double-ring i n f i l t r o m e t e r , the variaBl'e.Tdescribing the p o t e n t i a l of l a t e r a l flow have a great i n -fluence on both f i r s t and third-hour i n f i l t r a t i o n . This i s a s s o c i a -ted with the importance of the l a t e r a l component of s o i l water move-ment i n f o r e s t e d s o i l s i n upland areas. I t i s because of t h i s l a t e r -a l , subsurface flow which i n v a l i d a t e s the term " f i e l d c a p a c i t y " i n s l o p i n g f o r e s t e d s o i l s , a s i t u a t i o n emphasized by the work of Cole (1966) i n the U.S. P a c i f i c Northwest Region. -98-Table 21. Functional p r e d i c t i o n equations of f i r s t (Y1) and third-hour (Y3) i n f i l t r a t i o n r a t e s . A . Dependent Var i a b l e = f i r s t - h o u r i n f i l t r a t i o n r a te (Y1) _ . . . . . • .m Regression Standard Variance Independent Va r i a b l e C o e f f i c i e n t Deviation Ratio lo g X7 ( a e r a t i o n p o r o s i t y 0 - 3") 6.999 4.149 2.845 X67 ( p o t e n t i a l l a t e r a l flow layer)" 25.738 19.952 1.664 X68 ( l i m i t i n g l a y e r ) 37.169 16.087 5.339 X43 ( g r a v i m e t r i c water content n > r j 2 7 0 > Q 0 8 1 f J i 2 6 0 0 - 3 inch l a y e r ) Constant term = 14.28 n = 90 Standard e r r o r of estimate = - 6.43 i n . / h r . M u l t i p l e c o r r e l a t i o n c o e f f i c i e n t = 0.583 M u l t i p l e c o e f f i c i e n t of determination = 34.04% B. Dependent Var i a b l e = third-hour i n f i l t r a t i o n r a t e (Y3) Independent Variable Regression C o e f f i c i e n t Standard Deviation Variance Ratio X67 ( p o t e n t i a l l a t e r a l flow l a y e r ) 44.032 13.306 10.951 X68 ( l i m i t i n g l a y e r ) 42.615 12.757 11.159 X18 ) avg. aeration p o r o s i t y \ -0.001 62.299 3.405 (X6)(X48) l a v g . v o l . water content ) Constant term = -3.23 n = 90 Standard e r r o r of estimate = - 5.37 i n . / h r . M u l t i p l e c o r r e l a t i o n c o e f f i c i e n t = 0.622 M u l t i p l e c o e f f i c i e n t of determination = 38.73% -99-One other consequence of the attempt to p r e d i c t i n f i l t r a -t i o n from the f i e l d data i s the p o s s i b i l i t y that the wide v a r i a t i o n i n f i e l d c o n d i t i o n s does not render f u n c t i o n a l mathematical models of i n f i l t r a t i o n an e f f i c i e n t a n a l y t i c a l technique. Most of the f u n c t i o n a l models of i n f i l t r a t i o n described i n the l i t e r a t u r e mere developed t h e o r e t i c a l l y or from homogeneous co n d i t i o n s developed i n the l a b o r a t o r y . Hopefully, some f u n c t i o n a l way of accounting f o r n a t u r a l v a r i a t i o n s i n ecosystem components w i l l be found, but u n t i l such time s t a t i s t i c a l techniques w i l l remain as the best a l t e r n a t i v e . By i g n o r i n g i n t e r a c t i o n s between independent v a r i a b l e s and f u n c t i o n a l r e l a t i o n s h i p s , the development of m u l t i p l e regression equations f o r p o s s i b l e i n f i l t r a t i o n r a te p r e d i c t i o n was attempted. Although a much greater proportion of the sum of squares of both Y1 and Y3 was accounted f o r by the equations than was the case f o r those equations described i n Table 21, the s l i g h t improvement i n the stan-dard e r r o r s of estimates, the great number of independent v a r i a b l e s (3G) and the probable high l e v e l s of unexplainable i n t e r a c t i o n s be* tween independent v a r i a b l e s render these equations i m p r a c t i c a l and, as such, have not been presented here. In f a c t , these cumbersome equations are very good examples of the ways i n which m u l t i p l e r e -gression i s misused, as a research t o o l , since many more r e l a t i o n -ships are obscured than are c l a r i f i e d . -100-I I . EFFECTS OF SKIDROADS ON INFILTRATION The e f f e c t of skidroad c o n s t r u c t i o n and use,operating through a l t e r e d p h y s i c a l s o i l p r o p e r t i e s to i n f l u e n c e i n f i l t r a t i o n c a pacity are discussed p r i m a r i l y with reference to Block C. These r e s u l t s are compared and contrasted to the r e s u l t s of Lewis (1968) . who c a r r i e d out a s i m i l a r study on Blocks A and B. Two basis d i f -ferences e x i s t between the two skidroad s t u d i e s . On Blocks A and B, the skidroads were three years o l d at the time of the i n v e s t i g a -t i o n and the skidroad treatment was compared to the c o n t r o l . On Block C, the skidroad was ten years o l d and was compared to the c l e a r c u t treatment. Block C consisted of three experimental b l o c k s : Block 1 on concave r e l i e f , Block 2 on s l o p i n g r e l i e f , and Block 3 on convex r e -l i e f . One skidroad and one c l e a r c u t treatment w i t h i n each block were appraised from f i v e study s i t e s randomly l o c a t e d on each experimental u n i t . 1. O v e r a l l e f f e c t s A d i r e c t comparison of treatment means l a c k s v a l i d i t y due to the v a r i a t i o n i n c e r t a i n s o i l p r o p e r t i e s , a f f e c t i n g i n f i l t r a t i o n , not a t t r i b u t a b l e to treatment e f f e c t s . To counteract t h i s , the mean values were compared by covariance techniques. The m u l t i p l e r e g r e s s i o n equations developed f o r the covariance adjustment of f i r s t - h o u r i n f i l t r a t i o n \ ( Y 1 ) treatment means i s described i n Table 22. This t a b l e d i f f e r s from that used by Lewis (1968) since i t i n --101-cludes no s o i l v a r i a b l e s which describe the surface 12 inches of the s o i l . This was based on the assumption that a 07 cat, weighing 41,200 pounds and e x e r t i n g 10.8 pounds pressure per square inch of s o i l s urface, would a f f e c t considerable changes i n the surface s o i l during the skidding operation. Table 22. C h a r a c t e r i s t i c s of f i r s t - h o u r i n f i l t r a t i o n (Y1) m u l t i p l e regression equation used f o r c o v a r i -ance a n a l y s i s . T ,,„,,,„ Regression Standard l/ariance Independent v a r i a b l e „ „„. , ^ . . . „ . . ^ C o e f f i c i e n t Deviation Ratio X4 (bulk d e n s i t y , 12-18 i n . ) -2.190 8.223 0.071 X9 (ae r a t i o n p o r o s i t y , 12-18 i n . ) -4.544 12.774 0.127 X19 (% > 2 mm. mineral, 12-18 i n . ) 12.812 37.633 0.116 X24 (% sand, 12-18 i n . ) 12.768 37.631 0.115 X29 (% s i l i t plus c l a y , 12-18 i n . ) 13.022 37.618 0.12D X34 ( s o i l H2Q content, 12-18 i n . ) 0.118 0.155 0.578 X44 (% Q:.M. < 2 mm. 12-18 i n . ) -0.328 1.699 0.037 X49 (% t o t a l O.M. 12-18 i n . ) 12.810 37.600 0.116 Constant term = -1272.04 n = 30 Standard e r r o r of estimate = - 3.18 i n . / h r . M u l t i p l e c o r r e l a t i o n c o e f f i c i e n t = 0.691 M u l t i p l e c o e f f i c i e n t of determination = 47.72% The c o v a r i a n t s , although accounting f o r only a moderate f r a c t i o n of the Y1 sum of squares, vary s u f f i c i e n t l y between e x p e r i -mental u n i t s to j u s t i f y t h e i r use i n f i r s t - h o u r i n f i l t r a t i o n mean--102-adjustments (Table 23). I t i s extremely u n l i k e l y that treatment ex-erted major changes i n the cova r i a n t s although t h i s i s uncertain due to lack of knowledge p e r t a i n i n g to the c o n s t r u c t i o n of the skidroad. I t i s assumed, a l s o , that a f t e r one hour of i n f i l t r a t i o n , the wet-t i n g f r o n t had penetrated deeper than one foot i n t o the s o i l at each study s i t e . Table 23. Mean values of f i r s t - h o u r i n f i l t r a t i o n (Y1) covariance v a r i a b l e s by experimental u n i t . Block 1 Block 2 , Block 3 Skidroad Clearcut Skidroad Clearcut Skidroad Clearcut #, 1 X4 0.95 1.23 1.29 1.08 1.20 0.99 9 XS 0.17 0.18 0.23 0.29 0.24 0.33 X19 3 51.37 19.19 52.74 50.43 56.47 55.99 X24 3 17.59 29.36 33.40 26.04 27.31 22.88 X29 3 6.22 13.35 6.93 6.98 8.56 8.18 X34 3 33.17 25.98 26.73 20.11 25.14 19.22 X44 3 9.42 4.70 3.91 8.05 4.01 . 7.42 X49 3 24.80 8.10 6.91 16.59 7.66 12.95 1 grams per cubic centimeter 2 cubic centimeters per cubic 3 percent by weight The a n a l y s i s of covariance the f i r s t - h o u r i n f i l t r a t i o n r a t e i s roads than on the c l e a r c u t areas on centimeter of Y1 (Table 24) i n d i c a t e s that s i g n i f i c a n t l y lower on the s k i d -a l l three blocks. This i s i n -103-agreement with the f i n d i n g s of Lewis (1968) who found skidroads to have a s i g n i f i c a n t l y lower f i r s t - h o u r i n f i l t r a t i o n than c o n t r o l areas. E a r l i e r i n t h i s paper i t was shown that no s i g n i f i c a n t d i f f e r e n c e ex-i s t e d between the f i r s t - h o u r i n f i l t r a t i o n of c l e a r c u t and c o n t r o l areas oh Blocks A and B, thereby v a l i d a t i n g the use of c l e a r c u t as a comparison f o r skidroad e f f e c t s on i n f i l t r a t i o n on Block C. Table 24. Covariance a n a l y s i s of f i r s t - h o u r i n f i l t r a t i o n r ate (Y1). DBQX*BSS of Source of V a r i a t i o n _ H . Sum Square Mean Square F Value Freedom ^ Treatment 1 Block 2 Treatment X Block 2 Er r o r 16 814.560 20.814 19.840 165.05 814.560 10.407 9.920 10.316 78.96** 1.01 0.96 ** s i g n i f i c a n t at the 0.01 l e v e l of p r o b a b i l i t y Although determined to be not s i g n i f i c a n t l y d i f f e r e n t , i t i s i n t e r e s t i n g to speculate that the adjusted means of Y1 f o r the skidroad u n i t s (Table 25) may be i n d i c a t i v e of r e l i e f e f f e c t s . These e f f e c t s are such that f i r s t - h o u r i n f i l t r a t i o n r ate reduction i s great-er on concave r e l i e f than on s l o p i n g or convex r e l i e f . This hypothe-s i s w i l l be i n v e s t i g a t e d i n depth i n ensuing analyses of the mechan-ism of skidroad e f f e c t s on i n f i l t r a t i o n . -104-Table 25. Measured and adjusted means of f i r s t - h o u r i n f i l t r a t i o n (Y1) by experimental u n i t . _ Block 1 Block 2 Block 3 TrB3*tfnBnt» Measured Adjusted Measured Adjusted Measured Adjusted - inches per hour -Skidroad 6.97 3.93 7.03 7.98 8.27 8.77 Clearcut 21.29 20.91 20.71 21.88 20.07 20.87 The t h i r d - h o u r , more s t a b i l i z e d , i n f i l t r a t i o n r a te uas analyzed regarding i t s change by treatment i n the same may as f i r s t -hour i n f i l t r a t i o n (Table 26). This equation, nearly i d e n t i c a l to that f o r f i r s t - h o u r i n f i l t r a t i o n , accounts f o r a higher proportion of the sum of squares of Y3 and has a lower standard B r r o r of e s t i -mate. Since the independent v a r i a b l e s do not change over a period of s e v e r a l hours, the improved parameters of the equation are l i k e -l y a f u n c t i o n of increased wetting f r o n t penetration and thus great-er i n f l u e n c e of i n f i l t r a t i o n on the subsurface s o i l v a r i a b l e s . The a n a l y s i s of covariance of third-hour i n f i l t r a t i o n (Table 27) i s s i m i l a r to that f o r f i r s t - h o u r i n f i l t r a t i o n . Skidroads have a s i g n i f i c a n t l y d i f f e r e n t third-hour i n f i l t r a t i o n capacity than the c l e a r c u t areas on a l l b l a c k s . S t a t i s t i c a l l y , the skidroad i n f i l t r a t i o n r a t e s d i d not d i f -f e r between bloc k s , however, c e r t a i n trends, a l s o noted regarding f i r s t - h o u r i n f i l t r a t i o n , are detectable i n Table 28. The adjusted -105-Table 26. C h a r a c t e r i s t i c s of third-hour i n f i l t r a t i o n (Y3) m u l t i p l e regression equation used f o r covariance a n a l y s i s . Independent Variable X9 ( a e r a t i o n p o r o s i t y , 12-18 i n . ) X19 (% > 2 mm. mineral, 12-18 i n . ) X24 (% sand, 12-18 inch) X29 (% s i l t and c l a y , 12-18 i n . ) X34 ( s o i l H 20 content, 12-18 in.V) X39 (% D.M. > 2 mm. 12-18 i n . ) X44 (% O.M. < 2 mm. 12-18 i n . ) X49 (% t o t a l D.M. 12-18 i n . ) Regression Standard Variance C o e f f i c i e n t Deviation Ratio 7.864 10.562 0.554 23.354 31.789 0.540 23.214 31.795 0.533 23.587 31.794 0.550 0.053 0.126 0, 177 429.342 328.399 0.008 -28.917 328.409 0.008 52.507 334.512 0.025 Constant term = -2284.49 n = 30 Standard e r r o r of estimate = - 2.52 i n . / h r . M u l t i p l e c o r r e l a t i o n c o e f f i c i e n t = 0.723 M u l t i p l e c o e f f i c i e n t of determination = 52.29% Table 27. Covariance a n a l y s i s of third-hour i n f i l t r a t i o n r a te (Y3). Source of V a r i a t i o n Degrees of Freedom Sum Square Mean Square F Value Treatment 1 Block 2 Treatment X Block 2 Er r o r 16 936.47 24.856 0.869 205.95 936.47 12.428 0.434 0.129 72.75** 0.97 0.03 ** s i g n i f i c a n t at the 0.01 l e v e l of p r o b a b i l i t y -106-mean value of Y3 was lowest on the concave, highest on the convex, and intermediate Dn the s l o p i n g b l o c k s . This i s p a r t i c u l a t l y note-worthy because i t i s r e l a t e d to the p h y s i c a l c o n d i t i o n s of construc-t i o n and use of skidroads. Skidroad disturbance on convex t e r r a i n i s p r i m a r i l y due to r o l l i n g compaction, on s l o p i n g t e r r a i n a combin-a t i o n of r o l l i n g and scraping compaction, an on concave t e r r a i n r o l l -ing compaction of successive l a y e r s of accumulated d e b r i s . A more d e t a i l e d d i s c u s s i o n of these aspects i s not warranted i n t h i s t h e s i s and they are mentioned f o r purposes of p o s s i b l e research. Table 30. Measured and adjusted means of third-hour i n f i l t r a t i o n (Y3) by experimental u n i t . _ ' . Block 1- Block 2 Block 3 1 ppof r n p n T Measured Adjusted Measured Adjusted Measured Adjusted - inches per hour -Skidroad 4.27 3.32 3.11 3.67 5.82 5.73 Clearcut 18.54 17.90 18.36 19.21 20.43 20.71 In the study of skidroad e f f e c t s on i n f i l t r a t i o n on Blocks A and B, Lewis (1968) measured d i f f e r e n c e s i n i n f i l t r a t i o n between the blocks. He found skidroed i n f i l t r a t i o n r a t e s to average 5.18 i n . / h r . f o r the f i r s t - h o u r and 2.12 i n . / h r . f o r the third-hour on Black A, and 14.21 i n . / h r . f o r the f i r s t - h o u r and 10.41 i n . / h r . f o r the third-hour on Block B. The values given are unadjusted means and t h e i r d i f f e r e n c e s between blocks was accounted f o r according to use i n t e n s i t y . This explanation i s v a l i d i n that the skidroads on -107-both blocks uiere constructed and used i n the same summer. The Block C skidroad can not be compared to those on the other blocks on the basis of use i n t e n s i t y . Although i t s u f f e r e d heavy use, i t was con-s t r u c t e d and u t i l i z e d seven years p r i o r to those on the other blocks. 2. Mechanism of treatment e f f e c t s on i n f i l t r a t i o n The covariance a n a l y s i s of f i r s t and third-hour i n f i l t r a t i o n although i n d i c a t i n g the impact of skidroad c o n s t r u c t i o n and use, does not e x p l a i n how i n f i l t r a t i o n r ates were a f f e c t e d . Regresseion equa-t i o n s , simple and m u l t i p l e , were developed to e x p l a i n the mechanisms of treatment e f f e c t s on i n f i l t r a t i o n . The approach, thus taken, d i f f e r e d from that of Lewis (1968) i n that i n t e r a c t i o n s between independent v a r i a b l e s were taken i n t o account before an equation was developed. Lewis on the other hand, developed equations i n which independent v a r i a b l e i n t e r a c t i o n s ob-scured f u n c t i o n a l r e l a t i o n s h i p s . Although h i s conclusions are v a l i d , they tend to be vague and d i f f i c u l t to i n t e r p r e t . As was the case f o r Block A and B a n a l y s i s , s o i l a e ration p o r o s i t y was considered t o have the greatest e f f e c t of a l l s o i l prop-e r t i e s on i n f i l t r a t i o n . The other s o i l v a r i a b l e s p o t e n t i a l l y a l t e r e d by skidroads were assumed to i n f l u e n c e i n f i l t r a t i o n i n d i r e c t l y through t h e i r e f f e c t s on aer a t i o n p o r o s i t y . To t h i s end, simple regression equations were developed r e l a t i n g i n f i l t r a t i o n r a te to surface s o i l a e r a t i o n p o r o s i t y and m u l t i p l e regression equations were then devel-oped r e l a t i n g surface s o i l a e r a t i o n p o r o s i t y to i n f l u e n t i a l s o i l v a r i -ables assumed to have been a l t e r e d by treatment. -108-A. S a i l p o r o s i t y Aeration p o r o s i t y of the surface s o i l exerts a great i n -fluence on i n f i l t r a t i o n , due to i t s r o l e as the primary entry route of water passing i n t o the s o i l p r o f i l e . For t h i s reason, i t i s ex-pected, that any a l t e r a t i o n s to the aeration p o r o s i t y of the s o i l surface would s i g n i f i c a n t l y i n f l u e n c e i n f i l t r a t i o n . F i r s t - h o u r i n f i l t r a t i o n r ates were c o r r e l a t e d with the aer a t i o n p o r o s i t y ( f r a c t i o n by volume) of the 0 - 3 , and k - 1 inch s o i l l a y e r s (Table 29). I t i s notable, that the f i r s t - h o u r i n f i l -t r a t i o n r a t e i s more dependent on the ae r a t i o n p o r o s i t y of the 0 -3 inch l a y e r than that of the k - 7 inch l a y e r . The importance of t h i s i s f a i r l y evident when considering skidroad e f f e c t s on i n f i l t r a -t i o n . The high standard e r r o r of estimate and low c o e f f i c i e n t of determination i n equation (A) of Table 29, are p a r t i a l l y a r e s u l t of the poor r e s o l u t i o n of the method of ae r a t i o n p o r o s i t y determination. As i n d i c a t e d i n Figure 18, the r a t i o s of aer a t i o n p o r o s i t y (0 - 3, inch l a y e r ) to f i r s t - h o u r i n f i l t r a t i o n f o r the c l e a r c u t u n i t s , are much higher than those f o r the skidroad u n i t s . In the surface h a l f inch of s o i l , Dn almost a l l of the skidroad study s i t e s , a c o n d i t i o n of obvious "puddling" was observed. With the three inch core ex-t r a c t e d , the q u a n t i t a t i v e decrease i n aer a t i o n p o r o s i t y due to pudd-l i n g would not have been f u l l y r e a l i z e d . This aspect w i l l be e l u c i -dated i n ensuing analyses. -109-Table 29. Simple regression equations r e l a t i n g f i r s t - h o u r i n f i l t r a t i o n (Y1) to the aeration p o r o s i t i e s of the 0 - 3 , and 4 - 7 inch s o i l l a y e r s . A. Independent V a r i a b l e = XS ( a e r a t i o n p o r o s i t y , 0 - 3 inch l a y e r ) Regression c o e f f i c i e n t = 55.052 Constant term = -3.63 n = 30 Standard e r r o r of estimate = - 6.16 i n . / h r . C o r r e l a t i o n c o e f f i c i e n t = 0.591 C o e f f i c i e n t of determination = 34.94% B. Independent V a r i a b l e = X7 ( a e r a t i o n p o r o s i t y , 4 - 7 inch l a y e r ) Regression c o e f f i c i e n t = 55.521 Constant term = -1.95 n = 30 Standard e r r o r of estimate = - 6.78 i n . / h r . C o r r e l a t i o n c o e f f i c i e n t = 0.459 C o e f f i c i e n t of determination = 21.11% P a r a l l e l l i n g the f i r s t - h o u r i n f i l t r a t i o n a n a l y s i s , simple re g r e s s i o n equations r e l a t i n g third-hour i n f i l t r a t i o n to the aera-t i o n p o r o s i t y of the 0 - 3, and 4 - 7 inch s o i l l a y e r s were c a r r i e d out. With i n c r e a s i n g i n f i l t r a t i o n , wetting f r o n t penetration i s deeper and i n f i l t r a t i o n i s subsequently i n c r e a s i n g l y i n f l u e n c e d by subsurface p h y s i c a l s o i l p r o p e r t i e s . Although t h i s i s i n d i c a t e d i n the equations described i n Table 30. i t i s notable that the surface s o i l a e r a t i o n p o r o s i t y s t i l l e x e r t s a s i g n i f i c a n t e f f e c t on i n f i l -t r a t i o n a f t e r the three hours of water a p p l i c a t i o n . This e f f e c t O.50 0.40 -o to O O CL P g Cj 0.30 Q.20-O.IOf R 5 11 1 1 1 I 1 1 1 1 1 I 1 • s 11 n 50 1 I I I 1 1 - AO Vi Y3 xfc xi yi y3 xio x7 skidroad clearcut BLOCK I yi y3 xfo x7 yi V3 xfe X7 -skidroad. c l eo rcu t B L O C K 2 . y< y3 xt x-7 yi y3 xt, x7 skidroad clmrcob B L O C K 3 3o 20 - IO c 0) -1—J o d a i Figure 18. F i r s t and third-hour i n f i l t r a t i o n and 0-3 and 4-7 inch a e r a t i o n p o r o s i t y means by experimental u n i t . -111-uiould l i k e l y be a m p l i f i e d had the aeration p o r o s i t y of the "puddled", surface l a y e r of s o i l on the skidroad u n i t s been measured. The v a l -i d i t y of the puddled l a y e r concept i s borne out i n the comparison of the a e r a t i o n p o r o s i t y ( 0 - 3 inch l a y e r ) to third-hour i n f i l t r a t i o n r a t e r a t i o s (Figure 18). Table 30. Simple regression equations r e l a t i n g third-hour i n f i l t r a t i o n (Y3) to the ae r a t i o n p o r o s i t i e s of the 0 - 3 , and 4 - 7 inch s o i l l a y e r s . A. Independent Var i a b l e = X6 (aer a t i o n p o r o s i t y , 0 - 3 inch l a y e r ) Regression c o e f f i c i e n t = 61.176 Constant term = -7.60 n = 30 Standard e r r o r of estimate = - 6.59 i n . / h r . C o r r e l a t i o n c o e f f i c i e n t = 0.607 C o e f f i c i e n t of determination = 36.80% B. Independent Variable = X7 (aer a t i o n p o r o s i t y , 4 - 7 inch l a y e r ) Regression c o e f f i c i e n t = 64.336 Constant term = -6.79 n = 30 Standard e r r o r of estimate = - 7.20 i n . / h r . C o r r e l a t i o n c o e f f i c i e n t = 0.492 C o e f f i c i e n t of determination = 24.16% Lewis (1968), although i n c l u d i n g v a r i a b l e s d e s c r i b i n g aera-t i o n p o r o s i t y of the surface s o i l l a y e r s i n h i s m u l t i p l e regression equations, d i d not o f f e r i n t e r p r e t a t i o n s on the r o l e of aer a t i o n -112-p o r o B i t y on i n f i l t r a t i o n . Houevsr, from h i s data, i t i s p o s s i b l e to dram some comparisons (Table 31). The s l i g h t decrease i n surface s o i l a e r a t i o n p o r o s i t y on skidroads i s not s u f f i c i e n t to e x p l a i n the reduction i n i n f i l t r a t i o n . This, regarding f i r s t - h o u r i n f i l t r a t i o n e s p e c i a l l y , probably r e s u l t s from the f a i l u r e of the ae r a t i o n poros-i t y determination method to account for the puddled surface l a y e r on the skidroads. Table 31. Aeration p o r o s i t i e s of the 0 - 3 and 4 - 7 inch l a y e r s of the skidroad and c o n t r o l u n i t s of Blocks A and B. T ^ r , o + m = r , 4 . Qir,r,u Aeration P o r o s i t y (cc./cc.) Treatment Block D _ 3 i n c h k - 1 inch Skidroad A 0.21 0.20 Control A 0.24 0.22 Skidroad B 0.28 0.26 Control B 0.31 0.30 Inserted f o r purposes of c l a r i t y , Figure 19 i n d i c a t e s the v e r t i c a l d i s t r i b u t i o n of a e r a t i o n p o r o s i t y i n the average s o i l ped-on of each of the three blocks. Although reductions i n aeration p o r o s i t y have occurred at dspth, the most s i g n i f i c a n t are those i n the surface three inches. Ensuing d e s c r i p t i o n s are more r e a d i l y understood on the basis of t h i s a d d i t i o n a l information. -113-• _n o Q. l O -dl 15 .....I J L .3 k'ldrOCLcl cJeo.rc .ut I 0 2 0 0 2 5 0 . 3 0 0 . 2 5 0 . 3 0 0 . 3 5 0 . 4 0 0 . 2 5 0.30 0 . 3 5 0 . 4 0 B L O C K aera/t i OTX. povo 5 i tij £ cc / c c ) B L O C K 2. B L O C K 3 Figure 19. V e r t i c a l d i s t r i b u t i o n of aeration p o r o s i t y i n the average s o i l pedon of each experimental u n i t showing the i n c r e a s i n g v a r i a t i o n with decreasing depth. B. Other s o i l v a r i a b l e s The r e l a t i o n s h i p of other s o i l v a r i a b l e s i n f l u e n c e d by treatment with the ae r a t i o n p o r o s i t y of the surface s o i l l a y e r s was developed by m u l t i p l e r e g r e s s i o n techniques. The r e l a t i o n s h i p be-tween the a e r a t i o n p o r o s i t i e s of the 0 - 3 , and 4 - 7 inch s o i l l a y -ers to f i r s t and third-hour i n f i l t r a t i o n has been explained. -114-The m u l t i p l e regression equation r e l a t i n g the aeration p o r o s i t y of the D - 3 inch l a y e r (X6) to the more important p h y s i c a l s o i l p r o p e r t i e s a f f e c t i n g i t , i s described i n Table 32. A great many v a r i a b l e s each e x p l a i n a small part of the sum of squares of Y1, but t o t a l to a s i g n i f i c a n t amount. An a p p r a i s a l of the e f f e c t s of treatment on each of the independent v a r i a b l e s i s given l a t e r . Table 32. M u l t i p l e regression equation r e l a t i n g the aeration p o r o s i t y of the 0 - 3 inch s o i l l a y e r (X6) to other s o i l v a r i a b l e s . Independent Variable XI (bulk d e n s i t y , 0-3 inch) XII ( t o t a l p o r o s i t y , 0-3 inch) X21 (% sand, 0-3 inch) X26 (% s i l t and c l a y , 0-3 inch) X36 (% O.M. > 2 mm. 0-3 inch) X41 (% O.M. < 2 mm. 0-3 inch) X46 (% t o t a l O.M. 0-3 inch) X51 (% l i t t e r cover) X55 (% macro-vegetation) X56 (% micro-vegetation) Regression Standard Variance C o e f f i c i e n t Deviation Ratio -1.228 0.664 3.632 3.120 1.621 3.704 -0.004 0.002 4.687 -0.007 0.003 7.467 1.821 0.893 4.161 1.827 0.895 4.173 -1.820 0.892 4.163 0.001 0.001 2.233 0.001 0.001 3.256 0.001 0.001 3.998 Constant term = -2.71 n = 30 Standard e r r o r of estimate = - 0.05 cc./cc. M u l t i p l e c o r r e l a t i o n c o e f f i c i e n t = 0.847 M u l t i p l e c o e f f i c i e n t of determination = 71.74% -115-The m u l t i p l e r e g r e s s i o n equation r e l a t i n g the a e r a t i o n por-o s i t y of the 4 - 7 inch l a y e r (X7) to the more important v a r i a b l e s a f f e c t i n g i t i s described i n Table 33. Although a lower proportion of the sum of squares of Y3 i s accounted f o r than was the s i m i l a r case f o r Y1, the equation i s not as important as that f o r Y1. This i s p r i m a r i l y due to the f a c t that the s o i l p r o p e r t i e s of the 4 - 7 inch l a y e r would not have been as s t r o n g l y i n f l u e n c e d by treatment as those of the 0 - 3 inch l a y e r . This i s i n agreement with Lewis (1968) and i s a m p l i f i e d i n the ensuing d i s c u s s i o n . Table 33. M u l t i p l e regression equation r e l a t i n g the aeration p o r o s i t y of the 4 - 7 inch l a y e r (X7) to other s o i l v a r i a b l e s . Independent Variable Regression Standard Variance C o e f f i c i e n t Deviation Ratio X12 ( t o t a l p o r o s i t y , 4-7 inch) 0.388 0.093 17.237 X27 (% s i l t plus c l a y , 4-7 inch) -0.006 0.002 6.894 X37 (% O.M. > 2 mm. 4-7 inch) -0.002 0.001 5.135 Constant term =0.11 n = 30 Standard e r r o r of estimate = 0.05 cc./cc. M u l t i p l e c o r r e l a t i o n c o e f f i c i e n t = 0.667 M u l t i p l e c o e f f i c i e n t of determination = 44.49% -116-a. Bulk density Lewis (1968) found that bulk density d i d not s i g n i f i c a n t l y i n f l u e n c e i n f i l t r a t i o n on Blocks A and B d i r e c t l y , and he d i d not explore bulk density - a e r a t i o n p o r o s i t y i n t e r a c t i o n s . Bulk density was shown to i n f l u e n c e a e r a t i o n p o r o s i t y i n Table 32. Figure 20 describes the v a r i a t i o n of t h i s s o i l property ( 0 - 3 inch l a y e r ) be-tween experimental u n i t s . &kid cl«w skid clear skid cJeaf rc>ad cut road cwt road cut BLOCK I B L O C K 2. B L O C K 3 Figure 20. V a r i a t i o n of bulk density of the 0 - 3 inch s o i l l a y e r between experimental u n i t s Skidroads on Block C have a s i g n i f i c a n t l y higher bulk den-s i t y than c l e a r c u t areas. Due to the inverse r e l a t i o n s h i p between -117-bulk density and a e r a t i o n p o r o s i t y , any increase i n the former could be expected to r e f l e c t decreases i n i n f i l t r a t i o n r a t e s . The r e l a t i o n s h i p e s t a b l i s h e d between ae r a t i o n p o r o s i t y and bulk density, although v a l i d , i s somewhat i n s u f f i c i e n t due to two reasons. The tabulated bulk d e n s i t i e s f o r skidroad represent the average of the surface three inches of s o i l and do not adequately account for'the higher bulk d e n s i t i e s expected i n the puddled l a y e r . Also, bulk density i s i n f l u e n c e d by organic matter content which, even though i t becomes compacted, tends to reduce bulk density because of i t s very low oven-dry weight. Both of these e f f e c t s are such as to make the given bulk d e n s i t i e s conservative estimates. b. T o t a l p o r o s i t y Since aeration p o r o s i t y i s a component of t o t a l p o r o s i t y , i t would be expected that they were r e l a t e d . However, i t i s import-ant to note that any reduction of a e r a t i o n p o r o s i t y does not y i e l d the same volumetric decrease i n t o t a l p o r o s i t y (Figure 21). This i s due to the f a c t that a reduction i n a e r a t i o n p o r o s i t y r e s u l t s i n a somewhat p r o p o r t i o n a l increase i n water r e t e n t i o n p o r o s i t y . The net reduction i n both types of p o r o s i t y , due to the e f f e c t s of s k i d -road c o n s t r u c t i o n and use, i s evident i n Figure 21. Water r e t e n t i o n p o r o s i t y of the surface s o i l l a y e r s tends to have a negative e f f e c t on i n f i l t r a t i o n s i n c e , s h o r t l y a f t e r i n -f i l t r a t i o n has proceeded, most of the pores contain e i t h e r water or' trapped a i r . Thus, r e l a t i v e to the aeration pores, the water r e t e n -t i o n pores transmit a low proportion of i n f i l t e r e d water. -118-xTl * u ' * i 3 x T i J ? I 2 j?iiJti2 xn *i2 x n yi2 s k i d r o a d clearcut skidrotui c l e a r u t akldrcxxd c l e a r c u t B L O C K I BL O C K 2. S L O C K 3 Figure 21. V a r i a t i o n i n the t o t a l p o r o s i t y of the 0 - 3 (X11) and 4 - 7 (X12) inch s o i l l a y e r s between experimental u n i t s . c. S o i l texture M u l t i p l e r e g r e s s i o n equations i n d i c a t e d negative r e l a t i o n -ships between the aeration p o r o s i t y of the 0 - 3 inch l a y e r and per-cent sand and s i l t plus c l a y and also between the aer a t i o n p o r o s i t y of the 4 - 7 inch l a y e r and percent s i l t plus c l a y . The v a r i a t i o n i n the t e x t u r e , although not high, i s not low enough to avoid being considered as p o t e n t i a l l y a l t e r e d by treatment e f f e c t s . Any comments regarding treatment e f f e c t s on texture must be tempered by the f a c t that the values f o r percent mineral f r a c t i o n of the s o i l are wholly dependent on the values f o r organic matter content. Generally, -119-higher values of mineral components,, e s p e c i a l l y the sand content, occur on the skidroad treatment (Figure 22). .3 I J l 1 1 I III X2.I X 2 f c xzt X 2 i sUicUocuJ c l e a r e s t S L O C K / I 1 1 I I 1 1 1 I 1 1 1 22 X 2 7 X2l X 2 f c X 2 7 V 2 l * 2 f c X 2 7 V 2 l V2fe X 2 1 X 2 i X 2 f c ^ 2 7 i k idroa .c4 clearest s l d d r o a x l o/ea/*cuC BLOCK 2 BLOCK 3 Figure 22. Mean values of percent sand (0-3 inch l a y e r ) and percent s i l t plus c l a y (0-3 and 4-7 inch l a y e r s ) by experimental u n i t . Following the exposure of mineral s o i l by the blade and trac k of a t r a c t o r , raindrop splash erosion m o b i l i z e s the f i n e r s o i l p a r t i c l e s . The s i l t plus c l a y p a r t i c l e s thus are c a r r i e d deeper i n t o the s o i l pedon or, more l i k e l y , o f f the skidroad where slope c o n d i t i o n s favor runoff (Blocks 2 and 3). Consequently, a f t e r ten years of these processes, the p a r t i c l e s most r e s i s t a n t to movement by water (sand and gravel) remain as the primary components of the s o i l s urface. Any f u r t h e r conclusions concerning texture are u n r e l i a b l e -120-ouiing to small d i f f e r e n c e s between treatment u n i t s and organic mat-t e r content i n t e r a c t i o n s . d. Organic matter content Organic matter has been shown to be b e n e f i c i a l to a e r a t i o n p o r o s i t y . Since the s o i l surface was considered to be the atmos-p h e r e - s o i l i n t e r f a c e (surface of mineral s o i l i n Blocks A and B) the surface organic l a y e r s were sampled when they occurred. Skidroad c o n s t r u c t i o n , through i t s exposure of mineral s o i l , tends to reduce surface organic l a y e r s which i s r e f l e c t e d i n the values f o r organic matter contents presented i n Figure 23. a Ic'idrocLci decKcot •sleioVoa.d clearcoi .skidroad claxraut B L O C K i B L O C K 2 B I - O C K 3 Figure 23. Mean values of coarse organic matter of the 0 - 3 (X36) and 4 - 7 (X37) inch l a y e r s and f i n e organic matter of the 0 - 3 inch l a y e r (X41) by experimental u n i t . -121-I t was not p o s s i b l e to determine the depth of organic and mineral s o i l which had been displaced from the skidroad and conse-quently horizon comparisons are not attempted. The coarse organic matter s o i l f r a c t i o n represents the extent of the fermented l a y e r and large roots i n the 0 - 3 inch l a y e r of the c l e a r c u t u n i t s and bark and wood fragments from the skidding of logs i n the same s o i l l a y e r of the skidroad u n i t s . S i m i l a r l y , the coarse organic matter s o i l f r a c t i o n of the 4 - 7 inch l a y e r represents large roots i n the c l e a r -cut u n i t s and bark and wood fragments i n the skidroad u n i t s . The f i n e , c o l l o i d a l organic matter of the 0 - 3 inch l a y e r o r i g i n a t e d from the b i o l o g i c a l breakdown of dead plant m a t e r i a l on the c l e a r c u t u n i t s and from mechanical g r i n d i n g D f bark and wood fragments on the skidroad u n i t s . From these p o i n t s , i t f o l l o w s , that the mean values of the three organic matter v a r i a b l e s are c o n s i s t e n t l y lowest on the skidroad u n i t s . An important f a c t o r to be noted regarding the coarse organ-i c matter, not decipherable from Figure 23, i s i t s d i s p o s i t i o n i n the s o i l of the skidroad areas. The fragments of wood and bark are gen-e r a l l y p l a t e - l i k e and ori e n t e d h o r i z o n t a l l y i n the s o i l . Add to t h i s , the f a c t that the fragments were forced i n t o the mineral s o i l matrix under high pressure, and the r e s u l t i s a major reduction i n the cr o s s -s e c t i o n a l area of s o i l a v a i l a b l e f o r v e r t i c a l water flow. This was not wholly detected i n the data since these same fragments prevented securing of good q u a l i t y cores and as such were avoided. However, the importance of these fragments i s a t t e s t e d to by t h e i r very e x i s -tence i n a s o l i d form ten years l a t e r a f t e r t h e i r placement i n the s o i l . Their breakdown i s s t r o n g l y i n h i b i t e d due to the lack of a i r -122-and water ( r e s u l t i n g from reduced s o i l p o r o s i t y ) necessary f o r o p t i -mum decomposer organism a c t i v i t y . e. L i t t e r cover Although not h i g h l y i n f l u e n c i n g the aeration p o r o s i t y of the 0 - 3 inch l a y e r of s o i l , the percentage cover by l i t t e r i s somewhat i n d i c a t i v e of the dynamics of vegetation activity:,' since the time of disturbance (Table 34). I t i s not l i k e l y that the surface aeration p o r o s i t y of the c l e a r c u t areas i s s t r o n g l y i n f l u e n c e d by l i t t e r cover due to the deep fermented and humus l a y e r s c o n s i s t e n t l y found on these areas. I t i s e n t i r e l y v a l i d to suggest that l i t t e r cover actu-a l l y improves the aeration p o r o s i t y of the immediate s o i l surface on the skidroad u n i t s . However, the p r o t e c t i o n o f f e r e d the s o i l would at l e a s t prevent the perpetuation of raindrop inwashing e f f e c t s there-by p e r m i t t i n g the improvement i n aeration p o r o s i t y by other mechanisms i n c l u d i n g vegetation and microorganisms. Table 3 k . Mean values of percent l i t t e r cover (X51) by experimental u n i t . Treatment Block 1 Block 2 Block 3 Skidroad Clearcut 15.40 69.00 60.80 35.60 34.40 11.00 -123-f. Vegetation cover The percentage cover of macro- and microvegetation, shown to have a small and p o s i t i v e r e l a t i o n to the aeration p o r o s i t y of the 0 - 3 inch s o i l l a y e r , i s somewhat r e l a t e d to the organic matter con-tent and l i t t e r cover v a r i a b l e s . The mean values of the two vegeta-t i o n v a r i a b l e s , presented i n Table 35, i n d i c a t e a c o n s i s t e n t l y high-er vegetation cover on the c l e a r c u t u n i t s than on the skidroad u n i t s . Table 35. Mean values f o r percent macro (X55) and micro (X56) vegetation cover by experimental u n i t . t ' Block 1 Block 2 Block 3 ireatment x 5 5 ^ ^ ^ x 5 5 x 5 6 Skidroad 54.4 4.4 50.0 8.4 21.0 10.2 Clearcut 80.0 72.6 80.0 86.0 100.0 94.0 As has been suggested, denser vegetation u s u a l l y y i e l d s higher s o i l organic matter contents and l i t t e r cover. The crown cov-er of the vegetation acts as a b u f f e r to raindrop impact on the s o i l surface by absorbing some of the raindrop energy. A l l of these e f r - , f e c t s act to reduce the e f f e c t s of raindrop splash i n the plugging of aeration p o r o s i t y . -124-3. E f f e c t of skidroads on a r t i f i c i a l regeneration response During the course of the f i e l d stage of the i n f i l t r a t i o n s t u d i e s on Block C, i t was noticed that the trees on the skidroad were gen e r a l l y smaller than those on adjacent c l e a r c u t areas. In order to i n v e s t i g a t e t h i s f u r t h e r , the diameter at breast height (Dbh) and height of f i v e planted Douglas f i r trees near each study s i t e were recorded. The trees were planted when two years o l d and were twelve years o l d at the time of measurement. Simple regression equations developed to r e l a t e Dbh and height of the a r t i f i c i a l regeneration to the f i r s t and third-hour i n f i l t r a t i o n are presented i n Table 36. In the four s i g n i f i c a n t equations, i t i s notable that the equations f o r Y1 and Y3 on e i t h e r Dbh or height are very s i m i l a r . This i m p l i e s that the r e l a t i v e v a l -ues of i n f i l t r a t i o n at any time, on each of the treatments, i s alde-c i s i v e ecosystem c h a r a c t e r i s t i c i n a r t i f i c i a l regeneration response. I t i s als o notable that diameter seems to be more hig h l y i n f l u e n c e d by i n f i l t r a t i o n than height, however, reasons f o r t h i s would be overly c o n j e c t u r a l and as such they are ignored here. The mean values of Dbh and height of a r t i f i c i a l regeneration presented i n Table 37, i n d i c a t e f s i g n i f i c a n t l y lower values of these means on the skidroad treatment. This supression of tree growth on the skidroads r e s u l t s from the a l t e r a t i o n of those p h y s i c a l s o i l p r o p e r t i e s which also i n f l u e n c e i n f i l t r a t i o n . -125-Table 36. Simple reg r e s s i o n equations r e l a t i n g f i r s t (Y1) and third-hour (Y3) i n f i l t r a t i o n r a tes to aver-age Dbh (X59) and height (X60) of a r t i f i c i a l regeneration. Dependent Independent Regression 2 „ Var i a b l e V a r i a b l e C o e f f i c i e n t E X59 Y1 0.048 0.747 0.558 0.33 i n . X59 V3 0.044 0.737 0.543 0.33 i n . X60 Y1 0.232 0.648 0.420 2.08 f t . X60 Y3 0.214 0.648 0.420 2.08 f t . Table 37. Mean values of a r t i f i c i a l regeneration Dbh (X59) and height (X60) by e x p e r i -mental u n i t . V a r i a b l e Q l a c k 1 B l o c k 2 B l o c k 3 s k i d r Q a d c l e a r c u t Skidroad Clearcut Skidroad Clearcut X59 1.24 2.18 1.48 1.98 1.50 2.24 X60 9.14 13.88 10.78 12.66 11.12 15.14 High bulk density i n the surface s o i l of the skidroad pre-sents p h y s i c a l r e s i s t a n c e to l a t e r a l root penetration, Decreased aer a t i o n p o r o s i t y i n the same s o i l l a y e r severely i n h i b i t s the c i r -c u l a t i o n of a i r and water to and around r o o t s . These e f f e c t s tend to r e s t r i c t root development to e i t h e r the pocket of s o i l c u l t i v a t e d -126-during the p l a n t i n g operation, or to v e r t i c a l penetration to uncom-pacted s o i l l a y e r s deep i n the s o i l pedon. This reduction of tree vigor on skidroads was a l s o noted i n southwestern Washington by Steinbrenner and Gessel (1955), how-ever, they studied n a t u r a l regeneration s h o r t l y a f t e r establishment. This study i n d i c a t e s that the reduction of s i t e q u a l i t y i s p e r s i s t e n t and i s , t h e r e f o r e , of considerable importance to f o r e s t management. This l a t t e r point w i l l be discussed f u r t h e r i n a l a t e r s e c t i o n . k. I n f i l t r a t i o n p r e d i c t i o n equations, Block C M u l t i p l e regression techniques i n conjunction with the un-d e r l y i n g p r i n c i p l e s of the i n f i l t r a t i o n process were u t i l i z e d i n the development of i n f i l t r a t i o n p r e d i c t i o n equations. These equations, d e t a i l e d i n Table 38, f a i l i n s p i t e of t h e i r s t a t i s t i c a l s i g n i f i -cance, due to the large standard e r r o r s of estimate. However, since they include only two independent v a r i a b l e s , they can be used with ease i f a rough estimate of i n f i l t r a t i o n i s d e s i r e d . The aeration p o r o s i t y (cc./cc.) of the l i m i t i n g l a y e r has a major i n f l u e n c e on i n f i l t r a t i o n on Block C as w e l l as Blocks A and B. I t would seem, t h e r e f o r e , that the l a t e r a l flow of a i r and water as determined by the l i m i t i n g l a y e r aeration p o r o s i t y , i s an important c h a r a c t e r i s t i c of upland f o r e s t e d s o i l s and i s of p a r t i c u -l a r relevance i n the hydrologic study and f o r e s t management of these s o i l s . -127-Table 38. M u l t i p l e regression equations f o r the p r e d i c -t i o n of f i r s t and third-hour i n f i l t r a t i o n . A. Dependent Var i a b l e = Y1 ( f i r s t - h o u r , i n f i l t r a t i o n r a t e , i n . / h r . ) T n ^ n n n n n n * , . „ • K , Regression Standard Variance Independent Variable _ 3„_. . _ . .. _ .. C o e f f i c i e n t Deviation Ratio X6 ( a e r a t i o n p o r o s i t y , 0-3 inch) 47.229 12.609 14.031 X57 ( l i m i t i n g l a y e r ) -56.042 17.811 9.900 Constant term = 0.68 n = 30 Standard e r r o r of estimate = - 5.37 i n . / h r . M u l t i p l e regression c o e f f i c i e n t = 0.724 M u l t i p l e c o e f f i c i e n t of determination = 52.40% B. Dependent Variable = Y3 (third-hour i n f i l t r a t i o n r a t e , i n . / h r . ) Independent Va r i a b l e X6 ( a e r a t i o n p o r o s i t y , 0-3 inch) X57 ( l i m i t i n g l a y e r ) Regression Standard Variance C o e f f i c i e n t ( Deviation Ratio 54.710 14.411 14.413 -46.434 20.357 5.203 Constant term = 0.71 n = 30 Standard e r r o r of estimate = - 6.13 i n . / h r . M u l t i p l e regression c o e f f i c i e n t = 0.686 M u l t i p l e c o e f f i c i e n t of determination =47.01% The mean values of l i m i t i n g l a y e r p o r o s i t y presented i n Table 39, are gene r a l l y lomer on the c l e a r c u t areas, and must be modi-f i e d by a d d i t i o n a l i n f o r m a t i o n . The l i m i t i n g l a y e r f r e q u e n t l y occur--128-red at a very shallow depth i n the s o i l p r o f i l e and, as such, l a t e r a l flow was gen e r a l l y prevented by the co n c e n t r i c i n f i l t r o m e n t e r r i n g s . Dn the c l e a r c u t areas, however, the l i m i t i n g l a y e r u s u a l l y occurred deep i n the s o i l p r o f i l e and f r e e l a t e r a l flow of a i r and water was not prevented by the i n f i l t r o m e t e r r i n g s . Table 39. Mean values of the a e r a t i o n p o r o s i t y of the l i m i t i n g l a y e r (X57) by experimental u n i t . Treatment Block 1 Block 2 Block 3 Skidroad Clearcut * A l l values i n cubic centimeters per cubic centimeter of s o i l The r e l o c a t i o n of the l i m i t i n g l a y e r to a p o s i t i o n higher i n the s o i l p r o f i l e by skidroad c o n s t r u c t i o n and use was not con-si d e r e d by Lewis (1968). He used the v a r i a b l e s d e s c r i b i n g the poten-t i a l l a t e r a l flow and l i m i t i n g l a y e r s i n h i s covariance equations assuming, thereby, they were not i n f l u e n c e d by treatment. 0.13 0.14 0.17 0.12 0.18 0.10 -129-Summary The summary of the preceeding d i s c u s s i o n i s supplemented by the i n f i l t r a t i o n rate-time curves presented i n Figures 24, 25 and 26. The e f f e c t s of c l e a r c u t t i n g , slashburning, and skidroads on i n f i l t r a -t i o n are appraised i n terms of c o n t r o l (uncut) areas on Blocks A and B and c l e a r c u t areas on Block C. I t must be stressed that the f o l l o w -ing summarized r e s u l t s p e r t a i n only to the s p e c i f i c l o c a t i o n s of the three s o i l s i n v e s t i g a t e d . 1. Control or uncut The undisturbed f o r e s t areas on ac i d brown wooded (Block A) and degraded a c i d brown wooded (Block B) were used as comparisons f o r the c l e a r c u t and slashburn treatments. F i r s t - h o u r i n f i l t r a t i o n r a t e s , adjusted by covariance a n a l y s i s , were 24.39 inches per hour f o r Block A and 28.07 inches per hour f o r Block B. Third-hour adjusted i n f i l -t r a t i o n r a t e s were 16.71 inches per hour f o r Block A and 20.51 inches per hour f o r Block B. The high i n f i l t r a t i o n of the undisturbed c o n t r o l u n i t s i n h i b -i t the generation of overland flow thereby rendering the two s o i l s r e -s i s t a n t to er o s i o n . H y d r o l o g i c a l l y , the undisturbed f o r e s t represents the optimum i n i n f i l t r a t i o n capacity and other water transmission char-a c t e r i s t i c s . 2. Clearcut The c l e a r c u t areas, representing c l e a r - f e l l e d and highlead U0 sz c •r) 30 cu CO •u .c a •H to 20 - P 10 c o n t r o l c l e a r c u t sljshburned_ skidroad 2 Time (hrs.) i i Figure 25 . I n f i l t r a t i o n curves f o r Block B (smoothed from hourly means). Figure 26. I n f i l t r a t i o n curves f o r Block C (smoothed from hourly means). -133-yarded s e t t i n g s , i n d i c a t e d n o n s i g n i f i c a n t d i f f e r e n c e s i n i n f i l t r a t i o n c a pacity from those of comparative c o n t r o l areas. F i r s t - h o u r adjust-ed i n f i l t r a t i o n r a t e s were 24.83 inch per hour f o r Block A and 27.89 inches per hour f o r Block B. Due to the i n s i g n i f i c a n c e of the changes i n i n f i l t r a t i o n induced by c l e a r c u t t i n g , no conclusions can be off e r e d regarding the a d d i t i v i t y of c l e a r c u t t i n g and slashburning on i n f i l t r a t i o n . L i k e l y the only way p o s s i b l e a d d i t i v i t y could be ascertained would be a be-fore-and-after study on the same s i t e s . I f c l e a r c u t t i n g d i d reduce i n f i l t r a t i o n , the sampling methods employed i n t h i s study were not s u f f i c i e n t l y s e n s i t i v e to detect i t . Since the areas studied were on f a i r l y smooth topography, logging would have been f a i r l y simple, thereby r e s t r i c t i n g yarding disturbance to i s o l a t e d patches. This l e f t the majority of the s i t e covered by an undisturbed organic l a y e r . Both c l e a r c u t s i t e s studied maintained a vigorous caver of shrubs and advance regeneration and the moss a s s o c i a t i o n s were the same as those on adjacent undisturbed areas. Based on these f i n d i n g s , the c l e a r c u t treatment was used as the c o n t r o l f o r Block G. 3. Slashburned As g r a p h i c a l l y i l l u s t r a t e d i n Figures 24 and 25, slashburning s i g n i f i c a n t l y reduced i n f i l t r a t i o n r a t e s on the two s o i l s s tudied. The adjusted f i r s t - h o u r i n f i l t r a t i o n r a t e s were 17.49 inches per hour -134-f o r Black A and 19.61 inches per hour f o r Block B. The adjusted t h i r d - h o u r i n f i l t r a t i o n r a t e s were 12.03 inches per hour f o r Block A and 12.52 inches per hour f o r Block B. The use of a three inch s o i l core f o r determining s o i l phys-i c a l p r o p e r t i e s proved to be a major disadvantage i n e x p l a i n i n g causes of i n f i l t r a t i o n reduction by slashburning, due to i t s low r e s o l u t i o n . However, the use of m u l t i p l e regression techniques d i d permit the de-velopment of some g e n e r a l i z a t i o n s . The main cause of i n f i l t r a t i o n reduction was the reduction i n surface s o i l a e ration p o r o s i t y r e s u l t i n g , most l i k e l y , from the inwashings of organic and mineral p a r t i c l e s by raindrop splash mechan-isms. Measured aeration p o r o s i t i e s of the surface s o i l , although l e s s f o r slashburned areas than on comparable c o n t r o l areas, were an aver-age of the surface three inches of s o i l whereas inwashing i s only ac-t i v e i n the surface h a l f - i n c h of s o i l . C a lculated values of a e r a t i o n p o r o s i t i e s f o r the puddled l a y e r were 0.20 cc./cc. f o r Block A and 0.22 cc./cc. f o r Block B. These are s i g n i f i c a n t l y lower than 0.25 cc./cc. and 0.31 cc./cc. f o r Blocks ft and B c o n t r o l r e s p e c t i v e l y . S i m i l a r problems r e s u l t i n g from poor r e s o l u t i o n e x i s t e d i n the e v a l u a t i o n of changes, i n those s o i l p r o p e r t i e s i n f l u e n c i n g aera-t i o n p o r o s i t y , i n c u r r e d by slashburning. Small increases i n bulk den-s i t y , not measured but p r e d i c t e d , i n the surface h a l f - i n c h of s l a s h -burned s o i l s r e s u l t i n g from inwashing, reduced aeration p o r o s i t i e s somewhat. Reductions i n f i n e (<c 2 mm.) organic matter i n the surface -135-three inches of slashburned s o i l s , although averaging only 1.09% by weight i n Block A and 1.27% by weight i n Block B accounted f o r some of the reduction i n a e r a t i o n p o r o s i t y . Increases (< 1% by weight) i n coarse (> 2 mm.) organic matter contents on slashburned s o i l s indir-? e c t l y reduced a e r a t i o n p o r o s i t y by decreasing the c r o s s - s e c t i o n a l area-a v a i l a b l e to v e r t i c a l s o i l water flow. In a d d i t i o n to the i n d i r e c t e f f e c t of s o i l organic matter on i n f i l t r a t i o n was a d i r e c t e f f e c t r e -s u l t i n g from the unique water a f f i n i t y p r o p e r t i e s of organic m a t e r i a l . M u l t i p l e regression equations i n d i c a t e d coarse and f i n e organic matter contents of the surface three inches of s o i l accounted f o r 10% of the sums of squares of i n f i l t r a t i o n . I t would appear that i n f i l t r a t i o n i s s e n s i t i v e to very small d i f f e r e n c e s i n surface s o i l organic matter con-t e n t . The r e d u c t i o n i n l i t t e r cover from 92.27% on Block A-control to 53.67% on Block A-slashburned and 75.00% on Block B-control to 54.33% on Block B-slashburned were hi g h l y s i g n i f i c a n t and represented two years of l i t t e r accumulation f a l l o w i n g i t s consumption during slashburning. Low l i t t e r cover was h i g h l y associated with low surface s o i l a e r a t i o n p o r o s i t y . Slashburning e l i m i n a t e d the fermented and humus l a y e r s on many of the study s i t e s on both of the s o i l s s t u d i e d . This s i t u a t i o n , r e s u l t i n g i n the exposure of mineral s a i l allowed raindrop inwashing to plug the aeration pores of the surface s o i l with f i n e mineral p a r t -i c l e s dispersed by the ash deposits on the s o i l s urface. Density of shrubs and trees (macro-vegetation) was negatively associated with surface s o i l a e ration p o r o s i t y . High d e n s i t i e s of -136-fireweed on the slashburned p l o t s c h a r a c t e r i s t i c a l l y formed dense root mats at shallow depths i n the slashburned s o i l s . Slashburning reduces i n f i l t r a t i o n p r i m a r i l y through the mech-anism of raindrop e r o s i o n . This mechanism operates both on mineral s o i l s exposed by the consumption of the f o r e s t f l o o r by f i r e , and on fermented or humus l a y e r s f r e s h l y exposed by f i r e . Inwashing of f i n e ash, c h a r c o a l , organic and mineral p a r t i c l e s plug a e r a t i o n pores, i n -crease bulk density and increase water r e t e n t i o n p r o p e r t i e s of the surface s o i l . The values of i n f i l t r a t i o n on slashburned areas r e p o r t -ed i n t h i s study, are those measured two years a f t e r the burn and thus represent the tendency f o r n a t u r a l events to break down the puddled surface. The re-establishment of preburn s o i l c o n d i t i o n s and attend-ant i n f i l t r a t i o n capacity would l i k e l y average four years f o l l o w i n g the burn on the two s o i l s s t u d i e d . 4. Skidroads As i n d i c a t e d i n Figures 24, 25, and 26,.skidroads reduced the i n f i l t r a t i o n capacity of the s o i l s s tudied more than any other treat-? ment. A f t e r ten years, during which time they were not used, the skidroads on Block C had an average adjusted i n f i l t r a t i o n r a te of 6.B9 inches per hour f o r the f i r s t - h o u r and 4.23 inches per hour f o r the th i r d - h o u r . These compare with the corresponding c l e a r c u t i n f i l t r a t i o n r a t e s of 21.22 and 19.27 inches per hour. The reduction i n i n f i l t r a t i o n on Block C-skidroad was compar-able to those p r e v i o u s l y reported f o r skidroads on Blacks A and B (Lewis, 1968). Comparing the r e s u l t s from the three blocks indicates? -137-the reduction i n i n f i l t r a t i o n by skidroads to be d i r e c t l y p r o p o r t i o n a l to the i n t e n s i t y of t h e i r use. Of s p e c i a l note i s that i n f i l t r a t i o n measurements of skidroads, made two years f o l l o w i n g disturbance on Blocks A and B, were comparable to the measurements made on Block C-skidroads ten years f o l l o w i n g disturbance. Due to the magnitude of disturbance, the causes of i n f i l t r a -t i o n reduction on Block C were e a s i l y evaluated. In s p i t e of poor r e s -o l u t i o n of the s o i l cores, the aeration p o r o s i t y of the surface three inches of s o i l was reduced from an average of 0..37 cc./cc. on the c l e a r c u t to an average of 0.27 cc./cc. on the skidroad. As was the case f o r slashburned s o i l s , a dense puddled l a y e r e x i s t e d i n the sur-face h a l f - i n c h of skidroad s o i l s , the p r o p e r t i e s of which were obscured i n the three inches of s o i l sampled. The aeration p o r o s i t y accounted; f o r 60% of the sum of squares of i n f i l t r a t i o n on Block C. Aeration p o r o s i t y was associated with a number of s o i l v a r i -a bles, each of which accounted f o r a small amount, but c o l l e c t i v e l y accounting f o r 84.7% of the sum of squares of aer a t i o n p o r o s i t y . Bulk density was s i g n i f i c a n t l y increased from an average of 0.54 gm./cc. on c l e a r c u t areas to an average of 0.93 gm./cc. on s k i d -road areas. The increase r e s u l t e d from compaction during the yarding operation and sustained by raindrop impact. As was expected, raindrop erosion reduced the content o f f r s i l t -p l u s - c l a y on the skidroads since t h i s f r a c t i o n could be transported o f f the skidroads even at low v e l o c i t i e s of overland flow. Skidroads i n c u r r e d a l t e r a t i o n s i n the organic matter content -138-of the surface three inches of s o i l . Fine (<-2 mm.) organic matter was reduced|from an average of 17.19% to 6.80%. This caused a de-crease i n a e r a t i o n p o r o s i t y through aggregate breakdown. Coarse (> 2 mm.) organic matter was reduced from an average of 16.29%.,to 10.33%. Als o , the coarse organic matter was p r i m a r i l y composed of l i v e roots on the c l e a r c u t areas and p l a t y chips of bark and wood on skidroad areas. These c h i p s , embedded h o r i z o n t a l l y i n the compacted s o i l of the skidroad, reduced the c r o s s - s e c t i o n a l area a v a i l a b l e to v e r t i c a l s o i l water flow, consequently reducing i n f i l t r a t i o n . 5. Regeneration response I n v e s t i g a t i o n of the apparant lack of vigor of 12 year o l d planted Douglas f i r on the Block E-skidroad i n d i c a t e d i n f i l t r a t i o n r a te to be c o r r e l a t e d to both diameter at breast height (r=0.75) and t o t a l height (r=0.65). Regeneration averaged 1.41 inches i n Dbh and 10.35 f e e t i n height on skidroads and 2.13 inches i n Dbh and 13.56 feet i n height on c l e a r c u t areas. The lower vigor r e s u l t s from high r e s i s t a n c e of the s o i l to root penetration and reduced a i r and water c i r c u l a t i o n i n the root zone due to reduced ae r a t i o n p o r o s i t y . -139-Conclusion Although the key parameter i n determining erosion is-i the i n -f i l t r a t i o n r a t e of the s o i l , other parameters i n c l u d i n g slope length and roughness, and s o i l r e s i s t a n c e must be known before erosion poten-t i a l can be evaluated (Robins and Neff, 1963). The data c o l l e c t e d i n the s t u d i e s described i n t h i s paper do not permit the determination of erosion p o t e n t i a l s . However, some general i m p l i c a t i o n s f o r f o r e s t management can be i s o l a t e d . On the skidroads s t u d i e d , the generation of overland flow, because of very low i n f i l t r a t i o n r a t e s may, under c o n d i t i o n s of long steep slopes, lead to g u l l y i n g of lower skidroad slopes. Added to t h i s i s the reduction'of s i t e q u a l i t y on the skidroads r e f l e c t e d i n the low v i g o r regeneration.. Following the yarding operation, the f o r e s t mana-ger i s thus confronted with two a l t e r n a t i v e s . I f he chooses to main-the skidroad as a l i m i t e d access road f o r the management of future r o t a t i o n s , he must take measures to avoid e r o s i o n . These measures i n -clude ditches and c u l v e r t s and perhaps a s o i l s t a b i l i z e r such as grass cover. I f he chooses to plant the skidroads with a f o r e s t crop, he must break up the compacted s o i l to ensure optimum i n f i l t r a t i o n and water and a i r c i r c u l a t i o n i n the r o o t i n g l a y e r s of the s o i l . Erosion on slashburned areas, r e s u l t i n g from reduced i n f i l -t r a t i o n , may be v i s u a l l y imperceptible and s t i l l y i e l d s i g n i f i c a n t s o i l l o s s e s ( S a r t z , 1953). Reduced i n f i l t r a t i o n r a t e s may also i n f l u -ence ijn s i t u water d i s t r i b u t i o n due to d i f f e r e n t i a l water imputs. -140-Other e f f e c t s of slashburning include the i n c r e a s i n g of stream temperatures uhich i s detrimental to the f i s h e r y resource (Lev-no and Rothacher, 1967) the burning of p e r i p h e r a l timber, the p o l l u -t i o n of a i r and uater, the a l t e r a t i o n of p h y s i c a l , chemical and micro-b i o l o g i c a l s o i l p r o p e r t i e s p o t e n t i a l l y detrimental to the new f o r e s t crop and other e f f e c t s l i k e l y to be detected. Slashburning c o n s t i -t u t e s a major upset to many ecosystem components and i t s use as a man-agement t o o l i s shrouded i n u n c e r t a i n t y . Zivnuska (1968) s a i d that such u n c e r t a i n t l y was perhaps the most s i g n i f i c a n t aspect of the costs and b e n e f i t s of slashburning such that the greater the uncertainty of an investment s i t u a t i o n , the higher the p o s s i b l e returns must be to encourage investment. This w r i t e r does not n e c e s s a r i l y advocate the e l i m i n a t i o n of slashburning completely, but i t s use could be reduced or tempered with i n t e l l i g e n t planning. I t i s l u d i c r o u s to think that every c l e a r c u t setting 1' on the B.C.. coast r e q u i r e s slashburning, On those logging s e t t i n g s determined to require post-logging burning, s e t t i n g layout should be planned f o r both the logging and slashburning operations. C r i t e r i a to be e s t a b l i s h e d , would include s e t t i n g s i z e , aspect, topo-graphy and l e g a l boundaries (Henderson, 1968). The prevention of f o r -est f l o o r consumption by f i r e and subsequent exposure of mineral s o i l i s not as d i f f i c u l t as many f o r e s t e r s would t h i n k . The water content of the f o r e s t f l o o r i s the primary f a c t o r i n f l u e n c i n g consumption sus-c e p t i b i l i t y and i s e a s i l y determined before l i g h t i n g up (Frampton, 1968). F i r e asfija management t o o l , must be recognized as p o t e n t i a l l y dangerous and must be used with extreme caution. 1 -141-Although more research i s required i n t o the impact of f o r e s t management on the various ecosystems of c o a s t a l B.C., much i s already known. However, the a p p l i c a t i o n of research f i n d i n g s i s s t i l l i n i t s infancy i n t h i s region and w i l l l i k e l y remain as such u n t i l p r o f e s s i o n -a l f o r e s t managers become more f u l l y aware of t h e i r r e s p o n s i b i l i t i e s . A logger w i l l probably never read a research a r t i c l e on the e f f e c t s of h i s operations on f o r e s t ecosystems. I t i s the f o r e s t e r who must act as the l i n k between the research f i n d i n g s and the f i e l d operations and i f he f a i l s to do t h i s there i s not j u s t i f i c a t i o n f o r continued research e f f o r t s . -142-Literature Cited ADRIAN., D.D. and J.B. FRANZ I NX. 1966. Impedance to i n f i l t r a t i o n by pressure buildup ahead of the wetting front. 3. Geophys. Res. 71:5857-62. . ANNUAL REPORT OF THE FOREST SERVICE. 1967. Department of Lands, For-ests, and Water Resources. B.C. Forest Service. V i c t o r i a , B.C. 132 pp. AREND, J.L. 1941. I n f i l t r a t i o n as affected by the forest f l o o r . S o i l S c i . Soc. of Amer. Proc. 6:98-103. ARONOVICI, V.S. 1955. Model study of r i n g i n f i l t r o m e t e r performance under lou i n i t i a l s o i l moisture. S o i l S c i . Soc. of Amer. Proc. 19:1-6. AUSTIN, R.C. and D.H. BAISINGER. 1955. Some effe c t s of burning on forest s o i l s of western Oregon and Washington. Jour, of For. 53:275-80. BAVER, L.D. 1966. S o i l Physics. 3rd. ed. John Wiley and Sons Inc., New York. 489 pp. BEATON, J.D. 1959. The influence of burning on the s o i l i n the tim-ber range areas of Lac Le Jeune, B.C. Can. Jour, of S o i l S c i . 39:1-21. BERTONI, 3., W.E. LARSON and W.D. SHRADER. 1958. Determination of i n f i l t r a t i o n rates on Marshall s i l t loam from runoff and r a i n f a l l records. S o i l S c i . Soc. of Amer. Proc. 22:571-574. BETHLAHMY, N. 1962. F i r s t year e f f e c t s of timber removal on s o i l moisture. B i l l . Inter. Assoc. S c i . Hyd. 7:34-38. BINKLEY, V.W. 1965. Economics and design of a radio-controlled sky-l i n e yarding system. U.S. For. Serv. Pac. Northwest For. and Range Exp. Sta. Res. Pap. PNW-25:30 pp. BODMAN, G.B. and E.A. COLEMAN. 1944. Moisture and energy conditions during downward entry of water into s o i l s . S o i l S c i . Soc. of Amer. Proc. 8:116-122. BOND, R.D. 1964. The influence of microflora on the physical proper-t i e s of s o i l s - f i e l d studies on water repellant sands. Austral. Jour, of S o i l Res. 2:123-131. BYRNES, W.R. 1951. Eff e c t of s o i l texture on occurence and type of ground freezing. Jour, of For. 49:76. -143-BYNES, Id.R. and L.T. HARDDS. 1963. Hydrologic c h a r a c t e r i s t i c s of three s o i l s supporting natural hardwoods,, planted red pine and old f i e l d plant commumities. S o i l S c i . Soc. of Amer. Proc. 27:468-473. BUCHANAN, S.J. 1942. S o i l compaction. Univ. Texas C o l l . Engin. and Bur. Engin. Res. 5th Texas Conr. on S o i l Mechanics and Foundation Engineering. Proc. Pt. 2:28-37. CHESTERS, G., O.J. ATTOE and O.N. ALLEN. 1957. S o i l aggregation i n r e l a t i o n to various s o i l constituents. S o i l S c i . Soc. of Amer. Proc. 21:272-279. COLE, D.W. 1966. The forest s o i l - retention and flow of water. Proc. Soc. of Amer. For. Seattle, Wash. pp. 150-154. COOPER, C.F. 1961. Controlled burning and watershed condition i n the Unite Mountains of Arizona. Jour, of For. 59:438-442. DELL, J.D. and L.R. GREEN. 1968. Slash treatment i n the Douglas f i r Region - trends in the P a c i f i c Northwest. Jour, of For. 66:610-614. DE URIES, J. 1968. Jjn s i t u determination of physical properties of the surface layer of f i e l d s o i l s . U.B.C. Dept. of S o i l S c i . mineo. 22 pp. DORTIGNAC, E.J. and L.D. LOWE. 1961. I n f i l t r a t i o n studies on Ppn-, derosa pine ranges on Colorado. U.S. For. Serv. Rocky Mtn. For. and Range Exp. Sta. Sta. Paper 59:34pp. DRAPER, N.R. and H. SMITH. 1968. Applied regression analysis. John Wiley and Sons, Inc. New York. 407 pp. DULEY, F.L. 1939. Surface factors a f f e c t i n g the rate of intake of water by s o i l s . S o i l S c i . Soc. of Amer. Proc. 4:60-64. a n c l L.L. KELLY. 1941. Surface conditions of s o i l and time of application as related to intake of water. U.S.D.A. C i r c . No. 608 31 pp. and C.E. DOMINGO. 1944. E f f e c t of water temperature on rate of i n f i l t r a t i o n . S o i l S c i . Soc. of Amer. Proc. 8:129-131. DYRNESS, C T . 1965. S o i l surface condition following tra c t o r and highlead logging i n the Oregon Cascades. Jour, of For. 63:272-275. 1967. E r o d i b i l i t y and erosion potential of forest water-sheds. Inter. Symp. For. Hyd. Pergamon Press, pp. 599-609. -144-DYRIMESS, C T . 1967. S o i l surface conditions following skyline loggin U.S.. For. Serv. Pac. Northwest For. and Range Exp. Sta. Res. Note PNW-55 8 pp. .. 1967. Mass s o i l movement on the H.J. Andrews Experimental Forest. U.S. For. Serv. P a c i f i c Northwest For. and Range Exp. Sta. Res. paper PNW-42 12 pp. •' and C.T. YOUNGBERG. 1957. The e f f e c t of logging and slash burning on s o i l structure. S o i l S c i . Soc. of Amer. Proc. 21:444-447. C.T. YOUNGBERG and R.H. RUTH. 1957. Some e f f e c t s of log-ging and slashburning on physical s o i l properties i n the C o r v a l l i s Watershed. U.S. For. Serv. Pac. Northwest For. and Range Exp. Sta. Res. Paper 19 15 pp. EVANS, D.D.., D. KIRKHAM and R.K. FREVERT. 1950. I n f i l t r a t i o n and permeability i n s o i l overlying an impermeable layer. S o i l S c i . Soc. of Amer. Proc. 15:50-54. FRAMPTON, C S . 1968. Slashburning f u i d e l i n e s . The Trucklogger. 24:18-20 FREE, G.R. and V.J. PALMER. 1940. Interrelationships of i n f i l t r a t i o n a i r movement and pore size i n graded s i l i c a sand. S o i l S c i . Soc. of Amer. Proc. 5:390-398. GILM0UR, CM., O.N. .ALLEN and B. TRU0G. 1948 S o i l aggregation as i n -fluenced by growth of mould species, kind of s o i l and organ-i c matter. S o i l S c i . Soc. of Amer. Proc. 13:292-296. GRAY, D.M. and D.I. N0RUM. 1967. The e f f e c t of s o i l moisture on i n -f i l t r a t i o n as related to runoff and recharge. Sixth Can. Hyd. Symp. on S o i l Moisture. Univ. of Sask. Saskatoon. 23 pp. GREEN, R.E. 1963. I n f i l t r a t i o n of water into s o i l s as influenced by antecedent moisture. Dissert. Abs. 23:2270-2271. HADD0N, CD. 1967. Slash disposal - Vancouver forest d i s t r i c t . B.C. For. Serv. Protection Div. B u l l . V i c t o r i a , B.C. 35 pp. HALLIN, W.E. 1967. S o i l moisture and temperature trends i n cut-over and adjacent old-growth Douglas f i r timber. U.S. For. Serv. Pac. Northwest For. and Range Exp. Sta. R E S . Note No. 56 13 pp. HANKS, R.J. and S.A. BOWERS. 1962. Numerical solution of the mois-ture flow equations for i n f i l t r a t i o n into layered s o i l s . S o i l Sci.. Soc. of Amer. Proc. 26':530-534. -145-HAUPT, H.F. 1967. I n f i l t r a t i o n , overland flow and s o i l movement on frozen and show covered p l o t s . Water Resources Res. 3:145-161. HAWLEY, R.C. and D.M. SMITH. 1954 The practice of s i l v i c u l t u r e . John Wiley and Sons, Inc. New York. 525 pp. HENDERSON, R.C. 1968. Logging block layout - dual r e s p o n s i b i l i t y . The Truck Logger. 24:24-25. HEYldARD, F. 1939. Some moisture relationships of s o i l s from burned and unburned longleaf pine f o r e s t s . S o i l S c i . 47:313-324. HOLTAN, H.N. 1961. A concept for i n f i l t r a t i o n estimates i n watershed engineering. U.S.D.A. ARS 41-51. HORTON, R.E. 1933. The role of i n f i l t r a t i o n i n the hydrologic cycle. Amer. Geophys. Union Trans. 14:446-460. . 1940. An approach toward a physical interpretation of i n -f i l t r a t i o n capacity. S o i l S c i . Soc. of Amer. Proc. 5:399-417. HUBERTY, M.R. 1944. Compaction i n c u l t i v a t e d s o i l s . Amer. Geophys. Union Trans. 25:896-899. ISAAC, L.A. and H.G. HOPKINS. 1937. The forest s o i l of the Douglas f i r region and the changes wrought upon i t by logging and slashburning. Ecology 18:264-279. JEFFREY, id.U. 1968. Watershed management problems i n B r i t i s h Columbia: a f i r s t appraisal. Water Res. B u l l . No. 4. 53-70. JOHNSON, W.M. 1940. I n f i l t r a t i o n capacity of forest -soil as i n f l u -enced by l i t t e r . Jour, of For. 38:520. and CH. NIEDERHDF. 1941. Some relationships of plant cover to runoff, erosion and i n f i l t r a t i o n on g r a n i t i c s o i l s . Jour, of For. 39:854-353. KOSTIAKOV, A.N. 1932. On the dynamics of the c o e f f i c i e n t of water-percolation i n s o i l s and on the necessity for studying i t from a dynamic point of view for purposes of amelioration. Trans. 6th Corn. Internat. Soc. S o i l S c i . Russian Part A: 17-21. Orig. not seen. In P h i l i p , J.R. 1957. The theory of i n f i l t r a t i o n : 4. S o i l S c i . 84:257-263. KRYNINE, D.P.' 1941. S o i l Mechanics. McGraw-Hill Co. Inc. New York. 451 pp. LACATE, D.S. 1965. Forest land c l a s s i f i c a t i o n for the University of B r i t i s h Columbia Research Forest. Can. Dept. For., For. Res. Br. Dept. For. B u l l . No. 1107. 23 pp. -146-LETEY, J., 3. OSBORN and R.E.•PELISHEK. 1962. The influence of water-solid contact angle on water movement i n s o i l . B u l l . Inter. Assoc. of S c i . Hyd. 7(3):75-81. LEV/NO, A., and J. ROTHACHER. 1967. Increases i n maximum stream temperatures after logging i n old-growth Douglas f i r ' watersheds. U.S. For. Serv. Pac. Northwest For. and Range Exp. Sta. Res. Note PNW-65. 12 pp. LEWIS, T. 1968. The hydrologic consequences of compaction of coarse g l a c i a l s o i l s during forest harvesting i n coastal B r i t i s h Columbia. U.B.C. Faculty of Forestry. Unpub. B.S.F. Thesis. 92 pp. LI, J.C.R. 1964. S t a t i s t i c a l inference II. Edward Bros., Inc. Ann Arbor, Mich. 575 pp. LINSLEY, R.K., M.A. KOHLER and J.L.H. PAULHUS. 1949. Applied Hydrology. McGraw-Hill Book Co., Inc. New York. 494 pp. LOWDERMILK, W.C. 1930. Influence D f forest l i t t e r on runoff, perco-l a t i o n and erosion. Jour, of For. 28:474-491. LULL, H.liJ. 1959. S o i l compaction on forest and range lands. U.S.D.A. Misc. Pub. Nd. 768. 33 pp. LUTZ, J.F. and R.ld. LEANER. 1939. Pore-size d i s t r i b u t i o n as related to the permeability of s o i l s . S o i l S c i . Soc. of Amer. Proc. 4:28.-31. McCALLA, T.M. 1950. Studies on the e f f e c t of microorganisms on rate of percolation of water through s o i l s . S o i l S c i . Soc. of Amer. Proc. 15:182-191. McINTYRE, D.S. 1958. Permeability measurements of s o i l crusts form-ed by raindrop impact. S o i l S c i . 85:185-189. MARSHALL, T.J. and'G.B. S t i r k . 1950. The e f f e c t of l a t e r a l movement of water i n s o i l on i n f i l t r a t i o n measurement. Austral. Jour, of Agric. Res. 1:253-265. MARTIN, J.P. and S.A. bJAKSMAN. 1940. Influence of microorganisms on s o i l aggregation and erosion. S o i l S c i . 50:29-47. MOEHRING, D.M., C.X. GRANO and J.R. BASSETT. 1966. Properties of forested loess s o i l s after repeated prescribed burns. U.S. For. Serv. Southern For. Exp. Sta. Res. Note. SO-40 4 pp. MOLDENHAUER, U.C. and D.C. LONG. 1964. Influence o f . r a i n f a l l energy on s o i l l loss and i n f i l t r a t i o n rates : I. Effe c t over a range of textures. S o i l S c i . Soc. of Amer. Proc. 28:813-817. -147-MOORE, R.E. 1941. The r e l a t i o n of s o i l temperature to s o i l moisture: pressure potential, retention and i n f i l t r a t i o n rate. S o i l S c i . Soc. of Amer. Proc. 5:61-64. WEAL, H.J. 1938. The ef f e c t of the degree of slope and r a i n f a l l c h a r a c t e r i s t i c s on runoff and s o i l erosion. Univ. Miss. Res. B u l l . 280:48 pp. WEAL, J.L., E. WRIGHT and W.E. BOLLEN. 1965. Burning Douglas f i r slash. Res. Paper. For. Res. Lab. Oregon State University, C o r v a l l i s . 33 pp. PACKER, P.E. 1967. Forest treatment e f f e c t s on water qual i t y . In Inter. Symp. on For. Hyd. Pergamon Press, pp. 687-699. PEARSE, C.K. 1937. A simple device for measuring the adsorption rates of s o i l s . S c i . 85:459-460. PEELE, T.C. 1949. Relation of percolation rates through saturated cores to voluma of pores drained i n 15 and 20 minutes under 60 centimeters tension. S o i l S c i . Soc. of Amer. Proc. 14:359-361. PHILIP, J.R. 1957a. The theory of i n f i l t r a t i o n : I. The i n f i l t r a t i o n equation and i t s solution. S o i l S c i . 83:345-357. ' 1957b. The theory of i n f i l t r a t i o n : IV. Sorptivity and algabraic i n f i l t r a t i o n equations. S o i l S c i . 84:257-264. 1958. The theory of i n f i l t r a t i o n : VII. S o i l S c i . 86: 333-337. PIERCE, R.S. 1967. Evidence of overland flow on forest watersheds. In Inter. Synp. on For. Hyd. Pergamon Press: 247-252 REINHART, K.G., A.R.ESCHNER and G. R. TRIMBLE. 1963. Ef f e c t on strearnflow of four forest practices i n the mountains of West V i r g i n i a . U.S. For. Serv. Northeast For. and Range Exp. Sta. Res. Paper. NE-1 79 p.p. RICHARDS, L.A. 1952. Report of the subcommittee on permeability and i n f i l t r a t i o n , Committee on Terminology, S o i l Science 5ociety of America. . S o i l S c i . Soc. of Amer. Proc. 16:85-88. ROBINS, J.S. and E.L. NEFF. 1963,. P r i n c i p l e s of the erosion process. Forest Watershed Management Symp. Oregon State Univ. pp. 127-139. ROWE, J.S. 1959. Forest regions of Canada. A f f a i r s and Natural Res. For. Br. Can. Dept. Northern B u l l . 123.. 38 pp. -148-RLITH, R.H. 1967. S i l v i c u l t u r a l e f f e c t s of skyline crane and high-lead yarding. Jour, of For. 65:251-255. SAINI, G.R., A.A-. MacLEAN and J.J. DOYLE. .1966 The influence of some physical and chemical-properties on s o i l aggregation. Can. Jour, of S o i l S c i . 46:155-160. SARTZ, R.S. 1953. S o i l erosion on a fire-denuded forest area i n the Douglas f i r Region. Jour. S o i l and Water Cons. 8:279-281. SCHIFF, L. 1953. The e f f e c t of surface head on i n f i l t r a t i o n rates based on the performance of ring i n f i l t r o m e t e r s and ponds. Amer. Geophys. Union Trans. 34:257-266. SHULL, H. 1964. Influence of i n s t a l l a t i o n depth on i n f i l t r a t i o n from unbuffered cylinder i n f i l t r o m e t e r s . S o i l S c i . 97:279-280. SLATER, C.S. 1957. Cylinder i n f i l t r o m e t e r s for determining rates of i r r i g a t i o n . S o i l S c i . Soc. of Amer. Proc. 21:457-460. STAPLE, W.J. and :R.P. GUPTA. 1966. I n f i l t r a t i o n into homogeneous and layered columns of aggregated loam, s i l t loam and clay s o i l . Can. Jour, of S o i l S c i . 46:293-305. STEINBRENNER, E.C. 1955. The ef f e c t of repeated tractor t r i p s on the physical properties of forest s o i l s . Northwest S c i . 29:155-159. STEINBRENNER, E.C. and S.P.. GESSEL. 1955. Effext of tractor logging on s l i l s and regeneration i n the Douglas f i r region of Southwestern Washington. Proc. Soc. of Amer. For. Seattle, Wash. pp. 77-80. TACKETT, J.L. and R.W. PEARSON. 1965. Soma c h a r a c t e r i s t i c s of s o i l crusts formed by simulated r a i n f a l l . S o i l S c i . 99:407-413. TACKLE-, D. 1962. I n f i l t r a t i o n i n a western larch - Douglas f i r stand following cutting and slash treatment. U.S. For. Serv. Intermtn. Far. and Range Exp. Sta. Res. Note 89. 7 pp.. TARRANT, R.F. 1956. Ef f e c t of slashburning on some physical s o i l properties. For. S c i . 2:18-22. TRIMBLE,. G.R. and S. WEITZMAN. 1953. S o i l erosion from logging roads. S o i l S c i . Soc. of Amer. Proc. 17:152-154. , R.S. SARTZ and R.S.. PIERCE.; 1958. How type of s o i l f r o s t attects i n f i l t r a t i o n . Jour, S o i l and Water Cons. 13:81-82. W00LDRIDGE, D.D. 1960. Watershed disturbance from tra c t o r and skyline crane logging. Jour, of For. 58:369-372. -149-URIGHT, E. and R.F. TARRANT. 1957. Microbiological s o i l properties af t e r logging and slashburning. U.S. For. Serv. Pac. Northwest For. and Range Exp. Sta. Res. Note 157. 5 pp. _ and R.F.. TARRANT. 1958. Occurence of mycorrhizae aft e r logging and slashburning i n the Douglas f i r forest type. U.S. For. Serv. Pac. Northwest For. and Range Exp. Sta. Res. Note 160. 7 pp. a n d W.B. BOLLEN. 1961. Microflora of Douglas f i r forest s o i l . Ecology 42:825-828. ZIV/NUSKA, J.A. 1968. An economic view of the role of fore i n water-shed management. Jour, of For. 66:596-600. - i -APPEIMDIX I Forest Regions of the Vancouver Forest D i s t r i c t F O R E S T R E G I O N S O F T H E V A N C O U V E R F O R E S T - i i -i APPENDIX, I I S o i l P r o f i l e D e s c r i p t i o n s SOIL PROFILE DESCRIPTION* - Black A L - coniferous and deciduous debris intermingled with a dense moss cover F - 1.5 - 3.5 i n . of f e l t y , p a r t i a l l y decomposed debris permeated by fungal hyphae H - ).5 - 1.5 i n . of granular, dark humus - Granular mor* (Ae) - a discontinuous horizon having an abrupt t r a n s i t i o n to the underlying B, 5YR 5/1 grey, loamy sand, s t r u c t u r e -l e s s s i n g l e g r a i n , non-sticky, n o n - p l a s t i c , f r i a b l e , r o o t s common. (g e n e r a l l y found only under r o t t o n l o g s ) Bf 0-26" 5YR 4/5 reddi s h brown, g r a v e l l y sandy loam, weak med-ium subangular blocky, non-sticky, n o n - p l a s t i c , f r i a b l e , r o o t s abundant, having a gradual wavy lower boundary. BC 26-36" 7.5YR 5/5 brown, g r a v e l l y sandy loam, weak medium sub-angular blocky, non-sticky, n o n - p l a s t i c , f r i a b l e , roots abundant, pH =6.3, having a gradual wavy lower boun-dary. C 36-44" 2.5Y 6/4 y e l l o w i s h brown, g r a v e l l y sand, moderate med- ' ium subangular blocky, non-sticky, n o n - p l a s t i c , f r i -a ble, roots common, with an abrupt, smooth lower boun-dary. IIC 44"+ 5Y 7/3 pale yellow, s i l t y c l a y , s t r u c t u r e l e s s - massive, very s t i c k y , p l a s t i c , extremely f i r m e x h i b i t i n g con-c h o i d a l f r a c t u r e , roots r a r e , Whatcom glaciomarine. Moderately w e l l - d r a i n e d a c i d brown wooded developed i n Sunnyside g r a v e l l y sands over Whatcom glaciomarine. * -terminology and horizon nomenclature f o l l o w the National S a i l Survey Committee of Canada, October, 1965. * Report of the Sub-committee on Organic S o i l s Horizons of the National Committee on Forest Land, January 27, 1967. mimeo. SOIL PROFILE DESCRIPTION - Block B L - coniferous debris intermixed with a dense moss cover F - 2.0 - 4.0 i n . of f e l t y organic matter with abundant fungal hyphae H - 0.5 - 1.5 i n . of granular organic matter or humus - Granular mor Ae 0-1" 5YR 5/1 grey, sandy loam, weak medium subangular blocky, non-sticky, n o n - p l a s t i c , f r i a b l e , r o o t s common, pH = 4.0, d i s t i n c t wavy lower boundary. Bf1 1-18" 5YR 4/5 reddish brown, g r a v e l l y sandy loam, weak med-ium subangular blocky, non-sticky, n o n - p l a s t i c , f r i -a b l e , roots abundant. Within t h i s horizon from j u s t below the Ae to i t s lower boundary are found discon-tinuous humus-iron cemented pans % n t h i c k , 10YR 3/3, which appear permeable. Bf2 18-36" '7.5YR 5/5 brown, g r a v e l l y sandy loam with lenses of w e l l - s o r t e d sand,, s t r u c t u r e l e s s - s i n g l e g r a i n , non-s t i c k y , n o n - p l a s t i c , f r i a b l e , roots abundant. C 36-44" g r a v e l l y sand with lenses of sand, s i n g l e g r a i n , non-s t i c k y , n o n - p l a s t i c , loosej common, medium prominent mottles of 5YR 4/5 i n a matrix of 5Y 5/1. IIC 44"+ 5Y 5/2 o l i v e grey, g r a v e l l y sandy loam, s t r u c t u r e l e s s -massive, basal t i l l . A w e l l - d r a i n e d degraded a c i d brown wooded developed i n v a r i o u s l y reworked a b l a t i o n t i l l o v e r l y i n g basal t i l l . SOIL PROFILE DESCRIPTION - Black C L - coniferous and deciduous deb r i s intermixed with a dense moss cover F - 1.0 - 6.0 i n . of f e l t y , p a r t i a l l y decomposed debris with moderate l e v e l s of fungal hyphae H - 0.5 - 2.0 i n . of granular, dark humus - Granular mar Ah 0-8" 10YR 3/4 dark brown, sandy loam, weak subangular blocky, granular, s l i g h t l y s t i c k y , p l a s t i c , r oots abundant with a gradual lower boundary. Ahe 8-9" 5YR 2/1 dark reddish brown, sandy loam, weak subangular blocky, granular, s l i g h t l y s t i c k y , p l a s t i c , r oots abun-dant with a d i f f u s e lower boundary. Aeh 9-11" 10YR 5/1 dark grey, sandy loam, weak subangular blocky, granular, non-sticky, n o n - p l a s t i c , f r i a b l e , many r o o t s , with a wavy, d i f f u s e boundary. Ae 11-14" 10YR 4/2 dark greyish brown, sandy loam, weak subangu-l a r blocky, non-sticky, n o n - p l a s t i c , f r i a b l e , many root s with a gradual lower boundary. Bfh 14-19" 10YR 4/4 dark y e l l o w i s h brown, sandy loam, weak sub-angular blocky , non-sticky, n o n - p l a s t i c , f r i a b l e , many roots with a gradual lower boundary. Bf 19-24" 5YR 4/8 y e l l o w i s h red, loamy sand, weak subangular blocky, granular, non-sticky, n o n - p l a s t i c , f r i a b l e , many roots with a gradual lower boundary. BC 24-30" 10YR 5/8 l i g h t brownish-grey, loamy sand, lenses of w e l l sorted sand, s i n g l e g r a i n , non-sticky, n o n - p l a s t i c , loose o c c a s s i o n a l roots with a d i s t i n c t lower boundary. C 30"+ 10YR 6/6 y e l l o w i s h brown, g r a v e l l y , sand, s t r u c t u r e l e s s ^ massive, Whatcom glaciomarine, no r o o t s . A moderately w a l l - d r a i n e d o r t h i c podsol developed i n out-wash m a t e r i a l of a t e r r a c e o v e r l y i n g Whatcom glaciomarine. - i i i -APPEIMDIX I I I Vegetation C h a r a c t e r i s t i c s of Experimental U n i t s . Block Block Block VEGETATION CHARACTERISTICS ' A B C Key to. Species Cover Classes + rare or sparsely o c c u r r i n g 1 numerous but l i t t l e cover value 2 up to 0.1 cover 3 0.1 to 0.25 cover k 0.25 to 0.5 cover 03 c CO 3 3 r H o n o o U JZ u u T J W CO + > • H CO CO C _ r l r l D in ui u a n cu c • a ^ + > CO 3 3 <-H • X I O O T J to to - P • H co cu c I - I r - i o cn in cj C J T J - i J CO 3 a o p u T J CO • H CU - Y r H t n c_j TREE LAYER Acer c i r c i n a t u m Betula p a p y r i f e r a var. commutata + + + + Cornus n u t t a l l i i + + Prunus emarginata + + + + Pseudotsuga m e n z i e s i i + 2 2 3 Rhamnus purshiana + + Thuja p l i c a t a + 1 2 1 Tsuga h e t e r o p h y l l a + 2 + 1 1 1 SHRUB LAYER Acer c i r c i n a t u m + + + + 1 + + + Acer macrophyllum + + + Alnus rubra + + + + Betula p a p y r i f e r a var. commutata + + + + Corylus r o s t r a t a var. c a l i f o r n i c a + G a u l t h e r i a s h a l l o n + + + + + + + Linnaea b o r e a l i s + Menziesia f e r r u g i n e a + + • + Oplopanax horr i d u s + + + Prunus emarginata + + + Rhamnus purshiana + + + Rubus leucodermis + + + + + + + Rubus macropetalous 1 + + + + + + + Rubus p a r v i f l o r u s + + + + + + + + Rubus s p e c t a b i l i s + 1 1 + + + + Rubus ursinus + + + S a l i x s c o u l e r i a n a + + + + 1 Sambucus c a l l i c a r p a + + + + H-Spiraea d o u g l a s i i + + + + Tsuga h e t e r o p h y l l a + + + + Vaccinium alaskaensis + + + Vaccinium p a r v i f o l i u m + + + + + + + HERB LAYER Anaphalis margaritaceae + + + + + + + Athyrium f i l i x - f e m i n a + + 1 + + + + Blechnum spic a n t + + + + + + + Carex spp. + + + + 1 3 D co CD x CD cr 33 TJ ZT O • < I - -e+>< H- c+ Q . M H- (-" ca n Q . r r co c r-1 3 T3 c c 03 3 H' r-"T3 O CO CD H • C 3 CO C 3 T) 3 t-> 3 03 K " IO C H' 3 O C+TJ ZT C CO 3 o n c 3 C 3 CL C Hr1 03 c+ C 3 • 2 r -3 CD 1_. _ c n 3 o i—• H* CD 3 T3 03 03 H> H" I O CD •3 co 3 CO 3 N H' CO CO H-x m o « < C H -r - >i n 3 3" ^ n <: cn O 3 3 3 n c 3" 3 3 . C 3 03 T3 a CD CD 03 3 I O n CL. 03 CO CO 3 3 3 C 03 CO 3 .. -1) c 03 n CD JO < m za — i CO 3 c-f-03 t-1 H * 03 03 13 a 01 —I C/3 H - e+ 03 03 i-j a CO 3" l-"< r-> 03 03 n 4 I - 1 I—• H " -ij 03 O c+ H 03 H" 03 rr 03 'SS CD • CD H» 3 H- CD a n 03 H-i a a • < 03 C T3 t-T3 t a • at H-CO 33 T ) C e-r CD a. c 3 03 X I c H« I—' (-• 3 C 3 "0 T3 a d HQ) «< 03 TJ c f 03 n ZT C 2 C_i CT Cl c «; 3 3 n 3 c o CD a 03 C X 4 H TJ C H 1 3 C 3 3 O 3 Q . D. *i t-u *< H - a T3 c+ ro H " CO CD CT 0) 0) (->• C 3 C t—' rr 3" CO *-i 03 H" T3 03 T3 • CO 3-03 m n t j o 3 in c c o 3 03 3 03 03 D.CD 3 CO CO rt- H• H ' CD C 3 03 CO n o 3 e+ H" 3 C CO a + + + + + + + ro ro + + + + + + + + + + + + + + + + + r \ 3 + + + + + + + + -_ _\ + + + + + + + + + + + + __ + + + + + + + + + + + + + + ro + + + + + + + + + + + + A3 + + Skidroad Slashburned Clearcut.. C o n t r o l Skidroad Slashburned Clearcut C o n t r o l Skidroad Clearcut - i v-APPEWDIX.. IM Photographic Descriptions of Experimental Units B l o c k A Photograph 2. Slashburned Pho tog raph 3. C l e a r c u t Pho tog raph 4 . C o n t r o l Black B Photograph 6. Slashburned Photograph 7. Clearcut Photograph 8 . Control Block C Photograph 9. Skidroad Photograph 10. Clearcut APPENDIX V P r a c t i c a l Aspects of Ring I n f i l t r o m e t e r Use Photograph 1. Infiltrometers and a n c i l l a r y equipment ready to be unloaded and hand-packed to study s i t e s . Photograph 2. Gasoline pump, dam and impounded water supply required to operate ring i n f i l t r o m e t e r s . Photograph 3. F i l l i n g holding tanks near study s i t e (note in f i l t r o m e t e r i n the center of the photo) - v i -A'PPEIMDIX VI Hey to V a r i a b l e s HEY TO VARIABLES - Blocks A and B S o i l V a r i a b l e 0-3* 4-7 8-12 12-18 18-24 Averai Bulk density (grn./cc.) X1 X2 X3 X4 X5 X6 Aeration p o r o s i t y ( c c , /cc. ) X7 xa X9 X10 X11 X12 T o t a l p o r o s i t y (cc./cc .) X13 X14 X15 X16 X17 X13 S o i l f r a c t i o n > 2 mm. percent (wt.) X19 X20 X21 X22 X23 X24 Sand f r a c t i o n percent (wt.) X25 X26 X27 X28 X29 X30 S i l t f r a c t i o n percent (wt.) X31 X32 X33 X34 X35 X3S Clay f r a c t i o n percent (wt.) X37 X38 X39 X40 X41 X42 Antecedent s o i l water percent (wt.) X43 X44 X45 X46 X47 X48 Organic matter > 2 mm. percent (wt.) X49 X50 X51 X52 Organic matter < 2 mm. percent (wt.) X53 X54 X55 X56 T o t a l organic matter percent (wt.) X57 X58 X59 X60 P o t e n t i a l l a t e r a l flow l a y e r ( cc. / cc. of s o i l ) X67 L i m i t i n g l a y e r ( c c ./cc. of s o i l ) X68 * depth of s o i l l a y e r i n inches P l o t Character V a r i a b l e % L i t t e r cover X61 Depth of l i t t e r l a y e r (inches) X62 Depth of fermented l a y e r (inches) X63 Depth of humus l a y e r (inches) X64 Macro-vegetation cover (%) X65 Micro-vegetation cover (%) X6G I n f i l t r a t i o n V a r i a b l e s : F i r s t - h o u r i n f i l t r a t i o n r a t e ( i n . / h r . ) = Y1 Third-hour i n f i l t r a t i o n r a t e ( i n . / h r . ) = Y3 KEY TO VARIABLES - Block C S o i l V a r i a b l e 0-3* 4-7 8-12 12-18 A v e r a i Bulk density (gm./cc.) X1 X2 X3 X4 X5 Aeration p o r o s i t y (cc./cc.) X6 X7 X8 X9 X10 T o t a l p o r o s i t y (Cc./cc.) X11 X12 X13 X14 X15 S o i l f r a c t i o n > 2 mm. percent (wt.) X16 X17 X18 X19 X20 Sand f r a c t i o n percent (tut.) X21 X22 X23 X2U X25 S i l t plus c l a y f r a c t i o n percent (tut.) X26 X27 X26 X29 X30 Antecedent s o i l mater percent (wt.) X31 X32 X33 X34 X35 Organic matter > 2 mm. percent (wt.) X36 X37 X38 X39 X40 Organic matter < 2 mm. percent (wt.) X41 X42 X43 X44 X45 T o t a l organic matter percent (wt.) X46 X47 X4B X49 X50 P o t e n t i a l l a t e r a l flow l a y e r (cc./cc. of s o i l ) X57 L i m i t i n g l a y e r ( c c . / c c . of s o i l ) X58 * depth of s o i l l a y e r i n inches P l o t Character Va r i a b l e % L i t t e r cover X51 Depth of l i t t e r l a y e r (inches) X52 Depth of fermented l a y e r (inches) X53 Depth of humus l a y e r (inches) Y5k Macro-vegetation cover (.%) X55 Micro-vegetation cover (%) X56 A r t i f i c i a l regeneration x r. g diameter i n inches A r t i f i c i a l regeneration YBQ height i n f e e t F i r s t - h o u r i n f i l t r a t i o n r a t e ( i n . / h r . ) = Y1 Third-hour i n f i l t r a t i o n r a t e ( i n . / h r . ) = Y3 I n f i l t r a t i o n V a r i a b l e s : - v i i -APPEIMDIX VII Va r i a b l e C h a r a c t e r i s t i c s by Experimental Unit NUMBER OF O B S E R V A T I O N S = 15 BLOCK A SLASHBURNED SYMBOL MEAN XI 0 . 7 4 4 0 0 0 E 0 0 X2 0 . 7 5 4 6 6 7 E 0 0 X3 0 . 7 6 7 3 3 3 E 0 0 X4 0 . 8 1 3 3 3 3 E 0 0 X5 0 . 8 7 0 6 6 7 E 0 0 X6 0 . 7 8 2 0 0 0 F 0 0 X7 0 . 3 0 0 6 6 7 E 0 0 X8 0 . 2 9 0 6 6 7 E 0 0 X9 0 . 2 8 2 0 0 0 E 0 0 X IO 0 . 2 6 0 6 6 7 E 0 0 X l l 0 . 2 1 6 6 6 7 E 0 0 X12 0 . 2 7 3 3 3 3 E 0 0 X13 0 . 7 0 0 0 0 0 E 0 0 X14 0 . 7 0 0 0 0 0 E 0 0 X15 0 . 6 9 6 6 6 7 E 0 0 X16 0 . 6 9 6 0 0 0 E 0 0 X17 0 . 6 7 5 3 3 3 E 0 0 X18 0 . 6 8 3 0 0 0 E 00 X19 0 . 2 7 2 6 0 0 E 02 X20 0 . 2 6 4 6 6 7 E 02 X21 0 . 2 6 2 1 6 7 E 02 X22 0 . 2 6 6 8 0 0 E 02 X23 0 . 3 9 0 4 0 0 E 02 X24 0 . 2 9 2 1 6 7 E 02 X25 0 . 4 0 3 3 3 3 E 02 X26 0 . 4 5 3 3 3 3 E 02 X27 0 . 4 4 0 0 0 0 E 02 X28 0 . 5 0 0 0 0 0 E 02 X29 0 . 4 6 6 6 6 7 E 02 X30 0 . 4 5 3 3 3 3 E 02 X31 0 . 5 3 3 3 3 3 E 02 X32 0 . 4 6 6 6 6 7 E 02 X33 0 . 4 5 3 3 3 3 E 02 X34 0 . 3 9 0 0 0 0 E 02 X35 0 . 4 3 0 0 0 0 E 02 X36 0 . 4 5 3 3 3 3 E 02 X37 0 . 6 3 3 3 3 3 E 01 X38 0 . 8 0 0 0 0 0 E 01 X39 0 . 1 0 6 6 6 7 E 02 X40 0 . 9 6 6 6 6 7 E 01 X41 0 . 1 0 3 3 3 3 E 02 X42 0 . 9 3 3 3 3 3 E 01 X43 0 . 9 3 4 9 8 0 F 02 X44 0 . 8 2 8 8 6 7 E 02 X45 0 . 5 6 4 0 2 7 E 02 X46 0 . 4 6 6 2 8 0 E 02 X47 0 . 4 3 5 8 4 7 E 02 X48 0 . 6 4 6 6 5 3 E 02 X49 0 . 8 9 8 8 6 7 E 01 X50 0 . 6 8 0 5 3 3 E 01 X51 0 . 6 1 0 6 6 7 E 01 X52 0 . 7 3 0 1 3 3 E 01 X53 0 . 1 4 0 8 5 3 F 02 X54 0 . 1 2 2 5 0 7 E 02 X55 0 . 1 0 5 9 1 3 E 02 X56 0 . 1 2 0 8 5 3 E 02 X57 0 . 1 2 8 2 0 7 E 02 X58 0 . 1 0 8 9 7 3 E 02 X59 0 . 9 4 7 8 0 0 E 01 X60 0 . 1 1 0 5 6 0 E 02 X61 0 . 5 3 6 6 6 7 E 02 X62 0 . . 1 4 0 0 0 0 E 00 X6-3 - ' 0 . 3 1 1 3 3 3 E 01 X64 0 . 1 1 8 6 6 7 E 01 X65 0 . 4 0 1 3 3 3 E 02 X 66 0 . 6 4 6 6 6 7 E 02 X67 0 . 2 7 8 0 0 0 E 0 0 Y2 0 . 1 0 8 0 4 7 E 02 Y4 0 . 1 3 2 4 7 3 E 02 X68 0 . 2 1 4 0 0 G E 0 0 STANDARD MINIMUM MAXIMUM C O E F F I C I E N T OF D E V I A T I O N V A R I A T I O N 0 . 1 5 4 0 7 8 E 00 0 . 4 3 0 0 0 0 E 00 3 . 9 7 0 0 0 0 E 00 2 0 . 7 1 0 . U 5 4 4 1 E 00 0 . 5 3 0 O 0 0 E 0 0 0. 9 7 0 0 0 0 E 00 1 5 . 3 0 0 . 1 5 2 0 5 6 E 00 0 . 5 4 0 0 0 0 E 00 0. 1 1 0 0 0 0 E 01 1 9 . 8 2 0 . 2 0 1 9 7 8 E 00 0 . 5 4 0 0 0 0 E 0 0 0. 1 2 3 0 0 0 E 01 2 4 . 8 3 0 . 2 2 0 0 4 8 E 00 0 . 6 0 0 C 0 0 E 0 0 &. 1 2 9 0 0 0 E 01 2 5 . 2 7 0 . 1 2 3 3 5 8 E 00 0 . 6 1 0 0 0 0 E 0 0 0. 1 0 1 0 0 0 E 01 1 5 . 7 7 0 . 4 2 1 6 7 5 E - •01 0 . 1 9 0 0 0 0 E 0 0 0. 3 6 0 C 0 0 F 00 1 4 . 0 2 0 . 6 7 3 4 4 2 E - •01 0 . 1 2 0 0 0 0 E 0 0 J . 3 6 0 0 0 0 E 00 2 3 . 1 7 0 . 6 7 9 4 9 6 E - •01 0 . 1 6 0 0 0 0 E 0 0 c . 3 8 0 0 0 0 E 00 2 4 . 10 0 . 6 2 0 4 4 5 E - •01 0 . 1 2 0 0 0 0 F 0 0 c. 3 4 0 0 0 0 E 00 2 3 . 3 0 0 . 5 9 9 6 0 3 E - •01 0 . 1 1 0 G O O E 0 0 0. 3 1 0 0 0 0 F 00 2 7 . 5 7 0 . 5 1 5 0 1 3 E - •01 0 . 1 8 0 0 0 0 E 0 0 0. 3 5 0 0 0 0 ! : 00 1 8 . 8 4 0 . 5 8 3 0 9 7 E - •01 0 . 6 2 0 0 0 0 E 0 0 0. 820000L" 00 8 . 3 3 0 . 4 2 7 6 1 9 E - •01 0 . 6 2 0 0 0 0 E 0 0 0.7 8 0 0 0 0 E 00 6 . 1 1 0 . 5 8 3 9 1 2 E - 01 0 . 5 6 0 0 0 0 E 0 0 0. 7 8 0 0 0 0 E 00 8 . 3 3 0 . 7 5 2 9 0 1 E - •01 0 . 5 4 0 0 0 0 E 0 0 0. 8 0 0 0 0 0 E 00 1 0 . 8 2 0 . 7 6 3 3 2 7 E - •01 0 . 5 1 0 0 0 0 E 0 0 0. 7 7 0 C 0 0 E 00 11 . 30 0 . 4 5 2 2 9 8 E - •01 0 . 6 1 0 0 0 0 E 00 0 . 7 5 0 0 0 0 E 00 6 . 5 7 0 . 6 7 5 6 7 4 E 01 0 . 1 8 6 8 0 0 E 02 0. 3 4 5 0 0 0 G 02 2 4 . 79 0 . 5 4 3 3 8 3 E 01 0 . 1 9 0 9 0 0 E 02 0 . 308800L" 02 2 0 . 5 3 0 . 5 7 6 1 3 0 E 01 0 . 1 9 1 4 0 0 E 02 0 • 327 ' iOOE 02 2 1 . 9 8 0 . 1 5 9 7 1 7 E 01 0 . 2 5 5 9 0 0 E 02 . 0. 2 9 6 9 0 0 C 02 5 . 9 9 0 . 3 6 0 2 6 2 E 01 0 . 3 5 2 2 0 0 E 02 0.4 3 6 6 0 0 C 02 9 . 2 3 0 . 3 2 1 6 3 0 E 01 0 . 2 4 9 6 0 0 E 02 0. 3 2 2 9 0 0 E 0 2 1 1 . 0 1 0 . 9 6 1 1 5 0 E 01 0 . 3 1 0 0 0 0 E 02 0 • 5 3 0 0 0 0 E 02 2 3 . 3 3 0 . 1 0 4 3 1 2 E 02 0 . 3 5 0 0 0 0 E 02 0. 5 9 0 0 0 0 F 02 2 3 . 0 1 0 . 1 5 2 1 2 8 E 02 0 . 2 6 0 0 0 0 E 02 0. 6 2 0 0 0 0 F 02 3 4 . 5 7 0 . 1 1 1 8 0 3 E 02 0 . 4 0 0 0 C 0 E 02 C • 6 5 0 0 0 0 E 02 2 2 . 36 0 . 1 3 1 2 9 4 E 02 0 . 3 4 0 0 0 0 E 02 0. 6 4 0 0 0 0 E 02 2 8 . 1 3 0 . 12081 IE 02 0 . 3 3 0 0 0 0 F 02 0. 6 1 0 0 0 0 F 02 2 6 . 6 5 0 . 1 0 7 0 1 6 E 02 0 . 3 9 0 0 0 0 E 02 0. 6 3 0 0 0 0 c 02 2 0 . 0 7 ft. 1 0 2 2 3 7 E 02 0 . 3 3 0 0 0 0 E 02 0. 5 6 0 0 0 0 E 0? 2 1 . 9 1 0 . 1 4 3 7 5 9 E 02 0 . 2 8 0 0 0 0 E 02 0. 62' JOOOr 02 3 1 . 7 1 0 . 1 1 3 7 U 4 E 0? 0 . 2 4 0 0 0 0 E 02 0. 5 0 0 0 0 0 H 02 2 9 . 15 0 . 1 2 6 2 0 8 E 02 0 . 2 6 0 0 0 0 E - 02 0 • 5 4 0 0 0 0 E 02 2 9 . 3 5 0 . 1 1 7 2 1 0 E 02 0 . 3 0 0 0 0 0 E 02 0 . 5 7 0 0 0 0 E 02 2 5 . 8 6 0 . 1 2 9 0 9 9 E 01 0 . 5 0 0 0 0 0 E 01 0. 8 0 0 0 0 0 F 01 2 0 . 3 8 0 . 8 4 5 1 5 4 E 00 0 . 7 0 0 0 0 0 E 01 0 • 9 0 0 0 0 0 E 01 1 0 . 5 6 0 . 9 7 5 9 0 0 E 00 0 . 1 0 0 0 0 0 E 02 0. 12000011 02 9 . 1 5 0 . 1 2 9 0 9 9 E 01 0 . 8 0 0 0 0 0 F 01 0. U O O O O E 02 1 3 . 36 0 . 1 2 9 0 9 9 E 01 0 . 9 0 0 0 0 0 E 01 0. 1 2 0 0 0 0 E 02 1 2 . 4 9 0 . 4 3 7 9 5 0 E 00 0 . 9 0 0 0 0 0 F 01 0 . 1 0 0 0 0 0 E 02 5 . 2 3 0 . 8 1 5 0 3 4 E 02 0 . 2 0 3 7 0 0 E 02 0 . 2 8 9 1 6 0 E 03 8 7 . 1 7 0 . 8 8 9 9 3 5 E 02 0 . 1 9 3 8 0 0 E C2 0. 2 9 4 9 7 0 E 03 1 0 7 . 3 7 0 . 3 9 2 3 1 5 E 02 0 . 1 5 1 9 0 0 E 02 J . 1 7 5 9 8 0 E 03 6 9 . 56 0 . 2 215 3 7 E 02 0 . 1 3 2 8 0 0 E 02 0 . 9 9 0 3 0 0 F 02 4 7 . 5 1 0 . 1 2 5 4 4 7 E 02 0 . 1 8 2 7 0 0 E 02 0.6 7 8 8 0 0 E 02 2 8 . 7 8 0 . 4 2 8 3 8 7 E 02 0 . 1 8 5 2 0 0 E 02 u • 1 7 4 9 5 0 E 03 6 6 . 2 5 0 . 4 7 5 4 0 9 E 01 0 . 3 2 3 0 0 0 E 01 0 . 2 2 3 9 0 0 E 02 5 2 . 89 0 . 3 6 6 2 1 6 F 01 0 . 1 6 3 0 0 0 F 01 0 . 1 4 6 5 0 0 E 02 5 3 . 8 1 0 . 3 0 1 2 0 4 E 01 0 . 2 6 6 0 0 0 E 01 0 . 14*500fc 02 4 9 . 32 0 . 2 1 2 3 0 8 E 01 . 0 . 2 8 8 0 0 0 E 01 0. 1 1 5 3 0 0 C 02 2 9 . 0 8 0 . 4 8 1 1 4 8 E 01 0 . 8 5 3 0 0 0 E 01 0 . 2 4 3 3 0 0 E 02 3 4 . 1 6 0 . 5 2 3 4 0 1 E 01 0 . 5 0 4 0 0 0 E 01 0. 2 5 1 3 0 0 E 02 4 2 . 72 0 . 3 3 2 8 9 1 E 01 0 . 4 5 0 0 0 0 E 01 0 • 1 9 3 7 0 0 E 02 3 1 . 4 3 0 . 3 6 6 4 2 5 E 01 0 . 6 0 2 0 0 0 F 01 0. 1 9 4 6 0 0 E 02 3 0 . 32 0 . 4 1 3 1 0 5 E 01 0 . 8 2 0 0 C O E 01 0. 20 7600E 02 3 2 . 22 0 . 4 2 5 8 2 8 E 01 0 . 5 1 4 0 0 0 E 01 rt. 2 2 0 7 0 0 E 02 3 9 . 0 8 0 . 2 8 7 7 6 3 E 01 0 . 4 0 9 0 0 0 E 01 0. 1 6 5 0 0 0 E 02 3 0 . 36 0 . 3 3 5 4 2 5 E 01 0 . 5 9 5 C 0 0 F 01 0 . I 7 2 5 0 0 F 02 3 0 . 34 0 . 4 0 2 1 3 1 E 02 0 . 5 0 0 0 0 0 E 01 0. 1 0 0 0 0 0 E 0 3 7 4 . 9 3 0 . 1 4 0 4 0 8 E 00 0- c • 5 0 0 0 0 0 E 00 1 0 0 . ? 9 0 . 3 7 2 3 0 7 E 01 0 . 0. 1 3 C 0 0 0 E 02 1 1 9 . 5 8 0 . 3 4 2 2 7 9 E 01 0 . j . I 3 0 0 0 0 E 02 2 8 8 . 4 4 0 . 4 2 2 8 6 2 E 02 0 . 0 • 1 0 0 0 0 0 E 03 1 0 5 . 3 6 0 . 3 4 8 7 6 7 E 02 0 . 0 . l ooooor 03 5 3 . 93 0 . 4 5 5 4 4 3 E - •01 0 . 2 0 0 0 0 0 E 0 0 0 . 3 4 0 0 0 0 E 00 1 6 . 18 0 . 2 7 5 9 2 7 E 01 0 . 6 2 5 0 & 0 E 01 0. 1 4 6 7 0 0 E 02 2 5 . 5 4 0 . 2 7 5 6 3 9 E 01 0 . 9 5 6 0 0 0 E 01 0 . 1 7 8 7 0 0 C 02 2 0 . 8 1 0 . 5 2 6 1 7 2 E - •01 0 . 1 1 0 0 0 0 F 0 0 0 . 2 7 0 0 0 0 F 00 2 4 . 5 9 I NUMBER OF O B S E R V A T I O N S = 15 BLOCK A CLEARCUT SYMBOL MEAN STANDARD D E V I A T I O N MINIMUM MAXIMUM C O E F F I C I E N T OF V A R I A T I O N XI 0 . 7 4 2 6 6 7 E 0 0 0 . 1 5 8 9 0 1 E 0 0 0 . 4 4 0 0 0 0 E 0 0 0 . 1 0 0 0 0 0 E 01 2 1 . 4 0 X2 0 . 9 9 8 0 0 0 E 0 0 0 . 3 1 1 1 0 9 E 00 0 . 4 7 0 0 0 0 E 0 0 0 . 1 7 2 0 0 0 E 01 3 1 . 1 7 X3 0 . 9 9 7 3 3 3 E 0 0 0 - 2 0 8 7 2 0 E 0 0 0 . 6 7 0 0 0 0 E 0 0 0 . 1 4 3 0 0 0 E 01 2 0 . 9 3 X4 0 . 1 0 2 4 6 7 E 01 0 . 2 2 7 9 6 8 E 00 O . 5 5 0 0 O 0 E 0 0 0 . 1 3 3 0 0 0 E 01 2 2 . 2 5 X5 0 . 1 0 2 0 6 7 E 01 0 . 2 5 5 5 5 2 E 00 0 . 4 3 0 0 0 0 E 0 0 0 . 1 3 9 0 0 0 E 01 2 5 . 0 4 X6 0 . 9 4 0 6 6 7 E 0 0 0 . 1 6 9 0 5 1 E 0 0 0 . 5 6 0 0 0 0 E 0 0 0 . 1 1 9 0 0 0 E 01 1 7 . 9 7 X7 0 . 2 8 4 0 0 0 E 0 0 0 . 4 8 6 6 8 0 E - 01 0 . 1 9 0 0 0 0 E 0 0 0 . 3 4 0 0 0 0 E 00 1 7 . 1 4 X8 0 . 2 3 5 3 3 3 E 0 0 0 . 4 7 3 3 8 7 E - •01 0 . 1 6 0 0 0 0 E 0 0 0 . 3 4 0 0 0 0 E 0 0 2 0 . 1 2 X9 0 . 2 1 4 0 0 0 E 0 0 0 . 5 9 1 3 6 6 E - •01 0 . 4 0 0 0 0 0 E - •01 O . 2 8 0 O 0 O E 00 2 7 . 6 3 X IO O . 2 0 6 6 6 7 E 0 0 0 . 6 1 2 5 6 7 E - 01 0 . 4 0 0 0 0 0 E - •01 0 . 2 9 0 0 0 0 c 00 2 9 . 6 4 X U 0 . 2 2 3 3 3 3 E 0 0 0 . 5 0 8 0 3 1 E - 01 0 . 1 4 0 0 0 0 E 0 0 0 . 3 6 0 0 0 0 E 00 2 2 . 7 5 X12 0 . 2 3 0 6 6 7 E 0 0 0 . 3 4 7 3 7 1 E - 01 0 . 1 4 0 C 0 0 E 0 0 0 . 2 7 0 0 0 0 E 00 1 5 . 0 6 X13 0 . 7 0 6 0 0 0 E 0 0 0 . 6 2 4 2 7 3 E - 01 0 . 6 0 0 0 0 0 E 0 0 0 . 8 2 0 0 0 0 E 0 0 8 . 8 4 X14 0 . 6 0 8 6 6 7 E 0 0 0 . 1 1 8 8 5 6 E 0 0 0 . 3 4 0 0 0 0 E 0 0 0 . 8 1 0 0 0 0 E 00 1 9 . 5 3 X15 0 . 6 0 8 0 0 0 E 0 0 0 . 8 0 1 9 6 3 E - •01 0 . 4 5 0 0 0 0 E 0 0 0 . 7 3 0 0 0 0 E 0 0 1 3 . 1 9 X16 0 . 6 1 3 3 3 3 E 0 0 0 . 8 5 6 6 2 7 E - •01 0 . 5 0 0 0 0 0 E 0 0 0 . 7 9 0 0 0 0 E 00 1 3 . 9 7 X17 0 . 6 1 6 0 0 0 E 0 0 0 . 9 7 1 5 9 7 E - •01 0 . 4 8 0 0 0 0 E 0 0 0 . 8 4 0 0 0 0 E 00 1 5 . 7 7 X18 0 . 6 3 0 0 0 0 E 0 0 0 . 6 2 4 5 0 1 E - •01 0 . 5 4 0 0 0 0 E 0 0 0 . 7 7 0 0 0 0 E 00 9 . 9 1 X 1 9 0 . 4 2 3 9 3 3 E 02 0 . 4 5 6 8 0 8 E 01 0 . 3 6 1 8 0 0 E 02 0 . 4 6 0 1 0 0 E 02 1 0 . 7 8 X20 0 . 4 6 4 1 6 7 E 02 0 . 1 0 4 9 5 2 E 02 0 . 3 3 3 4 0 0 E 02 0 . 5 8 0 5 0 0 E 02 2 2 . 6 1 X21 0 . 4 2 5 4 0 0 E 02 0 . 5 1 3 3 7 6 E 01 0 . 3 5 8 5 0 0 E 02 0 . 4 7 7 1 0 0 E 02 1 2 . 0 7 X22 0 . 4 0 5 1 6 7 E 02 0 . 8 9 1 4 6 2 E 01 0 . 2 8 3 4 0 0 E 02 G . 4 6 3 4 0 0 E "02 2 2 . 0 0 X23 0 . 3 5 9 1 3 3 E 02 0 . 7 8 5 0 2 7 E 01 0 . 2 7 7 7 0 0 E 02 0 . 4 6 0 3 0 0 E 02 2 1 . 8 6 X24 0 . 3 8 4 9 0 0 E 02 0 . 7 4 8 1 8 5 E 01 0 . 3 2 3 0 0 0 E 02 0 . 4 8 6 3 0 0 E 02 1 9 . 4 4 X25 0 . 4 1 3 3 3 3 E 02 0 . 1 3 5 3 1 3 E 02 0 . 2 5 0 0 0 0 E 02 0 . 5 7 0 0 0 0 E 02 3 2 . 7 4 X26 0 . 5 3 3 3 3 3 E 02 0 . 3 9 9 4 )4E 01 0 . 4 8 0 0 0 0 E 02 0 . 5 7 0 0 0 0 E 02 7 . 4 9 X27 0 . 5 7 6 6 6 7 E 02 0 . 6 5 6 4 7 0 E 01 0 . 4 9 0 0 0 0 E 02 0 . 6 4 0 0 0 0 E 02 1 1 . 3 8 X28 0 . 5 4 6 6 6 7 E 02 0 . 1 4 5 4 8 8 E 02 0 . 3 5 C O O O E 02 0 . 6 7 0 0 0 0 E 02 2 6 . 6 1 X29 0 . 6 5 3 3 3 3 E 02 0 . 7 5 7 5 0 2 E 01 0 . 5 5 0 0 0 0 E 02 0 . 7 1 0 0 0 0 E 02 1 1 . 5 9 X30 0 . 5 4 3 3 3 3 E 02 0 . 6 7 7 8 8 2 E 01 0 . 4 6 0 C 0 0 E 02 0 . 6 2 0 0 0 0 E 02 1 2 . 4 8 X31 0 . 4 8 3 3 3 3 E 02 0 . 1 3 2 1 0 7 E 02 0 . 3 4 0 0 0 0 E 02 0 . 6 5 0 0 0 0 E 02 2 7 . 3 3 X32 0 . 3 7 0 0 0 0 E 02 0 . 3 6 8 3 9 4 E 01 0 . 3 4 0 0 0 0 E 02 U . 4 2 0 0 0 0 E 02 9 . 9 6 X33 0 . 3 4 6 6 6 7 E 02 0 . 6 3 8 3 3 8 E 01 0 . 2 9 0 0 0 0 E 02 0 . 4 4 0 0 0 0 E 02 1 9 . 8 6 X 34 0 . 3 6 0 0 0 0 E 02 0 . 1 4 7 3 5 8 E 02 0 . 2 4 0 0 0 0 E 02 0 . 5 6 0 0 0 0 E 02 4 0 . 9 3 X35 0 . 2 7 3 3 3 3 E 02 0 . 8 5 4 9 5 8 E 01 0 . 2 1 0 0 0 0 E 02 0 . 3 9 0 0 0 0 E 02 3 1 . 2 8 X36 0 . 3 6 3 3 3 3 E 02 0 . 6 8 3 1 3 0 E 01 0 . 2 9 0 0 0 0 E 02 0 . 4 5 0 0 0 0 E 02 1 8 . 8 0 X37 0 . 1 0 3 3 3 3 E 02 0 . 1 2 9 0 ^ 9 E 01 0 . 9 0 0 0 0 0 E 01 0 . 1 2 0 0 0 0 E 02 1 2 . 4 9 X38 0 . 9 6 6 6 6 7 E 01 0 . 4 8 7 9 5 0 E 0 0 0 . 9 0 0 0 0 0 E 01 0 . 1 0 0 0 0 0 E 02 5 . 0 5 X39 0 . 7 6 6 6 6 7 E 01 0 . 9 7 5 9 0 0 E 00 0 . 7 0 0 0 0 0 E 01 0 . 9 0 0 0 0 0 E 01 1 2 . 7 3 X40 0 . 9 3 3 3 3 3 E 01 0 . 4 8 7 9 5 0 E 00 0 . 9 0 0 0 0 0 E 01 0 . 1 0 0 0 0 0 E 02 5 . 2 3 X41 0 . 7 3 3 3 3 3 E 01 0 . 9 7 5 9 0 0 E 0 0 0 . 6 0 0 0 0 0 E 01 0 . 8 0 0 0 0 0 E 01 1 3 . 3 1 X42 0 . 9 0 0 0 0 0 E 01 0 . 0 . 9 0 0 0 0 0 E 01 0 . 9 0 0 0 0 0 E 01 0 . 0 0 X43 0 . 2 1 8 6 7 4 E 03 0 . 1 0 2 0 7 2 E 03 0 . 8 6 7 5 0 0 E 02 0 . 4 6 0 9 9 0 E 03 4 6 . 6 8 X44 0 . 1 5 5 2 4 0 E 0 3 0 . 1 1 4 7 4 8 E 03 0 . 4 6 4 4 0 0 E 02 0 . 3 6 6 9 2 0 E 03 7 3 . 9 2 X45 0 . 8 0 6 9 1 3 E 02 0 . 4 2 8 9 1 0 E 02 0 . 3 7 1 0 0 0 E 02 0 . 1 8 9 4 4 0 E 03 5 3 . 1 5 X46 0 . 7 9 5 7 8 0 E 02 0 . 4 0 1 0 1 5 E 02 0 . 2 6 5 9 0 0 E 02 0 . 1 5 4 4 6 0 E 03 5 0 . 3 9 X47 0 . 7 5 6 6 7 3 E 02 0 . 4 0 3 9 5 4 E 02 0 . 3 4 8 4 0 0 E 02 0 . 1 6 1 6 9 0 E 03 5 3 . 39 X48 0 . 1 2 1 9 7 2 E 03 0 . 4 7 3 3 4 1 E 02 0 . 6 5 4 6 0 0 E 02 0 . 2 0 7 8 8 0 E 03 3 8 . 8 1 X 4 9 0 . 4 1 4 8 6 7 E 01 0 . 3 2 5 0 3 2 E 01 0 . 1 2 9 0 0 0 E 01 0 . 1 2 5 8 0 0 E 02 7 8 . 3 5 X50 0 . 3 6 5 2 0 0 E 01 0 . 3 6 7 3 4 5 E 01 0 . 9 6 0 0 0 0 E 0 0 0 . 1 5 4 9 0 0 E 02 1 0 0 . 5 9 X51 0 . 3 6 9 2 0 0 E 01 0 . 4 6 3 9 9 3 E 01 0 . U 2 0 0 0 E 01 0 . 1 9 9 1 0 0 E 02 1 2 5 . 6 8 X52 0 . 3 8 5 2 6 7 E 01 0 . 2 9 9 9 9 8 E 01 0 . 1 2 0 0 0 0 E 01 0 . 1 3 1 2 0 0 E 02 7 7 . 8 7 X53 0 . 1 2 7 5 2 0 E 02 0 . 4 5 2 0 4 5 E 01 0 . 4 9 0 0 0 0 E 01 0 . 2 1 2 8 0 0 E 02 3 5 . 4 5 X54 0 . 1 2 5 4 8 0 E 02 0 . 4 5 0 0 1 9 E 01 0 . 6 5 2 0 0 0 E 01 0 . 2 1 1 1 0 0 E 02 3 5 . 86 X55 0 . 7 1 8 0 4 7 E 02 0 . 2 3 2 0 5 9 E 03 0 . 5 6 6 0 0 0 E 01 0 . 9 1 0 5 2 0 F 03 3 2 3 . 18 X56 0 . 1 2 3 6 4 0 E 02 0 . 3 9 3 9 7 3 E 01 0 . 5 8 1 0 0 0 E 01 0 . 2 0 8 7 0 0 E 02 3 1 . 8 6 X57 0 . 9 0 1 6 0 0 E u 1 0 . 3 0 2 4 0 0 E 01 0 . 3 3 4 0 0 0 E 01 0 . 1 6 4 9 0 0 E 02 3 3 . 5 4 X58 0 . 8 3 8 8 0 0 E 01 0 . 3 4 4 9 4 3 E 01 0 . 3 4 7 0 0 0 E 01 0 . 1 4 8 2 0 0 E 02 4 1 . 1 2 X59 0 . 8 3 0 8 0 0 E 01 0 . 3 0 8 9 3 0 E 01 0 . 3 5 4 0 0 0 E 01 0 . 1 4 7 1 0 0 E 02 3 7 . 1 8 X60 0 . 8 5 5 6 6 7 E 01 0 . 2 8 5 6 9 2 E 01 0 . 3 4 5 0 0 0 E 01 0 . 1 4 3 8 0 0 E 02 3 3 . 39 X61 0 . 9 7 9 3 3 3 E 02 0 . 5 1 4 7 3 5 E 01 0 . 8 1 0 0 0 0 E 02 0 . 1 0 0 0 0 0 E 03 5 . 2 6 X62 0 . 9 1 3 3 3 3 E 00 0 . 5 6 5 5 1 7 E 00 0 . 2 0 0 0 0 0 E 0 0 0 . 2 0 0 0 0 0 F 01 6 1 . 9 2 X63 0 . 5 6 2 6 6 7 E 01 0 . 1 5 0 6 9 5 E 02 0 . 5 0 0 0 0 0 E 0 0 0 . 6 0 0 0 0 0 E 02 2 6 7 . 8 2 X64 0 . 3 5 5 3 3 3 E 01 0 . 3 8 3 4 2 2 E 01 0 . 0 . 130000F. 02 1 0 7 . 9 0 X65 0 . 5 5 7 3 3 3 E 02 0 . 4 7 0 9 0 3 E 02 0 . 0 . 1 0 0 0 0 0 F 03 8 4 . 4 9 X66 0 . 9 2 0 0 0 0 E 01 0 . 2 0 0 2 9 3 E 02 0 . 0 . 7 0 0 0 0 0 E 02 2 1 7 . 7 1 X 6 7 , 0 . 2 5 4 6 6 7 E 0 0 0 . 2 9 2 4 4 5 E - -01 0 . 2 1 0 0 0 0 E 0 0 0 . 3 3 0 0 0 0 F 00 1 1 . 4 8 Y2 0 . 1 7 4 3 6 7 E 02 0 . 6 2 1 3 3 5 E 01 0 . 1 0 1 2 0 0 E 02 0 . 3 1 6 7 0 0 E 02 3 5 . 6 3 Y4 0 . 2 0 5 0 5 3 E 02 0 . 5 9 5 2 9 3 E 01 0 . 1 2 8 0 0 0 E 02 0 . 3 3 4 6 0 0 E 02 2 9 . 0 3 X68 0 . 1 7 6 6 6 7 E 0 0 0 . 4 7 6 0 9 5 E - -01 0 . 4 0 0 0 0 0 E - -01 0 . 2 5 0 0 0 0 E 0 0 2 6 . 9 5 NUMBER OF O B S E R V A T I O N S = 15 BlifJGK A CONTROL SYMBOL MEAN STANDARD DEVI AT ION MINIMUM MAXIMUM C O E F F I C I E N T OF V A R I A T I O N XI 0 . 6 3 2 6 6 7 6 0 0 0 . U 3 1 6 7 E 0 0 0 . 4 1 0 0 0 0 E 0 0 0 . 8 0 0 0 0 0 E 00 1 7 . 8 9 X2 0 . 7 5 2 6 6 7 E 0 0 0 . 1 4 6 3 1 0 E 00 0 . 5 6 C 0 0 0 E 0 0 0. 1 0 5 0 0 0 E 01 1 9 . 44 X3 0 . 8 3 7 3 3 3 E 0 0 0 . 2 4 9 6 7 0 E 0 0 0 . 4 7 0 0 0 0 E 0 0 0 . 1 3 9 0 0 0 E 01 2 9 . 8 2 X4 0 . 9 8 4 6 6 7 E 0 0 0 . 2 6 4 5 9 9 E 00 0 . 6 2 0 0 0 0 E 0 0 0. 1 5 3 0 0 0 E 01 2 6 . 87 X5 0 . 1 0 1 8 6 7 E 01 0 . 2 4 5 4 9 9 E 00 0 . 6 6 0 0 0 0 E 0 0 0. 1 4 4 0 0 0 E 01 2 4 . 10 X6 0 . 8 3 0 0 0 0 E 0 0 0 . 1 3 7 9 9 6 E 00 0 . 5 9 0 0 0 0 E 0 0 0. 1 2 1 0 0 0 E 01 1 6 . 6 3 X7 0 . 2 4 4 6 6 7 E 00 0 . 9 7 0 9 1 0 E - 01 0 . 7 0 0 0 0 0 E - 01 0. 3 7 0 0 0 0 E 00 3 9 . 6 8 X8 0 . 2 1 9 3 3 3 E 0 0 0 . 1 0 8 8 5 6 E 0 0 0 . 6 0 0 0 0 0 E - 01 0. 3 7 0 0 0 0 E 0 0 4 9 . 6 3 X9 0 . 2 0 4 0 0 0 E 0 0 0 . 1 0 2 8 0 4 E 00 0 . 6 0 0 0 0 0 E - 01 0. 3 6 0 0 0 0 E 00 5 0 . 39 X IO 0 . 1 5 6 0 0 0 E 0 0 0 . 9 6 0 5 0 6 E - 01 0 . 5 0 0 0 0 0 E - •01 0. 3 6 0 0 0 0 E UO 6 1 . 5 7 X l l 0 . 1 5 7 3 3 3 E 0 0 0 . 8 2 4 1 5 9 E - •01 0 . 4 0 0 0 0 0 E - •01 0. 2 8 0 0 0 0 E 00 5 2 . 38 X12 0 . 2 0 6 6 6 7 E 00 0 . 9 0 9 9 9 7 E - •01 0 . 7 0 C 0 0 0 E - •01 0. 3 3 0 0 0 0 E 00 4 4 . 0 3 X13 0 . 7 4 6 6 6 7 E 00 0 . 4 2 3 7 0 6 E - •01 0 . 6 9 0 0 0 0 E 0 0 0. 8 4 0 0 0 0 E 00 5 . 6 7 X14 0 . 6 9 9 3 3 3 E 0 0 0 . 5 8 4 8 9 3 E - •01 0 . 5 8 0 0 0 0 E 00 0.7 7 0 0 0 0 E 00 8 . 36 X15 0 . 6 7 1 3 3 3 E 0 0 0 . 9 6 2 7 8 4 E - •01 0 . 4 5 0 0 0 0 E 0 0 0. 8 1 0 0 0 0 E on 1 4 . 3 4 X16 0 . 6 2 9 3 3 3 E 0 0 0 . 1 0 0 6 7 4 E 00 0 . 4 2 0 0 0 0 E 00 0. 7 6 0 0 0 0 E 00 1 6 . 0 0 X17 0 . 6 2 4 0 0 0 E 0 0 0 . 8 8 3 8 2 3 E - •01 0 . 4 6 0 0 0 0 E 0 0 0. 7 5 0 0 0 0 E 00 1 4 . 16 X18 0 . 6 6 9 3 3 3 E 0 0 0 . 5 3 3 8 U E - •01 0 . 5 2 0 0 0 0 E 0 0 0. 7 5 0 0 0 0 E 00 7 . 9 8 X19 0 . 2 3 6 2 3 3 E 02 0 . 1 3 9 3 7 3 E 02 0 . 8 6 2 0 0 0 E 01 0. 4 1 2 8 0 0 E 02 5 9 . 0 0 X20 0 . 3 1 4 1 3 3 E 02 0., 1 1 1 1 7 6 E 02 0 . 1 6 6 7 0 0 E 02 0. 4 1 9 5 0 0 E 02 3 5 . 39 X21 0 . 3 6 6 7 3 3 E 02 0 . 4 9 8 6 5 6 E 01 0 . 3 0 8 0 0 0 E 02 0. 4 2 6 0 0 0 F 02 1 3 . 6 0 X22 0 . 3 7 3 4 6 7 E 02 0 . 1 2 1 8 5 0 E 02 0 . 2 1 1 6 0 0 E 02 0 . 4 8 3 1 0 0 E Or 3 2 . 6 3 X23 0 . 3 3 3 8 6 7 E 02 0 . 1 3 5 9 4 3 E 02 0 . 2 4 0 9 0 0 E 02 0 . 5 1 9 6 0 0 E 02 4 0 . 7 2 X24 0 . 3 2 4 8 6 7 E 02 0 . 1 0 1 7 S 8 E 02 0 . 2 1 4 3 0 0 E 02 0. 4 5 3 2 0 0 F 02 3 1 . 3 3 X25 0 . 3 9 0 0 0 0 E 02 0 . 2 0 7 1 9 2 E 02 0 . 1 5 0 0 0 0 E 02 0. 6 4 0 0 0 0 E 02 5 3 . 1 3 X26 0 . 5 6 0 0 0 0 E 02 0 . 1 1 1 8 0 3 E 02 0 . 4 6 C 0 0 0 E 02 0. 7 1 0 0 0 0 E 02 1 9 . 9 6 X27 0 . 5 3 6 6 6 7 E 02 0 . 1 0 7 6 C 1 E 02 0 . 3 9 0 0 0 0 E 02 0 . 6 2 0 0 0 0 E 02 2 0 . 0 6 X28 0 . 5 9 6 6 6 7 E 02 0 . 5 7 5 2 8 5 E 01 0 . 5 2 0 0 0 0 E 02 0. 6 5 0 0 0 0 E 02 9 . 6 4 X29 0 . 5 7 3 3 3 3 E 02 0 . 1 4 8 4 0 4 E 02 0 . 3 9 0 0 0 0 E 02 0. 740000fc 02 2 5 . 8 8 X30 0 . 5 3 0 0 0 0 E 02 0 . 1 2 2 7 6 6 E 02 0 . 3 8 0 0 0 0 E 02 0. 6 7 0 0 0 0 E 02 2 3 . 1 6 X31 0 . 5 0 6 6 6 7 E 02 0 . 1 5 9 7 6 2 E 02 0 . 3 6 0 0 0 0 E 02 0 . 7 2 0 0 0 0 E 02 3 1 . 5 3 X32 0 . 3 9 3 3 3 3 E 02 0 . 8 4 6 5 6 2 E 01 0 . 2 9 0 0 0 0 E 02 c . 4 9 0 0 0 0 E 02 2 1 . 5 2 X33 0 . 4 4 0 0 0 0 E 02 0 . 9 5 2 4 4 0 E 01 0 . 3 7 0 0 0 0 E 0 2 0 . 5 7 0 0 0 0 E 02 2 1 . 6 5 X34 0 . 3 7 3 3 3 3 E 02 0 . 4 1 6 9 0 5 E 01 0 . 3 4 0 0 0 0 E 02 0. 4 3 0 0 0 0 E 02 1 1 . 1 7 X35 0 . 4 0 3 3 3 3 E 02 0 . 1 3 5 5 7 6 E 02 0 . 2 5 0 0 0 0 E 02 0.5 7 0 0 0 0 E 02 3 3 . 6 1 X36 0 . 4 2 6 6 6 7 E 02 0 . 1 0 0 8 3 0 E 02 0 . 3 3 0 0 0 0 E 02 J . 5 6 0 0 0 0 E 02 2 3 . 6 3 X37 0 . 1 0 3 3 3 3 E 02 0 . 7 8 5 2 8 1 E 01 0 . 0 » 1 8 0 0 0 0 E 02 7 5 . 9 9 X38 0 . 4 6 6 6 6 7 E 01 0 . 3 8 U 0 1 E 01 0 . 0 . 9 0 0 0 0 0 c 01 8 1 . 6 6 X39 0 . 2 3 3 3 3 3 E 01 0 . 1 7 5 9 3 3 E 01 0 . 0. 4 0 0 0 0 0 E 01 7 5 . 4 0 X40 0 . 3 0 0 0 0 0 E 01 O . 2 2 3 6 0 7 E 01 0 . 0. 5 0 0 0 0 0 E 01 7 4 . 54 X41 0 . 2 3 3 3 3 3 E 01 0 . 1 2 9 0 9 9 E 01 0 . 1 0 0 0 0 0 E 01 0. 4 0 0 0 0 0 E 01 5 5 . 3 3 X 42 0 . 4 3 3 3 3 3 E 01 0 . 3 1 9 9 7 0 E 01 0 . 0. 7 0 0 0 0 0 E 01 7 3 . 8 4 X43 0 . 1 7 1 7 3 5 E 03 0 . 9 1 2 6 3 0 E 02 0 . 6 1 7 9 0 0 E 02 0. 3 6 7 6 4 0 E 03 5 3 . 1 4 X44 0 . 1 3 6 4 0 0 E 03 0 . 7 7 8 8 7 3 E 02 0 . 2 7 3 1 0 0 E 02 0. 3 1 8 6 0 0 E 03 5 7 . 1 0 X45 0 . 9 0 2 7 5 3 E 02 0 . 3 7 7 8 7 5 E 02 0 . 2 8 7 8 0 0 E 02 0. 1 5 8 1 8 0 E 03 4 1 . 8 6 X46 0 . 7 6 2 7 6 7 E 02 0 . 2 0 7 9 6 6 E 02 0 . 3 2 3 3 0 0 E 02 0. 9 7 0 2 0 0 E 02 2 7 . 2 6 X47 0 . 7 4 6 6 9 3 E 02 0 . 2 6 6 4 3 5 E 02 0 . 3 3 4 4 0 0 E 0 2 0.1 2 4 3 7 0 E 03 3 5 . 6 8 X48 0 . 1 0 9 8 7 0 E 03 0 . 3 8 5 3 9 9 E 02 0 . 4 1 8 8 0 0 E 02 0. 1 9 7 9 5 0 E 03 3 5 . 0 8 X49 0 . 3 9 1 8 6 7 E 01 0 . 2 4 6 S 3 4 E 01 0 . 1 5 0 0 0 0 E 01 *) • 9 6 6 0 0 0 E 01 6 2 . 9 9 X50 0 . 4 1 8 5 3 3 E 01 0 . 5 7 9 9 5 1 E 01 0 . 1 2 1 0 0 0 E 01 0. 2 4 7 1 0 0 C 02 1 3 8 . 5 7 X51 0 . 2 1 2 5 3 3 E 01 0 . 1 1 2 2 6 8 E 01 0 . 1 1 8 0 0 0 E 01 0. 5 0 1 U 0 0 E 01 5 2 . 8 2 X52 0 . 3 4 0 6 6 7 E 01 0 . 2 8 5 3 0 0 E 01 0 . 1 4 4 0 0 0 E 01 0. 1 3 1 1 0 0 E 02 8 3 . 75 X53 0 . 1 5 1 7 5 3 E 02 0 . 3 7 6 9 5 6 E 01 0 . 9 3 3 0 0 0 E 01 0 • 2 5 2 8 0 0 E 02 2 4 . 8 4 X54 0.1 4 3 8 1 3 E 02 0 . 4 5 3 5 6 2 E 01 0 . 5 0 5 0 0 0 E 01 0. 2 3 2 3 0 0 E 02 3 1 . 5 4 X55 0 . 1 2 0 5 1 3 E 02 0 . 3 4 5 4 0 2 E 01 0 . 7 4 2 0 0 0 E 01 0. 1 8 6 1 0 0 E 02 2 8 . 6 6 X56 0 . 1 3 8 5 8 7 E 02 0 . 2 8 9 9 1 0 E 01 0 . 9 9 8 0 0 0 E 01 0. 2 0 4 8 0 0 E 02 2 0 . 9 2 X57 0 . 1 2 3 8 3 3 E 02 0 . 3 4 9 6 6 0 E 01 0 . 8 1 6 0 0 0 E 01 0. 2 2 0 1 0 0 E 02 2 8 . 2 4 X58 0 . 1 1 1 8 8 7 E 02 0 . 4 4 9 9 2 3 E 01 0 . 3 9 7 0 0 0 F 01 0. 2 3 7 8 0 0 E 02 4 0 . 2 1 X59 0 . 8 3 6 5 3 3 E 01 0 . 2 2 5 1 2 4 E 01 0 . 5 2 2 0 O O E 01 0. 1 3 3 0 0 0 E 02 2 6 . 9 1 X60 0 . 1 0 6 5 9 3 E 02 0 . 2 6 3 5 9 0 E 01 0 . 8 2 2 0 0 0 E 01 0. 1 8 7 6 0 0 C 02 2 4 . 73 X61 0 . 9 2 2 6 6 7 E 02 0 . 2 1 8 9 7 4 E 02 0 . 2 1 0 0 0 0 E 02 0. 1 0 0 0 0 0 E 03 2 3 . 73 X62 0 . 3 0 0 0 0 0 E 00 0 . 2 0 7 0 2 0 E 00 0 . I O 0 O O 0 E 0 0 (J. 8 0 0 0 0 0 E 0 0 6 9 . 0 1 X63 0 . 1 9 6 6 6 7 E 01 0 . 2 3 8 5 5 7 E 01 0 . 2 0 0 0 0 0 E 0 0 0. 4 0 0 0 0 0 E 01 1 2 1 . 3 0 X64 0 . 1 2 2 0 0 0 E 01 0 . 1 0 6 1 U O E 01 0 . 2 0 0 0 0 0 E 0 0 0. 4 5 0 0 0 0 E 01 8 7 . 0 3 X65 0 . 1 0 0 0 0 0 E 03 0 . 0 . 1 0 0 0 0 0 E 03 0. 1 0 0 0 0 0 E 03 0 . 0 0 X66 0 . 1 8 6 0 0 0 E 02 0 . 3 2 2 1 5 3 E 02 0 . 0. 1 0 0 0 0 0 E 03 1 7 3 . 2 0 X67 0 . 2 4 6 6 6 7 E 00 0 . 1 0 4 4 4 9 E 00 0 . 7 0 0 0 0 0 E - •01 0. 3 6 0 0 0 0 E 00 4 2 . 34 Y2 0 . 1 5 0 8 7 3 E 02 0 . 8 3 8 9 9 7 E 01 0 . 1 0 5 0 0 0 E 01 0. 2 4 6 9 0 0 E 02 5 5 . 6 1 Y4 0 . 1 7 9 2 3 3 E 02 0 . 9 6 0 7 <5E 01 0 . 1 2 1 G 0 0 E C 1 J . 2 7 7 7 0 0 E 02 5 3 . 6 0 X68 0 . 1 5 1 3 3 3 E 0 0 0 . 7 0 2 9 1 9 E - -01 0 . 5 0 0 0 0 0 E - •01 0. 2 6 0 0 0 0 E 00 4 6 . 4 5 NUMBER OF O B S E R V A T I O N S = 15 BLOCK -B.SLASHBURNED SYMBOL MEAN STANDARD D E V I A T I O N MINIMUM MAXIMUM C O E F F I C I E N T OF V A R I A T I O N XI X2 X3 X4 X5 X6 X7 X8 X9 XIO X l l X12 X13 X14 X15 X16 X17 X18 X19 X20 X21 X22 X23 X24 X25 X26 X27 X28 X29 X30 X31 X32 X33 X34 X35 X36 X37 X38 X39 X40 X41 X42 X43 X44 X45 X46 X47 X48 X49 X50 X51 X52 X53 X54 X55 X56 X57 X58 X59 X60 X61 X62 X63 X64 X65 X66 X67 Y2 Y4 X68 0.958000E OO 0.984000E OO 0.11O667E 01 0.114067E 01 0.114467E 01 0.105067E 01 0.290000E 00 0.302667E 00 0.283333E 00 O.280000E 00 0.280667E 00 0.287333E 00 0.620000E 00 0.616000E 00 0.572667E 00 0.375333E 00 0.581333E 00 0.584667E 00 0.497700E 02 0.528767E 02 0.465567E 02 O.533200E 02 0.542433E 02 0.513567E 02 0.376667E 02 0.560000E 02 0.600000E 02 U.626667E 02 0.610000E 02 0.563333E 02 0.550000E 02 0.383333E 02 0.326667E 02 0.326667E u<i 0.336667E 02 0.383333E 02 0.733333E 01 0.566667E 01 0.733333E 01 0.466667E 01 0.533333E 01 0.533333E 01 0.540380E 02 0.421540E 02 0.322620E 02 0.330340E 02 0.357893E 02 0.394687E 02 0.801533E 01 0.553267E 01 0.595800E 01 0.651400E 01 0.117087E 02 0.872133E 01 0.830467E 01 0.957867E 01 0.102180E 02 0.709400E 01 0.730800E 01 0.820467E 01 0.543333E 02 0.253333E 00 0.222000E 01 0.713333E 00 0.828000E 02 0.571333E 02 0.304667E 00 0.165820E 02 0.17B653E 02 0.254667E 00 0.258158E 00 0.251675E 00 0.283566E 00 0.276805E 00 0.214105E 00 0.211845E 00 0.250714E-01 0.404381E-01 0.453032E-01 0.376070E-01 0.458985E-01 0.293907E-01 0.102260E 00 0.993408E-01 0.110548E 00 0.103501E 00 0.790901E-01 0.828826E-01 0.841472E 01 0.672238E 01 0.125989E 02 0.107089E 02 0.538539E 01 0.766182E 01 0.979553E 01 0.109870E 02 0.169031E 01 0.319970E 01 0.292770E 01 0.433699E 01 0.959911E 01 0.104994E 02 0.129099E 01 0.212692E u i 0.390360E 01 0.319970E 01 0.487950E 00 0.487950E 00 0.175933E 01 0.38U01E 01 0.975900E 00 0.129099E 01 0.567793E 02 0.497363E 02 0.332211E 02 0.428671E 02 0.428528E 02 0.330440E 02 0.351896E 01 0.232626E 01 0.401616E 01 0.250722E 01 0.342037E 01 0.240629E 01 0.302754E 01 0.166377E 01 0.285094E 01 0.207021E 01 0.331001E 01 0.169092E 01 0.420674E 02 0.3313756 00 0.369714E 01 0.101831E 01 0.307134E 02 0.431556E 02 0.279967E-01 0.376264E 01 0.399707E 01 0.412080E-01 0.160000E 00 0.370000E 00 0.200000E 00 0.210000E 00 0.440000E 00 0.400000E 00 0.250000E 00 0.220000E 00 0.200000E 00 0.220000E 00 0.200000E 00 0.230000E 00 0.510000E 00 0.500000E 00 0.440000E 00 0.440000E 00 0.480000E 00 0.510000E 00 0.395000E 02 0.466600E 02 0.305600E 02 0.410900E 02 0.487100E 02 0.420C00E 02 0.300000E 02 0.480000E 02 0.580000E 02 0.600000E 02 0.570000E 02 0.520000E 02 0.420000E 02 0.240C00E 02 0.310000E 02 0.300000E 02 0.310000E 02 0.340000E 02 0.700000E 01 0.500000E 01 0.500000E 01 0. 0.400000E 01 0.400000E 01 0.202800E 02 0.144900E 02 0.908000E 01 0.693000E 01 0.629000E 01 0.130000E 02 0.322000E 01 0.267000E 01 0.174000E 01 0.276000E 01 0.677000E 01 0.532000E 01 0.431000E 01 0.659000E 01 0.545000E 01 0.401000E 01 0.303000E 01 0.497000E 01 0.500000E 01 0. 0. 0. 0.120000E 02 0. 0.260000E 00 0.113900E 02 0.117600E 02 0.200000E 00 0.127000E 01 0.126000E 01 0.145000E 01 0.149000E 01 0.137000E 01 0.125000E 01 0.330000E 00 0.370000E 00 0.370000E 00 0.330000E 00 0.340000E 00 0.340000E 00 0.940000E 00 0.860000E 00 0.920000E 00 0.920000E 00 0.830000E 00 0.840000E 00 0.593800E 02 0.618400E 02 0.600600E 02 0.663900E 02 0.612100E 02 0.601000E 02 0.510000E 02 0.710000E 02 0.620000F 02 0.670000E 02 0.630000F 02 0.620000F. 02 0.630000E 02 0.460000E 02 0.340000F 02 0.350000E 02 0.390000E 02 0.410000E 02 0.800000E 01 0.600000E 01 0.9OO000E 01 0.900000F. 01 G.600000E 01 0.700000E 01 0.234910b 03 0.215280E 03 0.148070E 03 U.185780E 03 0.187140E 03 0.131760E 03 0.175600E 02 0.109200E 02 0.150100E 02 0.109700E 02 0.187800E 02 0.131800E 02 0.151500E 02 0.129900E 02 0.167500E 02 0.112700E 02 0.150000E 02 0.109100E 02 0.100000E 03 O.IOOOOOE 01 0.140000E 02 0.350000E 01 O.IOOOOOE 03 O.IOOOOOE 03 0.370000E 00 0.226700E 02 u.<;4it>uOE 02 0.330000E 00 26.95 25.58 25.62 24.27 18.70 20.16 8.65 13. 36 1 5.99 13.43 16.35 10.23 16.49 16.13 19.30 17.99 13.60 14. 18 16.91 12.71 27.06 20.08 9.93 14.92 26.01 19.62 2.82 3.11 4.80 7. 70 17.45 27.39 3.95 6.51 11.59 8.35 6.65 8.61 23.99 81.66 18.30 24.21 105.07 117.99 102.97 129.77 119.74 83.72 43.90 42.05 67.41 38.49 29.21 27.59 36.46 17.37 27.90 29. 18 45.29 20.61 77.42 130.81 166.54 142.75 37.09 75.53 9. 19 22.69 22.37 16.18 NUMBER OF O B S E R V A T I O N S 15 BLOCK B: CLEARCUT SYMBOL MEAN STANDARD D E V I A T I O N MINIMUM MAX I MUM C O E F F I C I E N T OF V A R I A T I O N XI 0.792667E 00 0.2548806 00 0. 160000E 00 0 . 115000E 01 32. 15 X2 0.928667E 00 0.281447E 00 0.280000E 00 0.136000E 01 30. 31 X3 0.103533E 01 0.201064E 00 0.630000E 00 0 . 130000E 01 19.42 X4 0.103067E 01 0.2290196 00 0.720000E 00 0 . 164000E 01 22.22 X5 0.107533E 01 0.2608476 00 0.530000E 00 0.172000E 01 24.26 X6 0.981333E 00 0.1749236 00 0.600000E 00 0.126000E 01 17.83 X7 0.326000E 00 0.3089176-•01 0.270000E 00 0.390000E 00 9.48 X8 0.318000E 00 0.400357E-•01 0.250000E 00 0.380000E 00 12.59 X9 0.282667E 00 0.378846E-•01 0.220000E 00 0.350000E 00 13.40 XIO 0.2 M667E 00 0.485308E-:01 G.190000E 00 0.350000E 00 17.67 X l l 0.246000E 00 0.841597E-•01 0. 110000E 00 0.390000E 00 34.21 X12 0.290667E 00 0.431719E-•01 0.210000E 00 0.360000E 00 14.85 X13 0.678000E 00 0. 105641E 00 0.530000E 00 0.940000E 00 15.58 X14 0.630000E 00 0.106369E 00 0.470000E 00 0.870000E 00 16.88 X15 0.592000E 00 0.706299E-•01 0.500000E 00 0.720000E 00 11.93 X16 0.612000E 00 0.868661E-•01 0.380000E 00 0.730000E 00 14.19 X17 0.594667E 00 0.987687E-•01 0.350000E 00 0.800000E 00 16.61 X18 0.609333E 00 0.647488E-•01 0.500000E 00 0.740000E 00 10.63 X19 0.470733E 02 0.473380E 01 0.434000E 02 0.535200E 02 10.06 X20 0.513600E 02 0.515832E 01 0.463300E 02 0.5815006 02 10.04 X21 0.512067E 02 0.633820E 01 0.457100E 02 0.597500E 02 12. 38 X22 0.435833E 02 0.820516E 01 0.365500E 02 0.546600E 02 18.83 X23 0.4358006 02 0.411767E 01 0.404100E 02 0.491900E 02 9.45 X24 0.4735676 02 0.563629E 01 0.432200E 02 0.550500E 02 11.90 X25 0.4433336 02 0.127148E 02 0.270000E 02 0.540000E 02 28.68 X26 0.596667E 02 0.381101E 01 0.550000E 02 0.640000E 02 6.39 X27 0.593333E 02 0.271679E 01 0.570000E 02 0.630000E 02 4.58 X28 0.600000E 02 0.670820E 01 0.510000E 02 0.660000E 02 T l . 18 X29 0.586667E 02 0.271679E 01 0.550000E 02 0.610000E 02 4.63 X30 0.563333E 02 0.543358E 01 0.490000E 02 0.610000E 02 9.65 X31 0.470000E 02 0.134164E 02 0.350000E 02 0.650000F 02 28.55 X32 0.330000E 02 0.3047256 01 0.300000E 02 0.370000E 02 9.23 X33 0.330000E 02 0.223607E 01 0.300000E 02 0.350000E 02 6.78 X34 0.340000E 02 0.7511906 01 O.270000E 02 0.440000E 02 22.09 X35 0.333333E 02 0.195180E 01 0.320000E 02 0.360000E 02 5.86 X36 0.366667E 02 0.480575E 01 0.320000E 02 0.430000E 02 13.11 X37 0.800000E 01 0.845154E 00 0.700000E 01 0.900000E 01 10.56 X38 0.733333E 01 0.975900E 00 0.600000E 01 0.800000E 01 13. 31 X39 0.766667E 01 0.487950E CO 0.700000E 01 0.ROOOOOE 01 6. 36 X40 0.600000E 01 0.845154E 00 0.500000E 01 0.700000E 01 14.09 X41 0.800000E 01 0.845154E 00 0.700000E 01 0.900000E 01 10.56 X42 0.700000E 01 0.845154E 00 0.600000E 01 0.800000E 01 12.07 X43 0.582440E 02 0.387040E 02 0.268400E 02 0.157660E 03 66.45 X44 0.323707E 02 0.1377486 02 0.161200E 02 0.708400E 02 42.55 X45 0.251280E 02 0.955996E 01 0.159000E 02 0.434500E 02 38.05 X46 0.281213E 02 0.1180876 02 0.954000E 01 0.458000E 02 41.99 X47 0.266700E 02 0.9452106 01 0.110300E 02 0.403000E 02 35.44 X48 0.341067E 02 0.108581E 02 0.193100E 02 0.549700E 02 31.84 X49 0.112447E 02 0.450075E 01 0.689000E 01 0.199000E 02 40.03 X50 0.107480E 02 0.101272E 02 0.313000E CI 0.448000E 02 94.22 X51 0.824000E 01 0.954296E 01 0.134000E 01 0.404000E 02 115.81 X52 0.100747E 02 0.735355E 01 0.486000E 01 0.347700E 02 72.99 X53 0.153987E 02 0.579608E 01 0.473000E 01 0.267900E 02 37.64 X54 0.127473E 02 0.352384E 01 0.655000E 01 0.181000E 02 27.64 X55 0.928933E 01 0.370771E 01 0.520000E 01 0.165000E 02 39.91 X56 0.124780E 02 0.257288E 01 0.799000E 01 0.1718006 02 20.62 X57 0.136167E 02 0.418596E 01 0.626000E 01 O.213000E 02 30.74 X58 0.118660E 02 0.687632E 01 0.471000E 01 0.336800E 02 57.95 X59 0.889467E 01 0.675601E 01 0.377000E 01 0.308300F 02 75.96 X60 0.1 14587E 02 0.484296E 01 0.646000E 01 0.269000E 02 42.26 X61 0.616667E 02 0.434621E 02 0.300000E 01 0.100000E 03 70.48 X62 0.206667E 00 0.305817E 00 o,. 0.110000E 01 147.98 X63 0.111067E 02 0.106883E 02 0.100000E 0 0 0.380000C 02 96.2 3 X64 0.813333E 00 0.775395E 00 0. 0.230000E 01 95.34 X65 0.6400006 02 0.465679E 02 0. 0.1000006 03 72. 76 X66 0.6646676 02 0.409003E 02 0. 0 . 100000E 03 61.54 X67 O.30200OE 00 0.380226E--01 0.220000E 00 0.360000E 00 12.59 Y2 0.229213E 02 0.504355E 01 0.140400E 02 0.321500E 02 22.00 Y4 0.256307E 02 0.487427E 01 0.174000E 02 0.340800E 02 19.02 X68 0.253333E 00 0.4835396--01 0.140000E 00 0.330OOOE 00 19.09 •NUMBER OF O B S E R V A T I O N S = 15 SYMBOL MEAN STANDARD O E V I A T I O N MINIMUM MAXIMUM C O E F F I C I E N T OF V A R I A T I O N X I 0.914667E 00 0. 122932E 00 0.750000E 0 0 0 . 1 1 9 0 0 0 E 01 1 3 . 4 4 X2 0.105200E 01 0 .137747E 00 o . e iooooE 00 0 . 135000E 01 1 3 . 0 9 X3 0 .111467E 01 0 .202197E 00 0.720000E 0 0 0 . 160000E 01 1 8 . 1 4 X4 0 . 1 1 5 1 3 3 E 01 0 .215767E 0 0 0.860000E 0 0 0 . 160000E 01 1 8 . 7 4 X5 0 . 1 1 6 6 6 7 E 01 0.162949E 0 0 0 . 8 8 0 0 0 0 E 00 0 . 146000E 01 1 3 . 9 7 X6 0.108067E 01 0 . 129530E 00 0.840000E 00 0 . 135000E 01 1 1 . 9 9 X7 0.309333E 00 0 .194448E- 01 O.28CO0OE 00 0 . 3 4 0 0 0 0 E 0 0 6 . 2 9 X8 0.298667E 00 0 .360291E-•01 0.240000E 0 0 0 . 3 6 0 0 0 0 6 0 0 1 2 . 0 6 X9 0 .295333E 00 0.315927E-•01 0 . 2 2 0 0 0 0 E 0 0 0 . 340000F 0 0 1 0 . 7 0 X IO 0.268UU0E 00 0 .466293E-•01 0.150000E 00 0 . 3 3 0 0 0 0 E 0 0 1 7 . 4 0 X l l 0 .286000E 00 0.3042566-•01 0.230000E 0 0 0 . 340000E 00 1 0 . 6 4 X12 0 . 2 9 2 0 0 0 E 00 0 .204241E-•01 0.230000E 0 0 0 . 310000E 00 6 . 9 9 X13 0.634667E 00 0 .479387E-•01 0.530000E 00 0 . 700000E 0 0 7 . 5 5 X14 0.586000E 00 0.5315766-•01 0.460000E 00 0 . 680000E 00 9 . 0 7 X15 0 . 5 6 6 0 0 0 E 00 0 .7642006-•01 0 .380000E 0 0 0 . 720000F 00 1 3 . 5 0 X16 0 . 5 6 5 3 3 3 E 00 0 .816672E-•01 O.4U0000E 00 0 . 6 8 0 0 0 0 E 00 1 4 . 4 5 X17 0 .560667E 00 0.620445E-•01 0.450000E 0 0 0 . 670000E 00 1 1 . 0 7 X18 0.573333E 00 0.482060E-•01 0.470000E 00 0 . 670000E 00 8 . 4 1 X19 0.429767E 02 0 . 110030E 02 0.279700E 02 0 . 512500E 02 2 5 . 6 0 X20 0.503067E 02 0.300723E 01 0.462000E 02 0 . 524700E 02 5 . 9 8 X21 0 .522067E 02 0.938602E 01 0.416900E 02 0 .638200E 02 1 7 . 9 8 X22 0 .541067E 02 0 .851701E 01 0 .430900E 02 0. 628600t 02 1 5 . 7 f X23 0.517800E 02 0.570798E 01 0.449000E 02 0.584000E 02 11 .02 X24 0 .502767E 02 0 .724308E 01 0.407700E 02 0 . 574100E 02 1 4 . 4 1 X25 0 . 4 5 3 3 3 3 E 02 0 .109978E 02 0 . 3 2 0 0 0 0 6 02 0. 580000E 02 2 4 . 2 6 X26 0 .536667E 02 0 .975900E 00 0.530000E 02 0 . 5 5 0 0 0 0 E 02 1.82 X27 0 . 6 0 6 6 6 7 E 02 0.708788E 01 0.510O00E 02 0. 6 6 0 0 0 0 E 02 1 1 . 6 8 X28 0 . 6 4 3 3 3 3 E 02 O.480575E 01 0.58C000E 02 0. 690000E 02 7 . 4 7 X29 0 . 6 C O O O O E 02 0 .609449E 01 0.520000E 02 0 . 6 6 0 0 0 0 E 02 1 0 . 16 X30 0 .566667E 02 0.495215E 01 0.500000E 02 0 . 610000E 02 8. 74 X31 0.490000E 02 0.114330E 02 0.360000E 02 0 . 630000E 02 2 3 . 33 X32 0 .386667E 02 0 .271679E 01 0.350000E 02 0 . 410000E 02 7 .03 X33 0.316667E 02 0 .728665E 01 0.240000E 02 0 . 410000E 02 2 3 . 0 1 X34 0.293333E 02 0 .495215E 01 0.23C0006 02 0 . 360000E 02 1 6 . 8 8 X35 0 . 3 3 6 6 6 7 E 02 0.509435E 01 0.280000E 02 0 . 4 0 0 0 0 0 E 02 1 5 . 1 3 X36 0 . 3 6 3 3 3 3 E 02 0.487950E 01 0 . 3 3 0 0 0 0 E 02 0 . 430000E 02 1 3 . 4 3 X37 0.566667E 01 0.487950E 00 0 . 5 0 0 0 0 0 E 01 0 . 6 0 0 0 0 0 E 01 8 .61 X38 0 . 7 6 6 6 6 7 E 01 0 .175933E 01 0 . 6 0 0 0 0 0 E 01 0 . 1 0 0 0 0 0 E 02 2 2 . 9 5 X39 0 . 7 6 6 6 6 7 E 0 ' 0 .212692E n i 0 . ^ 0 0 0 0 0 6 01 0 . VOOOOOE r , 2 2 7 . 74 X40 0 .633333E 01 0.487950E 00 0 . 6 0 0 0 0 0 E 01 0 . 700000E 01 7 . 7 0 X41 0 » 6 3 3 3 3 3 E 01 0 .1290996 01 0 . 5 0 0 0 0 0 E 01 0 . 8 0 0 0 0 0 E 01 2 0 . 3 8 X42 0 . 7 0 0 0 0 0 E 01 0 .845154E 00 0 . 6 0 0 0 0 0 E 01 0 . 8 0 0 0 0 0 E 01 1 2 . 0 7 X43 0.410287E 02 0 .210446E 0 2 0.1815006 02 0. 864200E 02 5 1 . 2 9 X44 0.273173E 02 0.9054336 01 0. 111000E 02 0 . 412100E 02 33 . 15 X45 0.257780E 02 0.9586156 01 0.1032006 02 0 . 406200E 02 3 7 . 1 9 X46 0 .224173E 02 0.904024E 01 0.797000E 01 0 . 358700E 02 4 U . 5 i X47 0.198427E 02 0.776178E 01 0.803000E 01 0 . 326300E 02 3 9 . 1 2 X48 0.272773E 02 0.874743E 01 0.118800E 02 0 . 428300E 02 32.07 X49 0.923200E 01 0.4861096 01 0 . 3 5 6 0 0 0 6 01 0 . 2 0 2 0 0 0 E 02 5 2 . 6 5 X50 0.631467E 01 0 .329424E 01 0.1470006 01 0 . 131000E 02 5 2 . 17 X51 0 .515000E 01 0 .292777E 01 0.137000E 01 0 . 127400E 02 5 6 . 8 5 X52 0 .6671336 01 0 .300322E 01 0.292000E 01 \J . 118200E 02 4 5 . 0 2 X53 0 .129833E 02 0 .3921106 01 0.88C000E 01 0 . 217900E 02 3 0 . 2 0 X54 0.113573E 02 0 .330424E 01 0.642000E 01 0.180000E 02 2 9 . 0 9 X55 0.881467E 01 0.268564E 01 0.376000E 01 0 . 129800E 02 3 0 . 4 7 X56 0.110493E 02 0 .262979E 01 0.661000E 01 0 . 156300E 02 2 3 . 8 0 X57 0.112660E 02 0 .4308706 01 0 .68C000E 01 0 . 206500E 02 3 8 . 2 5 X58 0.884067E 01 0 .3020216 01 0.450000E 01 0 . 157600E 02 3 4 . 16 X59 0 .688400E 01 0.249293E 01 0 . 2 7 2 0 0 0 6 01 0 . 120800E 02 3 6 . 2 1 X60 0.899667E 01 0.270224E 01 0.515G00E 01 0 . 135000E 02 3 0 . 0 4 X61 0 .750000E 02 0.331275E 02 0 . 9 0 0 0 0 0 E 01 0 . 1 0 0 0 0 0 E 03 4 4 . 1 7 X62 0.1266676 0 0 0.1099786 00 0 . 0 . 4 0 0 0 0 0 E 00 8 6 . 83 X63 0 .208000E 01 0 . 8 6 8 6 6 IE 0 0 0 . 5 0 0 0 0 0 E 0 0 0 . 360000F 01 4 1 . 7 6 X64 6 .646667E 00 0 .504079E 00 0 . 100000E 00 0 . 1 7 0 0 0 0 6 01 7 7 . 9 5 X65 0 . 9 3 3 3 3 3 E 02 0.258199E 02 0. 0 . 1 0 0 0 0 0 6 03 2 7 . 6 6 X66 0.812667E 02 0.256639E 02 0.270000E 02 0 . 1 0 0 0 0 0 E 03 3 1 . 5 8 X67 0 . 3 0 3 3 3 3 E 00 0.212694E-•01 0.270000E 00 0. 350000E 0 0 7 .01 Y2 0.235507E 02 0.291996E 01 0.174200E 02 0 • 2768006 02 1 2 . 4 0 Y4 0.259940E 02 0.310226E 01 0.188800E 02 0. 306400E 02. 11.93 X68 0.263333E 0 0 0.260950E--01 0 . 2 2 0 0 0 0 E 0 0 0. 3 0 0 0 0 0 E 00 9 . 9 1 NUM8ER OF OBSERVATIONS = 5 BLOCK O I SKIDROAD SYMBOL MEAN STANDARD MINIMUM MAXIMUM COEFFICIENT OF DEVIATION VARIATION XI 0 . 7 6 4 0 0 0 E 0 0 0 . 1 0 6 2 0 7 E 00 0 . 6 1 0 0 0 0 E 0 0 0. 8 9 0 0 0 0 E 00 1 3 . 90 X2 0 . 6 6 4 0 0 C E 0 0 0 . 2 5 9 3 8 4 E 0 0 0 . 4 1 0 0 0 0 E 0 0 0. 1 0 7 0 0 0 E 01 3 9 . 0 6 X3 0 . 1 0 0 6 0 0 E 01 0 . 2 5 2 8 4 4 E 00 0 . 5 8 0 0 0 0 E 0 0 0. 1 2 3 0 0 0 E 01 2 5 . 1 3 X4 0 . 9 5 0 0 0 0 E 0 0 0 . 4 4 0 6 2 5 E 00 0 . 2 9 0 0 0 0 E 0 0 0 • 1 5 2 0 0 0 E 01 4 6 . 38 X5 0 . 8 4 8 0 0 0 E 00 0 . 2 4 0 0 4 2 E 00 0 . 4 7 0 0 0 0 E 0 0 0 . 1 0 9 0 0 0 E 01 2 8 . 3 1 X6 0 . 2 0 8 0 0 0 E 0 0 0 . 4 6 5 8 3 3 E - 01 0 . 1 4 0 0 0 0 E 0 0 0. 2 5 0 0 0 0 E 00 2 2 . 4 0 X7 0 . 2 4 6 0 0 0 E 00 0 . 7 2 3 1 8 7 E - •01 0 . 1 3 0 0 0 0 E 0 0 0. 3 1 0 0 0 0 E 00 2 9 . 4 0 X8 0 . 1 8 0 0 0 G E 0 0 0 . 5 1 9 6 1 5 E - •01 0 . 1 1 0 0 0 0 E 0 0 0. 2 3 0 0 0 0 E 00 2 8 . 6 7 X9 0 .1 6 6 0 0 0 E 0 0 0 . 9 4 7 6 2 9 E - 01 0 . 2 0 0 0 0 0 E --01 0. 2 8 0 0 0 0 E 00 5 7 . 0 9 X10 0 . 1 9 6 0 0 0 E 0 0 0 . 3 3 6 1 5 5 E - •01 0 . 1 6 0 0 0 0 E 00 0 . 2 3 0 0 0 0 E 0 0 1 7 . 1 5 X I1 0 . 6 7 4 0 0 0 E 0 0 0 . 4 2 7 7 3 6 E - •01 0 . 6 2 0 0 0 0 E 00 0 . 7 3 0 0 0 C E 00 6 . 3 5 X12 0 . 6 8 6 0 0 0 E 0 0 0 . 8 9 6 1 0 3 E - •01 0 . 5 6 0 0 0 0 E 0 0 0. 8 1 0 0 0 0 E 00 1 3 . 0 6 XI 3 0 . 5 8 6 0 0 0 E 0 0 0 . 7 5 3 6 5 8 E - •01 0 . 5 2 0 0 0 0 E 0 0 u • 7 1 0 0 0 C E 0 0 1 2 . 8 6 X14 0 . 6 0 6 0 0 0 E 0 0 0 . 1 4 3 1 0 8 E 00 0 . 4 0 0 0 0 0 E 0 0 0 . 8 0 0 0 0 C E CO 2 3 . 6 2 X15 0 . 6 4 0 0 0 0 E 0 0 0 . 7 6 4 8 5 3 E - •01 0 . 5 6 0 0 0 0 E 0 0 0. 7 6 0 0 0 0 E 00 1 1 . 9 5 X16 0 . 3 4 0 8 0 0 E 02 0 . 1 2 4 3 2 0 E 02 0 . 2 4 7 2 0 0 E 02 0. 4 8 7 5 0 0 E 02 3 6 . 4 8 X17 0 . 3 5 9 4 8 0 E 02 0 . 7 0 3 6 0 6 E 01 0 . 2 5 8 8 0 0 E 02 0 . 4 3 3 9 0 0 E 02 1 9 . 5 7 X19 0 . 4 5 8 9 2 0 E 02 0 . 1 3 8 4 0 3 E 02 0 . 3 0 0 4 0 0 E 02 a . 6 4 5 1 0 0 F 0? 3 0 . 16 X19 0 . 5 1 3 8 6 0 E 02 0 . 2 6 5 8 S 3 E 02 0 . 7 4 1 0 0 0 E 01 c . 7 4 5 1 0 0 E 02 5 1 . 7 4 X20 0 . 4 1 8 2 6 0 E 02 0 . 1 0 9 1 0 8 E 02 0 . 2 3 1 9 0 0 E 02 0. 4 9 4 8 0 0 E 02 2 6 . 0 9 X21 0 . 2 6 3 9 6 0 E 02 0 . 4 9 2 8 5 9 E 01 0 . 2 0 1 8 0 0 E 02 0 • 3 3 1 3 0 0 F 02 1 8 . 6 7 X22 0 . 2 1 7 1 8 C E 02 0 . 7 0 1 9 9 0 E 01 0 . 1 1 4 6 0 0 E 02 0. 2 9 6 2 0 0 E 02 3 2 . 3 ? X23 0 . 2 8 2 7 8 0 E 02 0 . U 2 1 1 2 E 02 0 . 2 0 4 3 0 0 E 02 0. 4 6 4 5 0 0 C 02 3 9 . 6 5 X24 0 .1 7 5 9 2 0 E 02 0 . 1 0 5 2 6 3 E 02 0 . 4 1 1 0 0 0 E 01 0. 3 0 7 1 0 0 E 02 5 9 . 8 4 X25 0 . 2 3 4 C ) 6 0 E 02 0 . 5 0 5 3 7 9 E 01 0 . 1 7 7 9 0 0 E 02 0. 3 0 0 1 0 0 E 02 2 1 . 5 1 X26 0.1 5 2 2 4 0 E 02 0 . 4 8 2 7 0 7 E 01 0 . 9 0 5 0 0 0 E 01 0. 1 9 6 6 0 0 E 02 3 1 . 7 1 X27 0 . 1 1 6 8 2 0 E 02 0 . 4 9 3 6 9 9 E 01 0 . 4 9 2 0 0 0 E 01 0. 1 7 U 0 0 E 02 4 2 . 2 6 X78 0.1 0 5 8 2 0 E 02 0 . 3 0 6 4 2 0 E 01 0 . 6 7 1 0 0 0 E 01 0 . 1 3 9 7 0 0 E 02 2 8 . 9 6 X29 0 . 6 2 2 4 0 0 E 01 0 . 2 6 8 0 9 1 E 01 0 . 2 C 6 0 0 0 E 01 0. 9 2 0 0 0 0 E 01 4 3 . 0 7 X30 0 . 1 0 8 7 0 0 E 02 0 . 1 9 3 1 1 3 E 01 0 . 8 4 8 0 0 0 E 01 0. 1 3 2 3 0 0 E 02 1 7 . 7 7 X31 0 . 3 7 8 9 2 0 E 0 2 0 . 7 6 1 9 2 4 E 01 0 . 2 8 3 0 0 0 E 02 c . 4 6 7 1 0 0 E 02 2 0 . 1 1 X32 0 . 3 9 3 6 2 0 E 02 0 . 9 6 4 9 6 9 E 01 0 . 2 8 6 7 0 0 E 02 0. 5 0 2 4 0 0 L 0? 2 4 . 5 2 X33 0 . 3 8 8 5 6 0 E 02 0 . 2 6 4 7 6 3 E 02 0 . 1 5 4 7 0 0 E 02 0. 7 0 6 6 0 0 E 02 6 8 . 14 X34 0 . 3 3 1 6 8 0 E 02 0 . 9 8 5 4 3 5 E 01 0 . 2 3 3 5 0 0 E 02 0. 4 4 3 2 0 0 E 02 2 9 . 7 1 X35 0 . 3 7 3 2 0 0 E 02 0 . U 6 1 9 2 E 02 0 . 2 5 8 3 0 0 E 02 0. 5 1 4 6 0 0 L 02 3 1 . 1 3 X36 0 .1 0 7 8 4 0 F 02 0 . 4 1 2 3 1 7 E 01 0 . 5 7 8 0 0 0 F 01 0. 1 6 3 8 0 0 E 02 3 8 . 2 3 X37 0 .1 9 1 7 2 0 E 02 0 . 1 4 5 6 8 0 E 02 0 . 5 4 7 0 0 0 E 01 c . 4 2 1 5 0 0 E 02 7 5 . 9 9 X38 0 . 7 7 8 8 0 0 E 01 0 . 8 8 5 1 6 4 E 01 0 . 1 2 6 0 0 0 E 01 0. 2 3 2 5 0 0 E 02 1 1 3 . 6 6 X39 0 . 1 5 3 7 8 0 E 02 0 . 2 5 4 1 2 3 E 02 0 . 3 1 6 0 0 0 E 01 0.6 0 8 1 0 0 E 02 1 6 5 . 2 5 X40 0 . 1 3 2 7 8 0 E 02 0 . 1 0 8 9 3 0 E 02 0 . 4 8 3 0 0 0 E 01 0. 3 1 0 1 0 0 E 02 8 2 . 0 4 X41 0 . 1 3 9 1 6 0 E 02 0 . 4 3 6 5 3 6 E 01 0 . 8 6 7 0 0 0 E n i 0 . 1 7 9 3 0 0 E 02 3 1 . 3 7 X42 0 . H 5 2 0 O E 02 0 . 3 7 0 2 0 3 E 01 0 . 6 3 2 0 0 0 E 01 0 • 1 6 1 8 0 0 C 02 3 2 . 14 X43 0 . 8 0 6 0 0 0 E 01 0 . 3 1 7 3 5 4 E 01 0 . 4 7 6 0 0 0 E 01 0. 1 2 9 2 0 0 E 02 3 9 . 3 7 X44 0 . 9 4 2 0 0 0 E 01 0 . 9 1 R 1 5 8 E 01 0 . 3 0 4 0 0 0 E 01 0 • 2 5 6 1 0 0 E 02 9 7 . 4 7 X45 0.1 0 7 3 0 0 E 02 0 . 4 0 3 9 0 8 E 01 0 . 6 9 1 0 0 0 E 01 0. 1 7 4 8 0 0 E 02 3 7 . 6 4 X46 0 . 2 4 7 0 0 0 E 02 0 . 4 8 7 3 9 2 E 01 0 . 1 8 9 6 0 0 E 02 0 . 3 1 6 0 0 0 E 02 1 9 . 73 X47 0 . 3 0 6 5 2 0 E 02 0 . 1 3 2 2 5 1 E 02 0 . 1 5 8 7 0 0 E 02 c. 4 8 4 7 0 0 E 02 4 3 . 15 X40 0 .1 5 4 4 8 0 E 02 0 . 1 0 6 4 2 4 E 02 0 . 8 3 5 0 0 0 E 01 0. 3 4 1 7 0 0 E 02 6 8 . 89 X49 0 . 2 4 7 9 8 0 E 02 0 . 3 4 5 0 1 2 E 02 0 . 7 5 3 0 0 0 E 01 0 . 8 6 4 2 0 0 E 02 1 3 9 . 1 3 X50 0 . 2 4 0 0 8 0 E 02 0 . 1 4 0 4 2 6 E 02 0 . 1 5 5 9 0 0 E 02 0. 4 8 4 9 0 0 E 02 5 8 . 4 9 X51 0". 1 5 4 0 0 0 E 02 0 . 1 3 4 4 6 2 E 02 0 . 3 0 0 0 0 0 E 01 c . 3 7 0 0 0 0 E 02 8 7 . 3 1 X52 0. 0 . 0 . 0. 0 . 0 0 X53 0 . 0 . 0 . 0 . 0 . 0 0 X54 0. 0 . 0 . 0 • 0 . 0 0 X55 0 . 5 4 4 0 0 0 E 02 0 . 4 5 8 9 9 9 E 02 0 . 0. lOOOOOF 03 8 4 . 3 7 X56 0 . 4 4 0 0 0 0 E 01 0 . 9 8 3 8 7 0 E 01 0 . 0 . 2 2 0 0 0 0 E 02 2 2 3 . 6 1 X57 0 . 1 2 8 0 0 0 E 00 0 . 6 6 8 5 8 1 E --01 0 . 2 0 0 0 0 0 E --01 0. 1 8 0 0 0 0 E 00 5 2 . 2 3 XS8 0 .1 9 8 0 0 0 E 0 0 0 . 1 1 4 7 6 1 E 00 0 . 0. 3 0 0 0 0 0 E 0 0 5 7 . 9 6 X5 9 0.1 2 4 4 0 U E 01 0 . 5 3 8 5 9 1 E 00 0 . 6 0 0 0 0 0 F 0 0 0. 2 0 0 0 0 0 E 01 4 3 . 3 0 X6U 0 . 9 1 4 0 0 0 E 01 0 . 3 2 0 5 9 3 E 01 0 . 5 8 0 0 0 0 E 01 0. 1 3 4 0 0 0 E 02 3 5 . 0 8 X61 0.1 6 7 6 8 0 E 03 0 . 1 2 0 5 6 2 E 03 0 . 0. 3 2 8 9 0 0 E 03 7 1 . 9 0 YI 0 . 6 9 7 2 0 0 E 01 0 . 3 6 2 7 6 6 E 01 0 . 1 6 8 0 0 0 E 01 0. 1 1 J 8 0 0 F 02 5 2 . 3 3 Y2 0 . 4 8 4 6 0 0 E 01 0 . 2 0 2 3 0 5 E 01 0 . 2 0 3 0 0 0 E 01 0 . 7 2 9 0 0 0 E 01 4 1 . 7 5 Y3 0 . 4 2 7 2 0 C F 01 0 . 2 5 4 9 1 9 E 01 0 . 3 0 0 0 0 0 E 0 0 'J. 6 6 2 0 0 0 E 01 5 9 . 6 7 Y4 0 . 8 5 2 7 8 0 E 02 0 . 4 3 5 3 6 0 E 02 0 . 2 1 0 7 0 0 E 02 0 . 1 3 J 1 9 0 E 03 5 1 . 0 5 Y5 0 . 5 6 8 6 0 0 E 01 0 . 2 9 0 4 3 4 E 01 0 . 1 4 0 0 0 0 E 01 0. 8 8 8 0 0 0 E 01 5 1 . 0 9 NUMBER OF OBSERVATIONS = BLOCK C-l CLEARCUT SYMROL MEAN STANDARD DEVI AT ION MINIMUM MAXIMUM COEFFICIENT OF VARI AT I3N XI X2 X3 X4 X5 X6 X7 X8 X9 XIO XI 1 X12 X13 X14 X15 X16 X17 X18 X19 X20 X21 X22 X23 X24 X25 X26 X27 X28 X29 X30 X31 X32 X33 X34 X35 X36 X37 X38 X39 X40 X41 X42 X43 X44 X45 X46 X47 X48 X49 X50 X51 X52 X53 X54 X55 X56 X57 X58 X59 X60 X61 YI Y2 Y3 Y4 Y5 0.530000E 00 0.582000E 00 0.988000E 00 0.122800E 01 0.834000E 00 0.296000E 00 0.272000E 00 0.214000E 00 0.176000E 00 0.246000E 00 0.766000E 00 0.744000E 00 0.602000E 00 0.518000E 00 0.656000E 00 0.230920E 02 0.312880E 02 0.441140E 02 0.491880E 02 0.369180E 02 0.267160E 02 0.192600E 02 0.316120E 02 0.293640E 02 0.267380E 02 0.159540E 02 0.948800E 01 0.124B20F 02 0.133480E 02 0.133220E 02 0.368600E 02 0.34168GE 02 0.231340F 02 0.259840E 02 0.30C300E 02 0.166480E 02 0.281520E 02 0.362600E 01 0.340400E 01 0.129600E 02 0.175700E 02 0.U8120E 02 0.816600E 01 0.469600E 01 0.100620E 02 0.342380E 02 0.399640E 02 0.117920E 02 0.810000E 01 0.230220E 02 0.690000E 02 0.140000E 00 0. 0.42000GE 00 0.800000E 02 0.726000E 02 0.142000E 00 0.242000E 00 0.218400E 01 0.138800E 02 0.35650GE 03 0.212920E 02 0.196320E 02 0.185440E 02 0.301792E 03 0.201160E 02 0.243002E 00 0.250000E 00 0.800000E 00 45.85 0.343468E 00 0.170000E 00 0.102000E 01 59.02 0. 172395E 00 0.750000E 00 0.116000E 01 17.45 0.460565E 00 0.890000E 00 0.195000E 01 37.51 0.135204E 00 0.620000E 00 0.940000E 00 16.21 0.502991E-•01 0.230000E 00 0.370000E 00 16.99 0.501996E-•01 0.200000E 00 0.3200O0E 00 18.46 0.650385E-•01 0. 130000E 00 0.290000E 00 30. 39 0.673053E-•01 0.600000E-•01 0.230000E 00 38.24 0.304959E-•01 0.200000E 00 0.270000E 00 12.40 0.820367E-•01 0.670000E 00 0.860000E 00 10.71 0.111938E 00 0.600000E 00 0.870000E 00 15.05 0.645755E-•01 0.540000E 00 0.690000E 00 10.73 0.169470E 00 0.250000E 00 0.650000E 00 32. 72 0.461520E-•01 0.620000E 00 0.730000E 00 7.04 0.131656E 02 0.860000E 01 0.344600E 02 57.01 0.216101E 02 0.115000E 01 0.601400E 02 69.07 0.123836E 02 0.274500E 02 0.607200E 02 28.08 0.166054E 02 0.358900E 02 0.687800E 02 33.76 0.957674E 01 0.241700E 02 C.506500E 02 25.94 0.122165E 02 0.968000E 01 0.382600E 02 45.73 0.143672E 02 0.510000E 00 0.351800E 02 74.60 0. 109191E 02 0.179100E 02 0.460200E 02 34.54 0.115023E 02 0.171500E 02 0.440100E 02 39. 17 0.103980E 02 0. 132200E 02 0.363900E 02 38.89 0.551007E 01 O.88C000E 01 0.236100E 02 34.54 0.629423E 01 0.124000E 01 0.173800E 02 66.34 0.401200E 01 0.874000E 01 U.180300F 02 32. 14 0.705799E 01 0.516000E 01 0.215000E 02 52.88 0.376133E 01 0.924000E 01 0.173700E 02 28.23 0.107919E 02 0.284000E 02 0.556700E 02 29.28 0.211014E 02 0.118300E 02 0.691900E 02 61.76 0.406498E 01 0.176100E 02 0.286200E 02 17.57 0.679144E 01 0.167200E 02 0.343700E 02 26.14 0.907061E 01 0.202500E 02 0.447700E 02 30.21 0.184004E 02 0.462000E 01 0.472000E 02 110.53 0.358761E 02 0.336000E 01 0.864500E 02 127.44 0.179641E 01 0.130000E 01 0.538000E 01 49.54 0.8R3080E 00 0.247000E 01 0.432000E 01 25.94 0.131523E 02 0.427000E 01 0.343700E 02 101.48 0.115392E 02 0.818000E 01 0.369100E 02 65.68 0.473227E 01 0.481000E 01 0 . 177500F 02 40.06 0.264486E 01 0.497000E 01 0.117600E 02 32.39 0.250509E 01 0.254000E 01 0.750000E 01 53.35 0.279980E 01 0.657000E 01 0.130700E 02 27.83 0.246676E 02 0.128000E 02 0.639100b 02 72.05 0.370177E 02 0.817000E 01 0.971000E 02 92.63 0.326274E 01 0.756000E 01 0.161400E 02 27.67 0.263785E 01 0.512000E 01 0.116100E 02 32.57 0.142350E 02 0.110500E 02 0.446000E 02 61.83 0.282400E 02 0.380000E 02 0.950000E 02 40.93 0.207364E 00 0. 0.500000E 00 148.12 0. 0. 0. 0.00 0.277489E 00 0. 0.700000E 00 66.07 0.447214E 02 0. O.IOOOOOE 03 55.90 0.377995E 02 0.250000E 02 0.100000E 03 52.07 0. 593296E--01 0.600000E--01 0.200000E 00 41.78 0.683374E--01 0.130000E 00 0.300000E 00 28.24 0.256671E 00 0.178000E 01 0.240000E 01 11.75 0.123774E 01 0.121000E 02 0.149000E 02 8.92 0.816738E 02 0.261200E 03 0.466700E 03 22.91 0.332997E 01 0.173300E 02 0.262800E 02 15.64 0.243494E 01 0.169700E 02 0.221500E 02 12.40 0.276532E 01 0.150900E 02 0.212100E 02 14.91 0.203H9E 02 0.269450E 03 0.320180E 03 6.73 0. 135256E 01 0. 179600E 02 0.213400E 02 6.72 NUMBER OF OBSERVATIONS = BLOCK C-2 SKIDROAD SYMBOL MEAN STANDARD DEVI AT I ON MINIMUM MAXIMUM C O E F F I C I E N T DF V A R I A T I O N XI 0.116000E 01 0.332791E GO 0. 76000OE 00 0.158000E 01 28.69 X2 0.129400E 01 0.324160E 00 0. 830000E 00 G.169000E 01 25.05 X3 0.129600E 01 0.176862E 00 0. 102000E 01 0.147000E 01 13.65 X4 0.129000E 01 0.236114E 00 0. 890000E 00 0.151000E 01 18.30 X5 0.124800E 01 0.164530E 00 0. 980000E 00 0. 1.38000E 01 13.18 X6 0.290000E 00 0.418330E-•01 0. 240000E 00 0.350000E 00 14.43 X7 0.26600CE 00 0.427785E-•01 0. 230000E 00 G.330000E 00 16.08 XO 0.254000E 00 0.403733E-•01 0. 210000E 00 0.310000E 00 15.89 X9 0.2390006 00 0.851469E-•01 0. 900000E-•01 0'. 3000006 00 37.02 XIO 0.260000E 00 0.418330E-•01 0. 200000E 00 0.300000E CO 16.09 XI 1 0.538000E 00 0.120291E 00 0. 390000E 00 0.6e0000E 00 22.36 XI? 0.4940006 00 0.115672E 00 0. 350000E 00 G.660000E 00 23.42 XI 3 0.496000E 00 0.638749E-•01 0. 430000E 00 0.590000E 00 12.88 X14 0.500000E 00 0.3803416-•01 0. 420000E 00 0.650000E 00 17.51 X15 0.504000E 00 0.559464E-•01 0. 460000E 00 0.600000E 00 11.10 X16 0.431400F 02 0.6073006 01 0. 365000E 02 0.496400E 02 14.08 XI 7 0.519180E 02 0.1142166 02 0. 360400E 02 0.657300E 02 22.00 XI 8 0.529460E 02 0.113793E 02 0. 369600E 02 0.666700E 02 21.49 X19 0.527360E 02 0.B68275E 01 0. 428500E 02 0.616200E 02 16.46 X20 0.50186GE 02 0.720133E 01 0. 420400E 02 G.591500E G? 14.35 X21 0.309520E 02 0.112472E 02 0. 183500E 02 G.476100E 02 36.34 X22 0.310040E 02 0.832935E 01 0. 236100E 02 0.408100E 02 26.87 X?3 0.334720F 02 0.870590E 01 0. 215600E 02 0.426100G 02 26.01 X24 0.334040E 02 0.5047G2E 01 0. 286400E 02 0.410600E 02 15.11 X25 0.322080E 02 0.688273E 01 0. 249800E 02 G.411100F 02 21.37 X26 0.15170CE 02 0.682140E 01 0. 959000E 01 0.263900E 02 '44.97 X?7 0.R45000E Ot 0.4427426 01 0. 397000E 01 0.1513006 02 52.40 X28 0.796000E 01 0.341656E 01 0. 474000E 01 0.U9700E 02 42. 92 X29 0.693200E 01 0.134762E 01 0. 526000E 01 0.R72000E 01 19.44 X30 0.933200E 01 0.195600E 01 0. 6290006 01 0.114900E 02 20.96 X31 0.418880E 02 0.634533E 01 0. 347700E 02 0.522100E 02 15.15 X32 0.363620E 02 0.152065E 02 0. 208700E 02 C.540300E 02 41.82 X33 0.54440GE 0 2 0.366514E 02 0. 201300E 02 0.100450E 03 67. 32 X34 0.267280E 02 0.264921E 01 0. 237500E 02 0.3079006 02 9.91 X35 0.398560E 02 0.127850E 02 0. 252700E 02 0.546800F 02 32. 08 X36 0.340000E 01 0.232357E 01 0. 138000E 01 0.722000E 01 68.34 X37 O.332200E 01 0.303765E 01 0. 1230OOE 01 C.868000E 01 91.44 X38 0.26940GE 01 0.168127E 01 0. 11600CE 01 G.552000E 01 62.41 X39 0.300000E 01 0.254687E 01 0. 166000E 01 0-755000E 01 84. 90 X40 0.310400E 01 0.156617E 01 0. 193000E 01 0.583000E 01 50.46 X41 0.7338006 01 0.351616E 01 0. 340000E 01 0•12 71 OOF 02 47.92 X42 0.53060GE 01 0.289917E 01 0. 292G00E 01 0.941000E 01 54. 64 X4 3 0.492800E 01 0.266542E 01 0. 236000E 01 0.869000E 01 54.09 X44 0.391400E 01 0.244145E 01 0. 189000E 01 0.789000E 01 62.38 X45 0.53700GE 01 0.213281E 01 0. 345000E 01 0.868000E 01 39.72 X46 0.1073BUE 02 0.573588E 01 0. 524000E 01 0.199300E 02 53.42 X47 0.862800E 01 0.568918E 01 0. 415000E 01 0.180900E 02 65.94 X48 0.76220GE 01 0.398255E 01 0.462000E 01 0.142100E 02 52.25 X49 0.691400E 01 0.485730E 01 0. 379000E 01 0.154400E 02 70.25 X50 0.847400E 01 0.358316E 01 0. 538000E 01 0.1451006 02 42.28 X51 0.60800GE 02 0.478926E 02 0. 500000E 01 0.100000E 03 78. 77 X5 2 0.240000E 00 0.288097E 00 0. 0.700000E 00 120.04 X53 0. 0. 0. 0. 0.00 X54 0. 0. 0. c . 0.00 X55 0.500000E 02 0.500000E 02 0. 0.100000E 03 100.00 X56 0.840000E 01 0.122597E 02 0; 0.270000E 02 145.95 X57 0.17U0O0E 00 0.6964196-•01 0. 900000E--01 0.2400006 00 40.97 X58 0.276000E 00 0.415933E-•01 0. 230000E 00 0.330000E 00 15.07 X59 0.147600E 01 0.2527456 GO 0. 116000E 01 0.178000E 01 17.12 X60 0.107800E 02 0.144465E 01 0. 900000E 01 0.125000E 02 13.40 X61 0.35140GE 03 0.158570E 03 0. 200100E 03 0.614800E 03 45. 13 YI 0.702600E 01 0.215690E 01 0. 469000E 01 0.933000E 01 30.70 Y2 0.406400E 01 0.169462E 01 0. 173000E 01 0.646000E 01 41.70 Y3 0.310600E 01 0.107623E 01 0. 144000E 01 0.444000E 01 34.65 Y4 0.778560E 02 0.217681E 02 0. 459800E 02 0.103780E 03 27.96 YS O.519000E 01 0.145295E 01 0. 306000E 01 0.692000E 01 28.00 NUMBER OF OBSERVATIONS = BLOCK C=2 CLEARCUT SYMBOL MEAN STANDARD DEVIATION MINIMUM MAXIMUM COEFFICIENT OF VARIATION XI 0.5240D0E 00 X2 0.730000E 00 X3 0.854000E 00 XA O.108000E 01 X5 0.798000E 00 X6 0.414000E 00 X7 0.328000E 00 X8 0.33000GE 00 X9 0.294000E 00 XIO 0.340000E 00 X l l 0.760000E 00 X12 0.68400GE 00 X13 0.64600GE 00 X14 0.56200GE 00 X15 0.664000E 00 X16 0.340980E 02 X17 0.333500E 02 X18 0.424560E 02 X19 0.504320E 02 X20 0.400820E 02 X ? l 0.18268GE 02 X22 0.26656GE 02 X23 0.268840E 02 X24 0.260400E 02 X25 0.244620E 02 X26 0.96980.0E 01 X27 0.93040UE 01 X28 0.101880E 02 X29 0.697600E 01 X30 0.913400E 01 X31 0.55862GE 02 X32 0.29468GE 02 X33 0.279780E 02 X34 0.701060E 02 X35 0.328540E 02 X36 0.207080E 02 X37 0". 166500E 02 X38 0. 10864GE 02 X39 0.853800E 01 X40 0.141920E 02 X41 0.168280E 02 X42 0.1404006 02 X43 0.960800E 01 X44 0.805400E 01 X45 0.121300E 02 X46 0.375360E 02 X47 0.306900E 02 X48 0.204720E 02 X49 0.16592GE 02 X50 0.263220E 02 X51 0.356000E 02 X52 0.600000E--01 X53 0.220000E 00 X54 0.360000E 00 X55 0.800000E 02 X56 0.86000GE 02 X57 0.12200GE 00 X58 0.304000E 00 X59 0.198400E 01 X60 0.126600E 02 X61 0.575660E 03 YI 0.207100E 02 Y2 0.185380E 02 Y3 0.183640E 02 Y4 0.292638E 03 Y5 0.195060E 02 0.201321E 00 0.310000E 00 0. 820000E 00 38.42 0.335485E 00 0.370000E 00 0. 127000E 01 45.96 0.281656E 00 0.520000E 00 0 . 111000E 01 32.9R 0.3424186 00 0.650000E 00 0.139000E 01 31.71 0.258496E 00 0.480000E 00 0 . 115000E 01 32. 39 0.585662E-•01 0.350000E 00 0. 500000E 00 14.15 0.7395946-•01 0.210000E 00 0 . 410000E 00 22.55 0.3605556-•01 0.280000E 00 0. 370000E 00 10.93 0.3209366-•01 0.250000E 00 0. 330000E 00 10.92 0.339117E-•01 0.300000E 00 0 . 380000E 00 9.97 0.6595446-•01 0.660000E 00 0 . 820000E 00 8.68 0.103586E 00 0.510000E 00 0. 780000E 00 15.14 0.915423E-•01 0.560G00E 00 0 . 750000E 00 14.17 0.1100916 00 0.460000E 00 0. 680000E 00 19.59 0.7987496-•01 0.550000E 00 0.750000E 00 12.03 0.113098E 02 0.155900E 02 0 . 464500E 02 33. 17 0.122795E 02 0.130800E 02 0.437500E 02 36.82 0.914007E 01 0.285900E 02 0 . 527800E 02 21.53 0.132743E 02 0.312300E 02 0.667600E 02 26.32 0.738623E 01 0.269200E 02 0 . 444000E 02 18.43 0.650319E 01 0.969000E 01 0. 233I00E 02 35.60 0.159148E 02 0.768000E 01 0 . 500100E 02 59. 70 0.457532E 01 0.202100E 02 0 . 330700E 02 17.02 0.107895E 02 0.180500E 02 0. 446200E 02 41.43 0.819207E 01 0.155200E 02 0 . 375500E 02 33.49 0.294731E 01 0.644000E 01 G. 140000E 02 30. 39 0.216723E 01 0.579000E 01 0 . I10900E 02 23.29 0.360795E 01 0.394000E 01 0. 130200E 02 35.41 0.360750E 01 0.185000E 01 0 . 11U00E 02 51.71 0.259921E 01 0.472000E 01 0 . 112000E 02 28.46 0.156941E 02 0.388300E 02 0. 775700E 02 28.09 0.881181E 01 0.180100E 02 G. 423000R 02 29.90 0.955484E 01 0.138500E 02 0- 391000F 02 34. 15 0.580579E 01 0.104500E 02 u . 245100E 02 28.88 0.549560E 01 0.232600E 02 0 . 370400E 02 16.73 0.160755E 02 0.745000E 01 0 . 444100E 02 77.63 0.197285E 02 0.990000E 00 0 . 508200E 02 118.49 0.133532E 02 0.272000E 01 0 . 344100E 02 122.91 0.108478E 02 0.111000E 01 0 . 276200E 02 127.05 0.126844E 02 0.307000E 01 0 . 357100E 02 89.38 0.468534E 01 0.109800E 02 0. 233700E 02 27.64 0.741819E 01 0.457000E 01 0 . 226300E 02 52.84 0.36041 IE 01 0.532000E- 01 0 . 138300E 02 37.51 0.647581E 01 0.307000E 01 0 . 181400E 02 80.40 0.387505E 01 0.707000E 01 0 . 171300E 02 31.95 0.197376E 02 0.184300E 02 V. 682800E 02 52. 58 0.260608E 02 0.556000E 01 0. 7345006 02 84.92 0.158453E 02 0.884C00E 01 0 . 4726006 02 77.40 0.170147E 02 0.550000E 01 0 . 457600E 02 102.55 0.159148E 02 0.101400E 02 0 . 528400E 02 60.46 0.378259E 02 0.500000E 01 0 . 100000E 03 106.25 0.134164E 00 0. 0.300000E 00 223.61 0.491935E 00 0. 0. 110000E 01 223.61 0.114018E 00 0.200000E 00 0 . 500000E 00 31.67 0.447214E 02 0. 0 . 100000E 03 55.90 0.313050E 02 0.300000E 02 0.100000E 03 36.40 0.491935E-•01 0.100000E 00 0. 210000E 00 40. 32 0.466905E--01 0.250000E 00 0 . 370000E 00 15.36 0.249560E 00 0. 172000E 01 0 . 226000E 01 12.58 0.950264E 00 0.114000E 02 0 . 137000E 02 7.51 0.254046E 03 0.126100E 03 0 . 723300E 03 44. 13 0.540408E 01 0.139100E 02 0.269400E 02 26.09 0.524848E 01 0. 127700F 02 0.262100E 02 28.24 0.528994E 01 0.130100E 02 0 . 262100E 02 28.81 0.761146E 02 0. 199660E 03 D. 398270E 03 26.01 0.507432E 01 0.133100E 02 0 . 265500E 02 26.01 NUMBER OF OBSERVATIONS = 5 BLOCK C-3 SKIDROAD SYMBOL MEAN STANDARD DEVIATION MINIMUM MAXIMUM COEFFICIENT OF VARI AT I3N XI 0-862000E 00 0.216956E 00 X2 0.113000E 01 0.355457E 00 X3 0.125400E 01 0.207798E 00 X4 0.119600E 01 0.160873E 00 X5 0.111200E 01 0. 1706466 00 X6 0.324000E 00 0.270185E-•01 X7 0.282000E 00 0.672309E-•01 X8 0.250000E 00 0.447214E- 01 X9 0.240000E 00 0.441588E-•01 XIO 0.274000E 00 0.279285E-•01 XII 0.650000E 00 0.799999E-•01 XL2 0.554000E 00 0.136858E 00 X13 0.528000E 00 0.402492E-•01 X14 0.5300006 00 0.570088E-•01 X15 0.564000E 00 0-554978E-•01 X16 0.433880E 02 0.112082E 02 X17 0.530360E 02 0.135856E 02 X18 0.554280E 02 0. 1079.38E 02 X19 0.564680E 02 0.175498E 02 X20 0.520800E 02 0.831220E 01 X21 0.310980E 02 0.493393E 01 X22 0.301060E 02 0.110445E 02 X23 0.28344GE 02 0.682483E 01 X24 0.273140E 02 0.124876E 02 X25 0.292140E 02 0.599973E 01 X26 0.955000E 01 0.262133E 01 X27 0.927400E 01 0.749623E 01 X28 0.839600E 01 0.430859E 01 X29 0.855800E 01 0.664946E 01 X30 0.893400E 01 0.315286E 01 X31 0.401620E 02 0.697212E 01 X32 0.321740E 02 0.575285E 01 X33 0.300500E 02 0.480320E 01 X34 0.25140CE 02 0.337434E 01 X35 0.318800E 02 0. 147926E 01 X36 0.623200E 01 0. 19057 IE 01 X3.7 0.304400E 01 0.188569E 01 X38 0.299200F 01 0.159774E 01 X39 0.364600E 01 0.229438E 01 X40 0.398400E 01 0.115294E 01 X41 0.973200E 01 0.388344E 01 X42 0.452000E 01 0.172538E 01 X43 CJ.490000E 01 0.171721E 01 X44 0.4014006 01 0.169147E 01 X45 0.579000E 01 0.188891F 01 X46 0.159640E 02 0.551894E 01 X47 0.758400E 01 0.304820E 01 X48 0.783200E 01 0.262697E 01 X49 0.766000E 01 0.371952E 01 X50 0.977200E 01 0.289155E 01 X51 0.34400GE 02 0.344137E 02 X52 O.IOOOOOE 00 0.122474E 00 X53 0. 0. X54 0. 0. xr>5 0.210000E 02 0.442154E 02 X56 0.102000E 02 0.939149E 01 X57 0.182000E 00 0.491935E-•01 X58 0.270000E 00 0.484768E-•01 X59 0.150400E 01 0.343045E 00 X60 0.1U200E 02 0.127358E 01 X61 0.337820E 03 0.199026E 03 YI 0.827O00E 01 0.314951E 01 Y2 0.665600E 01 0.400731E 01 Y3 0.582000E 01 0.332606E 01 Y4 0.107812E 03 0.508894E 02 YS 0.717600E 01 0.339942E 01 0.610000E 00 0.530000E 00 0.104000E 01 0.101000E 01 0.930000E 00 0.290000E 00 0.190000E 00 0.190000E 00 0.180000F 00 0.250000E 00 0.560000E 00 0.450000E 00 0.480000E 00 0.470000E 00 0.490000E 00 0.351800E 02 0.393200E 02 0.424200E 02 0.330100E 02 0.421200E 02 0.226100E 02 0.137900E 02 0.192400E 02 0.111800E 02 0.238800E 02 0.601000E 01 0.322000E 01 0.402000E 01 0.210000E 01 0.497000F 01 0.299800E 02 0.246300E 02 0.245400E 02 0.198500E 02 0.306100E 02 0.352000E 01 0.116000E 01 0.149000E 01 0.136000F 01 0.198000E 01 0.488000E 01 0.212000E 01 0.207000E 01 0.242000E 01 0.287000E 01 0.840000E 01 0.338000E 01 0.356000E 01 0.408000E 01 0.485000E 01 0.200000E 01 0. 0. 0. 0. 0. O.IOOOOOE 00 0.190000E 00 0.900000F 00 0.890000E 01 0.988000E 02 0.394000E 01 0.193000E 01 0.211000E 01 0.437800E 02 0.292000E 01 0.110000E 01 0.143000E 01 0.160000E 01 0.137000E 01 0.137000E 01 0.350000E 00 0.370000F 00 0.300000E 00 G.300000E 00 0.320000E 00 0.750000E 00 0.790000E 00 0.590000E 00 0.600000E 00 0.630000E 00 0.629800E 02 0.724800E 02 0.692100E 02 0.795200E 02 0.630200E 02 0.350100E 02 0.444500E 02 0.346500E 02 0.454500E 02 0.388800E 02 0.119500E 02 0.217500E 02 0.155200E 02 0.197800E 02 0.131700E 02 0.472000E 02 0.383800E 02 0.363300E 02 0.277400E 02 0.340700E 02 0.842000E 01 0.591000E 01 0.482000E 01 0.699000E 01 0.493000E 01 0.144800E 02 0.699000E 01 0.652000E 01 0.666000E 01 0.811000E 01 0.229000E 02 0.105100E 02 0.104400E 02 0.136500E 02 0.125400E 02 0.850000E 02 0.300000E 00 0. 0. O.IOOOOOE 03 0.200000E 02 0.2200006 00 0.310000E 00 0.174000E 01 0.120000E 02 0.644700E 03 0.120900E 02 0.124400E 02 U.103900E 02 0.175970E 03 0.117300E 02 25. 17 31.46 16.57 13.45 15.35 8.34 23.84 17.89 18.40 10.19 12.31 24.70 7.62 10. 76 9.84 25.83 25.62 19.47 31.08 15.96 15.87 36.69 24.08 45.72 20. 54 27.45 80.83 51.32 77. 70 35.29 17.36 17.88 15.98 13.42 4.64 30.58 61.95 53.40 62.93 28.94 39.90 38. 17 35.05 42. 14 32.62 34.57 40. 19 33.54 48. 56 29.59 100.04 122.47 0.00 0.00 210.55 92.07 27.03 17.95 22.81 11.45 58.91 38. 08 60.21 57.15 47.20 47.37 NUMBER OF OBSERVATIONS BLOCK C-3 CLEARCUT SYMBOL MEAN STANDARD DEVIATION MINIMUM MAXIMUM COEFFICIENT OF VARIATION XI X2 X3 X4 X5 X6 X7 X8 X9 XIO X l l X12 X13 X14 X15 X16 X17 X18 X19 X20 X21 X22 X23 X24 X25 X26 X27 X28 X29 X30 X31 X32 X33 X34 X35 X36 X37 X38 X39 X40 X41 X42 X43 X44 X45 X46 X47 X48 X49 X50 X51 X52 X53 X54; X55 X56 X57 X53 X59 X60 X61 YI Y2 Y3 Y4 Y5 0.576000E OO 0.668000E OO 0.704000E OO 0.990000E OO 0.738000E OO 0.396000E OO 0.336000E OO 0.328C00E OO 0.332000E OO 0.346000E OO 0.742000E OO 0.710000E OO 0.692000E OO 0.602000E OO 0.686000E OO 0.438620E 02 0.394900E 02 0.365840E 02 0.559900E 02 0.439800E 02 0.204080E 02 0.264900E 02 0.217120E 02 0.228800E 02 0.228760E 02 0.702800E 01 9.742800E 01 0.321400E 01 0.817600E 01 0.751000E 01 0.125862E 03 0.556360E 02 0.18338CE 02 0.192200E 02 0.547640E 02 0.142180E 02 0.132100E 02 0.172960E 02 0.553000E 01 0.131640E 02 0.144840E 02 0.133820E 02 0.161940E 02 0.742400E 01 0.128700E 02 0.287020E 02 0.265920E 02 0.334900E 02 0.129540E 02 0.260340E 02 0.110000E 02 0.200000E-01 0.800000E-01 0.420000E 00 0.100000E 03 0.940000E 02 O.IOOOOOE 00 0.332000E 00 0.224400E 01 0.151400E 02 0.698460E 03 0.200660E 02 0.199060E 02 0.204320E 02 0.301818E 03 0.201180E 02 0.944987E-•01 0.480000E 00 0. 720000E 00 16.41 0.169470E 00 0.480000E 00 0. 940000E 00 25.37 0.313576E 00 0.320000E 00 0.112000E 01 44.54 0.367967E 00 0.590000E 00 0 . 145000E 01 37. 1 7 0.217071E 00 0.510000E 00 0. 106000E 01 29.41 0.260769E-•01 0.370000E 00 0.430000E 00 6.59 0.181659E-•01 0.320000E 00 0. 360000E 00 5.41 0.258843E-•01 0.290000E 00 0. 360000E 00 7.89 0.454973E-•01 0.270000E 00 0. 380000E 00 13.70 0.114017E-•01 0.330000E 00 0. 360000E 00 3. 30 0.327109E-•01 0.710000E 00 0. 780000E 00 4.41 0.561249E-•01 0.620000E 00 0. 770000E 00 7.90 0.101833E 00 0.550000E 00 0. 810000E 00 14.72 0.128725E 00 0.440000E 00 0. 750000E 00 21.38 0.698570E-•01 0.580000E 00 0. 760000E 00 10.18 0. 111402E 02 0.300200E 02 0. 6C3100E 02 25.40 0. 104355E 02 0.262500E 02 0. 533600E 02 26.43 0.225920E 02 0.299000E 01 0. 578900E 02 61.75 0.119682E 02 0.431800E 02 0. 725700E 02 21.38 0. 130769E 02 0.273700E 02 0. 610300E 02 29. 73 0.791066E 01 0.738000E 01 0 . 281600E 02 38. 76 0.442224E 01 0.215800E 02 0. 334100E 02 16.69 0.388006E 01 0.178100E 02 0. 264500E 02 17.87 0.377534E 01 0.173000E 02 0. 278000E 02 16.50 0.197163E 01 0.197000E 02 0. 248600E 02 8.62 0.425216E 01 0.195000E 01 0. 137200E 02 60.50 0.228953E 01 0.510000E 01 0. 110000E 02 30.82 0.593078E 01 0.497000E 01 0. 188000E 02 72.20 0.275758E 01 0.408000E 01 0.108200E 02 33.73 0.218686E 01 0.573000E 01 0. 103200E 02 29.12 0.430913E 02 0.597000E 02 0. 165420E 03 34.24 0.494088E 02 0.152600E 02 0. 130720E 03 88.81 0.763687E 01 0.108800E 02 0. 312700E 02 41.65 0.435926E 01 0.139000E 02 0.245400E 02 22.68 0.59U08E 01 0.476600E 02 0. 634100E 02 10. 79 0.153906E 02 0.651000E 01 0. 417100E 02 108.25 0.922936E 01 0.394000E 01 0. 266500E 02 69.87 0.133789E 02 0.451000E 01 0. 364100E 02 77. 35 0.326142E 01 0.263000E 01 0. 951000E 01 58.98 0.699399E 01 0.444000E 01 0. 233700E 02 53.13 C.727377E 01 0.701000E 01 u . 262300E 02 50.22 0.398498E 01 0.703000E 01 0. 163900E 02 29.78 0.128015E 02 0.618000E 01 0.368800E 02 79.05 0.499526E 01 0.307000E 01 u . 137900E 02 67.29 0.679902E 01 0.591000F 01 0. 233200E 02 52.83 0. 150665E 02 0. 137000E 02 0. 519800E 02 52.49 0. 118545E 02 0.109700E 02 0. 421300E 02 44.58 0.254002E 02 0.106900E 02 0. 732900E 02 75.84 0.816555E 01 0.605000E 01 0. 224100E 02 63.03 0.112603E 02 0.103500E 02 0. 382000E 02 43.25 0.547723E 01 0.500000E 01 0.200000E 02 49.79 0.447214E-•01 0. 0. 100000E 00 223.61 0.447214E-•01 0. 0. 100000E 00 55.90 0.438178E 00 0.200000E 00 0. 120000E 01 104.33 0. 0. 100000E 03 0. 100000F 03 0.00 0.894427E 01 0.800000E 02 0. 100000E 03 9.52 0.965051E-•05 0. 100000E 00 0. 100000E 00 0.01 0.454973E-•01 0.270000E 00 0. 380000E 00 13.70 0.58992BE--01 0.220000E 01 0. 234000E 01 2.63 0.234051E 01 0.134000E 02 0. 192000E 02 15.46 0.386817E 02 0.644500E 03 0. 747000E 03 5.54 0.279603E 01 0.154200E 02 0.227200E 02 13.93 0.264192E 01 0.153100E 02 0. 221000E 02 13.27 0.327483E 01 0.148200E 02 0. 230000E 02 16.03 0.413122E 02 0.228470E 03 0. 326180E 03 13.69 0.275325E 01 0.152300E 02 0. 217400E 02 13.69 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0103990/manifest

Comment

Related Items