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Methods for describing distribution of soundwood in mature western hemlock trees Munro, Donald Deane 1968

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METHODS FOR DESCRIBING DISTRIBUTION OF SOUNDWOOD IN MATURE WESTERN HEMLOCK TREES by DONALD D. MONRO B.S.F„, U n i v e r s i t y , of B r i t i s h Columbia, 1960 M.S., Oregon State U n i v e r s i t y , 1964 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n the Department of FORESTRY We accept t h i s t h e s i s as conforming to the re q u i r e d standard . THE UNIVERSITY OF BRITISH COLUMBIA May, 1968 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 the r e q u i r e m e n t s f o r an advanced deg ree a t 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 , I a g r ee t h a t t he 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 udy . I f u r t h e r a g r ee 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 he Head o f my Department o r by hiis r e p r e s e n t a t i v e s . It 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 . Depar tment o f The U n i v e r s i t y o f B r i t i s h Co l umb i a Vancouver^ 8, Canada . ABSTRACT Supervisor: P r o f e s s o r J . H. G. Smith E s t i m a t i o n of soundwood volume and value i s p a r t i c u l a r l y important i n B r i t i s h Columbia because n e a r l y h a l f of the f o r e s t s are overmature or decadent. The o b j e c t i v e of t h i s t h e s i s was to develop - a n a l y t i c a l techniques to d e f i n e d i s t r i b u t i o n of gross and net volumes w i t h i n i n d i v i d u a l standing trees i n order that appropriate reductions f o r decay could be made f o r estimates of volumes of logs of s p e c i f i e d s i z e s and grades. R e l a t i o n s h i p s of heartr-ot to stand and tree c h a r a c t e r i s t i c s and to e x t e r n a l a b n o r m a l i t i e s were analysed f o r 369 western hemlock (Tsuga h e t e r o p h i l l a (Rafn.) Sarg.) trees from the Yale P u b l i c Sustained Y i e l d U n i t i n B r i t i s h Columbia. Comprehensive s o r t i n g , c o r r e l a t i o n and r e g r e s s i o n analyses were c a r r i e d out on an I . B. M. 7044 e l e c t r o n i c computer. One m u l t i p l e r e g r e s s i o n equation provided estimates of t o t a l decay volume w i t h i n i n d i v i d u a l trees from DBH, t o t a l height and e x t e r n a l i n d i c a t o r s of decay. I t had a standard e r r o r of estimated decay volume of 18.7 cubic f e e t (19.5 per c e n t ) . A second equation estimated decay volume w i t h i n i n d i v i d u a l logs i n standing t r e e s from the above v a r i a b l e s and from s e c t i o n height. I t had standard e r r o r s of estimate ranging from 13.7 cubic f e e t (31.6 per cent) i n butt logs to 0.1 cubic f e e t (2.9 per cent) i n top logs. The best taper f u n c t i o n which could be derived to estimate upper stem diameters i n s i d e bark had a standard e r r o r of estimate of 1.29 inches using measures of DBK and t o t a l height. Combination of the log and tree decay e s t i m a t i n g f u n c t i o n s and the taper f u n c t i o n f a c i l i t a t e d complete d e s c r i p t i o n of.the soundwood volumes i n the sample of 369 t r e e s . A g r a p h i c a l a n a l y s i s was developed whereby percentages of trees i n a stand w i t h more or l e s s than s p e c i f i e d decay volumes could be estimated. P r e l i m i n a r y chemical s t u d i e s of western hemlock wood i n f e c t e d w i t h Echinodontium t i n e t o r i u m E. and E. i n d i c a t e d that c e l l u l o s e y i e l d s were s l i g h t l y l e s s than those from soundwood. Such p a r t l y decayed wood might be used f o r the manufacture of pulp without se r i o u s reductions i n y i e l d on a volume or weight b a s i s . F u r t h e r research i s needed to s u b s t a n t i a t e the p o s s i b l e c y c l i c nature of decay losses and to determine the i n f l u e n c e of bark thickness and n a t u r a l pruning on the d i s t r u b u t i o n of decay w i t h i n i n d i v i d u a l t r e e s . A p p l i c a t i o n of the a n a l y t i c a l techniques developed f o r western hemlock to other species should r e s u l t i n more p r e c i s e estimates of soundwood volumes and v a l u e s , thereby c o n t r i b u t i n g to improved management planning and u t i l i z a t i o n . I l l ACKNOWLEDGEMENTS The author wishes to express h i s thanks and a p p r e c i a t i o n to the f o l l o w i n g : The l a t e Dr. J . E. B i e r f o r h e l p f u l suggestions during the planning stages of the study. Dr. B i e r was to have served as Co-chairman of my S u p e r v i s i n g Committee. M.W. Bradshaw f o r a s s i s t a n c e i n p r o v i d i n g data and f o r many hours of p a t i e n t e x p l a n a t i o n and d i s c u s s i o n . The B r i t i s h Columbia F o r e s t S e r v i c e , Inventory D i v i s i o n , f o r p r o v i s i o n of the b a s i c stem a n a l y s i s data used h e r e i n . The Computing Centre, U n i v e r s i t y of B r i t i s h Columbia, f o r p r o v i s i o n of computing f a c i l i t i e s . The F a c u l t y of F o r e s t r y , U n i v e r s i t y of B r i t i s h Columbia, e s p e c i a l l y Dean J . A. F. Gardner, f o r f i n a n c i a l a s s i s t a n c e and pro-v i s i o n of o f f i c e and l a b o r a t o r y space. Dr. R.E. F o s t e r f o r h e l p f u l a n a l y t i c a l advice and review of the manuscript. Dr. R. W. Kennedy f o r advice i n experimental design and chemical analyses of decayed wood and review of the manuscript. J . K i s s f o r c h e e r f u l a s s i s t a n c e and guidance during f i e l d observations near Blue R i v e r , B.C.. Dr. A. Kozak who r e g u l a r l y acted as my s t a t i s t i c a l ''sounding board" and who, from time to time, e x t r i c a t e d me from seemingly unresolvable computer programming d i f f i c u l t i e s . MV Lambden f o r draughting the f i g u r e s . The N a t i o n a l Research C o u n c i l of Canada f o r f i n a n c i a l a s s i s t a n c e f o r a f i e l d t r i p . Dr. V i d a r J : Nordin f o r p r o v i s i o n of l i s t i n g s from the INTREDIS R e g i s t e r System f o r L i t e r a t u r e R e t r i e v a l i n f o r e s t pathology. Dr. J . H. G. Smith f o r i n s p i r a t i o n , encouragement and c o n s t r u c t i v e c r i t i c i s m throughout the study. Dr. R. W. Wellv/ood f o r suggestions during the p r e p a r a t i o n of the l i t e r a t u r e review and f o r review of the manuscript. E. L. Young f o r permission to use the data c o l l e c t e d by the -Inventory D i v i s i o n of the B r i t i s h Columbia F o r e s t S e r v i c e . F. Adams, M. Jackson and G. P l e s t e r f o r a s s i s t a n c e i n data coding and l a b o r a t o r y analyses. T. Bapty, D. MacLelian and L. P o l o n i c h f o r t y p i n g the manuscript. Numerous North American f o r e s t p a t h o l o g i s t s who so k i n d l y responded to my m a i l survey of the status of work i n t h i s f i e l d . F i n a l l y , I wish to express my s p e c i a l a p p r e c i a t i o n to my wife Nona, and to my sons Lance and Deane f o r t h e i r p a t i e n c e , understanding, encouragement and s a c r i f i c e throughout t h i s study, p a r t i c u l a r l y during the l a t t e r stages of manuscript p r e p a r a t i o n . TABLE OF CONTENTS ABSTRACT ACKNOWLEDGEMENTS... TABLE OF CONTENTS LIST OF TABLES. . . . . . . . . . . . . . . . . LIST OF FIGURES . . . . . LIST OF PHOTOGRAPHS . . . . . . . . . . . . . . • . CHAPTER I INTRODUCTION . . . . . . . . . . CHAPTER I I LITERATURE REVIEW. . . . . . . . Important Heartrot Fungi i n B r i t i s h Columbia's F o r e s t s . . . . . . . . . . . . Echinodontium t i n c t o r i u m E. and E. . Fomes p i n i (Thore) Lloyd Important H e a r t r o t Fungi i n Western Hemlock Environmental Conditions Required For Fungal Establishment and Growtb. Food A i r . Temperature Moisture Decay Resistance Regional v a r i a t i o n Sapwood-heartwood r e l a t i o n s h i p s . . . © v i Page P o s i t i o n i n tree '.' 26 E f f e c t s of Decay on Wood Q u a l i t y . . 26 Chemical 26 Mechanical . . . . . . . . . . . . . . . . . . . . . 27 S p e c i f i c G r a v i t y . . . . . . . . . 29 C o l o r . . . . . . . . . . . . . . . . . . . . . . . . . 29 - M o i s t u r e - h o l d i n g - c a p a c i t y 30 U t i l i z a t i o n of Decayed Wood . . . . . . . . . . . . . . . 31. Pulp . 31 Other manufactured products. . 34 R e l a t i o n s h i p s Among Tree and Stand Age, DBH, S i t e Q u a l i t y and Decay. . . 35 E x t e r n a l I n d i c a t o r s of Decay. . 40 D i s t r i b u t i o n of Log S i z e and Gross , Volume W i t h i n Trees . 50 Conclusion 53 CHAPTER I I I DATA COLLECTION AND INITIAL;, SUMMARIZATION . 55 CHAPTER IV DEVELOPMENT OF TREE DECAY . FACTORS 93 S e l e c t i o n of Equation Form 93 R e s u l t s and fiiscussion. 94 Conclusion 101 CHAPTER V DEVELOPMENT OF LOG POSITION DECAY FACTORS 108 S e l e c t i o n of Equation Form 108 Results and D i s c u s s i o n • I l l v i i Page Conclusion. . . . . . . . . . . . . . . . . 119 CHAPTER VI DEVELOPMENT OF TAPER.FUNCTION . . . . . . . . . 120 D e r i v a t i o n of Basic Function 120 Res u l t s and D i s c u s s i o n . ' 122 : Conclusion. . 131 CHAPTER V I I ESTIMATION OF VOLUME AND VALUE OF SOUND AND DECAYED WOOD. . . . . . . . . . . . . 136 E s t i m a t i o n of Tree and Stand Volumes and Values. . . . . '." . . . . . . . . 136 E s t i m a t i o n of Log Volumes and Values 142 Es t i m a t i o n of C e l l u l o s e Quantity and Q u a l i t y i n Decayed Wood. . . . 146 Laboratory procedures 147 Res u l t s and d i s c u s s i o n 148 Conclusion 153 CHAPTER V I I I SUMMARY AND SUGGESTIONS FOR FURTHER RESEARCH 154 LITERATURE CITED . . 158 APPENDIX I Log p o s i t i o n decay f a c t o r s f o r western hemlock 169 APPENDIX I I Comparison of estimated per cent, of gross tree volume decayed 'from tree decay equation (A) and l o g ; ' p o s i t i o n decay equation (B) f o r ' . s e v e r a l suspect classes'. . ." ..• v '. 1178 APPENDIX I I I Taper ta b l e for'western hemlock• 180 APPENDIX IV T a b u l a t i o n (Part I) and e x p l a n a t i o n (Part I I ) of values d e r i v e d during c a l c u l a t i o n sequence f o r e s t i m a t i o n oof gross and net cubic f o o t volumes by l o g p o s i t i o n w i t h i n a tree . . . APPENDIX V Tree stem and decay p r o f i l e s f o r three western hemlock trees . . . . i x LIST OF TABLES able . Page f 1 Area c l a s s i f i c a t i o n .of B r i t i s h Columbia. . . . . . . 1 2 Volumes i n B r i t i s h Columbia f o r e s t s 3 3 Gross volumes of commercial species on commercial f o r e s t land i n B r i t i s h Columbia. . . . . . . . . . . . 4 4 T o t a l volume of accumulated decay i n trees 10 i n . DBH+ i n f o r e s t s i n B r i t i s h Columbia 5 5 Soundwood, decay and gross volume i n coast and i n t e r i o r f o r e s t s 5 6 Average annual decay losses i n f o r e s t s i n B r i t i s h C O XllTTlL) 13. • • • • • . • • • • • • . • • • • • 7 7 Comparison of annual decay l o s s and annual growth i n the f o r e s t s i n B r i t i s h Columbia 7 8 Common butt r o t s and host s p e c i e s . . . . . . . . . . . 10 9 Common trunk r o t s and host species . 11 10 R e l a t i v e i n f e c t i o n s and decay volumes f o r important h e a r t r o t s of western hemlock i n s e v e r a l geographic l o c a t i o n s 19 11 P a t h o l o g i c a l age cl a s s e s defined by the B r i t i s h Columbia Forest S e r v i c e 37 12 I n f l u e n c e of age and s i t e on the p r o p o r t i o n of trees w i t h v i s i b l e i n d i c a t i o n s of defects • 41 13 D i s t r i b u t i o n of t r e e c l a s s e s by DBH cl a s s e s f o r western hemlock i n f i v e P u b l i c Sustained Y i e l d U n i t s (P. S. Y. U.) i n B r i t i s h Columbia 42 14 Per cent decay i n western hemlock trees having v a r y i n g numbers of sporophores . . . . . . . . . . . 46 15 D i s t r i b u t i o n of decay volumes a s s o c i a t e d w i t h sporophores of F. p i n i and E. t i n c t o r i u m on western hemlock 47 16 Regression equations f o r e s t i m a t i o n of per cent decay f o r i n d i v i d u a l t r e e s 49 17 The frequency and occurrence and r e l a t i v e importance of a b n o r m a l i t i e s of decay s i g n i f i c a n c e on l i v i n g western hemlock i n the upper Columbia r e g i o n . . . . 50 Table Page 18 Number of t r e e s , s i t e index, per cent m e r c h a n t a b i l i t y and average age by sample number. . 57 19 C l a s s i f i c a t i o n of stands sampled by sample number and area 58 20 E x t e r n a l a b n o r m a l i t i e s tabulated and analyzed in r e l a t i o n to tree decay 60 21 D i s t r i b u t i o n of ba s i c data by DBH c l a s s e s . . . . . . 63 22 H e a r t r o t i d e n t i f i c a t i o n s , d e s c r i p t i o n s and frequency of observation i n 369 western hemlock t r e e s . . 64 23 Summary of sound and decayed trees by tree c l a s s . . 67 24 Basic data summary f o r a l l (369) western hemlock trees 68 25 Basic data summary f o r 97 sound western hemlock tre e s 69 26 Basic data summary f o r 272 decayed western hemlock t r e e s 70 27 Summarytof average s t a t i s t i c s f o r 272 decayed western hemlock trees f o r v a r i o u s kinds of e x t e r n a l a b n o r m a l i t i e s 71 28 Basic data summary f o r 111 " r e s i d u a l " western hemlock trees ' 72 29 B a s i c data summary f o r 278 "suspect" western hemlock tr e e s 73 30 Frequencies and r e l a t i v e frequencies of occurrence of numbers of trees having v a r y i n g numbers of e x t e r n a l a b n o r m a l i t i e s . 75 31 Frequencies and r e l a t i v e frequencies of occurrence of e x t e r n a l a b n o r m a l i t i e s and a s s o c i a t e d decay in 369 western hemlock trees 76 32 D i s t r i b u t i o n of trees w i t h v a r i o u s e x t e r n a l a b n o r m a l i t i e s 77 33 Frequency of occurrence and maximum, minimum and average heights of e x t e r n a l a b n o r m a l i t i e s i n 369 western hemlock t r e e s . . . 78 x i Table Page 34 Frequency of occurrence and maximum, minimum and average heights of e x t e r n a l a b n o r m a l i t i e s i n 97 sound western hemlock trees 79 35 Frequency of occurrence and maximum, minimum and average heights of e x t e r n a l a b n o r m a l i t i e s i n 272 decayed western hemlock t r e e s . . . . . . . . 80 36 The frequency of occurrence of e x t e r n a l a b n o r m a l i t i e s , s i n g l y and i n combination, on 97 sound western hemlock t r e e s . . 81 37 The frequency of occurrence of e x t e r n a l a b n o r m a l i t i e s , s i n g l y and i n combination, on V272 decayed western hemlock trees 82 38 Summary of r e l a t i v e numbers of trees w i t h v a r y i n g amounts of decay by t r e e c l a s s 86 39 Summary of percentages of trees w i t h v a r y i n g p r o p o r t i o n s of decay f o r v a r i o u s e x t e r n a l a b n o r m a l i t i e s . . . 87 40 Numbers of t r e e s , a c t u a l ' percentage m e r c h a n t a b i l i t y and percentage m e r c h a n t a b i l i t y as p r e d i c t e d through B r i t i s h Columbia F o r e s t S e r v i c e (1966) l o s s f a c t o r s f o r 369 western hemlock trees 91 41 Simple c o e f f i c i e n t s of c o r r e l a t i o n f o r v a r i a b l e s / considered f o r use i n development of t r e e decay f a c t o r s 95 42 Some p r e l i m i n a r y r e g r e s s i o n equations and s t a t i s t i c s f o r use i n the e s t i m a t i o n of per cent decay volume i n i n d i v i d u a l trees w i t h from 1 to 10 independent v a r i a b l e s 99 43 Some p r e l i m i n a r y r e g r e s s i o n equations and s t a t i s t i c s f o r use i n the e s t i m a t i o n of cubic f o o t volume of decay i n i n d i v i d u a l trees w i t h from 1 to 9 independent v a r i a b l e s 100 44 Some r e g r e s s i o n equations and s t a t i s t i c s f o r use i n the e s t i m a t i o n of per cent decay volume i n i n d i v i d u a l trees w i t h v a r i o u s groups and combinations of e x t e r n a l a b n o r m a l i t i e s 102 45 T r i a l r e s u l t s f o r s e l e c t e d equation used to p r e d i c t decay volume i n i n d i v i d u a l trees 106 x i i Table - Page 46 Estimated decay volume expressed as a percentage of t o t a l t r e e volume by DBH c l a s s e s f o r s e v e r a l e x t e r n a l abnormality groupings.. 107 47 Summary of b a s i c data by l o g p o s i t i o n f o r 369 western hemlock t r e e s . . . . . . . . ...... . . 109 48 Simple c o e f f i c i e n t s of c o r r e l a t i o n f o r v a r i a b l e s considered f o r use i n development of l o g -.position decay f a c t o r s . . . . . . . . . . . . . . . 112 : 49 Some p r e l i m i n a r y r e g r e s s i o n equations and s t a t i s t i c s f o r use i n e s t i m a t i o n of per cent decay volume to s p e c i f i e d heights (h) i n i n d i v i d u a l trees w i t h from 1 to 10 independent v a r i a b l e s . . . . . . . . . . . . . . . 114 50 Some r e g r e s s i o n equations and s t a t i s t i c s f o r use i n e s t i m a t i o n of per cent decay volume to . s p e c i f i e d heights (h) i n i n d i v i d u a l trees w i t h v a r i o u s groups and combinations of e x t e r n a l a b n o r m a l i t i e s . . . . . . . . 115 51 Summary of a c t u a l and estimated decay volumes by l o g p o s i t i o n w i t h i n t r e e s . . . 117 52 Summary of average diameters i n s i d e bark (d) and heights (h) at v a r i o u s cut se c t i o n s f o r 369 western hemlock trees 123 53 Simple c o r r e l a t i o n c o e f f i c i e n t s f o r v a r i a b l e s considered f o r use i n development of a f u n c t i o n to estimate upper stem diameters (d) . 124 54 Some p r e l i m i n a r y r e g r e s s i o n equations and s t a t i s t i c s f o r use i n e s t i m a t i o n of (d/DBH) w i t h from 1 to 9 independent v a r i a b l e s 125 55. Comparisons of a c t u a l and estimated stem diameters i n s i d e bark at v a r i o u s tree heights f o r s e v e r a l e s t i m a t i n g equations 127 2 56 Regression equations f o r e s t i m a t i o n of (d/DBH) f o r polynomials from degree one to f i v e ' 130 57 Comparisons of a c t u a l and estimated values (d/DBH) from the independent v a r i a b l e h/H f o r polynomials from degree one to f i v e 132 58 The extent of bias i n the e s t i m a t i o n of stem diameters from 5th degree polynomial equation f o r s e v e r a l DBH c l a s s e s 133 X I 1 1 -Table Page 2 59 E s t i m a t i n g equation f o r (d/DBH) i n c o r p o r a t i n g v a r i a b l e s and i n t e r a c t i o n s as suggested i n method proposed by Bruce et a l . (1968).. . . . . . . 134 60 Two equations f o r use i n e s t i m a t i o n of cubic f o o t tree volume between a 1-foot stump height and a 4-inch top diameter. 137 61 A n a l y s i s of variance f o r p h y s i c a l y i e l d s from western hemlock wood with v a r i o u s -stages of h e a r t r o t caused by Echinodontium t i n c t o r i u m 149 62 A n a l y s i s of var i a n c e f o r h o l o c e l l u l o s e y i e l d s from wood of western hemlock w i t h v a r i o u s stages of h e a r t r o t caused by Echinodontium t i n c t o r i u m . . . . 149 63 Comparison of average p h y s i c a l y i e l d s and holo and alpha c e l l u l o s e y i e l d s from western hemlock wood w i t h v a r i o u s stages of h e a r t r o t caused by Echinodontium t i n c t o r i u m . . . . . . . . . . . . . . . . 150 64 A n a l y s i s of var i a n c e f o r alpha c e l l u l o s e y i e l d s from western hemlock wood w i t h v a r i o u s stages of h e a r t r o t caused by Echinodontium t i n c t o r i u m . . . . 151 65 S p e c i f i c g r a v i t y of western hemlock wood i n f e c t e d w i t h v a r i o u s stages of h e a r t r o t caused by "Echinodontium t i n c t o r i u m . . 152 x i v XIST OF FIGURES Figure Page 1 R e l a t i v e cumulative frequency of decay percentages i n i n d i v i d u a l western hemlock trees by B r i t i s h Columbia Forest S e r v i c e (1966) tree c l a s s e s . . . . . 89 2 R e l a t i v e cumulative frequency.of decay percentages i n i n d i v i d u a l western hemlock tr e e s w i t h v a r i o u s types of e x t e r n a l a b n o r m a l i t i e s . 90 3 S c a t t e r diagram showing per cent merchantability. and s i t e index f o r 14 sample l o c a t i o n s . . . . . . . 97 4 R e l a t i o n s h i p between estimated accumulated decay volume percentage and r e l a t i v e height f o r 20-inch DBH c l a s s trees f o r s e v e r a l e x t e r n a l abnormality groupings, w i t h an adjustment f o r other DBH c l a s s e s . 118 2 5 The r e l a t i o n s h i p between (d/D) and h/H showing a 5t h degree polynomial curve f i t t e d to average values of the b a s i c data 129 6 Tree value ( q u a l i t y ) and DBH r e l a t i o n s h i p by s i t e index c l a s s e s f o r B r i t i s h Columbia i n t e r i o r Douglas f i r 140 X V LIST OF PHOTOGRAPHS Photograph Page I T y p i c a l o l d growth stand of western hemlock, Blue R i v e r , B.C. . . . . . . . . . . . . . . . . 59 I I P o r t i o n of a western hemlock tree sectioned f o r decay measurement 62 I I I Stump and top secti o n s of western hemlock t r e e . • " ' "Heartwood destroyed by Echinodontium t i n c t o r i u m . 65 IV Sporophores of Echinodontium t i n c t o r i u m on western hemlock f e l l e d f o r decay measurement . . 74 V Small scars do not i n d i c a t e s i g n i f i c a n t amounts of decay i n western hemlock 84 VI F r o s t cracks do not i n d i c a t e s i g n i f i c a n t amounts of decay i n western hemlock 85 VI I Large open scars i n d i c a t e s i g n i f i c a n t amounts of decay i n western hemlock. 103 V I I I Broken tops i n d i c a t e s i g n i f i c a n t amounts of - dec.ay i n western hemlock 104 IX Dead tops i n d i c a t e s i g n i f i c a n t amounts of decay i n western hemlock 105 1 CHAPTER I INTRODUCTION Probably mensurationists have devoted more time to the study of t r e e volume than to any other t o p i c (Spurr, 1952) yet there i s i n c r e a s i n g concern now f o r improved determinations of log s i z e s and volumes as they are d i s t r i b u t e d w i t h i n t r e e s . Modern manufacturing methods, coupled w i t h the m u l t i p l i c i t y of p o s s i b l e end-uses of a s i n g l e log i n an i n t e g r a t e d operation, r e q u i r e that the f o r e s t e r provide d e t a i l e d i n f o r m a t i o n regarding the raw m a t e r i a l supply. Data f o r the modern f o r e s t inventory must be c o l l e c t e d i n a manner that permits f l e x i b l e and comprehensive analyses. Estimates of t o t a l volume per acre no longer s u f f i c e . Now the volume of m a t e r i a l a v a i l a b l e i n c e r t a i n s i z e s and q u a l i t i e s must be estimated w i t h high standards of p r e c i s i o n and accuracy. The u l t i m a t e success of any f o r e s t inventory depends upon the accuracy of e s t i m a t i o n of • soundwood volume. No matter how accurate estimates of gross volume may be, p r e d i c t i o n s of soundwood volume w i l l be i n e r r o r unless r e l i a b l e methods f o r e s t i m a t i n g decay volumes have been developed and a p p l i e d . In B r i t i s h Columbia, where f o r e s t r y i s the major i n d u s t r y and 136.7 m i l l i o n acres or 58 per cent of the land area i s c l a s s e d as commercial f o r e s t land (Table 1), the e s t i m a t i o n of soundwood volume i s p a r t i c u l a r l y important. B r i t i s h Columbia's f o r e s t s c o n t a i n a gross volume of 495 b i l l i o n cubic f e e t i n trees 4 inches DBH and l a r g e r and 403 b i l l i o n c ubic feet i n trees'10 inches DBH and l a r g e r (Table 2). Approximately Table 1. Area c l a s s i f i c a t i o n of B r i t i s h Columbia. Class of land and f o r e s t M i l l i o n s of acres Forest land Bearing commercial f o r e s t Productive Low s i t e T o t a l Not bearing commercial f o r e s t Non-commercial cover Not s a t i s f a c t o r i l y restocked T o t a l S e l e c t i v e l y logged f o r e s t T o t a l f o r e s t land Non-forest land Water T o t a l area i n province 110.1 7.9 12.0 6.4 118.0 18.4 0.3 136.7 91.3 6.1 234.1 Source: B r i t i s h Columbia Forest Service^ 1957 Table 2.^  Volumes i n B r i t i s h Columbia f o r e s t s . 3 ,_ . Gross volume ( b i l l i o n s of cu. f t . ) Class of f o r e s t , . -.„„• - i n • n-6nj. 4m. DBH+ 10 i n . DBH+ Commercial f o r e s t P r o ductive s i t e Low s i t e 442 27 365 23 T o t a l 469 388 "Non-productive f o r e s t 16 10 Not s a t i s f a c t o r i l y restocked 10 5 T o t a l 495 403 ^ Source: B r i t i s h Columbia Forest S e r v i c e , 1957 96 per cent of the volume or 388 b i l l i o n cubic feet i s located on commer-c i a l f o r e s t land. Spruce species (Picea spp.) , western hemlock (Tsuga  h e t e r o p h y l l a (Rafn.) Sarg.), lodgepole pine (Pinus contorta Dougl.) and balsam species (Abies spp.) are the most abundant (Table 3). Together they account for n e a r l y 72 per cent of the gross wood volume i n trees 4 inches DBH and l a r g e r i n the p r o v i n c e . Average decay percentages vary w i d e l y among species (Table 4), ranging from 2 per cent i n a l d e r (Alnus rubra Bong.) to 57 per cent i n cottonwood (Populus t r i c h o c a r p a Torr. and Gray). Western red cedar (Thuja p l i c a t a Donn.) and balsam species are the most s e r i o u s l y defec-t i v e c o n i f e r s w i t h average decay percentages of 32 and 19 per cent, r e s p e c t i v e l y . The t o t a l volume of decay i n a l l l i v i n g trees 10 inches DBH and l a r g e r i s 63.4 b i l l i o n cubic feet (Table 5) and the annual decay loss i s approximately 681 m i l l i o n cubic feet (Table 6). In mature Table 3-.1 Gross- volumes of commercial species f o r e s t land i n B r i t i s h Columbia. on commercial Species Gross volume ( b i l l i o n s of cu. f t . ) 4 i n . DBH+ 10 i n . DBH+ Spruce species 130 107 Hemlock 80 73 Lodgepole pine 72 46 Balsam species 55 45 Western red cedar 48 46 Douglas f i r 38 35 Aspen 17 13 Cottonwood " 10 8 B i r c h 6 4 Yellow cedar 4 4 Larch 3 2 Yellow pine 3 2 White pine 2 2 Alder 1 1 Maple 0.1 0 T o t a l 469 388 Source: B r i t i s h Columbia Forest Service_, 1957 Table 4.^ T o t a l volume of accumulated decay i n trees 10 i n . DBH+ i n f o r e s t s i n B r i t i s h Columbia. 2 3 T o t a l volume decay Average per cent Species / 4, . , , • (thousands cu. f t . ) decay Western red cedar 13,046,831 32 Hemlock 12,399,435 18 Spruce species 11,685, 157 11 Balsam species 8,087,461 19 Aspen.. 5,371,602 42 Cottonwood 4,685,775 57 Douglas f i r 3, 163,654 9 Lodgepole p i n e 2,871,349 6 B i r c h 890,336 24 Yellow cedar 731,707 23 Larch 216,587 10 White pine 157,506 9 Yellow pine 125,814 5 Maple 21,607 14 Alder 16,959 2 T o t a l 63,471,780 17 Source: B r i t i s h Columbia Forest S e r v i c e , 1957 B a s i s : l i v e merchantable trees i n commercial f o r e s t s Average percentage decay i n gross cub'ic foot volume to cl o s e u t i l i z a t i o n standards. Table 5. Soundwood, decay and gross volumes i n coast and i n t e r i o r f o r e s t s . Volumes i n b i l l i o n s of cubic feet 10 i n . DBH+ Loc a t i o n . , , soundwood decay gross I n t e r i o r 216.9 39.5 256.4 Coast 89.5 23.9 113.4 Province 306.4 63.4 369.8 Source: B r i t i s h Columbia Forest S e r v i c e , 1957 • -6 f o r e s t s , annual decay losses amount to 583 m i l l i o n cubic feet or 316 per cent of estimated net'growth. In immature f o r e s t s , however, decay losses are only 98 m i l l i o n cubic f e e t or 4.6 per cent of net annual growth (Table 7). Regional average decay percentages are of l i t t l e or no prac-t i c a l use on a l o c a l b a s i s . Often, the v a r i a b i l i t y i n decay i n one species from d i f f e r e n t areas i s greater than the decay v a r i a b i l i t y among s e v e r a l species from the same area. Browne (1956) reported that analyses c a r r i e d "out by the B r i t i s h Columbia Forest S e r v i c e i n d i c a t e d that each tre e species r e q u i r e s separate c o n s i d e r a t i o n w i t h i n a f o r e s t r e g i o n and a p a r t i c u l a r f o r e s t s i t e . F o ster, Thomas and Browne (1953) observed that decay l o s s f a c t o r s w i t h i n l o c a l areas i n the Upper Columbia r e g i o n ranged from 39 to 74 per cent of t o t a l gross volume. Foster (1957) reported that decay i n western red cedar ranged from 24 per cent i n c o a s t a l regions to 47 per cent i n i n t e r i o r r e g i o n s . Western hemlock has been reported to be 7 per cent d e f e c t i v e on" the Queen C h a r l o t t e I s l a n d s (Foster and Foster, 1951), 10 per cent d e f e c t i v e i n western Oregon and Washington (E n g l e r t h , 1941), 18 per cent d e f e c t i v e near A l b e r n i ( F o s t e r , 1946) and 31 per cent d e f e c t i v e i n the K i t i m a t area (Fo s t e r , Browne and Foster, 1958). Although r e a s o n a b l y . r e l i a b l e estimates of decay volume per-centages are a v a i l a b l e f o r inventory zones ( B r i t i s h Columbia Forest S e r v i c e , 1966) i n B r i t i s h Columbia, there i s a s c a r c i t y of r e l i a b l e i n f o r m a t i o n f o r l o c a l - a r e a s . Comparisons of s t a t i s t i c s reported o f t e n are complicated because of the f a c t that methods of c a l c u l a t i n g decay volumes have not been standardized. The need f o r such s t a n d a r d i z a t i o n was c l e a r l y i l l u s t r a t e d by Foster (1958) who proposed standards of procedure and measurement f o r decay investigations„ Table 6. Average annual decay losses i n f o r e s t s i n B r i t i s h Columbia. L o c a t i o n Volume i n cubic f e e t 4 i n . DBH+ Coast 127,114,000 I n t e r i o r 553,838,000 Province 680,952,000 Source: B r i t i s h Columbia Forest S e r v i c e , 1957 Table 7.^ Comparison of annual decay loss and annual growth i n the f o r e s t s i n B r i t i s h Columbia. D e s c r i p t i o n , Volume i n m i l l i o n s of cubic f e e t Immature f o r e s t s Growth 2,127 Decay . 98 Mature f o r e s t s Growth 184 Decay 583 A l l f o r e s t s Growth 2,311 Decay 681 Source: B r i t i s h Columbia Forest S e r v i c e , 1957 8 Most e x i s t i n g decay loss t a b l e s and equations are premised on gross t r e e volume i n s i d e bark w i t h some m o d i f i c a t i o n f o r age c l a s s , diameter c l a s s , s i t e c l a s s or e x t e r n a l abnormality groupings. A m a i l survey of n e a r l y 100 f o r e s t p a t h o l o g i s t s i n North America, a compre-hensive search of the l i t e r a t u r e , and' e l e c t r o n i c computer l i s t i n g s from INTREDIS (Hepting, 1967) which covered pathology a r t i c l e s a b s t r a c t e d i n F o r e s t r y A b s t r a c t s , Review of A p p l i e d Mycology, B i o l o g i c a l A b s t r a c t s -and-Air P o l l u t i o n A b s t r a c t s during the p e r i o d 1958 to 1966 revealed no equations which could be used to provide i n f o r m a t i o n on the amount or extent of decay i n i n d i v i d u a l logs w i t h i n t r e e s . Such in f o r m a t i o n could be of.value to f o r e s t e r s i n v a l u a t i o n , scheduling of harvests and planning f o r i n t e g r a t e d f o r e s t operations. The major o b j e c t i v e s of t h i s t h e s i s , therefore,, are to develop and t e s t a n a l y t i c a l techniques that w i l l permit the determination' of the d i s t r i b u t i o n of gross and net volumes w i t h i n i n d i v i d u a l standing t r e e s i n order that appropriate r e d u c t i o n s f o r decay can be made f o r estimates of volumes of logs of s p e c i f i e d s i z e s and grades. Western hemlock data were chosen f o r the study because the species e x h i b i t s a wide v a r i a b i l i t y i n decay volume percentage and hemlock i s exceeded only by spruce species i n gross cubic foot volume of the f o r e s t resource i n B r i t i s h Columbia. Although t h i s study i s most concerned w i t h d i s t r i b u t i o n of soundwood volume, some aspects of l o g value w i l l be discussed i n r e l a t i o n to t r e e grades. Because of the very large volumes a v a i l a b l e , u t i l i z a t i o n of decayed wood f o r pulp i s considered b r i e f l y . 9 CHAPTER I I LITERATURE REVIEW Important Heart Rot Fungi i n B r i t i s h Columbia's Forests Although decays can be, and oft e n are, described according t o " t h e i r pos'ition i n " the" l i v i n g t r e e , the same species of fungi" can -cause decay i n r o o t s , butts and stems of l i v i n g t r e e s . The decays commonly a s s o c i a t e d w i t h b u t t s and stems of l i v i n g trees l i s t e d i n Tables 8 and 9 r e s p e c t i v e l y , a r e considered to be the most important i n the P a c i f i c Northwest r e g i o n of the United States and Canada ( B i e r , 1949; Baxter, 1952; Boyce, 1961). E x c e l l e n t i l l u s t r a t i o n s and d e s c r i p t i o n s of most of these decay-causing f u n g i were reported by B i e r (1949). Two species of f u n g i l i s t e d i n Tables 8 and 9 are r e s p o n s i b l e f o r a s i g n i f i c a n t p r o p o r t i o n of the t o t a l decay volume i n B r i t i s h Columbia c o n i f e r s , p a r t i c u l a r l y western hemlock. These are Echinodontium t i n e t o r i u m E. and E. and Fomes p i n i (Thore) L l o y d . Kinsman (1964) examined 235 western hemlock trees i n the Kitwanga P u b l i c Sustained Y i e l d U n i t (P0S.Y„U.) and reported that F_. p i n i and E. t i n c t o r i u m were the cause of a l l decay observed i n a t o t a l of 60 tre e s c o n t a i n i n g measurable amounts of decay. Foster _et a l . (1954) found that E. t i n c t o r i u m and F. p i n i accounted f o r 60 per cent and 16 per cent r e s p e c t i v e l y , o f gross volume of decay i n western hemlock i n the Big Bend area of B r i t i s h Columbia. Thomas and Thomas (1954) reported that F_. p i n i was as s o c i a t e d w i t h n e a r l y h a l f of the decay volume i n c o a s t a l Douglas f i r (Pseudotsuga menzies.ji (Mirb.) Franco) 10 Table 8. Common butt r o t s and host species. Fungus Important host(s) A r m i l l a r i a me I l e a (Vahl.) Quel. ( s h o e s t r i n g fungus, honey mushroom) spruces, pines, oaks, chestnuts Fomes annosus (Fr.) Cke. (white s t r i n g y root r o t ) Fomes applanatus (Pers.) G i l l , ( s h e l f fungus, a r t i s t ' s conk o l d growth western hemlock, most c o n i f e r s hardwoods, most c o n i f e r s polyporus S c h w e i n i t z i i F r . (v e l v e t top fungus) Douglas f i r , spruces, l a r c h e s , pines Polyporus balsameus Pk. (balsam conk, brown butt r o t ) true f i r s , western red cedar P o r i a We i r i i Murr . (yellow r i n g r o t ) western red cedar, Douglas f i r P o r i a a l b i p e l l u c i d a Baxter (laminated r o t , paper r o t ) western red cedar Por i a a s . i a t i c a ( P i l a t ) Overh. (brown c u b i c a l r o t ) western red cedar P o r i a subacida (Pk.) Sacc. (feather r o t , s t r i n g y butt r o t ) true f i r s • 11 Table 9. Common trunk r o t s and host s p e c i e s . Fungus Echinodontium t i n c t o r i u m E. and E. (brown s t r i n g y trunk r o t ) Fomes p i n i (Thore) Lloyd ( r i n g s c a l e , pecky r o t ) Fomes p i n i c o l a (Swartz) Cke. (red b e l t fungus) Fomes l a r i c i s (Jacq.) Murr. (quinine fungus) Hydnum sp. (long p i t t e d trunk r o t ) Lentinus Kauffmanii Smith (brown pocket r o t ) P o r i a monticola Murr. Stereum sanguinolentum A. and S. (red heart r o t ) Stereum abietinum Pers. (brown c u b i c a l pocket r o t ) Important host(s) western hemlock, true f i r s Douglas f i r , l a r c h e s , pines, western hemlock, spruces, western red cedar Douglas f i r , S i t k a spruce, western hemlock, true f i r s Douglas f i r , S i t k a spruce western hemlock, yellow pine, western l a r c h western hemlock, true f i r s S i t k a spruce Douglas f i r , western hemlock, S i t k a spruce, true f i r s dead sapwood of most c o n i f e r s most c o n i f e r s western hemlock, true-f i r s S i t k a spruce true f i r s , p i n e s, spruces western "hemlock, true f i r s Polyporus sulphureus ( B u l l . ) F r . (sulphur fungus) Polyporus a b i e t i n u s D i c k s , ex F r . ( p i t t e d saprot, hollow pocket r o t ) Polyporus volvatus Pk. (pouch fungus) P o r i a tsugina (Murr.) Sacc. and T r o t t . (white trunk r o t ) Trametes s e r i a l i s F r . (dry r o t ) S i t k a spruce, Douglas f i r 12 Nearly 30 per cent of the decay volume of a l l species i n Ontario i s caused by F. p i n i (Basham and Morawski, 1964) and about 74 per cent of decay i n Engelmann spruce (Picea Engelmanni P a r r y ) , lodgepole pine and subalpine f i r (Abies a m a b i l i s (Dougl.) Forbes) i n Colorado (Hornibrook, 1950). Nearly h a l f of the decay i n balsam i n the upper Fraser r e g i o n of B r i t i s h Columbia i s caused by -F. p i n i ( B i e r et_ a l . , 1948). Because of the importance of these two species of f u n g i , they are discussed i n more d e t a i l i n the f o l l o w i n g s e c t i o n s . • Echinodontium t i n c t o r i u m E. and E. Echinodontium t i n e t o r i u m , commonly c a l l e d the Indian P a i n t Fungus, causes a brown s t r i n g y r o t i n the heartwood of l i v i n g coniferous trees throughout North America. According to Thomas (1958) i t has been reported to commonly a t t a c k western hemlock and most species of Abies and to o c c a s i o n a l l y a t t a c k Engelmann spruce and western white spruce (Picea glauca (Moench) Voss). The western North American genera Chamaecyparis, Juniperus, L a r i x , Pinus, Taxus and Thuja appear to be e i t h e r non-susceptible or only very s l i g h t l y s u s c e p t i b l e to E. t i n c t o r i u m . Spores are produced on b a s i d i a i n a hymenium which extends over a spiny s t r u c t u r e on the lower side of the f r u i t i n g body. The sporophores are p e r e n n i a l and by adding a new hymenium annually can remain a c t i v e f o r s e v e r a l years. The spores are airborne to p o t e n t i a l i n f e c t i o n c o u r t s , commonly branch stubs and open scars (Thomas, 1958). In appearance, the sporophores or conks, are b l a c k and rough or cracked on the upper s u r f a c e . The lower surface i s a d u l l grey and i s charac-t e r i z e d by hard coarse spines. When broken open, the i n t e r i o r e x h i b i t s a r u s t y red c o l o r (Boyce, 1961) . F r u i t i n g bodies as wide as one foot 13 have been reported (Baxter, 1952). I n c i p i e n t l y decayed wood i s c h a r a c t e r i z e d by light-brown areas of d i s c o l o r a t i o n , sometimes a s s o c i a t e d w i t h small r a d i a l pockets. As decay progresses, r e d d i s h streaks f o l l o w the g r a i n , the wood becomes s o f t and separates along the springwood i n the annual r i n g s . In the f i n a l stages, the wood i s reduced to a brown, f i b r o u s , s t r i n g y mass (Boyce, 1961). (Despite the brown c o l o r of the r o t t e d wood, t h i s fungus has been c a t e g o r i z e d p a t h o l o g i c a l l y as a " w h i t e - r o t " fungus (Nobles, 1948; Gross, 1964; Maloy, 1967. See page 26 of t h i s t h e s i s . ) The r o t i s not g e n e r a l l y confined to any p o r t i o n of the tree stem but some i n v e s t i g a t i o n s have shown i t to be more prevalent i n the middle s e c t i o n (Kinsman, 1964). Thomas (1958) surveyed the occurrence of t h i s fungus throughout B r i t i s h Columbia and concluded the f o l l o w i n g : 1. The d i s t r i b u t i o n and abundance of the fungus c l o s e l y f o l l o w s the occurrence of s p e c i f i c f o r e s t types. Maximum i n f e c t i o n l e v e l s are a s s o c i a t e d w i t h trees of low v i g o r , p a r t i c u l a r l y those trees which r e t a i n dead branches f o r long periods of t ime. 2. Maximum i n f e c t i o n p o t e n t i a l occurs when high summer tempera-tures and sustained high h u m i d i t i e s are present i n combination. 3. The presence of the fungus i n i n d i v i d u a l stands i s determined, i n p a r t , by the p r o p o r t i o n of the stem length over which favourable temperatures and h u m i d i t i e s p r e v a i l . 4. Wi t h i n l o c a l c l i m a t i c r e g i o n s , a l t i t u d e has an important e f f e c t on the fungus because of i t s i n f l u e n c e i n the deter-mination of r a i n f a l l and temperature. -14 5. D i f f e r e n t host species may have inherent s u s c e p t i b i l i t i e s to i n f e c t i o n . The requirements of high temperature i n combination w i t h h i g h humidity f o r maximum i n f e c t i o n p o t e n t i a l are su b s t a n t i a t e d i n pa r t by M i l l e r ' s (1962) f i n d i n g s t h a t , i n c u l t u r e , the basi d i o s p o r e s have s t r i n g e n t moisture requirements and may even r e q u i r e an aqueous s o l u t i o n before germination-can occur. The extremely large amounts of decay caused by t h i s fungus i n western hemlock i n the. upper Columbia r e g i o n , contrasted w i t h n e g l i g i b l e amounts i n c o a s t a l areas, l ed Foster and C r a i g (1957) to hypothesize that " . . . c e r t a i n of the excessive c u l l a s s o c i a t e d w i t h hemlock may be a t t r i b u t e d to unfavourable s i t e c o n d i t i o n s . " and to suggest t h a t : " . . . c o n s i d e r a t i o n should.be given i n fu t u r e management to the encouragement on some s i t e s of species other than hemlock i n order to minimize f u t u r e losses from di s e a s e . " A f t e r a thorough and comprehensive review of the l i t e r a t u r e Maloy (1967) s t a t e d : • "Despite the many and v a r i e d s t u d i e s on E_. t i n c t o r i u m , 'information on t h i s fungus and i t s a c t i v i t i e s i s s t i l l fragmentary. There i s l i t t l e doubt that E. t i n c t o r i u m i s a major cause of decay i n true f i r s and hemlock, but i s i t the only cause? I t i s d i f f i c u l t to r e c o n c i l e the very slow growth of the fungus i n c u l t u r e and i t s slow r a t e of growth i n i n o c u l a t e d wood blocks w i t h the exten-s i v e decay columns found i n r e l a t i v e l y young t r e e s . The c o n s i s t e n t recovery of s e v e r a l imperfect f u n g i and the oc c a s i o n a l i s o l a t i o n of other decay f u n g i leads to the t e n t a t i v e c o n c l u s i o n that E. t i n c t o r i u m may be merely the climax species of a succession of f u n g i c o l o n i z i n g .the heartwood of these t r e e s p e c i e s . " There i s an obvious need f o r f u r t h e r research regarding t h i s fungus i f adequate and e f f i c i e n t c o n t r o l measures are to be developed. 15 Fomes p i n i (Thore) Lloyd Fomes p i n i , commonly c a l l e d red r i n g r o t , r i n g s c a l e , red heart or conk r o t causes a white pocket r o t , u s u a l l y confined to the heartwood, i n almost a l l North American coniferous t r e e species w i t h the exception of Cupressus spp. Economic losses caused by t h i s fungus r e p o r t e d l y exceed those from any other wood-decaying fungus (Boyce,_ . 1961). Spores are produced on b a s i d i a i n a hymenium which l i n e s numerous t u b e - l i k e s t r u c t u r e s on the lower side of the f r u i t i n g body. The sporophores are p e r e n n i a l and extremely v a r i a b l e i n s i z e and shape (Baxter, 1952). They range from 1 i n c h to more than 12 inches i n width, but u s u a l l y average about 6 inches i n width and are commonly hoof-shaped. The upper surface i s d u l l grey or brownish and i s c h a r a c t e r i z e d by c i r c u l a r furrows p a r a l l e l to the margin., The lower surface i s u s u a l l y brownish i n c o l o r w i t h tube mouths ranging from small and c i r c u l a r to large and i r r e g u l a r (Boyce, 1961). The i n t e r i o r i s y e l l o w i s h brown and punky i n - t e x t u r e . I n c i p i e n t l y decayed wood i s c h a r a c t e r i z e d by a pronounced r e d d i s h d i s c o l o r a t i o n i n the heartwood. As decay advances, elongated w h i t i s h pockets develop p a r a l l e l to the wood g r a i n and sometimes become f i l l e d w i t h r e s i n . Zone l i n e s are o f t e n d i s t r i b u t e d i r r e g u l a r l y through-out i n f e c t e d wood. In the f i n a l stages of decay, the white pockets may merge and become i n d i s t i n g u i s h a b l e so the e n t i r e decayed area i s reduced to a mass of white, f i b r o u s m a t e r i a l (Boyce, 1961). -Usually the decay i s confined to the heartwood but i n Douglas f i r p a r t i c u l a r l y , i t a l s o a t t a c k s sapwood and k i l l s the host i n a r e l a t i v e l y short time (Boyce and Wagg, 1953) . I n f e c t i o n s are not confined to p a r t i c u l a r 16 s e c t i o n s of the bole, but are u s u a l l y l e s s prevalent i n butt logs than i n top logs (Boyce, 1961)... Swollen knots or punk knots are o f t e n formed at p o i n t s where o l d conks have d e t e r i o r a t e d or f a l l e n o f f . These, along w i t h b l i n d conks, which are-punk knots overgrown by sapwood, are u s e f u l e x t e r n a l i n d i c a t o r s of decay i n Douglas f i r (Boyce and Wagg, 1953). Some i n v e s t i g a t o r s have observed that r o t caused by t h i s fungus extends much f a r t h e r i n the t r e e above the sporophore than below i t . B i e r and Foster (1944) reported that r o t i n S i t k a spruce r a r e l y extended a p p r e c i a b l e d i s t a n c e s below the lowest v i s i b l e sporophore. Analyses of 354 t r e e s i n the Queen C h a r l o t t e I s l a n d s i n d i c a t e d that t h i s fungus was confined almost e n t i r e l y to the upper portions/ of the bo l e . Kinsman (1964) on the other hand, found t h i s fungus to be more pre v a l e n t on the lower t h i r d of stems of western hemlock i n the Kitwanga P.S.Y.U. f Ohlmann (1959) observed that the moisture content of wood of Pinus S y l -v e s t r i s ' L. i n f e c t e d w i t h F. p i n i was higher than heal t h y wood and hypothesized that wood moisture content v a r i a b i l i t y might account f o r the f a c t that the fungus progresses f a s t e r up the stem than down. Bratus and K i r i l e n k o (1960) suggested that d i f f e r e n c e s i n n a t u r a l r e s i n content, not moisture content, explained d i f f e r e n t i a l growth r a t e s of ' the fungus. Boyce and Wagg (1953) conducted one of the most extensive and thorough i n v e s t i g a t i o n s of F. p i n i i n Douglas f i r . The concluded t h a t : 1. The development of conk r o t i n i n d i v i d u a l t r e e s increases w i t h t r e e i age. \ 2. The development of conk r o t i n stands i s c y c l i c a l . 17 I n f e c t i o n and decay development i s greater on good s i t e s than on poor s i t e s . E xtensive r o t development i s a s s o c i a t e d w i t h areas of higher temperature and that temperature may be a c o n t r o l l i n g f a c t o r i n the growth of the fungus. Important He a r t r o t Fungi i n Western Hemlock In a d d i t i o n to Fomes p i n i and Echinodontium t i n c t o r i u m discussed i n the previous s e c t i o n , there are other h e a r t r o t f u n g i which cause s i g n i f i c a n t amounts of decay i n western hemlock. Kimmey (1964) estimated that the t o t a l volume of decayed wood i n commercial sawtimber stands of western hemlock throughout i t s geographic range amounts to 120 b i l l i o n board fee t (roughly 25 per cent of gross volume). He reported that approximately 50 species of f u n g i cause h e a r t r o t i n west-ern hemlock but t h a t only 13 species produce s i g n i f i c a n t volumes of decay. Some of * these fungi, are abundant, absent from, or i n s i g n i f i c a n t i n c e r t a i n areas i n the range of western hemlock. A knowledge of t h e i r d i s t r i b u t i o n i s important because many species d i f f e r c o n s i d e r a b l y i n the amount and type of decay they can cause. Foster and Foster (1951) conducted an e x c e l l e n t review of the l i t e r a t u r e on s t u d i e s p e r t a i n i n g to decay of x^estern hemlock i n B r i t i s h Columbia, Washington, Oregon and Alaska and concluded: "From t h i s review of l i t e r a t u r e , i t i s evident that s i g n i f i c a n t d i f f e r e n c e s on a r e g i o n a l b a s i s are to be a n t i c i p a t e d i n the complex of decay-producing f u n g i , and t h e i r a s s o c i a t e d volumes of c u l l . In view of the apparent l a c k of i n f o r m a t i o n r e l a t i n g to the a n a l y s i s of f a c t o r s c o n t r i b u t i n g to excessive v a r i a t i o n s of the nature mentioned, i t i s evident that r e g i o n a l boundaries cannot, at present, be defined w i t h any degree of accuracy." .3. 4. 18 Decay-causing f u n g i i n t a b l e ID are l i s t e d i n order of importance f o r w h i t e - r o t s and brown-rots, r e s p e c t i v e l y , i n the c e n t r a l c o a s t a l r e g i o n of Oregon, Washington and B r i t i s h Columbia reported by Kimmey (1964). As i s evident from t a b l e 10, the r e l a t i v e amount of h e a r t r o t caused by any one fungus species v a r i e s markedly i n d i f f e r e n t geographic areas. For example, no volumes of decay caused by Echino-dontium t i n c t o r i u m are reported f o r the Queen C h a r l o t t e I s l a n d s and F r a n k l i n R i v e r area on Vancouver I s l a n d . In the Upper Columbia r e g i o n i n the i n t e r i o r of B r i t i s h Columbia, however, i t i s by f a r the most important decay-causing f u n g i , accounting f o r 62 per cent of the t o t a l decay volume i n western hemlock. Fomes p i n i c o l a , on the other hand, i s of minor importance i n the Upper Columbia, accounting f o r only 4.8 per cent of decay volume, but i n the F r a n k l i n R i v e r Area i t accounted f o r 40.8 per cent of t o t a l decay volume. I t i s important to consider the l o c a t i o n of the decay w i t h i n the tr e e caused by d i f f e r e n t species of f u n g i . Some of the root and bu t t r o t s , such as Fomes annosus, Polyporus s c h w e i n i t z i i and P. sulphureus may extend a considerable d i s t a n c e up the tree bole, thus causing h i g h decay losses i n wood of high q u a l i t y b u t t l o g s . Others, such as A r m i l l a r i a meIlea, P o r i a subacida and Fomes applanatus u s u a l l y decay only r o o t s or b u t t s . Rots caused by Fomes p i n i and Echinodontium  t i n c t o r i u m o f t e n enter the bole through branch stubs but decay caused by these f u n g i can a f f e c t the e n t i r e t r e e b o l e . Table 10. R e l a t i v e i n f e c t i o n s and decay volumes f o r important h e a r t r o t s of western hemlock i n s e v e r a l geographic l o c a t i o n s . Geographic L o c a t i o n Organism Queen C h a r l o t t e F r a n k l i n K i t i m a t 3 Is lands R i v e r 2 I n f e c t i o n s Decay (per cent Volume I D I . D of t o t a l ) (per cent of t o t a l ) White-rots ( I ) (D) Fomes annosus (Fr.) Cke. 10.3 11.2 6.9 7.3 1.6 1.1 P o r i a subacida (Pk.) Sacc. 10.7 4.8 20.6 10.2 0.3 0.6 Fomes p i n i (Thore) Lloyd 6.3 12.9 9.1 12.8 24.1 47.9 Fomes robustus K a r s t . - - 3.4 2.6 -A r m i l l a r i a me I l e a (Fr.) Quel. 6.8 7.1 14.0 6.4 4.1 . 2.6 Fomes applanatus (Pers.) G i l l . 3.1 .4.0 1.4 Trace - -Stereum sanguinolentum A.& S. ex F r . 0.4 Trace - - 18.1 V 6.6 P h o l i o t a adiposa (Fr.) Quel. - - - - ' -Echinodontium t i n c t o r i u m E.& E. - - . - - . 17.5 19.8 Brown-rots Fomes p i n i c o l a (Sw.) Cke. 12.1 14.6 20.0 40.8 6.3 4.6 Polyporus sulphureus ( B u l l . ) F r . 5.7 9.4 1.8 0.8 0.5 0.3 Stereum abietinum Pers. 8.2 5.4 5.7 3.0 11.8 5.8 Polyporus s c h w e i n i t z i i F r . 0.9 1.3 - - -.Other or unknown 35.5 29.3 .21.5 18.7 12,3 9.1 I n f e c t e d Trees (per cent of t o t a l ) 48.3 32.5 66.0 Decay volume (per cent of gross v o l . ) 10.6 25.0 31.0 £ Foster and F o s t e r , 1951. ' Buckland e_t a l . , 1949. 3 Foster et a l . , 1958. Table 10. R e l a t i v e i n f e c t i o n s and decay volumes .for important h e a r t r o t s of western hemlock i n s e v e r a l geographic -locations ( cont'd.). Geographic Location-Organism Western Wash, and Oregon 4 Upper Columbia-* I D I D White-rots Fomes annosus (Fr.) Cke. 17.7 22.8 0.8 0.2 P o r i a subacida (Pk.) Sacc. - 2.8 1.4 Fomes p i n i (Thore) Lloyd 19.1 15.8 12.6 25.2 Fomes robustus K a r s t . - - - -A r m i l l a r i a mellea (Fr.) Quel. 7.2 3.9 - -Fomes applana.tus (Pers.) G i l l . 9.2 15.8 - -Stereum sanguinolentum A.& S. ex F r . - - '2.0 0.2 P h o l i o t a adiposa (Fr.) Quel. - - • - -Echinodontium t i n c t o r i u m E.& E. 8.3 4.9 56.8 62.4 Brown-rots Fomes p i n i c o l a (Sw.) Cke. 12.6 4.9 4.4 4.8 Polyporus sulphureus ( B u l l . ) F r . 1.5 3.9 - -Stereum ab'ietinum Pers. • - - 2.8 1.9 Polyporus s c h w e i n i t z i i F r . 2.3 1.0 - -Other or unknown 22.1 25.0 17.8 3.9 I n f e c t e d Trees (per cent of t o t a l ) 60.1 Not a v a i l a b l e Decay volume (per cent of gross v o l . ) 10.1 50.8 4 E n g l e r t h , 1942. 5 Foster et al., 1954. 21 In dense stands of c o a s t a l areas, growth of branches which c o n t a i n s i g n i f i c a n t amounts of heartwood to act as avenues of i n f e c t i o n i s prevented by n a t u r a l pruning,and decay caused by these f u n g i i s o f t e n confined to upper po r t i o n s of the t r e e b o l e . Many h e a r t r o t s are a s s o c i a t e d w i t h trunk wounds and the l o c a t i o n of the r o t i s t h e r e f o r e d i c t a t e d by the l o c a t i o n of the wound. Western hemlock has a p a r t i c u l a r l y t h i n bark and the bole i s s u s c e p t i b l e to s c a r r i n g from f a l l i n g trees ( E n g l e r t h , 1942). Many such scars are s u p e r f i c i a l and heal over q u i c k l y . Large sc a r s , however, do not heal over r a p i d l y because of the i n a b i l i t y of western hemlock to produce r e s i n i n large q u a n t i t i e s and they o f t e n serve as entrance courts f o r decay-causing f u n g i (Kimmay, 1964). I t appears that fungal a c t i v i t y i n a given area i s governed to a large extent by environmental c o n s i d e r a t i o n s (Boyce, 1961) and, t h e r e f o r e , a knowledge of environmental c o n d i t i o n s r e q u i r e d f o r fungal establishment and growth should a i d i n developing methods to d e s c r i b e decay d i s t r i b u t i o n s w i t h i n t r e e stems. 22 Environmental Conditions Required f o r Fungal Establishment and. Growth In common w i t h other members of the p l a n t kingdom to which they belong, f u n g i r e q u i r e s u i t a b l e environmental c o n d i t i o n s f o r growth. The main f a c t o r s involved - food, a i r , temperature and moisture - were reviewed i n d e t a i l by Munro (1967a) and are t h e r e f o r e considered only b r i e f l y here. Food With the exception.of the mould and s t a i n i n g f u n g i , a l l f u n g i which infect, wood r e q u i r e wood, or at l e a s t some of the components of wood, as food. Very broadly, wood-destroying f u n g i can be separated i n t o two d i s t i n c t c l a s s e s . The f i r s t c l a s s c o n s i s t s of those which de-compose a l l components of wood, i n c l u d i n g l i g n i n . These are c a l l e d white-r o t f u n g i . The second c l a s s c o n s i s t s of those which decompose only c e l -l u l o s e and i t s a s s o c i a t e d pentosans, l e a v i n g l i g n i n r e l a t i v e l y unchanged u n t i l decay i s w e l l advanced. These are c a l l e d brown-rot f u n g i . Wood affected.'by w h i t e - r o t f u n g i i s g e n e r a l l y white i n c o l o r although i t may be yellow to l i g h t brown. I t may be completely reduced to a spongy, s t r i n g y or f i b r o u s c o n d i t i o n , or p o r t i o n s of undecayed wood may bo separated by white pockets or streaks of r o t . Wood a f f e c t e d by brown-r o t f u n g i i s e v e n t u a l l y reduced to a brownish-colored crumbly mass. Both c l a s s e s of wood-destroying f u n g i feed on components of the c e l l w a l l . Various types of f u n g i a t t a c k d i f f e r e n t c e l l s and d i f f e r e n t c e l l w a l l components. Depending on the f u n g i , h o l o c e l l u l o s e or l i g n i n may be e q u a l l y a f f e c t e d or one or the other may be attacked p r e f e r e n t i a l l y . The a c t u a l decay of the wood i s caused by fungal enzyme s e c r e t i o n s which transform the v a r i o u s components' of the c e l l 23 w a l l s i n t o substances of n u t r i t i v e , value to the fungus. I t i s thought that the primary chemical r e a c t i o n s involved are o x i d a t i o n and h y d r o l y s i s ( F i n d l a y , 1932, 1940, 1956). The secreted enzymes can a f f e c t wood components even i f the fungal hyphae are not i n d i r e c t contact w i t h the wood. Decay progresses as the fungal hyphae grow and f i n d t h e i r way through the wood. The hyphae g e n e r a l l y adhere c l o s e l y to the inner w a l l s of c e l l s and progress along the long a x i s of the c e l l . They pass from c e l l to c e l l , e i t h e r d i r e c t l y through the c e l l w a l l or through the p i t membranes. Passage of hyphae through c e l l w a l l s i s accomplished by the chemical r e a c t i o n of hyphal secreted enzymes on the c e l l w a l l . A p o r t i o n of the c e l l w a l l i s ch e m i c a l l y d i s s o l v e d by these enzymes to f a c i l i t a t e passage of the hyphae. As decay advances, the hyphae and hyphal holes i n the c e l l w a l l s become more numerous. In brown-rotted wood, diagonal or s p i r a l shrinkage cracks' may appear i n the c e l l w a l l s . C e l l s may become f i l l e d w i t h i r r e g u l a r l y deposited decomposition products; secondary c e l l w a l l s may become uneven i n t h i c k n e s s ; the middle l a m e l l a may d i s s o l v e ; p i t c a v i t i e s may become enlarged or destroyed; or the e n t i r e c e l l w a l l may d i s i n t e g r a t e . I n some c e l l s , r e s i n deposits may occur (Boyce, 1961). Elongated, c r y s t a l - l i k e c a v i t i e s i n the secondary c e l l w a l l s , o r i e n t e d t o the angle of the c e l l u l o s e f i b r i l s , are a s s o c i a t e d w i t h the s o f t r o t f u n g i (Duncan, I960). They are thought to be e n z y m a t i c a l l y produced and caused by the l o n g i t u d i n a l p e n e t r a t i o n of the c e l l w a l l s by the fungal hyphae (Boyce, 1961; Cartwright and F i n d l a y , 1958). Wood decayed by s o f t r o t f u n g i u s u a l l y r e t a i n s i t s shape, but becomes extremely s o f t when wet and b r i t t l e when dry. When a l l m a t e r i a l n u t r i t i v e to e i t h e r c l a s s of f u n g i has 24 been exhausted from the wood i t i s thought that the hyphae themselves d i s i n t e g r a t e (Boyce, 1961). At t h i s p o i n t , the i n f e c t e d wood has been g r e a t l y reduced i n s t r e n g t h and i n most instances w i l l c o n s i s t of nothing more than a crumbly mass of fungal decomposition products. A i r As f a r as can be determined, a l l wood-destroying f u n g i r e q u i r e f r e e oxygen i n order to maintain l i f e . According to Boyce (1961), an amount of a i r equivalent to more than 20 per cent of the volume of a piece of wood i s necessary before decay can occur. Temperature Tests of f u n g i i n c u l t u r e have provided some in f o r m a t i o n on temperatures r e q u i s i t e f o r growth' of wood-destroying f u n g i . Cartwright and F i n d l a y (1958) reported optimum temperatures ranging from 20° to 36°C (68° to 97°F) f o r most f u n g i . They a l s o reported that the optimum temperature f o r 147 species tes t e d at the U n i v e r s i t y of Michigan was between 76° and 86°F. The lowest optimum recorded was 68°F and the highest 94°F. Moisture Fungal spore germination and growth r e q u i r e moisture and i t i s g e n e r a l l y recognized that wood i n a p a r t i a l l y a i r - d r y c o n d i t i o n ( i . e . below about 18 per cent moisture content) i s immune ( F r i t z , 1952). I f wood i s i n f e c t e d and then a i r - d r i e d , fungal growth w i l l cease, but the f u n g i w i l l not be k i l l e d . They may remain i n a c t i v e f o r many years and when s u f f i c i e n t moisture i s l a t e r obtained, r e v i v e and continue to 25 grow (Baxter, 1952; F r i t z , 1952). Of considerable importance, i s the balance between moisture and a i r , because both are r e q u i r e d f o r growth. Since a i r i s necessary for wood-destroying f u n g i , the more wood substance i n a given volume of wood, the l e s s f r e e water i t w i l l hold before the a i r supply i s reduced below the minimum requirement. Decay Resistance Regional v a r i a t i o n Baxter (1952) prepared an abbreviated l i s t of the n a t u r a l d u r a b i l i t y of common North American woods. Duncan and Lombard (1965) c l a s s e d western hemlock as n o n - r e s i s t a n t and stat e d t h a t : "...the l o c a l c l i m a t e , s i t e and a v a i l a b i l i t y of favorable host species are probably the dominant d i s t r i b u t i o n f a c t o r s f o r the m a j o r i t y of f u n g i . " Sapwood- •- .heartwood•'.relationships.. The sapwood of n e a r l y a l l s p e cies, even i n those which have h i g h l y durable heartwood, i s s u s c e p t i b l e to i n f e c t i o n by wood-destroying f u n g i . The greater d u r a b i l i t y of heartwood i s mainly due to the presence of extraneous m a t e r i a l s , some of which are t o x i c to f u n g i . Other f a c t o r s which may e x p l a i n the greater d u r a b i l i t y of heartwood are lower moisture content, lower r a t e of d i f f u s i o n , and b l o c k i n g of c e l l c a v i t i e s by gums and r e s i n s which a f f e c t the air-moisture, balance necessary f o r fungal growth. Various f u n g i c i d a l e x t r a c t i v e s are common i n coniferous woods, but none have been i s o l a t e d from western hemlock wood (Panshin, deZeeuw and Brown, 1964). 26 Density Cartwright and F i n d l a y (1958) c i t e d seven authors, a l l of whom conducted extensive r e s e a r c h i n t o the c o r r e l a t i o n of wood d e n s i t y and d u r a b i l i t y and concluded that i t was not s t a t i s t i c a l l y s i g n i f i c a n t . Even w i t h i n species or i n d i v i d u a l t r e e s , v a r i a t i o n s i n d e n s i t y were not shown to be r e l a t e d to d u r a b i l i t y . -P o s i t i o n i n tre e The d u r a b i l i t y of wood from various p o s i t i o n s i n the tre e i s determined l a r g e l y by the e x t r a c t i v e d i s t r i b u t i o n , the r e l a t i v e amounts of sapxtfood and heartwood and the s p e c i f i c fungal organisms. There seems to be no general r e l a t i o n s h i p between d u r a b i l i t y and the p o s i t i o n of the wood i n the trunk f o r a l l woods. D u r a b i l i t y d i f f e r e n c e s among i n d i v i d u a l trees are as great as those from the same p o s i t i o n s i n d i f f e r e n t trees '(Baxter, 1952). E f f e c t s of Decay on Wood Q u a l i t y Chemical As mentioned on page 22, the wood-destroying f u n g i are commonly c l a s s i f i e d i n t o two groups - the w h i t e - r o t s and the brown-rots. Accord-ing to F i n d l a y (1949) these groups can be defined as: "...those f u n g i which produce h y d r o l y z i n g enzymes and • a t t a c k c e l l u l o s e and a s s o c i a t e d pentosans, b r i n g i n g about "brown" c a r b o n i z i n g r o t s which leave the wood i n a f r i a b l e powdery c o n d i t i o n and those which produce o x i d i z i n g as w e l l as h y d r o l y z i n g enzymes, a t t a c k i n g a l l the c o n s t i t u e n t s of the wood, i n c l u d i n g l i g n i n , and b r i n g about white or l i g h t - c o l o r e d r o t s . " 27 Garren (1-938) detected a t o t a l of 20 d i f f e r e n t enzymes pro-duced by wood-destroying f u n g i . Although most f u n g i can be c l a s s i f i e d i n one of the above groups, there are some s o - c a l l e d brown-rots which are capable of eventu-a l l y d e s t r o y i n g a l l the wood c o n s t i t u e n t s . Cartwright and F i n d l a y (1958) reviewed the progress of resea r c h on the chemical processes involved i n the decay of wood and . sta t e d that the general decay process i s f a i r l y w e l l understood but that l i t t l e i n f o r m a t i o n i s a v a i l a b l e about intermediate products formed during decomposition. They a l s o s t a t e d : "The successive degradation of c e l l u l o s e and of the other polysaccharides i n the wood appears to begin w i t h a shortening of the c e l l u l o s e chains, and t h i s , w i t h i n -c r e a s i n g h y d r o l y s i s of the po l y s a c c h a r i d e s , leads to the breakdown of the condensation products of the various wood sugars w i t h formation of the corresponding hexoses and pentoses, which a t c e r t a i n stages i n decay are formed more r a p i d l y than the fungus can u t i l i z e them, so that an e x t r a c t from decayed woods shows s t r o n g l y reducing p r o p e r t i e s when t e s t e d w i t h F e h l i n g ' s solution....when the s t r u c t u r e of t h i s substance ( l i g n i n ) i s b e t t e r under-stood i t w i l l be p o s s i b l e to f i n d out how c l o s e l y the r e s i d u a l l i g n i n l e f t a f t e r fungal decay resembles the o r i g i n a l m a t e r i a l as i t occurs i n the c e l l w a l l s of the wood." Mechanical I n the advanced stages of decay, i t i s obvious that decayed wood i s s o f t e r , more b r i t t l e and not as strong as sound wood. In the i n c i p i e n t stages, however, the e f f e c t of fungal i n f e c t i o n may not be r e a d i l y apparent. According to Cartwright and F i n d l a y (1958), Longyear (1926) was the f i r s t researcher to p u b l i s h the r e s u l t s of a c a r e f u l s e r i e s of mechanical t e s t s on samples exposed to decay. His r e s u l t s showed 28 considerable s t r e n g t h losses before weight l o s s occurred. These r e s u l t s have been confirmed by s e v e r a l i n v e s t i g a t o r s (Cartwright e_t a l . , 1931; Mulholland, 1954). Cartwright and F i n d l a y (1958) s t a t e d that more severe and r a p i d reductions i n s t r e n g t h p r o p e r t i e s are caused by brown-rot f u n g i than by w h i t e - r o t f u n g i . Loss i n strength'caused by w h i t e - r o t f u n g i i s due mainly t o "the d e p l e t i o n and a l t e r a t i o n of the c e l l u l o s e and i t s a s s o c i a t e d pentosans." The eventual d e p l e t i o n of l i g n i n apparently only adds to an a l r e a d y w e l l advanced mechanical breakdown. From a comprehensive l i t e r a t u r e review on t h i s t o p i c , Cartwright and F i n d l a y (1958) concluded t h a t : 1. "Fungi causing brown-rots ( i n which a t t a c k i s mainly d i r e c t e d against the c e l l u l o s e ) b r i n g about a f a i r l y r a p i d drop i n s t r e n g t h p r o p e r t i e s of wood." 2. "Fungi causing w h i t e - r o t s ( i n which a l l c o n s t i t u e n t s of the wood are attacked) may a l s o , i n the case of c e r t a i n s pecies, b r i n g about a r a p i d drop i n toughness, but probably l e s s r a p i d l y than by brown r o t s . " 3. "Toughness, or r e s i s t a n c e to impact, as measured by impact, bending or the "Izod" t e s t , i s the s t r e n g t h q u a l i t y which i s most r a p i d l y a f f e c t e d by fungal i n f e c t i o n - followed i n approximate order of s u s c e p t i b i l i t y by ben-ding s t r e n g t h , compressive stren g t h , hardness and e l a s t i c i t y . " 4. "The s t r e n g t h p r o p e r t i e s of i n f e c t e d wood must not be assumed to be unimpaired, even i f i t i s hard and f i r m . " Kennedy (1961) i n v e s t i g a t e d the i n f l u e n c e of i n c i p i e n t decay caused by two w h i t e - r o t f u n g i and two brown-rot f u n g i on the micro-t e n s i l e s t r e n g t h of s e v e r a l woods. He concluded that the amount of t e n s i l e s t r e n g t h r e d u c t i o n before measurable weight loss was s i g n i -f i c a n t l y d i f f e r e n t from the r a t e of t e n s i l e s t r e n g t h r e d u c t i o n per u n i t of weight loss f o r various combinations of f u n g i and woods t e s t e d . 29 ..Specific g r a v i t y ~ The loss i n dry weight expressed as a percentage of o r i g i n a l dry weight can provide a s t a t i s t i c which i s u s e f u l i n comparing amounts of decay i n wood. I n some insta n c e s , however, i t may not be r e l i a b l e . In brown-rots, f o r example, where l i g n i n i s u s u a l l y not decomposed u n t i l decay i s w e l l advanced, the maximum weight loss that can occur i s _about 70 per cent (Cartwright and Find l a y , 1958). In other cases, se r i o u s s t r e n g t h losses may occur before a p p r e c i a b l e changes i n d e n s i t y can be detected ( S c h e f f e r , 1936) .• Glennie and Schwartz (1950) pointed out that i n some cases the d i f f e r e n c e i n d e n s i t y between decayed and sound wood, i s not greater than the normal v a r i a t i o n i n d e n s i t y between d i f f e r e n t samples of sound wood from any one species. The loss of wood weight provides a s t a t i s t i c which i n d i c a t e s the d i r e c t l o s s of wood substance due to v o l a t i l i z a t i o n of the end products of decay, but does not r e f l e c t the degeneration of n o n v o l a t i l e intermediate products (Glennie and Schwartz, 1950). However, because of the s i m p l i c i t y of determining weight l o s s , i t i s the most common lab o r a t o r y method used as a measure of the extent of decay. Color As decay progresses i n wood i t i s sometimes accompanied by c o l o r changes. In the i n c i p i e n t stages, these are often d i f f i c u l t to det e c t . Because one fungus can cause the formation of d i f f e r e n t c o l o r s i n d i f f e r e n t host species, and heartwood i n many species has n a t u r a l c o l o r v a r i a t i o n s , i t i s d i f f i c u l t to diagnose decay i n wood on the b a s i s of c o l o r alone. MacLean and Gardner (1956) observed that c o l o r v a r i a t i o n s i n the heartxv'ood of western red cedar were r e l a t e d to the 30 concentrations of t h u j a p l i c i n s and water-soluble phenols - both n a t u r a l f u n g i c i d e s . A change from a l i g h t to a darker c o l o r c o i n c i d e d w i t h a decrease i n f u n g i c i d a l c o n c e n t r a t i o n s . Roff, Whittaker and Eades (1962) c a r r i e d out comprehensive st u d i e s on the r e l a t i o n s h i p between c o l o r and decay i n logs from three western red cedar t r e e s . They showed t h a t , i n general, brown heartwood from logs which contained obvious r o t was low i n decay r e s i s t a n c e . From s i m i l a r p o s i t i o n s i n the t r e e , straw-colored wood was most r e s i s t a n t and tan-yellow wood was l e a s t r e s i s t a n t . With the p o s s i b l e exception of the spruces and t r u e f i r s , western hemlock wood i s u n l i k e other important coniferous species i n B r i t i s h Columbia i n that i t e x h i b i t s very l i t t l e n a t u r a l c o l o r v a r i a -t i o n . The wood i s g e n e r a l l y a uniform w h i t i s h to y e l l o w i s h brown c o l o r . The heartwood i s not d i s t i n c t from the sapwood and without the a i d of m a g n i f i c a t i o n or s e n s i t i v e c o l o r t e s t s i t i s d i f f i c u l t to d i s t i n g u i s h any t r a n s i t i o n l i n e s e parating the two.. (Brown, Panshin and F o r s a i t h , 1949). In many instances small white chemical deposits c a l l e d f l o c c o s o i d s , which occur n a t u r a l l y , are e a s i l y confused w i t h c o l o r a t i o n caused by w h i t e - r o t s (Barton, 1963). M o i s t u r e - h o l d i n g c a p a c i t y Decayed wood absorbs and loses water more r a p i d l y than sound-wood, probably because the hyphal bore holes a l l o w r a p i d entry and d i s s e m i n a t i o n of moisture throughout the decayed wood (Panshin, deZeeuw and Brown, 1964). Although the e q u i l i b r i u m moisture content of decayed wood may d i f f e r from that of soundwood i n a given r e l a t i v e humidity, the d i f f e r e n c e i s g e n e r a l l y small and of l i t t l e p r a c t i c a l s i g n i f i c a n c e . I f 31 -decayed" wood i s subjected to a l t e r n a t e periods of we t t i n g and d r y i n g , however, i t r e t a i n s moisture f o r a longer- period of time than does soundwood subjected to the same treatment. I t appears, t h e r e f o r e , that once.wood i s i n f e c t e d , moisture c o n d i t i o n s favourable f o r fungal growth w i l l be r e t a i n e d f o r a longer time than i n soundwood (Cartwright and F i n d l a y , 1958). . U t i l i z a t i o n of Decayed Wood Pulp . Creamer (1950) summarized l i t e r a t u r e up to 1949 regarding the use of decayed wood f o r p u l p i n g and pointed out that although decay does not a f f e c t the gross volume of wood, the d e n s i t y can be g r e a t l y reduced and w i t h i t the y i e l d of pulp per u n i t of wood volume. In a d d i t i o n to c e l l u l o s e losses due to decay, excessive chip losses caused by brashness of the p a r t i a l l y decayed wood are common. Mechanical or h y d r a u l i c debarking of decayed wood a l s o r e s u l t s i n higher than normal wood l o s s e s . Creamer s t a t e d : " I t i s extremely d i f f i c u l t to c o r r e l a t e the degree of decay w i t h changes i n the chemical or p h y s i c a l p r o p e r t i e s of wood or pulp but most work i n t h i s f i e l d i s i n general agreement w i t h the f o l l o w i n g e f f e c t s of decay:" 'Groundwood Pulp - Use of decayed wood causes lower y i e l d s , lower s t r e n g t h , darker c o l o r , more d i r t and s h i v e s , and les s permanency, the only advantageous e f f e c t being lower power consumption. The f e a t u r e s , of course, depend on the extent of the decay.-' 'Sulphite Pulp - Lower y i e l d s , darker c o l o r , lower s t r e n g t h , d i r t arid s h i v e s , higher bleach consumption and higher chi p p i n g losses f o l l o w the use of decayed wood. Although a s h o r t e r cooking time i s r e q u i r e d , i t i s not p o s s i b l e to take advantage of the s l i g h t change unless an e n t i r e d i -gester charge of uniform l y decayed wood i s accumulated. Since grading of decayed wood i s very d i f f i c u l t , chips of va r y i n g degrees of soundness u s u a l l y f i n d t h e i r way i n t o the same d i g e s t e r and the r e s u l t i s overcooking f o r the decayed chips or undercooking f o r the sound chips.•" 32 A l k a l i n e Pulps - Use of decayed wood causes lower y i e l d , higher consumption of chemicals and higher chipping losses. D i r t and dark colors make l i t t l e d i f f e r e n c e i n unbleached k r a f t grades and the a l k a l i n e cooking liquor dissolves degraded carbohydrates, thus guaranteeing a f a i r l y high al p h a - c e l l u l o s e content and a f a i r strength for the r e s u l t i n g pulp. For these reasons the k r a f t process i s best suited for the u t i l i z a t i o n of p a r t i a l l y decayed pulpwood." Glennie and Schwartz (1950), a f t e r a comprehensive search of the l i t e r a t u r e on the e f f e c t s of decay i n pulpwood on pulp q u a l i t y , stated: N l "Although decayed wood may give lower y i e l d s of sulphite pulp than sound wood, i n general i t can be said that t h i s pulp suffers only s l i g h t loss i n q u a l i t y when the decay i s not far advanced." Aft e r an extensive series of pulping tests of Douglas f i r wood { v. decayed by F. p i n i , Martin (1949) concluded: "A possible composition containing decayed (Douglas f i r ) wood and a minimum amount of the associated species that would produce a sulphate pulp having the same q u a l i t i e s as one made e n t i r e l y from sound Douglas f i r might be made up of 65 percent sound wood, 25 percent incipient-decayed wood, and 1C* percent associated species." Bjorkman e_t al_. (1964) c a r r i e d out extensive sulphate and sulphite pulping tests on spruce (P.abies(L). K) and pine (Pinus s i l v e s t r i s ) . A l i n e a r r e l a t i o n s h i p between pulp y i e l d and the proportion of decayed wood included was observed i n a l l cases. Firm dark and fir m l i g h t rot types u s u a l l y caused only small reductions i n pulp y i e l d s , even when included i n r e l a t i v e l y high proportions. On the other hand, s o f t l i g h t and soft dark r o t types reduced pulp y i e l d s i n approximately d i r e c t proportion to the percentage of rot included i n the test cooks. i ^  \ S t a t i s t i c a l analyses of sulphate pulp strengths indicated that i n almost a l l instances there was no s i g n i f i c a n t d i f f e r e n c e between pulp from soundwoodd and pulp from mixtures of sound and decayed wood. 33 I t was observed, however, that b u r s t i n g s t r e n g t h and tear f a c t o r were s l i g h t l y lower when higher proportions of decayed wood were inc l u d e d . Bjorkman e_t a_l. (1964) concluded the f o l l o w i n g regarding the production of pulp from coniferous species i n v e s t i g a t e d : 1. "Soft dark and s o f t l i g h t r o t proved to r e s u l t i n a great increase i n wood consumption and impairment of the q u a l i t y of the pulp. When bleaching of the pulp takes p l a c e , such r o t may, however, be admitted. . A volume deduction of 100 percent f o r the damaged volume of such decay i s suggested." 2. "Firm dark r o t , apart from i t s impairment of q u a l i t y , a l s o gave a lower y i e l d than the corresponding soundwood. A c e r t a i n p r o p o r t i o n might t h e r e f o r e be included i n pulp wood provided that some deduction i s allowed f o r . A deduction of 100 percent f o r the volume of decayed wood seems unneces-s a r i l y high but might be j u s t i f i e d by the need f o r the maximum s i m p l i f i c a t i o n of the assessment i n p r a c t i c e . " 3. "Firm l i g h t r o t d i d not cause an app r e c i a b l e Impairment of the pulp, whatever p r o p o r t i o n was included. Although there was undoubtedly some i n i t i a l breakdown and loss of streng t h , t h i s type of decayed wood may conveniently be included without deduction and thus counted as a " t o l e r a n c e d e f e c t " . Some compensation for the too great deduction f o r the f i r m dark r o t i s thereby obtained." Since 1948 i n Sweden, wood c o n t a i n i n g top r o t caused by Stereum sanguinolentum has been used i n the manufacture of pulp. S c a l i n g r e g u l a t i o n s i n that country do not permit deductions f o r t h i s defect because i t has been shown that pulp q u a n t i t y and q u a l i t y i s not s i g n i -f i c a n t l y impaired by i n c l u s i o n of t h i s m a t e r i a l when mixed w i t h sound-wood (Bjorkman e_t a_l., 1964). Sheridan (1958) summarized inform a t i o n provided by pulp m i l l s represented i n the T e c h n i c a l S e c t i o n of the Canadian Pulp and Paper A s s o c i a t i o n regarding the use of decayed wood f o r p u l p i n g . Two m i l l s , ( M i l l B and M i l l C) reported on studies of sulphate p u l p i n g of decayed wood. In one instance, the decay organism was p o s i t i v e l y i d e n t i f i e d as 34 Fomes p i n i , i n the other, the fungus was not p o s i t i v e l y i d e n t i f i e d , but the r o t d e s c r i p t i o n was s i m i l a r t o that of r o t caused by F. p i n i . M i l l B concluded: "...the heavy c u l l i n g of punky wood i s a w a s t e f u l p r a c t i c e because most of the i n f e c t e d wood produced a f a i r y i e l d of s u i t a b l e p u l p . " M i l l C concluded: "Pulpwood i n f e c t e d w i t h Fomes p i n i should not be c u l l e d i n i t s e a r l y stages of decay because i t only a t t a c k s the c e l l u l o s e " i n the more advanced stages of r o t . " Other manufactured products The use of decayed wood f o r the manufacture of products other than pulp i s l i m i t e d . For example, the scaling regulations* of the B r i t i s h Columbia Forest S e r v i c e (1963) r e q u i r e that logs of most t r e e species w i t h l e s s than o n e - t h i r d of t h e i r gross s c a l e i n soundwood content ( l e s s than one-half f o r some species) be c l a s s e d as c u l l s . I t i s only r a r e l y that c u l l e d m a t e r i a l i s removed from the f o r e s t and converted i n t o u s e f u l products. In most inst a n c e s , decayed wood that reaches a manufacturing p l a n t i s e l i m i n a t e d during the manufacturing process. P e e l e r l o g grade r u l e s are s t r i c t i n s p e c i f i c a t i o n s concerning p e r m i s s i b l e decay a l l o w -ances. U s u a l l y only a minor amount of h e a r t r o t i s allowed, and t h i s must be s m a l l enough i n s i z e t o enable the l o g t o be s e c u r e l y held i n a l a t h e chuck (Plywood Manufacturers A s s o c i a t i o n of B r i t i s h Columbia). No decay i s permitted i n plywood (Canadian Standards A s s o c i a t i o n , 1961, 1961a). \ • \ ' Lumber grades i n use i n B r i t i s h Columbia ( B r i t i s h Columbia Lumber Manufacturer s ' A s s o c i a t i o n , 1959) do not permit the use of decayed / 35 wood i n any but the. lowest grades. " U t i l i t y " grades permit the use of unsound wood " i n small spots and streaks wall s c a t t e r e d . " "Economy" grades, g e n e r a l l y s u i t a b l e f o r use as c r a t i n g , b r a c i n g , c r i b b i n g or dunnage, permit the use of decayed wood i n lumber lengths longer than eig h t feet provided that "at l e a s t 75 percent of the piece i s usable a f t e r i t has been cut i n t o two or three p i e c e s . " The use of decayed wood i n the manufacture of poles and p i l i n g i s g e n e r a l l y not permitted. R e l a t i o n s h i p s Among Tree and Stand Age, DBH, S i t e Q u a l i t y and Decay Incidence of i n f e c t i o n s and volu m e t r i c decay losses i n trees are o f t e n observed to increase p r o g r e s s i v e l y w i t h t r e e s i z e as measured by DBH. Probably more decay st u d i e s have been summarized and presented on a diameter c l a s s b a s i s than any other (e.g. B i e r , S a l i s b u r y and Waldie, 1948; Waldie, 1949; Thomas and Thomas, 1954; Etheridge, 1958; Estep and Hunt, 1964; Aho, 1966). For western hemlock i n the K i t i m a t r e g i o n of B r i t i s h Columbia, i n f e c t i o n s increased from 31 per cent i n 15-inch DEH trees to 100 per cent i n 50-inch DBH t r e e s , w h i l e decay volumes increased frcm 4 per cent to 47 per cent f o r the same DBH range (Foster ejt a_l., 1958). For the Queen C h a r l o t t e I s l a n d s , Foster and Foster (1952) reported that r e l a t i v e frequencies of i n f e c t i o n s i n hemlock t r e e s increased from 19 per cent i n the 15-inch DBH c l a s s to 100 per cent i n the 60-inch DBH c l a s s . Decay volume losses increased from 1.5 per cent to 30.9 per cent of gross volume i n the same DBH c l a s s e s . The B r i t i s h Columbia Forest Service analysed about 32,000 trees throughout B r i t i s h Columbia and concluded that decay i s c l o s e l y c o r r e l a t e d w i t h DBH f o r 35 - a l l commercial s p e c i e s . Decay loss f a c t o r s , segregated by DBH c l a s s e s and p r o v i n c i a l f o r e s t inventory zones, have been prepared f o r a l l commercial t r e e species i n B r i t i s h Columbia (Forest Club, 1959; B r i t i s h Columbia Forest S e r v i c e , 1966). Auckland et al_. (1949) found that DBH was more u s e f u l i n the e s t i m a t i o n of volumes of decay i n Douglas f i r , western hemlock, western red cedar and Abies species near F r a n k l i n River than e i t h e r age or — e x t e r n a l i n d i c a t o r s of decay. I n general, i t can be concluded that increases i n the decay volume of trees are almost always a s s o c i a t e d w i t h increases i n DBH. This author was able t o f i n d only one r e p o r t i n the l i t e r a t u r e where attempts to c o r r e l a t e decay volume and t r e e DBH were u n s u c c e s s f u l . Aho (1966) reported no c o r r e l a t i o n of DBH and decay volume i n western l a r c h i n Washington and Oregon.' I t should be pointed out that although tree DBH and decay volume are u s u a l l y s i g n i f i c a n t l y c o r r e l a t e d , the p r e c i s i o n w i t h which amounts of decay i n i n d i v i d u a l t r e e s can be estimated from DBH i s u s u a l l y low and extremely v a r i a b l e . A wide range of decay percentages among i n d i v i d u a l t r e e s of the same DBH c l a s s i s common, th e r e f o r e r e c o g n i t i o n of other f a c t o r s i s necessary. Numerous stu d i e s have shown that increases i n the incidence and volume of decay are o f t e n a s s o c i a t e d w i t h increases i n the age of tre e s and stands (e.g. B i e r and F o s t e r , 1944; Foster, 1946; B i e r , Foster and S a l i s b u r y , 1946; F o s t e r , 1947; B i e r , S a l i s b u r y and Waldie, 1948; Morawski jst a_l., 1958). The B r i t i s h Columbia Forest S e r v i c e (1966) reported age to be a s i g n i f i c a n t f a c t o r i n decay e s t i m a t i o n and published decay loss f a c t o r s f o r s e v e r a l " p a t h o l o g i c a l " age c l a s s e s (Table 11). 37 Table 11. " P a t h o l o g i c a l age cl a s s e s defined by the B r i t i s h Columbia Forest S e r v i c e . „ Age c l a s s Stand type _ a n , . Immature Older immature Mature Deciduous 1-20 y r . 21-40 y r . 41 y r . + Lodgepole pine 1-60 y r . 61-80 y r . 81 y r . + Other coniferous 1-80 y r . 81-120 y r . 121 y r . + ^ Source: B r i t i s h Columbia Forest S e r v i c e , 1966 Although numerous authors have found c o r r e l a t i o n s between decay volume and t r e e and stand age, there are s e v e r a l r e p o r t s of unsuc c e s s f u l attempts (Waldie, 1949; Loman and Paul , 1963; Hinds and Hawksworth, 1966; Aho, 1966). According to Fos t e r , Browne and Foster (1958), the p r a c t i c e of demonstrating i n c r e a s i n g decay w i t h i n c r e a s i n g age has: - "apparently developed from a concept of f o r e s t growth and m o r t a l i t y which recognizes that tree species l i v e f o r a maximum pe r i o d and may d e t e r i o r a t e w i t h i n c r e a s i n g r a p i d i t y during a pe r i o d of d e c l i n e . " They pointed out that i n some stands t h i s assumption may not be v a l i d and t h a t : " i t may be necessary to consider that c y c l i c m o r t a l i t y depreciates most stands and consequently that percentage of decay and net volume f l u c t u a t e w i t h advancing stand age." Decay i n western hemlock and a m a b i l i s f i r i n the K i t i m a t area showed some c y c l i c trends w i t h advancing age,, however, these trends were not s i g n i f i c a n t enough to enable the formation of v a l i d conclusions (Foster, Browne and Foster, 1958). 38 Thomas and Thomas (1954) reported that percentage decay-volumes i n Coas t a l Douglas f i r increased to a maximum w i t h i n c r e a s i n g age and then d e c l i n e d . They a t t r i b u t e d t h i s i r r e g u l a r i t y to i n f l u e n c e s of s i t e q u a l i t y , l a t i t u d e and stand h i s t o r y . I n subalpine f i r i n Colorado Hinds, Hawkswofth and Davidson .(1960) found that decay volume.per acre increased w i t h age to a peak i n the 150 to 200 year age c l a s s , then d e c l i n e d to a minimum i n the 250 to 300 year o l d age c l a s s , then increased again to a second peak i n the 350 to 400 year age c l a s s . They suggested that f a c t o r s con-t r i b u t i n g to t h i s r e l a t i o n s h i p were : "1. some of the trees i n f e c t e d w i t h decay e a r l y i n l i f e are k i l l e d d i r e c t l y by p a r a s i t i s m of the decay f u n g i or i n d i r e c t l y by windthrow or wind breakage. 2. growth of the remaining trees i s enhanced by the re l e a s e due to the loss of the more decadent t r e e s . " Boyce and Wagg (1953) studied decay caused by F_. p i n i i n mature Douglas f i r i n Oregon. Their a n a l y s i s of i n d i v i d u a l trees and stands i n d i c a t e d a c y c l i c a l behavior of decay. Decay volume per acre was minimal at ages 120, 250 and 350 years and maximal at ages 200 and 320 years. Sampling was not s u f f i c i e n t i n stands older than 360 years to enable the r e c o g n i t i o n of pronounced trends. According to Boyce and Wagg (1953), the f a c t o r s c o n t r o l l i n g c y c l e s of F. p i n i decay are d i f f i c u l t to a s c e r t a i n because l i t t l e i s known about the a c t u a l growth of F. p i n i i n heartwood. They suggested however, that decay was c y c l i -c a l because: "the weakening a c t i o n of F. p i n i and the competitive a c t i o n of a s s o c i a t e d trees causes the death of many i n f e c t e d trees., thus a f f o r d i n g r e l e a s e to the remainder. This has a twofold i n f l u e n c e on the volume of decayed wood i n the stand. The decay volume i s reduced by death of i n f e c t e d t r e e s , and at the. same time, the r a t e o f growth of sound trees i n c r e a s e s . " 39 I t has been suggested (Foster, Browne and Foster, 1958) that i n uneven aged stands of t o l e r a n t species, r a p i d decay need not n e c e s s a r i l y be a s s o c i a t e d w i t h advancing, age, but that decay volume per acre might be more or l e s s constant f o r considerable periods of time. I n v e s t i g a t i o n s of the r e l a t i o n s h i p of s i t e q u a l i t y to decay f o r a number of species have f a i l e d to give c o n s i s t e n t r e s u l t s (Boyce, 1961) . For some f u n g i , decay has been found to increase w i t h i n c r e a s i n g s i t e index; f o r others the opposite has been observed. Weir and Hubert (1918) found that decay caused by E. t i n c t o r i u m on western hemlock was more severe and i n f e c t i o n s occurred at an e a r l i e r age i n r i v e r bottom types than on slope types. Foster et_ a_l. (1954) noted a d e f i n i t e increase i n the incidence of i n f e c t i o n s caused by t h i s fungus w i t h decreasing s i t e index. In the same stands however, decay caused by F. p i n i was observed to decrease w i t h decreasing s i t e index. Boyce and Wagg (1963) noted a s i m i l a r r e l a t i o n s h i p w i t h F. p i n i and Douglas f i r i n stands over 110 years of age. They s t a t e d : "there i s no obvious e x p l a n a t i o n f o r the greater incidence of conk r o t on b e t t e r s i t e s . " Thomas (1958) noted that poor v i g o r was u s u a l l y a s s o c i a t e d •with increased i n f e c t i o n s of JS. t i n c t o r i u m on western hemlock but B i e r et a l . (1948) were not able to detect any i n f l u e n c e of s i t e on t h i s fungus i n Abies s p e c i e s . Smith et a_l. (1961) reported S i s ' observations on the i n f l u e n c e of age and s i t e on the proport i o n s of r e s i d u a l (TCI) and suspect (TC2) ( t h e r e f o r e probably more decayed) trees i n stands of western hemlock, western red cedar and Douglas f i r . Although the r e l a t i v e number of suspect t r e e s increased w i t h age, no r e l a t i o n s h i p 40 could be detected f o r s i t e q u a l i t y (Table 12)-. Hamilton (1967.) summarized r e l a t i v e numbers of r e s i d u a l (TCI), suspect (TC2) and dead (TC4) trees by diameter classes f o r western hemlock i n f i v e P u b l i c Sustained Y i e l d Units i n B r i t i s h Columbia (Table 13) but was not able to d i s c e r 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 pro p o r t i o n s of suspect or dead trees among u n i t s . The i n f l u e n c e of c l i m a t e , topography, a l t i t u d e , a i r moisture _and' humidity, aspect, host v i g o r and n a t u r a l r e s i s t a n c e appear to i n t e r a c t w i t h s i t e index in. the determination of fungal a c t i v i t y i n a given area. E x t e r n a l I n d i c a t o r s of Decay I n d i v i d u a l trees i n mature coniferous stands may be e a s i l y -segregated i n t o recognizable c l a s s e s by t h e i r possession or lack of c e r t a i n v i s i b l e a b n o r m a l i t i e s i n d i c a t i v e of decay (Foster, Thomas and Browne, 1953). Increased p r e c i s i o n i n defect e s t i m a t i o n i s o f t e n obtained when trees are c l a s s i f i e d according to the presence or absence of such a b n o r m a l i t i e s . The l a t e Chief J u s t i c e Gordon Sloan (1956) was impressed by the r e l a t i v e amounts o f decay a s s o c i a t e d w i t h r e s i d u a l and suspect c l a s s e s of trees i n s e v e r a l areas of B r i t i s h Columbia. A f t e r con-s i d e r i n g the much l a r g e r percentages of decay volume i n the suspect tr e e s than i n the r e s i d u a l t r e e s he s t a t e d : "...comparisons could be made to support my conclusions that the estimated amounts of accumulated decay and y e a r l y losses due to incidence of diseases are not extravagant, but co n s e r v a t i v e . " A n a l y s i s of trees of a l l commercial species i n B r i t i s h Columbia ( B r i t i s h Columbia Forest S e r v i c e , 1966) showed that c l a s s i -Table 12. Influence of age and s i t e on the p r o p o r t i o n of trees w i t h v i s i b l e i n d i c a t i o n s of d e f e c t s . Species Douglas f i r Western hemlock Western red cedar No. %T.C.l %T.C2 No... 7.T.C.1 7.T.C.2 No. 7.T.C.1 .%T.C.2 Number and p r o p o r t i o n of trees by age cl a s s e s Under 100 1,311 85 15 2,561 73 27 1,409 81 19 years Mixed young 172 87 13 664 77 23 129 72 28 and o l d Mature 112 73 27 1,381 72 28 461 41 59 Number and p r o p o r t i o n of trees by s i t e c l a s s e s S i t e index 21-40 142 71 29 80 60 40 41-60 199 86 14 434 71 29 197 51 49 61-80 138 84 16 266 60 40 548 85 15 81-100 266 90 10 688 71 29 647 71 29 101-120 138 86 14 1,677 74 26 323 67 33 121-140 378 79 21 1,222 79 21 141 70 30 141-160 295 81 19 59 53 47 161-180 153 85 15 - — 4 75 25 181-200 28 100 0 Source: Smith et a l . , 1961 42 1 2 Table 13. D i s t r i b u t i o n of tree c l a s s e s by DBH cl a s s e s f o r western hemlock i n f i v e P u b l i c Sustained Y i e l d U n i t s (P.S.Y.U.) i n B r i t i s h Columbia. Dean P .S.Y.U. DBH Tree c l a s s 1 Tree c l a s s 2. Tree c l a s s t :lass N.T. % • N.T. % N.T. % 4 - 16523 63.6 -7562 29.2 •-• 1880 7.2 8 6696 61.8 2918 26.9 1214 11.2 12 2535 54.1 1796 38.4 351 7.5 16 1086 45.8 1041 43.9 245 10.3 20 .578 40,2 676 47.0 184 12.8 24 279 31.4 493 55.5 116 13.1 28 138 23.5 364 62,1 84 14.4 32 99 29.0 166 48.5 77 22.5 36 28 16.2 77 44.5 68 39.3 40 21 20.2 • 58 55.8 25 24.0 44 6 14.3 27 . 64.3 9 21.4 48 6 20.7 16 55.2 7 24.1 H a r r i s o n P.S.Y.U. DBH Tree c l a s s 1 Tree c l a s s 2 Tree c l a s s 4 c l a s s N.T. % N.T. 1 N.T. % 4 6412 61.0 3714 35.4 380 3.6 8 2230 48.0 1975 42.5 438 9.5 12 1117 41.4 1325 49.1 258 . 9.5 16 747 35.8 1145 54.8 197 9.4 20 521 33.2 865 55.2 182 11.6 24 267 21.8 798 65.2 158 13.0 28 145 17.6 547 66.4 132 16.0 32 63 13.1 351 73.1 66 13.8 36 24 8.1 221 74.2 53 17.7 40 18 9.8 129 69.7 38 20.5 44 6 4.3 101 72.7 32 23.0 48 3 3.9 48 63.2 25 32.9 Table 13. (Continued) Ch i l l i w a c l c . P.S.Y.U. Tree c l a s s 1 Tree c l a s s 2 Tree c l a s s 4 N.T. % N.T. % N.T. % 4 1695 57.8 1147 39.1 92 3.1 8 558 51.9 422 39.3 95 8.8 12 198 45.2 217 49.5 23 5.3 16 109 43.1 129 50.9 15 6.0 20 79 40.3 96 49.0 21 10.7 24 37 22.8 109 67.3 16 9.9 28 58 29.9 117 60.3 19 9.8 32 24 18.2 86 65.2 22 16.6 36 19 14.2 82 60.7 34 25.2 40 8 10.3 53 67.9 17 21.8 44 3 5.1 42 71.2 14 23.7 48 5 11.6 34 79.1 4 9.3 52 2 6.7 24 80.0 4 13.3 Terrace P •S.Y.U. DBH Tree c l a s s -1 Tree c l a s s 2 Tree c l a s s < :lass . N.T. % N.T. N.T. 7» 4 17680 62.7 7853 27.8 2674 9.5 8 8376 55.4 5281 34.9 1454 9.7 12 3505 46.8 3434 45.8 556 7.4 16 1742 38.2 2438 53.5 375 8.3 20 953 29.0 2015 61.2 323 9.8 24 466 21.3 1455 66.5 266 12.2 28 173 12.8 993 73.7 182 13.5 32 110 12.2 645 71.4 148 16.4 36 48 10.5 345 75.0 67 14.5 40 27 11.7 174 75.3 30 13.0 44 2 1.7 107 89.2 11 9.1 48 3 5.2 41 70.6 14 24.2 Table 13. (Continued) Shuswap P.S.Y.U. DBH Tree c l a s s 1 • Tree; c l a s s 2 Tree c l a s s < :lass N.T. % N.T. % N.T. % 4 6713 68.8 2819 28.9 299 2.3 8 1825 63.5 887 30.8 164 5.7 12 610 52.6 503 43.4 46 4.0 16 445 48.5 408 44.4 65 7.1 20. 209 35.2 322 . 54.2 63 10.6 24 116 32.1 209 57.9 36 10.0 28 • 60 24.3 165 66.8 22 8.9 32 16 14.4 80 72.1 15 13.5 36 2 4.6 30 69.8 11 25.6 40 6 27.3 14 63.6 2 9.1 44 3 23.1 14 63.6 2 9.1 48 0 0.0 2 100.0 0 0.0 Source: Hamilton, 1967 Tree c l a s s 1 i s r e s i d u a l . Tree c l a s s 2 i s suspect. Tree c l a s s 4 i s dead standing. No. of t r e e s . 45. f i c a t i o n of trees as r e s i d u a l and suspect was of p r a c t i c a l s i g n i f i c a n c e i n decay e s t i m a t i o n . I n v e s t i g a t i o n s have shown that b a s a l and trunk scars provide entrance courts f or decay-causing f u n g i and that they are oft e n u s e f u l as i n d i c a t o r s of i n t e r n a l decay i n the tree (Nordin ej^ a l . , 1955; Nordin, 1958; Parker, 1958; Thomas, 1958; Aho, 1966). Kinsman (1964) reported that s m a l l , medium and .large open scars were a s s o c i a t e d w i t h decay 64, 77 and 100 per cent of the time r e s p e c t i v e l y i n western hemlock i n the Kitwanga P.S.Y.U. Closed scars were a s s o c i a t e d w i t h decay l e s s f r e q u e n t l y - the percentages being 23, 23 and 33 f o r s m a l l , medium and large s c a r s . Open scars were a s s o c i a t e d w i t h an average decay volume of 5.8 cubic fe e t and closed scars were a s s o c i a t e d w i t h an average decay volume of only 1.6 cubic f e e t . Shea (1960) observed evidence of decay i n 91 per cent of the logging scars on 90-year-old western hemlock. A f t e r 17 years from the date of logging, decay losses averaged 0.9 per cent of gross merchantable t r e e volume. In a 114-year-old stand of Douglas f i r and western hemlock i n western Washington, decay was a s s o c i a t e d w i t h 92 per cent of 10-year-ol d logging scars on western hemlock (Shea, 1961). In the older stand, decay volumes averaged 6.0 per cent of gross merchantable hemlock volume. The f r u i t i n g bodies or sporophores of f u n g i , when present, are v i r t u a l l y c e r t a i n i n d i c a t o r s of decay. The absence of sporophores i s , of course, no guarantee that decay i s absent. Some species of f u n g i do not produce f r u i t i n g bodies u n t i l decay i s w e l l advanced, others only produce sporophores o c c a s i o n a l l y , s t i l l others produce f r a g i l e sporophores which l a s t f o r only a short time. 46 Foster e_t a_l. (1954) reported that the only e x t e r n a l i n d i c a t o r s of s i g n i f i c a n c e i n decay e s t i m a t i o n i n western hemlock i n the B i g Bend area were sporophores. of Echinodontium t i n c t o r i u m and Fomes. p i n i . A t o t a l of 60 per cent, of the trees c o n t a i n i n g measurable decay volumes had one or more sporophores v i s i b l e from the ground. Table 14 i n d i c a t e s volumes of decay a s s o c i a t e d w i t h v a r y i n g numbers of sporophores on i n d i v i d u a l t r e e s . They concluded: "...the e n t i r e decay volume i s not n e c e s s a r i l y a s s o c i a t e d w i t h sporophores when they are present. Despite the preceeding q u a l i f i c a t i o n s , the r e l a t i v e decadence of i n d i v i d u a l trees may be estimated through the occurrence and l o c a t i o n of sporophores and a more accurate inven-t o r y of diseased stands of the nature sampled may be r e a l i z e d . " . Table 14. Per cent decay i n western hemlock trees having v a r y i n g numbers of sporophores 2 Number of sporophores Per cent gross per tree volume decayed 0 1-2 3-4 5-6 7+ 57.2 71.5 76.9 88.3 93.3 Source: Foster et a l . , 1954 I n c l u d i n g sporophores of E. t i n c t o r i u m , F. p i n i and F. p i n i c o l a . 47 Kinsman (1964) reported that decay volumes i n western hemlock i n Kitwanga were c l o s e l y a s s o c i a t e d w i t h v i s i b l e sporophores. K i s r e s u l t s are summarized i n Table 15. Table 15. D i s t r i b u t i o n of decay volumes a s s o c i a t e d w i t h sporophores of F. p i n i and E. t i n c t o r i u m on western hemlock. Average decay Average d i s t a n c e volume per of decay below r , , Decay f u n g i , , of decay above sporophore sporophore (cu. f t . ) ( f t . ) Average d i s t a n c e f sporophore ( f t . ) F. pj.ni 9.89 11 22 E. t i n c t o r i u m 19.41 16 20 ^ Source: Kinsman, 1964 Numerous attempts have been made to a s s o c i a t e various other e x t e r n a l a b n o r m a l i t i e s such as f o r k s , crooks, f r o s t cracks, m i s t l e t o e i n f e c t i o n s , r o t t e n branches, branch stubs, dead or broken tops, cankers and g a l l s w i t h decay i n the l i v i n g t r e e . The usefulness of these a b n o r m a l i t i e s f o r the e s t i m a t i o n of defect v a r i e s w i t h the species of f u n g i , the host species and the l o c a l area. I t i s u s u a l l y common to f i n d more than one kind of e x t e r n a l abnormality or decay i n d i c a t o r on a s i n g l e t r e e . When the s i g n i f i c a n c e of these a b n o r m a l i t i e s i s assessed s i n g l y and i n va r i o u s combinations or groups, increased p r e c i s i o n i n defect e s t i m a t i o n i s oft e n p o s s i b l e . 48 The t o t a l number of i n d i c a t o r s , i r r e s p e c t i v e of t h e i r type, was s i g n i -f i c a n t l y r e l a t e d t o per cent decay of western hemlock tre e s i n the Kitwanga P.S.Y.U. (Kinsman, 1964). A simple l i n e a r r e g r e s s i o n of per cent decay and number of i n d i c a t o r s present accounted f o r 52 per cent of the v a r i a b i l i t y , i n decay volume -in s i n g l e trees.; The standard e r r o r of estimate of per cent decay was + 16 per cent. The a d d i t i o n of DBH as an independent v a r i a b l e i n the r e g r e s s i o n equation only accounted f o r an a d d i t i o n a 1 -5 per cent of the v a r i a b i l i t y i n decay percentage i n s i n g l e - t r e e s . Aho (1966) derived r e g r e s s i o n equations based on v a r i o u s e x t e r n a l i n d i c a t o r s f o r s e v e r a l t r e e species i n Washington and Oregon (Table 16). His best equation accounted f o r n e a r l y 58 per cent of the v a r i a b i l i t y i n decay volume i n i n d i v i d u a l t r e e s . He used s e v e r a l e x t e r n a l i n d i c a t o r s and values f o r s u b s t i t u t i o n i n m u l t i p l e r e g r e s s i o n equations f o r the determination of per cent decay i n i n d i v i d u a l t r e e s . Foster, Thomas and Browne (1953) reported that swollen knots and sporophores were the most s i g n i f i c a n t e x t e r n a l i n d i c a t o r s i n western hemlock i n the upper Columbia r e g i o n . The r e l a t i v e importance of various i n d i c a t o r s i n that area are l i s t e d i n Table 17. A n a l y s i s of trees throughout B r i t i s h Columbia by the B r i t i s h Columbia Forest S e r v i c e (1966) showed that i n a d d i t i o n to sporophores, s c a r s , f o r k s , crooks, f r o s t cracks, m i s t l e t o e , r o t t e n branches and dead or broken tops were u s e f u l as i n d i c a t o r s of decay. In general, i t can be concluded that e x t e r n a l a b n o r m a l i t i e s are u s e f u l a i d s i n the e s t i m a t i o n of decay volumes i n l i v i n g t r e e s . One notable exception occurs, however, when the decay-causing f u n g i enter through the roots and provide no v i s i b l e evidence u n t i l decay i s Table 16.* Regression equations f o r e s t i m a t i o n of per cent decay f o r i n d i v i d u a l t r e e s . C o e f f i c i e n t s f o r e x t e r n a l i n d i c a t o r s Species A B C D E I L T fist. Term: R2 f r e e s Grand f i r • 1 .049 6.410 27.222 -.271 4 .123 -1.805 • 5 7 9 679 .560 2 7.918 28.. 170 -.128 5 .376 3.276 Engelmann spruce 1 .046 13.126 .139 .1.798 6.150 -5.108 212 151 .169 2 13.696 .324 2.032 5.587 -1.124 Douglas f i r 1 2 7.679 25.316 25.010 .082 .098 .771 . .690 X 6.027 . 835.X 5.9 20 - .745 - .893 .501 1 6 0 Larch 1 2 4.150 9.828 10.833 22.910 7.178 8.176 .578 2.002 °350 go .283 ^ Source Aho, 1966 . l A = tr e e age i n years E - 1 i f top i n j u r y present; B = 1 i f one or more b a s a l i n j u r i e s present > 0 i f no top i n j u r y present 0 i f no b a s a l i n j u r y present I = 1 i f one or more top or trunk i n j u r i e s present; C = 1 i f one or more conks present; 0 i f no top or trunk i n j u r i e s present 0 i f no conks present L = b a s a l scar length, rounded to the nearest foot D = t r e e DBH i n inches T = 1 i f one or more trunk i n j u r i e s longer than one foot present; 0 i f no trunk i n j u r i < is present. 50 w e l l advanced.. I t i s important to note, a l s o , that the usefulness of any abnormality f o r decay e s t i m a t i o n v a r i e s s i g n i f i c a n t l y w i t h the species of f u n g i , the host species and the l o c a l area. Table 17. The frequency and occurrence and r e l a t i v e importance of a b n o r m a l i t i e s of decay s i g n i f i c a n c e on l i v i n g western hemlock' i n the upper Columbia r e g i o n . Frequency of Per cent of a f f e c t e d . t r e e s Abnormality occurrence - w i t h decay In c l o s e per cent of l i v i n g In d i r e c t t r e e s a f f e c t e d a s s o c i a t i o n a s s o c i a t i o n Sporophores 47.9 .100 100 F r o s t cracks 30.4 62 78 Scars 11.6 60 65 Dead tops 8.5 80 80 Rotten branches 7.1 90 90 Forked trees 3.6 60 71 Swollen knots 2.2 100 100 M i s t l e t o e 0.8 75 75 Source: F o s t e r , Thomas and Browne, 1953 D i s t r i b u t i o n of Log S i z e and Gross Volume Wi t h i n Trees Despite the large amount of research devoted to t r e e volume e s t i m a t i o n , development of f l e x i b l e methods f o r e s t i m a t i n g the d i s t r i -b u t i o n of volume i n standing trees has been slow. Spurr (1952) s t a t e d : "As i n medicine, where the large number of remedies proposed f o r the common co l d i n d i c a t e s the i n e f f e c t i v e n e s s of any one, so the large number of approaches to the problem of volume e s t i m a t i o n may be taken as an i n d i c a t i o n that no one approach has r e c e i v e d more than p a r t i a l r e c o g n i t i o n . " 51 Log p o s i t i o n volume t a b l e s ' ( e . g . Mason, Bruce and G i r a r d , 1949; Skinner, 1955; B r i t i s h Columbia Forest S e r v i c e , 1959; Bones, 1963) which are designed f o r 16-or 32-foot log lengths are r e s t r i c t e d i n present day a p p l i c a t i o n s because of t h e i r f i x e d l o g length and t h e i r l a c k of diameter inform a t i o n f o r various logs, Honer and Sayn-W i t t g e n s t e i n (1963) s t a t e d : "We must develop a mathematical tre e volume expression which can be e f f i c i e n t l y programed f o r g e n e r a l l y a v a i l a b l e e l e c t r o n i c computing equipment to y i e l d t r e e and stand volumes from inputs of t r e e diameter outside bark and t o t a l heights (form estimates o p t i o n a l ) and f o r any demanded stump height and top diameter." I n the l i g h t of present day requirements the above statement should be r e v i s e d to includ e log volumes and log s i z e s i n a d d i t i o n to tree and stand volumes. S e v e r a l authors have attempted to describe tree form and taper and to develop mathematical formulae f o r the determination of t r e e volume between s p e c i f i e d stump heights and top diameters.- Wright (1927) was the f i r s t Canadian f o r e s t e r to prepare general taper curves f o r Canadian t r e e s . Depending on species examined and a n a l y t i c a l techniques used, t r e e form has been shown to resemble a quadratic p a r a b o l o i d (Gray, 1956; Newnham, 1958), a cubic p a r a b o l o i d (Metzger, Busgen and Munch, 1929), a hyperbola (Before, 1923) or some form intermediate between a p a r a b o l o i d and hyperbola (Grosenbaugh, 1954, 1967). M u l t i v a r i a t e methods have been used to describe tree form ( F r i e s , 1965; F r i e s and Matern, 1965; Kozak and Smith, 1966, 1967). Comprehensive r e g r e s s i o n methods have been used i n the development of taper and volume t a b l e s f o r red a l d e r (Bruce jet a l . , 1967; C u r t i s and VanCoevering, 1967). These were based on the work of Matte (1949) who found that stem p r o f i l e of l o b l o l l y pine above breast height could be described by the equation \ n y » x \ ax + bx + c where i "y" was r a t i o of diameter i n s i d e bark a t p o i n t of measurement t o diameter i n s i d e bark at breast height. "x" was r a t i o of d i s t a n c e from t i p to measurement p o i n t , to t o t a l height of t r e e above breast h e i g h t , a + b + c = 1 and • "a" "b" " c " were c o e f f i c i e n t s found by l e a s t squares a n a l y s i s . The B r i t i s h Columbia Forest S e r v i c e (1962) has developed taper curves f o r the commercial t r e e species of B r i t i s h Columbia, However these were constructed by the method of harmonized curves and i t i s not easy to f i n d a mathematical f u n c t i o n which adequately describes, them. B u r s t a l l and Duff (1959) prepared combined taper and volume t a b l e s f o r ]?. r a d i a t a B - and Douglas f i r i n New Zealand. These t a b l e s too, are l i m i t e d i n a p p l i c a t i o n . They are r e s t r i c t e d to 10-foot l o g lengths (or m u l t i p l e s thereof) and are based on harmonized curves. The t a r i f t a b l e s of T u r n b u l l e t ' a l . (1963) are designed s p e c i f i c a l l y f o r e l e c t r o n i c computer a p p l i c a t i o n s and are-probably the-most f l e x i b l e volume t a b l e s a v a i l a b l e . Volumes can be obtained f o r 4, 6, or 8-inch top diameters i n cubic f e e t or i n board f e e t . They do not however, provide the i n f o r m a t i o n needed on the d i s t r i b u t i o n of l o g s i z e and volume w i t h i n trees.' F r i e s (1965) used Eigenvector analyses i . \ to show that b i r c h and pine have s i m i l a r form i n Sweden and i n B r i t i s h Columbia. He d i d not attempt to d e f i n e log volumes, s i z e s or d i s t r i -b u t i o n of logs w i t h i n t r e e stems. y' ; 53 -Honer (1964, 1967) developed a system of equations which permit s a n e s t i m a t i o n of volume of any p o r t i o n of the t r e e stem defined by.two measures of merchantable height and determination of merchantable volume to any s p e c i f i e d top diameter and stump height. He found that r a t i o s of merchantable volume to t o t a l volume are p r o p o r t i o n a l to the r a t i o s of merchantable height to t o t a l height and of the square of diameter at merchantable height to diameter at breast height. He d e r i v e d equations which, according t o a p r e l i m i n a r y a n a l y s i s based on 11 t r e e s , adequately described t r e e volume t o various u t i l i z a t i o n standards. His equations can be manipulated through a s e r i e s of successive s u b t r a c t i o n s to provide estimates of i n d i v i d u a l log volumes w i t h i n t r e e s . I t i s a l s o p o s s i b l e t o s p e c i f y a log length or a log diameter and o b t a i n l o g volumes. His s e l e c t i o n of v a r i a b l e s does not however, permit the s p e c i f i c a t i o n of both a diameter and a length at the same time. An i d e a l method would permit the determination of l o g volumes f o r s p e c i f i e d l o g lengths and diameters. Conclusion -From t h i s review of l i t e r a t u r e , i t i s apparent that although much i s known about decay-causing f u n g i and t h e i r e f f e c t on wood, f u r t h e r r e s e a r c h i s needed to provide i n f o r m a t i o n necessary f o r the development of f o r e s t management methods by which decay losses can be reduced. Much good q u a n t i t a t i v e i n f o r m a t i o n i s a v a i l a b l e regarding r e l a t i o n s h i p s betx^een e x t e r n a l a b n o r m a l i t i e s and decay w i t h i n l i v i n g , standing t r e e s . However, there i s no q u a n t i t a t i v e i n f o r m a t i o n a v a i l a b l e on the d i s t r i b u t i o n of decay w i t h i n t r e e stems and the r e l a t i o n s h i p of t h i s d i s t r i b u t i o n to t r e e s i z e and e x t e r n a l a b n o r m a l i t i e s . S i m i l a r l y , 54 h o . f l e x i b l e methods are a v a i l a b l e to enable the p r e d i c t i o n of volumes of i n d i v i d u a l logs of s p e c i f i e d lengths and diameters i n standing t r e e s . There i s c l e a r l y a need f o r the development of an e f f i c i e n t q u a n t i t a t i v e method to de s c r i b e the d i s t r i b u t i o n of soundwood and decay volumes w i t h i n t r e e stems. 55 . . . CHAPTER I I I DATA COLLECTION AND INITIAL SUMMARIZATION Since 1952, the Inventory D i v i s i o n of the B r i t i s h Columbia Forest S e r v i c e has been engaged i n a program to c o l l e c t stem a n a l y s i s data from trees throughout the province to provide r e l i a b l e i n f o r m a t i o n f o r volume t a b l e s , decay l o s s f a c t o r s and s i t e index curves. By 1966, analyses were completed f o r 32,056 trees of 15 commercial species i n a l l f o r e s t zones of B r i t i s h Columbia ( B r i t i s h Columbia Forest S e r v i c e , 1966). These analyses were c a r r i e d out i n accordance w i t h s t r i c t standards and procedures ( B r i t i s h Columbia Forest S e r v i c e , 1954, 1967) and were s i m i l a r to those which the author had the opportunity to observe near Blue R i v e r , B.C. i n J u l y , 1967. I n d i v i d u a l t r e e records are maintained i n a w e l l organized and e f f i c i e n t f i l i n g system i n V i c t o r i a , B.C. I t was recognized e a r l y i n t h i s study that data such as the above would be i d e a l f o r use i n the development of methods to assess d i s t r i b u t i o n of soundwood volume i n t r e e s . To enable a complete and exhaustive a n a l y s i s i n a resonable time p e r i o d , i t was necessary to r e s t r i c t the data to a r e l a t i v e l y s m a ll number of t r e e s . Consequently, a sample of 369 western hemlock trees was s e l e c t e d from 14 sample p l o t s e s t a b l i s h e d i n 1965 i n the Yale P.S.Y.U. ( s i t u a t e d i n the Cascade-Coast mountain r e g i o n of Thomas' (1958) c l a s s i f i c a t i o n at approximately 121° 15' west longitude and 49° 30' north l a t i t u d e ) . Approximately 15 computer programs were w r i t t e n by the author to f a c i l i t a t e analyses of the data. Computer programs f o r 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 (Kozak and Smith, 1965) and a n a l y s i s of variance were obtained from the F a c u l t y of F o r e s t r y , U n i v e r s i t y of B r i t i s h 56 Columbia, and modified where necessary. A l l computing was c a r r i e d ' out on an IBM 7044 i n the computing centre of the U n i v e r s i t y of B r i t i s h Columbia. Numbers of t r e e s , s i t e index, per cent m e r c h a n t a b i l i t y and average stand age are summarized f o r each sample i d e n t i f i e d by r e g i o n , compartment and sample number i n Table 18. Species composition, height c l a s s , s i t e c l a s s and gross cubic foot volume per acre i n stems 5.1 inches DBH and l a r g e r are tabulated-i n Table 19.. (Unless s p e c i f i e d otherwise i n t h i s study, gross volume means t o t a l wood volume i n s i d e bark between a 1-foot stump height and 4-inch top diameter i n s i d e bark.) No samples were a v a i l a b l e from immature stands, t h e r e f o r e a l l samples used f o r t h i s study were e s t a -b l i s h e d i n o l d growth or overmature stands (Photograph I ) . Sample 16. o r i g i n a t e d i n the youngest stand w i t h an average age of 196 years. Each sample c o n s i s t e d of a t o t a l area of one acre and was composed of four subplots, each of which was one-quarter acre i n s i z e . A l l t r e e s 11.1 inches DBH and l a r g e r were marked f o r f e l l i n g and s e c t i o n i n g f o r decay a n a l y s i s . Trees 7.1 inches to 11.0 inches DBH were measured and marked f o r f e l l i n g and s e c t i o n i n g on subplots one-tw e n t i e t h acre i n s i z e s i t u a t e d at the centre of each one-quarter acre p l o t . A l l p l o t boundaries were c a r e f u l l y e s t a b l i s h e d w i t h tape and compass, blazed, and marked w i t h s t r i n g . Before f e l l i n g , diameters i n s i d e bark were measured at 1, 1.5, 2, 3, 4.5 and 5 f e e t above the assumed p o i n t of germination. Notes were taken regarding t r e e q u a l i t y and t r e e c l a s s , and the type and p o s i t i o n of a l l e x t e r n a l a b n o r m a l i t i e s (Table 20) were recorded. A f t e r the above measurements were completed, each marked tre e was f e l l e d and sectioned at 16-foot i n t e r v a l s above a 57 Table 18. Number of t r e e s , s i t e index, per cent m e r c h a n t a b i l i t y and average age by sample number. Area and sample no. No. trees S i t e index height at 100 y r s . ( f t . ) . Per cent Average merchantable age (yrs.) R 10 C6A S5 10 89 86.05 250 R 10 C6A S6 17 87 70.90 389 R 10 C6A S12 21 106 77.69 299 R 11 C4J S34 11 103 69.61 267 R 12 C3 S16 21 113 91.72 196 R 12 C3 S17 19 109 80.27 256 R 12 C3 S18 18 112 75.72 228 R 12 C3 S19 10 115 96.65 254 R 12 C3 S20 14 107 94.14 254 R 12 C7 S16 39 98 77.32 289 R 26 C2 S40 10 71 98.38 266 R 26 C2 S41 6 78 64.94 252 R 26 C2 S42 13 136 83.63 258 R 26 CIO S61 160 71 95.18 259 Table 19. C l a s s i f i c a t i o n of stands sampled by sample number and area. , .a _• . .,_. 1 Height c l a s s S i t e Volume per acre Area and sample no. Species composition % , , c ... „„ T T , . . v • * ( f t . ) c l a s s (5.1" DBH + gross c.f.) RIO C6A S5 B 6 H 3 (Cy) RIO C6A S6 H 5 B 4 (Cy) RIO C6A S12 H 5 B 3 (C) R l l C4J S34 H7 B3 R12 C3 S16 H 6 C 2 (B) R12 C3 S17 H 4 C4 B2 R12 C3 S18 B 5 H 4 (C) R12 C3 S19 B8 (H) R12 C3 S20 B 8 H 2 R12 C7 S16 H 6 C 3 (B) R26 C2 S40 B4 Cy 3 H3 R26 C2 S41 H 5 \ (Cy) R26 C2 S42 B 6 H 3 R26 CIO S61 H 7 B 2 (Cy) 156 -• 185 poor 12,290 96 -- 125 poor 9,471 126 -• 155 poor 12,281 126 -• 155 medium 13,442 156 -• 185 med ium 10,387 126 -• 1 5 5 medium 11,099 126 -• 155 medium 9,078 156 -• 185 medium 14,262 126 -• 155 good 11,237 126 -• 155 medium 13,428 96 -• 125 poor 8, 150 96 -• 125 poor 10,074 156 -• 185 good 18,778 96 -• 125 poor 9,521 Su b s c r i p t s denote species present to nearest 10 per cent. Photograph I . T y p i c a l old growth s t a n d of western hemlock. Blue R i v e r , 3 - C. Table 20. E x t e r n a l a b n o r m a l i t i e s tabulated and analyzed i n r e l a t i o n to tree decay. E x t e r n a l abnormality Code no. Echinodontium t i n c t o r i u m conks 1 Fomes p i n i conks 2 " B l i n d " conks of Fomes p i n i 3 Conks of a l l other f u n g i 4 Small open scars ( l e s s than 5 feet i n length) 5 Med. open scars (from 5 to 10 feet i n length) 6 Large open scars (longer than 10 f e e t ) 7 Small closed scars ( l e s s than 5 feet i n length) 8 Med. closed scars (from 5 to 10 feet i n length) 9 Large closed scars (longer than 10 feet ) ' 10 Small f r o s t cracks ( l e s s than 5 feet i n length) 11 Med. f r o s t cracks (from 5 to 10 feet i n length) 12 Large f r o s t cracks (longer than 10 feet ) 13 M i s t l e t o e i n f e c t i o n 14 Rotten branches 15 Dead or broken tops 16 Small forks 17 Crooks 18 Other 19 61 one-foot stump height. Diameters i n s i d e bark at each cut s e c t i o n were recorded to the nearest 1-inch c l a s s and lengths were recorded to the nearest one-tenth f o o t . In a d d i t i o n to the above cuts and measurements at r e g u l a r i n t e r v a l s , a cut was made at each e x t e r n a l abnormality to determine i f the abnormality was an entrance court f o r decay. When decay was encountered at any cut s e c t i o n , a d d i t i o n a l cuts were made at approximately 2-foot i n t e r v a l s u n t i l the maximum diameter of the decay column and the beginning and ending p o i n t s of the column could be deter-mined w i t h i n plus or minus one foot of height above ground l e v e l (Photograph I I ) . C h a r a c t e r i s t i c s of the decay were noted and described and, i f f i e l d i d e n t i f i c a t i o n of the fungus was not p o s s i b l e , a d d i t i o n a l d e s c r i p t i o n s of the r o t were recorded. In some instances, samples of decayed wood were c o l l e c t e d f o r c u l t u r e to permit accurate i d e n t i f i -c a t i o n of the decay-causing f u n g i i n the l a b o r a t o r y . No attempt was made during the f i e l d work to separate, f o r r e c o r d i n g purposes, the presence or absence of wood i n s e v e r e l y decayed s e c t i o n s , i n c i p i e n t , advanced stages or intermediate stages of decay. For the purpose of t h i s study, the term "decayed wood" includes a l l wood which has been v i s i b l y i n f e c t e d w i t h wood r o t t i n g f u n g i . The f i r s t step i n the analyses was to assess and summarize the tr e e s by v a r i o u s c l a s s e s and to segregate the types of decay to enable g r a p h i c a l examination of trends and the p o s t u l a t i o n of a n a l y t i c a l techniques that might prove to be u s e f u l i n the development of decay e s t i m a t i n g equations. D i s t r i b u t i o n of the 369 trees by DBH c l a s s e s , w i t h numbers of samples, average height, average cubic foot volume and average per cent m e r c h a n t a b i l i t y i s presented i n Table 21. The m a j o r i t y of samples i s located i n the DBH range from 11 to 24 inches. A s l i g h t Photograph I I . p o r t i o n of a western hemlock tree sectioned f o r decay measurement. Table 21. D i s t r i b u t i o n of b a s i c data by DBH c l a s s e s . DBH c l a s s (inches) No. trees Avg. h t . ( f t . ) Average v o l . Gross ( c . f . ) Merch. Avg. per cent merch. v o l . 8 5 44.0 5, .0 4.8 96.0 9 3 55.0 7 .5 6.9 92.0 10 9 67.2 14 .4 12.8 88.9 11 24 63.7 15, .7 14.7 93.6 12 36 70.1 20 .6 18.7 90.8 13 33 74.2 24, .4 23.5 96.3 14 31 80.1 30, .7 29.0 94.5 15 28 80.9 35, .2 33.6 95.4 16 21 86.8 44 .6 40.6 91.0 17 18 93.5 50 .4 45.6 90.5 18 16 85.4 55, . 1 53.5 97.1 19 8 98.8 73, .0 63.7 87.3 20 13 97.2 75, .1 64.4 85.7 21 11 98.5 85, .0 76.3 89.8 22 9 102.3 91, .9 77.6 84.4 23 10 121.7 121 .5 104.2 85.6 24 7 111.6 129, .5 112.4 86.8 25 5 122.4 145, .4 124.0 85.3 26 6 122.7 164, .7 130.4 79.2 27 8 123.6 173 .0 136.5 78.9 28 9 128.1 198 .5 157.1 79.1 29 8 142.4 217 .4 197.2 90.7 30 8 123.5 211, .9 187.0 88.2 31 5 133.2 246, .2 .198.1 80.5 32 7 136.0 272 .2 183.5 67.4 33 3 124.7 232 .4 192.1 82.6 34 5 143.4 297 .5 272.1 91.5 35 5 136.6 308 .9 223.1 72.2 36 4 153.3 359 .4 293.2 81.6 37 2 .147.5 368, .6 293.3 79.6 38 3 152.3 376 .5 294.4 78.2 39 3 146.0 383 .2 299.3 78.1 40+ 6 157.0 522 .2 379.3 72.6 64 trend, of decreasing per cent m e r c h a n t a b i l i t y i s evident w i t h i n c r e a s i n g DBH and height. This trend i s not w e l l defined, however, and the v a r i a b i l i t y from DBH c l a s s to DBH c l a s s i s l a r g e . For example, f i v e trees i n the 34-inch DBH c l a s s average 91.5 per cent merchantable w h i l e nine trees i n the 10-inch DBH c l a s s average only 88.9 per cent merchant-a b l e . Summarization of the h e a r t r o t i d e n t i f i c a t i o n s and d e s c r i p t i o n s made'by B r i t i s h Columbia Forest S e r v i c e personnel (Table 22) r e v e a l s that E. t i n c t o r i u m and F. p i n i were p o s i t i v e l y i d e n t i f i e d . e i t h e r from Table 22. Heart r o t i d e n t i f i c a t i o n s , d e s c r i p t i o n s and frequency of observation i n 369 western hemlock t r e e s . Item Frequency of observations' I d e n t i f i c a t i o n ( p o s i t i v e ) Echinodontium t i n c t o r i u m  Fomes p i n i  Stereum sp. D e s c r i p t i o n E a r l y stages Brown columnar Advanced stages Brown columnar^ Brown c u b i c a l Brown s t r i n g y ^ White p i t t e d 32 37 4 27 253 21 212 28 A l l brown s t r i n g y r o t s were a l s o described as brown columnar. 65 Photograph III. Stump and top sect i o n s of western hemlock t r e e . Heartwood destroyed by Echinodontiraa tinctoriun-.. 66 sporophores or c u l t u r e i n n e a r l y equal proportions (32 E. t i n c t o r i u m i n f e c t i o n s versus 37 F. p i n i i n f e c t i o n s ) . In the r o t d e s c r i p t i o n s , however, where a l l r o t s were described according to appearance, the m a j o r i t y were described as brown s t r i n g y and columnar, r a t h e r than white or white p i t t e d which i s t y p i c a l of F. p i n i . I t would appear from the r o t d e s c r i p t i o n s that very l i t t l e r o t caused by F. p i n i wa-s present without sporophores to a i d i n p o s i t i v e f i e l d i d e n t i f i c a t i o n . The author has conferred w i t h personnel of the B r i t i s h Columbia Forest S e r v i c e r e s p o n s i b l e f o r the f i e l d a n a l y s i s of these trees and i t i s t h e i r o p i n i o n that probably the m a j o r i t y of the r o t was caused by E. t i n c t o r i u m , w i t h only a minor amount caused by F. p i n i . U n f o r t u n a t e l y , most of the c u l t u r e t e s t s of the samples taken were not s u c c e s s f u l . Without p o s i t i v e i d e n t i f i c a t i o n from c u l t u r e or from the presence of sporophores, i t i s not p o s s i b l e to s t a t e p o s i t i v e l y the species of f u n g i i n the t r e e s examined. This i s p a r t i c u l a r l y true of r o t caused by E. t i n c t o r i u m (Photograph I I I ) which i s o f t e n and e a s i l y confused w i t h that caused by Stereum sanguinolentum (Maloy, 1967). Unless p o s i -t i v e f i e l d i d e n t i f i c a t i o n was made from the presence of sporophores, the heart r o t was described according to appearance and the causal organism recorded as species unknown. In the t o t a l sample, 272 trees or n e a r l y 74 per cent contained measurable amounts of decay, but, only 209 of these trees had e x t e r n a l a b n o r m a l i t i e s which could be regarded as p o s s i b l e i n d i c a t o r s of decay i n the tree stem (Table 23). B a s i c data are summarized by s e v e r a l t r e e c l a s s groupings i n Tables 24, 25, 26, 27, 28 and .29. In Table 27, data are summarized f o r each suspect abnormality c l a s s and ranked i n i n c r e a s i n g order of decay volume expressed as a percentage of gross t r e e volume. 67 Table 23. Summary of sound and decayed tr e e s by t r e e c l a s s . „ , Number of trees Tree c l a s s Decayed Sound T o t a l Resldua'l 1 63 48 111 S uspect 2 209 49 258 A l l 272 97 369 I ^ Trees with no external abnormalities 2 ' ' • Trees w i t h one or more of the e x t e r n a l a b n o r m a l i t i e s l i s t e d i n Table 20. / Many trees bore more than one e x t e r n a l abnormality. Table 30 i n d i c a t e s the frequency w i t h which more than one e x t e r n a l abnormality was observed on decayed and sound t r e e s . Considering a l l trees w i t h measurable decay volume, n e a r l y 64 per cent had two a b n o r m a l i t i e s or l e s s (23.2 per cent had none, 23.2 per cent one and, 18.0 per cent two a b n o r m a l i t i e s ) . This i s i n c o n t r a s t to the "sound; tr e e s where 85 per cent of the t r e e s had one abnormality or less." The d i f f e r e n c e i n incidence of two or more a b n o r m a l i t i e s between sound and decayed tr e e s suggests that c e r t a i n combinations of e x t e r n a l a b n o r m a l i t i e s might be more u s e f u l than i n d i v i d u a l a b n o r m a l i t i e s i n the e s t i m a t i o n of decay volume w i t h i n standing t r e e s . The r e l a t i v e usefulness of e x t e r n a l abnor-m a l i t i e s as decay i n d i c a t o r s can be i n f e r r e d from Table 31 where the absolute and r e l a t i v e numbers of t r e e s w i t h a b n o r m a l i t i e s a s s o c i a t e d r • • • w i t h decay are t a b u l a t e d . Where the number of t r e e s w i t h decay i n a i • • \ .• I •. s p e c i f i c abnormality c l a s s approaches 100 per cent, then that abnormality may be u s e f u l as an i n d i c a t o r of decay. I t i s a l s o important t o Table 24. B a s i c data summary f o r a l l (369) western hemlock t r e e s . V a r i a b l e Average Minimum Maximum Stan, dev. No. obs, Tree DBH (inches) 19.07 Height ( f e e t ) 94.63 Age (years) 265.38 Gross v o l . ( c . f . ) 94.92 Merch. v o l . ( c . f . ) 79.20 Net v o l . ( c . f . ) 73.85 F i r s t decay column Low height ( f e e t ) 14.90 High height ( f e e t ) 46.96 Ht. of max. d i a . ( f e e t ) 25.15 Max. d i a . (inches) ' 8.90 7.5 29.0 109.0 2.6 2.6 2.6 1.0 2.0 1.0 1.0 55.1 178.0 512.0 912.0 519.9 510.6 70.0 160.0 81.0 35.0 8.11 29.89 63.20 112.28 88.83 85.00 16.76 28.19 20.00 6.55 369 369 369 369 369 369 272 272 272 272 Second decay column Low height ( f e e t ) 44.48 High height ( f e e t ) 66.60 Ht. of max. d i a . ( f e e t ) 53.67 Max. d i a . (inches) 5.88 8.0 16.0 13.0 1.0 124.0 148.0 130.0 21.0 28.55 29.16 27.85 4.25 48 48 48 43 oo 69 Table 25. Basic data summary f o r 97 sound western hemlock t r e e s . V a r i a b l e Average Minimum Maximum Stan.dev. No.obs. Tree DBH (inches) 15.2 7 .5 39.9 5.98 97 Height ( f e e t ) 81.80 29 .0 172.0 : 25.63 97 Age (years) 242.39 109 .0 318.0 42.09 97 Gross v o l . ( c . f . ) 52.67 2 ,6 472.4 74.26 97 Merch. v o l . ( c . f . ) 52.67 2 .6 47214 74.26 97 Net v o l . ( c . f . ) 52.59- 2 .6 472.4 74.28 97 know what volume of decay i s a s s o c i a t e d w i t h each of the above i n d i c a t o r s . I t i s p o s s i b l e that,, although decay i s c o n s i s t e n t l y a s s o c i a t e d w i t h a p a r t i c u l a r abnormality, the a c t u a l decay volume i s r e l a t i v e l y s m a l l . For those decay columns i n which entrance courts were confirmed by s e c t i o n i n g , scars were a s s o c i a t e d w i t h the l a r g e s t decay volumes and fo r k s w i t h the l e a s t . The d i s t r i b u t i o n s and frequency w i t h which e x t e r n a l a b n o r m a l i t i e s appear on sound and decayed trees are summarized i n t a b l e 32. The mpst f r e q u e n t l y o c c u r r i n g abnormality i n both sound and decayed trees i s small f r o s t cracks. These appear on 12.4 per cent of the sound trees and 29.4 per cent of the decayed t r e e s . A wide d i f f e r e n c e between the percentage of sound trees w i t h a p a r t i c u l a r i n d i c a t o r and decayed trees w i t h the same i n d i c a t o r could p o i n t to p o t e n t i a l l y u s e f u l decay i n d i c a t o r s . As an obvious example, conks were a s s o c i a t e d w i t h decay 100 per cent of the time and can t h e r e f o r e be considered r e l i a b l e i n d i c a t o r s of decay (Photograph I V ) . On the other hand, m i s t l e t o e occurred w i t h almost equal frequency on sound and decayed t r e e s , thus suggesting that the presence of m i s t l e t o e does not i n d i c a t e decay w i t h i n the tree stem. S i m i l a r l y s m all forks are Table 26. B a s i c data summary f o r 272 decayed western hemlock t r e e s . V a r i a b l e Average Minimum Maximum Stan. dev. No. obs. Tree DBH (inches) 20.30 Height ( f e e t ) 99.21 Age (years) 273.58 Gross v o l . ( c . f . ) 109.99 Merch. v o l . ( c . f . ) 88.66 Net v o l . ( c . f . ) 81.43 F i r s t decay column Low height ( f e e t ) 14.90 High height ( f e e t ) 46.96 Ht. of max. d i a . ( f e e t ) 25.15 Max. d i a . (inches) • 8.90 Second decay column Low height ( f e e t ) 44.48 High height ( f e e t ) 66.60 Ht. of max. d i a . ( f e e t ) 53.67 Max. d i a . (inches) 5.88 7.6 42.0 125.0 5.4 5.4 3.9 1.0 2.0 1.0 1.0 8.0 •16.0 .13.0 1.0 55.1 178.0 512.0 912.0 519.9 510.6 70.0 160.0 81.0 35.0 124.0 148.0 130.0 21.0 8.41 30.02 67.38 119.58 •91.77 87.39 16.76 28.19 20.00 6.55 28.55 29.16 27.85 4.25 272 272 272 272 272 272 272 272 272 272 48 48 48 48 o T a b l e 27. Summary of average s t a t i s t i c s f o r 272 decayed western hemlock t r e e s f o r v a r i o u s kinds of e x t e r n a l a b n o r m a l i t i e s . Code Per cenc No. decay Decay volume DBII ( i n . ) Tota 1 height T o t a l age Low he i g h t F i r s t decay column High he i g h t Mid height Max. diameter No . of t r e e s Second decay column low height High he i g h t Mid h e i g h t Max. d ia'meter No. of t r e e s ( c . f . ) ( f t . ) ( y r s . ) ( f t . ) ( f t . ) ( f t . ) ( i n . ) ( f t . ••) (n. .) ( f t . ,) ( i n .) 14 5. .3 6.7 22. ,4 115 .5 234 '5 .2 '26 .0 13 .0 8 .2 4 33 .0- 50. •P 37 . 6 5 .3 3 19 6. .9 23.8 34, .3 174 .0 233 1 .0 .0 1 .0 25 .0 1 0, .0 ' 0 ,0 0. .0 0 .0 0 9 14. .9 37 .5 29, .5 138 .5 266 1 .5 43 . 1 8 .8 15 .3 12 47. .4 . 66. .0 53 . 2 7 .8 5 5 L7. .7 21.6 21 , 3 102 . 1 260 13 .3 43 .0 22 .0 9 .3 42 40. .0 64 , .0 50. 1 6, .0 13 18 13, 1 13.5 18, ,5 89 .3 238 17 . 1 41 .6 25 .9 7 .6 45 44, , 5 59, ,0 5 1. 5 4. .5 12 11 19. T 28.4 '23. .0 109 .4 277 11 .4 46 .3 21 . 4 10 .2 80 47: .3 • 69, .2. 56. 1 5; .2 ' 22 12 . 19 , 9 25.2 21, .6 108 .6 255 11 .0 44 .3 18 .9 10 .0 34 40, . 1 . 60, .9 49 .2 6. .5 12 6 20, , I 46.5 • 29, . 1 130 .8 277 5 .7 -50 .0 19 . 1 • 16 . 1 8 27 .5 53, .5 41 . 0 10 .0 2 15 20. .4 38.1 26, ,3 117 .0 237 L . 7 36. .7 ' 8 .3 14 0 8 38, . 5 57. 5 44 . 7 5'. .0 , 4 17 2 1. , 1 . 1.8.9 20. .0 88 .5 304 17 .0 51, .8 ' 29 .6 • ' 9 .5 8 52, ;0 85 . 0 66. 0 9 , .0 1 u 22. .8 37.8 25, .3 1 19 .0 2S6 S .6 49. .4 19 .3 1 1 .8 17 48. . 1 •73. . 1." 60. 7 7. C 9 8 ' 25, 8 34.1 21. .3 100 .4 270 13 .4 52 .9 23 .0 10 . 1 41 ' 54 , .0 67. .0 59 . 1 4 . 3 6 10 27, , ? 89.1 32, . 1 137 .8 271 2 . 1 54 .'3 10 .3 19 .0 . 8 66 . 2 . 82. .5 7 1. .7 • 5, .5 4 16 27. .3 23.4 17. , 8 86 .3 273 . 12 .S 48, . 1 23 .6 8 .8 33 32, 5 ;• 52. 8 ' 40. 3 3. .5 6 4 28, , 3 64.4 28, .9 126 .0 253 1 .0 55, .6 6 .3 17 .3 3 ' 102. •0 ; • 138. ,0 1.13. 0 6. .0 I 1 JO, .6 23.7 18, .3 87 .4 305 '11 .9 52 .0 26 .6 10 .0 27- 34, ,0 66, ,3 45. 0 5, ,67 3 7 .36 , 2 75.8 24 .9 108 .4 2S9 1 I . 4 51 , 2 16 . 1 12 .5 7 11. .6 23, .6 15 , 6 3, .6 3 2 36 .5 59.6 24 .7 113 .7 2 SO 3 .9 71 . 2 18 . 6 14 . 7 33 ; 85 .0 108 .5 94, .5 6 .0 2 3 39 .7 61.1 23 .7 112 . 1 303 2 _ 0 ' 64 .3 15 .3 14 . 7 17 . 102 .0 138 .0 113 .0 6 .0 1 a b n o r m a l i t y code No.; see t a b l e 20 Lor key. Table 28. B a s i c data summary f o r 111 " r e s i d u a l " western hemlock t r e e s . V a r i a b l e Average Minimum Maximum Stan. dev. No. obs. Tree DBH (inches) Height ( f e e t ) Age (years) Gross v o l . ( c . f . ) Merch. v o l . ( c . f . ) Net v o l . ( c . f . ) 15.97 86.00 260.62 55.81 52.75 51.11 7.5 29.0 109.0 2.6 2.6 2.6 40.1 150.0 472.0 444.3 349 .9 326.8 5.84 23.42 54.38 66.22 60.30 58.92 111 111 111. I l l 111 • 111 F i r s t decay column Low height ( f e e t ) 23.03 High height ( f e e t ) 47.41 Ht. of max. d i a . ( f e e t ) 33.48 Max. d i a . (inches) 5.68 1.0 2.0 1.0 1.0 61.0 77.0 65.0 21.0 17.49 19.98 19 .09 3.93 63 63 63 63 Second decay column Low height ( f e e t ) High height ( f e e t ) Ht. of max. d i a . ( f e e t ) Max. d i a . (inches) 51.00 77.67 63.00 3.67 28.0 55.0 49.0 2.0 88.0 99.0 91.0 7.0 32.35 22.03 24.24 2.88 3 3 3 o Table 29. Ba s i c data summary f o r 258 "suspect" western hemlock t r e e s . V a r i a b l e Average Minimum Maximum Stan. dev. No. obs. Tree DBH (inches) Height ( f e e t ) Age (years) Gross v o l . ( c . f . ) Merch. v o l . ( c . f . ) Net v o l . ( c . f . ) 20.40 98.35 267.43 111.75 90.57 83.64 7.6 41.0 125.0 5, 5, 3, .4 .4 .9 55.1 178.0 512.0 912.0 519.9 510.6 8.58 31.60 66.64 123.41 96.50 92.41 258 258 258 258 258 258 F i r s t decay column Low height ( f e e t ) 12.40 High height ( f e e t ) 46.78 Ht. of max. d i a . ( f e e t ) 22.45 Max. d i a . (inches) 9.87 1.0 2.0 1.0 1.0 70.0 160.0 81.0 35.0 15.77 30.32 19.40 6.87 209 209 209 209 Second decay column Low height ( f e e t ) 44.04 High height ( f e e t ) 65.87 Ht. of max. d i a . ( f e e t ) 53.04 Max. d i a . (inches) 6.02 8.0 16.0 13.0 1.0 124.0 148.0 130.0 21.0 28.64 29.62 28.20 4.31 45 45 45 45 — J u> 7 4 Photograph IV, Sporophores of Echinodontiutn t i n c t o r i t n a on western hemlock f e l l e d for decay measurement. 75 Table 30. Frequencies and r e l a t i v e frequencies of occurrence of numbers of trees having v a r y i n g numbers of e x t e r n a l a b n o r m a l i t i e s . Number of abn o r m a l i t i e s 272 decayed trees 97 sound tre e s Number Per cent Number Per cent 0 63 23.2 48 49.5 1 63 23.2 33 34.0 2 49 18.0 12 12.4 3 38 13.9 3 3.1 4 25 9.2 1 1.0 5 14 5.1 0 0.0 6 6 2.2 7. 7 2.6 • 8+ 7 2.6 of no value as decay i n d i c a t o r s - they occur more o f t e n on sound trees than on decayed t r e e s . - Table 33, 34 and 35 show f o r a l l t r e e s , sound trees and decayed trees r e s p e c t i v e l y , the frequency of occurrence of each e x t e r n a l abnormality, the maximum and minimum heights w i t h i n which i t occurred and the average height above the ground a t which i t occurred C o r r e l a t i o n c o e f f i c i e n t s between height of abnormality and l o c a t i o n of decay column as defined by maximum, minimum and average height were .170, .295 and .232 r e s p e c t i v e l y . Although s t a t i s t i c a l l y s i g n i f i c a n t , such low values i n d i c a t e a poor a s s o c i a t i o n between p o s i t i o n of e x t e r n a l a b n o r m a l i t i e s and decay columns w i t h i n t r e e stems. Generally, conks occurred most of t e n near the top p o r t i o n of the f i r s t butt l o g , small scars and f r o s t cracks occurred nearer to the ground and l a r g e r scars and other defects were most prevalent i n the centre p o r t i o n s of the bole . The occurrence of each abnormality s i n g l y and i n combination •with every other abnormality i s summarized f o r sound tr e e s i n t a b l e 36 and f o r decayed trees i n t a b l e 37. Examination of these t a b l e s r e v e a l s 'that n e a r l y any i n d i c a t o r can be a s s o c i a t e d w i t h any other, and, as 76 Table 31. Frequencies and r e l a t i v e . f r e q u e n c i e s of occurence of e x t e r n a l a b n o r m a l i t i e s and as s o c i a t e d decay i n 369 western hemlock t r e e s . E x t e r n a l Code L i v i n g trees A f f e c t e d trees A f f e c t e d t r e e s abnormality No. a f f e c t e d V7ith decay w i t h decay i n a s s o c i a t i o n w i t h abnormality No. No. I 'er cent No Per cent Echinodontium conks 1 27 27 100.0 27 100.0 Fomes conks 2 33 33 10070 33 100.0 " B l i n d " conks 3 17 17 100.0 17 100.0 "Other" conks 4 4 4 • 100.0 4 100.0 Small open scars 5 47 42 89.4 13 27.6 Med. open scars 6 7 6 85.7 3 42.8 Large open scars 7 7 7 100.0 3 42.8 Small closed scars 8 50 41 82.0 5 10.0 Med. closed scars 9 14 12 85'. 7 4 28.5 Large closed scars 10 8 8 100.0 2 25.0 Small f r o s t cracks 11 92 80 86.9 9 9.7 Med. f r o s t cracks 12 39 34 87.2 2 5.1 Large f r o s t cracks 13 19 17 89.5 5 26.3 M i s t l e t o e 14 5 4 80.0 1 20.0 Rotten branches 15 8 8 100.0 1 12.5 Dead or broken tops 16 42 33 78.6 6 14.2 Forks (small) 17 12 8 66.7 2 16.6 Crooks 18 55 45 81.8 17 30.9 Other 19 1 1 100.0 1 100.0 E x t e r n a l No. Entrance Courts Average Decay abn o r m a l i t i e s a b n o r m a l i t i e s a s s o c i ated w i t h ob served entrance > courts No. Per cent cu. f t . Per cent of of No. of grQss tre e vo ab n o r m a l i t i e s Echinodontium conks 44 - - - -Fomes cOnks 91 - - -• Scars 176 21 11.9 31.5 24.3 F r o s t cracks 183 5 2.7 1.8 3.6 M i s t l e t o e 5 1 20.0 1.6 1.4 Rotten branches 10 1 10.0 24.9 31.2 Dead tops 42 6 14.2 1.7 8.0 Forks 12 1 8.3 0.3 0.0 Crooks 59 13 22.0 6.9 15.8 77 Table 32. D i s t r i b u t i o n , of trees w i t h various e x t e r n a l a b n o r m a l i t i e s . E x t e r n a l abnormality Code No. 97 sound trees 272 decayed tr< No. Per cent No. Per cen Echinodontium conks 1 0 0 27 9.92 Fomes conks 2 0 0 33 12.13 " B l i n d " conks 3 0 0 17 6.25 "Other" conks 4 0 0 4 1.47 Small open scars 5 5 5.15 42 15.44 Med. open scars 6 1 1.03 6 2.20 Large open scars 7 0 0 7 2.57 Small closed scars 8 9 9.27 41 15.07 Med. closed scars 9 2 2.06 12 4.41 Large closed scars 10 0 o 8 2.94 Small f r o s t cracks 11 12 12.37 80 29.41 Med. f r o s t cracks 12 ' 5 5.15 34 12.50 Large f r o s t cracks 13 2 2.06 17 6.25 M i s t l e t o e 14 1 1.03 4 1.47 Rotten branches 15 0 0 8 2.94 Dead or broken tops 16 9 9.27 33 12.13 Forks (small) 17 4 4.12 8 2.94 Crooks 18 10 10.30 45 16.54 Other 19 0 0 1 0.36 78 Table 33. Frequency of occurrence and maximum, minimum and average heights of e x t e r n a l a b n o r m a l i t i e s i n 369 western hemlock t r e e s . E x t e r n a l abnormality Code No. Frequency Max. h t . Min. h t . Avg. h t . "Echinodontium conks 1 44 65 4 34.7 Fomes conks 2 91 75 7 30.2 " B l i n d " conks 3 29 51 3 21.6 "Other" conks 4 4 52 •11 35.5 Small open scars 5 61 .. 94 1 26.0 Med. open scars 6 9 59 3 21.1 Large open scars 7 7 79 2 36.4 Small closed scars 8 71 134 i i 18.4 Med. closed scars 9 ' 19 34 2 8.6 l a r g e closed scars 10 9 44 3 10.4 Small f r o s t cracks 11 122 66 1 4.6 Med. f r o s t cracks 12 41 72 3 12.1 Large f r o s t cracks 13 20 78 6 21.0 M i s t l e t o e 14 5 - 3 7 19 27.4 Rotten branches 15 10 113 11 45.5 Dead or broken tops 16 42 - -Forks (small) 17 12 107 2 47.3 Crooks 18 59 133 1 48.5 Other 19 1 - - -79 Table 34. Frequency of occurrence and1 maximum, minimum and average heights of e x t e r n a l a b n o r m a l i t i e s i n 97 sound western hemlock t r e e s . E x t e r n a l Code „ , , „ ' Frequency Max. h t . Mm. h t . Avg. ht. abnormality No. • Echinodontium conks 1 0 - - -Fomes conks 2 0 - -" B l i n d " conks 3 0 - - -"Other" conks 4 0 - - -Small open scars 5 6 47 3 11.8 Med. open scars 6 1 21 21 21.0. Large open scars 7 0 - - -Small closed scars 8 11 50 3 14.4 Med. closed scars 9 4 9 3 5.0 Large closed scars 10 0 -' - -Small f r o s t cracks 11 16 7 1 2.8 Med. f r o s t cracks 12 5 16 4 6.6 Large f r o s t cracks 13 2 25 10 17.5 M i s t l e t o e 14 1 19 19 19.0 Rotten branches 15 0 - - -Dead or broken tops 16 9 - - - . Forks (small) 17 4 58 4 41.3 Crooks 18 11 99 2 40.0 Other 19 0 - - -80 Table 35. Frequency of occurrence and'maximum, minimum and average heights of e x t e r n a l a b n o r m a l i t i e s i n . 272 decayed western hemlock t r e e s . E x t e r n a l abnormality Code No. Frequency Max. h t . Min. h t . Avg. h t. Echinodontium conks 1 44 65 4 , 34.7 Fomes conks 2 91 75 7 30.2 " B l i n d " conks 3 29 51 3 , 21.6 "Other" conks 4 4 52 11 35.5 Small open scars 5 55 94 1 27.6 Med. open scars 6 8 59 3 21.1 l a r g e open scars 7 7 79 2 36.4 Small closed scars 8 . 60 134 1 19.2 Med. closed scars 9 15 34 2 ' 9.5 Large closed scars 10 9 44 3 10.4 Small f r o s t cracks 11 106 66 1 4.9 Med. f r o s t cracks 12 36 72 3 12.9 Large f r o s t cracks 13 18 78 6 21.4 M i s t l e t o e 14 4 "37 21 29.5 Rotten branches 15 10 113 11 45.5 Dead or broken tops 16 33 - - -Forks (small) 17 8 107 2 50.4 Grooks 18 48 133 1 50.5 Other 19 1 - -Table 36. The frequency of occurrence of e x t e r n a l a b n o r m a l i t i e s , s i n g l y and i n combination, on 97 sound western hemlock t r e e s . ^ To read t a b l e s e l e c t a column f o r an e x t e r n a l abnormality and read down to f i n d numbers of other e x t e r n a l a b n o r m a l i t i e s found i n combination. See Table 20 f o r key t o e x t e r n a l a bnormality codes. Table 37. The frequency of occurrence of e x t e r n a l a b n o r m a l i t i e s , s i n g l y and i n combination, on 272 decayed western hemlock t r e e s . 1 E x t e r n a l abnormality codes2 •• • > - • 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 No. of 2 ? 33 1 7 4 42 6 7 41 12 8 80 34 17 4 8 33 8 45 l \ . tr e e s • ; To read t a b l e s e l e c t a column f o r an e x t e r n a l abnormality and read down to f i n d numbers of other e x t e r n a l a b n o r m a l i t i e s found i n combination. See Table 20 f o r key to e x t e r n a l a b n o r m a l i t y codes. 83 would be expected, none are mutually e x c l u s i v e . For example, the most common a b n o r m a l i t i e s , s m all scars (Photograph V) and f r o s t cracks (Photograph VI) and crooks are found i n a s s o c i a t i o n w i t h almost every other abnormality t a b u l a t e d . The absence of a b n o r m a l i t i e s on sound tre e s i s i n marked c o n t r a s t to the abundance of a b n o r m a l i t i e s on t r e e s which are decayed. This p o i n t s out i n yet another manner the p o t e n t i a l usefulness of e x t e r n a l a b n o r m a l i t i e s as i n d i c a t o r s of decay. I t must be r e a l i z e d , however, that the trees which are decayed but do not have e x t e r n a l a b n o r m a l i t i e s are masked i n t h i s t a b u l a r p r e s e n t a t i o n . From t a b l e 23 p r e v i o u s l y discussed, i t can be seen that of 111 r e s i d u a l trees classed as having no a b n o r m a l i t i e s , 63 trees or more than h a l f a c t u a l l y had measurable decay volumes. The volume of decay a c t u a l l y a s s o c i a t e d w i t h a p a r t i c u l a r abnormality or group of a b n o r m a l i t i e s i s of great p r a c t i c a l s i g n i f i -cance (Table 31).. I f a method can.be found t o p r e d i c t the amount of decay a s s o c i a t e d w i t h important e x t e r n a l i n d i c a t o r s or groups of i n d i c a t o r s , then decay e s t i m a t i o n i n standing trees can be improved. Table 38 shows r e l a t i v e numbers of trees having more, than s p e c i f i e d decay volume percentages f o r r e s i d u a l and suspect t r e e s . The frequency w i t h which s p e c i f i e d decay volume percentages occur can be determined from t h i s t a b l e . For example, 72.1 per cent of r e s i d u a l t r e e s had l e s s than 5 per cent of gross volume decayed, whereas l e s s than 50 per cent of the suspect trees had less than 5 per cent of gross volume decayed. S i m i l a r l y , almost 95 per cent of r e s i d u a l t r e e s had l e s s than 20 per cent of gross volume decayed whereas only 78 per. cent of suspect t r e e s had l e s s than 20 per cent of gross volume decayed. Table 39 provides the same breakdown for- decay volume as S3 Photograph VI. Frost cracks do not i n d i c a t e s i g n i f i c a n t amounts of decay i n western hemlock. Table 38. Summary of r e l a t i v e numbers of trees w i t h v a r y i n g amounts, of decay by tree c l a s s . Percentage of trees having l e s s than Decay as per cent . ,° . , _ - , i n d i c a t e d amounts of decay of t o t a l tree volume ( c . f . ) " R e s i d u a l " trees "Suspect" trees 0 ". 47.7 22.5 5 72.1 48.4 10 80.2 ,60.5 15 91.0 -^ 66.3 20 94.6 72.9 25 98.2 77.9 30 99.1 82.9 35 99.1 87.2 40 99.1 91.9 45 100.0 94.6 50 100.0 97.3 55 100.0 98.1 60 100.0 « 99.6 65 100.0 99.6 70 100.0 100.0 Table 39. Summary of percentages of tre e s w i t h v a r y i n g .proportions of decay f o r various e x t e r n a l a b n o r m a l i t i e s . E x t e r n a l Percentages of tre e s having l e s s than the percentage abnormality of decay volume i n d i c a t e d by column number 0 5 10. 15 20 25 30 35 40 45 50 55 60 " 6-5 7 0 Echinodontium conks 0 .0 3 .7 14 .8 29 .6 51, .8 66 .7 70 .4 74 .1 81 .5 92 .6 100 .0 Fomes conks 0 .0 0 .0 3 .0 6 .1 12 .1 18 .2 39 .4 57 .6 72 .7 .78 .8 87 .8 90. 0 97 .0 97 .0 100. 0 " B l i n d " conks 0 .0 5 .9 5 .9 5 .9 5 .9 11 .8 23 .5 47 .0 64 .7 76 .5 82 .3 88. 2 94 .1 94 .1 100. 0 "Other" conks 0 .0 0 .0 -33 .3 33 .3 33 .3 66 .6 66 .6 66 .6 66 .6 100 .0 Small open scars 17 .0 51 .1 61 .7 70 .2 78 .7 80 .8 87 .2 87 .2 91 .5 93 •6 95 .7 95. 7 97 .8 97 .8 100. 0 Med. open scars 11 .1 22 .2 44 .4 55 A J L 66 .6 77 .7 77 .7 88 .9 100 .0 Large open scars 0 .0 28 .6 28 .6 28 .6. 57 .1 71 .4 71 .4 85 .7 85 .7 85 .7 85 .7 100. 0 Small closed scars 20 .0 60 .0 64 .0 72 .0 78 .0 82 .0. 88 .0 94 .0 94 .0 96 .0 98. 0 100 .0 Med. closed scars 7 .1 50 .0 64 .3 64 .3 71 .4 71 .4 78 .6 85 .7 100 .0 Large closed scars 0 .0 0 .0 37 .5 50 ,0 62 .5 62 .5 75 .0 75 .0 75 .0 75 .0 75 .0 100. 0 Small f r o s t cracks 17 .2 52 .7 62 .3 67 .7 70 10 77 .4 81 .7 87 .1 93 .5 96 .7 96 .7 98. 9 100 .0 Med. f r o s t cracks 12 .8 41 .0 53 .8 64 .1 69 .5 76 .9 79 .5 84 .6 87 .2 89 .7 89 .7 92. 3 97 .4 97 .4. .100. 0 Large f r o s t cracks 5 .5 33 .3 ^0 ,0 55 .5 61 .1 61 .1 66 .7 72 .2 77 .8 88 .9 94 .4 94. 4 100 .0 M i s t l e t o e 20 .0 £0,0 60 .0 80 .0 80 .0 100 .0 Rotten branches 0 .0 25 .0 37 .5 37 .5 .62 jJL 75 .0 75 .0. 75 .0 87 .2 87 .2 87 .2 87-. 2 87 .2 87 .2 100. 0 Dead or broken tops 26 .2 59 .5 61 .9 71 .4 76 .2 78 .5 80 .9 83 .3 . 85 .7 90 .4 92. 8 100 .0 Forks (small) 41 .7 50 .0 58 .3 58 .3 66 .6 91 .7 91 .7 91 .7 91 .7 91 .7 100 .0 Crooks 20 .0 56 t3_ 74 .5 81 .8 85 .4 87 .3 87 .3 89 .1 96 .3 98 .2 98 .2 98. 2 100 •0 Other a b n o r m a l i t i e s 0 .0 0 .0 100 .0 R e s i d u a l t r e e s 47 .7 72 .1 80 .2 91 .0 94 .6 98 .2 99 .1 99 .1 99 .1 99 . 1 100 .0 Suspect c l a s s 1 13 .2 37 .7 .56 .8 60 .0 69 .7 77 .7 80 .8 85 .1 90 .2. 90 .5 93 .9 97. 2 98 .7 99 .5 i o o . 0 Suspect c l a s s 2 0 .0 2 .4 14 .2 18 .7 25 .8 40 .8 50 .0 61 .3 71 .4 87 .0 92 .5 94. 6 97 .8 97 .8 100. 0 A l l trees 20 .3 37 .4 -50 _-5_ 56 .6 63 .3 72 .2 76 .6" 81 .8 87 9 92 .5 95 .4 97. 3 98 .8 99 .9 100. 0 See text f o r explanation of u n d e r l i n i n g . 88 Table 38, but i n d e t a i l f o r each e x t e r n a l abnormality. The p o s i t i o n of the underlined f i g u r e s i n Table 39 are u s e f u l i n a s s e s s i n g the impor-tance of a b n o r m a l i t i e s as i n d i c a t o r s of s p e c i f i e d amounts of decay. Each underlined f i g u r e i n d i c a t e s the column at which approximately 50 per cent of the trees w i l l have l e s s than the per cent decay i n d i c a t e d by the column i n which the u n d e r l i n i n g occurs. In the case of r e s i d u a l t r e e s , approximately h a l f have decay and h a l f have no decay. For trees w i t h E. t i n c t o r i u m conks, as many tre e s have l e s s than 20 per cent decay as have more than 20 per cent decay. From t h i s t a b l e i t i s apparent that conks, large open scars and r o t t e n branches are the e x t e r n a l a b n o r m a l i t i e s which are a s s o c i a t e d w i t h the l a r g e s t amounts of decay volume percentage. Figures 1 and 2 i l l u s t r a t e values from Tables 38 and 39 f o r s e v e r a l t r e e c l a s s e s and s e l e c t e d a b n o r m a l i t i e s . The large d i f -ferences i n decay volume percentages between r e s i d u a l trees and trees w i t h conks (suspect c l a s s "2") are c l e a r l y evident i n these f i g u r e s . The lower decay volume percentages a s s o c i a t e d w i t h dead or broken tops compared to trees w i t h conks are a l s o evident. Comparisons of a c t u a l percentage m e r c h a n t a b i l i t y and estimated percentage m e r c h a n t a b i l i t y as p r e d i c t e d f o r t h i s sample by the l o s s f a c t o r s prepared by the B r i t i s h Columbia Forest S e r v i c e f o r t h i s area ( B r i t i s h Columbia Forest S e r v i c e , 1966) are favourable f o r most tree c l a s s e s (Table 40). With the excep-t i o n of suspect c l a s s "2" i n t r e e c l a s s I I where d i f f e r e n c e between a c t u a l and estimated decay volume percentage i s 6 per cent and i n the smaller DBH c l a s s where the number of samples i s s m a l l , the agreement i s e x c e l l e n t . I t i s probable that suspect c l a s s "2" would a l s o be i n c l o s e r agreement had the sample been l a r g e r . From these i n i t i a l summaries i t i s apparent that c e r t a i n 89 Figure !'• Relat ive cumulat ive frequency of decay percentages in ind i v idua l western hemlock trees by B r i t i s h Co lumbia Forest Serv ice (1366) tree c lasses-Abnormality residual trees suspect class " ' " all classes suspect class "2" 20 30 40 Per cent of gross tres volume decayed 60 9 0 Figure 2- Re la t i ve cumulat ive f requency of decay percentages in i nd i v i dua l western hemlock trees with var ious types of external abnormal i t ies-0 10 20 30 40 50 60 Per cent of gross tree volume decayed 91 Table 40. Numbers of trees , a c t u a l percentac ;e m e r c h a n t a b i l i t y . and percentage m e r c h a n t a b i l i t y as p r e d i c t e d through B r i t i s h Columbia Forest S e r v i c e (1966) l o s s f a c t o r s f o r 369 western hemlock t r e e s . DBH l i m i t Tree c l a s s "0" Tree c l a s s I (inches) No. A c t u a l B.C.F.S. No. A c t u a l B.C.F.S. 7.1-9.0 8 96 . 9 8 5 95 99 9.1-11.0 12 94 97 5 90 99 11.1+ 349 83 83 101 95 93 Tree c l a s s IT. Suspect I I ^ I I Suspect "2" No. A c t u a l B.C.F.S. No. A c t u a l BoCoFoS. 7.1-9.0 3 98 96 9.1-11.0 5 99 96 2 86 70 11.1+ 182 88 86 66 65 59 e x t e r n a l a b n o r m a l i t i e s are p o t e n t i a l l y u s e f u l as i n d i c a t o r s of decay w i t h i n t r e e s . Some ab n o r m a l i t i e s such as. s m a l l scars and large f r o s t cracks are n e a r l y always a s s o c i a t e d w i t h decay, but the a c t u a l decay volume i s u s u a l l y s m a l l . On the other hand, other a b n o r m a l i t i e s such as conks, large open scars and dead tops are a s s o c i a t e d w i t h l a r g e r volumes of decay. In some insta n c e s , combinations of ab n o r m a l i t i e s are p o t e n t i a l decay i n d i c a t o r s . I t i s c l e a r that any technique developed to p r e d i c t decay volume must provide f o r the i n c o r p o r a t i o n of e x t e r n a l a b n o r m a l i t i e s , both s i n g l y and i n combination. One promising a n a l y t i c a l technique i s m u l t i p l e c o r r e l a t i o n and r e g r e s s i o n analyses. The f i r s t use of t h i s i n forest, pathology was by Hepting (1935) who r e l a t e d the 92 height of decay above f i r e scars i n M i s s i s s i p p i d e l t a hardwoods to a t o t a l of s i x independent v a r i a b l e s . 93 CHAPTER IV DEVELOPMENT OF TREE DECAY FACTORS S e l e c t i o n of Equation -Form The usefulness of tree decay f a c t o r s depends to a great extent upon t h e i r accuracy, p r e c i s i o n and ease of a p p l i c a t i o n . Tree decay f a c t o r s are commonly expressed e i t h e r i n u n i t s of cubic f e e t or per cent of gross tree, volume. Both of the above measures have advantages and disadvantages. The cubic foot has the advantage that i t i s the primary u n i t of i n t e r e s t and does not r e q u i r e t r a n s f o r -mation and decoding. The percentage u n i t must be decoded to cubic fee t before answers can be obtained regarding volumes of wood decayed. Mathematical manipulations c a r r i e d out w i t h percentage u n i t s o f t e n r e s u l t i n biased answers when decoded to n a t u r a l u n i t s . Percentage transformations a l s o may c o n t r i b u t e to a r t i f i c i a l l y high v a r i a t i o n , e s p e c i a l l y when the base u n i t i s small or approaches zero. Analyses c a r r i e d out w i t h the cubic foot u n i t and conclusions reached therefrom, however, may be d i f f i c u l t to apply to other samples i n s i m i l a r areas. V a r i a t i o n i n tree form, bark thickness and volume equations can be marked w i t h i n a narrow geographic range. Decay f a c t o r s developed on a cubic foot u n i t can be misle a d i n g and inaccurate because of' changes i n tree form and r e s u l t a n t changes i n gross tree volume from area to area. In many instances, decay l o s s f a c t o r s developed on a cubic foot b a s i s f o r one area could approach or even exceed gross t r e e volume f o r some trees i n other areas. Factors expressed as a percentage of gross t r e e volume are not subject to these 94 disadvantages and can be a p p l i e d w i t h Consistency to a wide range of form c l a s s e s . For the sake of t h i s f l e x i b i l i t y , i t was decided to develop tre e decay f a c t o r s on a percentage b a s i s and to attempt to minimize, i f p o s s i b l e , any biases which might be introduced as a r e s u l t of the percentage tr a n s f o r m a t i o n . In the p r e l i m i n a r y analyses, t r i a l s were d u p l i c a t e d f o r both cubic foot and percentage u n i t s f o r comparison purposes. Results and D i s c u s s i o n -The f i r s t step i n the a n a l y s i s was a c o r r e l a t i o n a n a l y s i s to determine which tre e v a r i a b l e s were c o r r e l a t e d w i t h decay volume and decay volume percentage (Table 41). V a r i a b l e s most h i g h l y c o r r e l a t e d w i t h per cent decay were DBH, height, age, presence or absence of conks, gross t r e e volume i n cubic feet and the combined v a r i a b l e DBH squared times t o t a l height. Grouping of s i m i l a r s i n g l e v a r i a b l e s , s p e c i f i c a l l y i n the cases of conks and f r o s t cracks, r e s u l t e d i n higher simple c o r r e l a t i o n c o e f f i c i e n t s . S i t e index of each t r e e was not s i g n i f i c a n t l y c o r r e l a t e d w i t h percentage decay volume and was only b a r e l y c o r r e l a t e d w i t h cubic foot decay' volume (Table 41). In view of the accounts i n the l i t e r a -t ure of the r e l a t i o n s h i p of decay to s i t e index, p a r t i c u l a r l y f o r E_. t i n e t o r ium, f u r t h e r analyses were deemed necessary.. Average heights and ages for a l l dominant and codominant hemlock tr e e s on each plot, were c a l c u l a t e d and s i t e index f o r each p l o t was i n t e r p o l a t e d to the nearest foot from s i t e index t a b l e s (Barnes, 1962). Per cent soundwood volume was p l o t t e d against s i t e index (Figure 3) f o r the e n t i r e sample. No trends between per cent m e r c h a n t a b i l i t y and s i t e 95 - / Table 41. Simple c o e f f i c i e n t s of c o r r e l a t i o n :for v a r i a b l e s " considered f o r use i n development of tree decay f a c t o r s . V a r i a b l e Decay ' volume  ( c . f . ) (per cent) simple c o r r e l a t i o n c o e f f i c i e n t s ( r ) DBH (inches) 2 ,654 .399 T o t a l height (f e e t ) .491 .278 Age (yrs.) .402 .343 S i t e index ( f t . ) - . 105 -.059 Gross v o l . ( c . f . ) .719 .364 Merch. v o l . ( c . f . ) ,478 .159 Echinodontium conks ~ .059 .259 Fomes conks .360 .539 " B l i n d " conks .261 .421 "Other" conks . 115 .092 Small open scars .036 .053 Medium open scars ..106 .056 Large open scars .219 .102 Small c l o s e d scars .127 .069 Med. c l o s e d scars .085 .036 Large c l o s e d scars .286 .123 96 Table 41. (cont'd). Simple c o e f f i c i e n t s of c o r r e l a t i o n f o r v a r i a b l e s considered f o r use i n development of tree decay f a c t o r s . V a r i a b l e Decay vo lume  ( c . f . ) (per cent) simple c o r r e l a t i o n c o e f f i c i e n t s ( r ) Small f r o s t cracks .132 .084 Medium f r o s t cracks .056 .125 Large f r o s t cracks .118 .142 M i s t l e t o e .032 - .018 Rotten branches .087 .118 Dead or broken tops .025 .117 Forks -.015 .027 Crooks - .051 -.040 Other .011 - .012 2 (DBH) ( T o t a l tree height) .714 .347 A l l conks .362 .649 Med. + large f r o s t cracks .078 .137 e x t e r n a l a b n o r m a l i t i e s assigned value of "1" i f present, "0" if absent. " r " values l a r g e r than 0.100 are s t a t i s t i c a l l y s i g n i f i c a n t at p.05 Figure 3- Scat ter d i ag ram showing per cent merchantabi l ity and site index for 14 sample locations-100 X X 90 ~ 80 70 X 140 Site Index ' Site index after Barnes (1962)-98 index could be discovered. Even i n the m u l t i p l e r e g r e s s i o n analyses, where s i t e could have been s i g n i f i c a n t a f t e r the i n t e r a c t i o n s and e f f e c t s of age and tree s i z e had been removed, i t was u s u a l l y among the f i r s t group of v a r i a b l e s to be e l i m i n a t e d . There i s l i t t l e doubt that f o r t h i s sample there i s no s i g n i f i c a n t r e l a t i o n s h i p between percentage decay and s i t e index. Regression analyses were used to assess a l l e x t e r n a l abnormal-i t i e s and to s i n g l e out those which could prove u s e f u l i n t r e e decay-f u n c t i o n s . A l l v a r i a b l e s w i t h s t a t i s t i c a l l y s i g n i f i c a n t simple c o r r e l -a t i o n c o e f f i c i e n t s were analysed w i t h a stepwise m u l t i p l e l i n e a r regres-s i o n program (Kozak, and Smith, 1965) to obta i n v a r i o u s e s t i m a t i n g equations f o r tree decay volume percentages (Table 42). S t a t i s t i c a l l y , the "best" equation incorporated ten e x t e r n a l a b n o r m a l i t i e s and t r e e parameters and accounted f o r 57.9 per cent of the t o t a l v a r i a b i l i t y i n decay volume percentage. The standard e r r o r of estimate was 9.46 per cent. S i m i l a r p r e l i m i n a r y r e g r e s s i o n equations f o r the e s t i m a t i o n of cubic foot volume of decay are presented i n Table 43. The "best" of these equations accounted f o r 68.6 per cent of the v a r i a b i l i t y i n decay volume i n cubic f e e t and had a standard e r r o r of 21.72 cubic f e e t . A l l of the v a r i a b l e s i n equations presented i n Tables 42 and 43 are s t a t i s t i c a l l y s i g n i f i c a n t . The choice of p r e d i c t i n g equation f o r use must be made on the b a s i s of p r a c t i c a b i l i t y , p r e c i s i o n and accuracy d e s i r e d . Even though more v a r i a b i l i t y i n decay volume was accounted f o r by the use of the cubic foot e s t i m a t i n g f u n c t i o n r a t h e r than by the percentage e s t i m a t i n g f u n c t i o n , subsequent analyses showed that the standard e r r o r s , when r e c a l c u l a t e d as a percentage and decoded, were a c t u a l l y l e s s f o r the percentage e s t i m a t i n g equations than the cubic Table 42. Some p r e l i m i n a r y r e g r e s s i o n equations and s t a t i s t i c s f o r use i n the e s t i m a t i o n of per cent decay volume i n i n d i v i d u a l trees w i t h 1 to 10 independent v a r i a b l e s . 1 . Regression c o e f f i c i e n t s V a r i a b l e Constant term 7.963 6.593 -3.157 -3.179 -4.131 -3.912 -16.43 -17.8.1 -13.23 -14.35 Fomes conks 27 .12 28.49 25.19 20.56 20.70 21.02 21.27 2\.22 21.15 21.24 Echinodontium conks 17.05 17.14 17 .53 17.10 17 .38 17.23 17.22 16.71 16.55 DR1-I (inches) .5264 .5068 .5261 .5033 .5848 .5785 .9130 ,9019 "Blind." conks 16.97 16.41 16.61 16.31 16.03 16.33 15.99 Dead or broken tops 5.516 5.102 5.081 5.089 4.507 4.689 Large open scars 10.82 11.09 10.06 9.493 8.628 S i t e index ( f t ) 3.970 4.441 4.168 4.561 Large f r o s t cracks 4.744 5.057 5 .522 T o t a l height ( f t ) -.1068 -.1057 Rotten branches 6.710 C o e f f i c i e n t of determination (R) .291 .386 .469 .522 .536 .547 .558 .563 .574 .579 Standard e r r o r of estimate, °L 12.1 11.3 10.5 10.0 9.86 9.76 9.65 9.23 9.49 9.46 a l l v a r i a b l e s are s t a t i s t i c a l l y s i g n i f i c a n t at p.05, re g a r d l e s s of the combinations i n which they are used; e x t e r n a l a b n o r m a l i t i e s assigned value of "1" i f present, "0" i f absent. Table 43. Some p r e l i m i n a r y r e g r e s s i o n equations and s t a t i s t i c s f o r use i n the e s t i m a t i o n of cubic f o o t volume of decay i n i n d i v i d u a l trees w i t h 1 to 9 independent v a r i a b l e s . 1 Regression c o e f f i c i e n t s V a r i a b l e Constant term -6.304 -7.781 -3.374 5.237 3.279 6.028 7 .109 7 .042 -13.96 (D.2,H) /100 .0438 .0411 .0375 .0594 .0573 .0579 .0580 .0589 .0599 Fomes conks 31.56 31.28 33.94 34.90 29.03 29.71 29.35 29.91 Age (yrs.) . 1048 .1144 .1136 : .1049 .0930 .0872 .0644 T o t a l height ( f t . ) - .5576 - .5308 -.5435 - .5329 - .5137 - .4752 Large open scars 31.38 31.85 32.93 31.60 32 .71 " B l i n d " conks 21.45 22.36 22.so: 22.77 Echinodontium conks 12.26 ; 12.09 13.18 Med. c l o s e d scars -15 .31 -14.03 S i t e index ( f t . ) 8.208 C o e f f i c i e n t of determination (R2) .510 .563 .590 . 644 .657 .668 .675 .680 ; .686 Standard e r r o r of estimate, c . f . 26.84 25.36 24.62 22.94 22.58 22.23 22,04 21.89 21.72. a l l v a r i a b l e s are s t a t i s t i c a l l y s i g n i f i c a n t a t p.05, regardless of the combinations in. which they are used; e x t e r n a l a b n o r m a l i t i e s assigned value of "1" i f present; "0" i f absent. 10 foot e s t i m a t i n g equations. In n e a r l y a l l p r e l i m i n a r y equations t e s t e d , the independent v a r i a b l e s used i n the equations tabulated i n Table 44 were s t a t i s t i c a l ! ; s i g n i f i c a n t . The "best" of these equations accounted f o r 52.6 per cent of the v a r i a t i o n i n decay volume percentage w i t h i n i n d i v i d u a l t r e e s and had a standard e r r o r of estimate of 9.95 per cent. This p r e d i c t i n g equation was tested by e s t i m a t i n g the volume of decay i n the 369 trees used f o r the study sample. The decay volume w i t h i n each tre e was e s t i -mated by means of the equation, u s i n g as independent v a r i a b l e s DBH i n inches, the presence (1) or absence (0) of conks, large open scars (Photograph VII) and dead or broken tops (Photographs V I I I and I X ) . A d i r e c t estimate of the standard e r r o r of estimate of decay volume i n cubic f e e t w i t h i n i n d i v i d u a l t r e e s was obtained by s o l v i n g the formula SE = l / ( a c t u a l decay volume - e s t , decay volume)^ V n - r - 1 Table 45 shows* the r e s u l t s of the comparisons of a c t u a l and estimated decay volumes. These show that the equation i s p r a c t i c a l l y unbiased and has a standard e r r o r of estimate of 18.66 cubic f e e t which i s l e s s than the standard e r r o r of 21.72 cubic f e e t f o r the "best" p r e d i c t i n g equation using cubic foot u n i t s r a t h e r than percentage u n i t s . Table 46 i s a t a b u l a t i o n of t h i s p r e d i c t i n g equation f o r two-inch DBH c l a s s e s from 8 to 50 inches f o r a l l p o s s i b l e combinations of the independent v a r i a b l e s s e l e c t e d . Conclusion Analyses of m u l t i p l e c o r r e l a t i o n and r e g r e s s i o n show that the Table 44. Some r e g r e s s i o n equations and s t a t i s t i c s f o r use i n the e s t i m a t i o n of per cent decay volume i n i n d i v i d u a l trees w i t h v a r i o u s groups and combinations of e x t e r n a l a b n o r m a l i t i e s . Equation numbers and r e g r e s s i o n c o e f f i c i e n t s V a r i a b l e 1 2 3 ' 4 Constant term 5.998 -3.452 -3.295 -4.136 A l l conks 24.18 22.19 22.56 22.26 DBH (inches) .5245 .4908 .5111 Large open scars 11.97 10.98 Dead or broken top 4.643 C o e f f i c i e n t of determination (R^) .422 .503 .516 .526 Standard e r r o r of 10.9 10.2 10.0 9.95 estimate, % a l l v a r i a b l e s are s t a t i s t i c a l l y s i g n i f i c a n t at p.05, r e g a r d l e s s of the combinations i n which they are used; e x t e r n a l a b n o r m a l i t i e s assigned value of "1" i f present; "0" i f absent. Photograph V I I , Large open scars indicate? s i g n i f i c a n t amounts decay i n western h e t o l o c k . . 104 9 105 Photograph IX. Dead tops i n d i c a t e s i g n i f i c a n t amounts of decay i n western hemlock. 106 Table 45. T r i a l r e s u l t s f o r s e l e c t e d equation used to p r e d i c t decay volume i n i n d i v i d u a l t r e e s . V a r i a b l e Value No. of t r e e s 369 T o t a l a c t u a l decay volume 5802.6 cubic f e e t T o t a l estimated decay volume 5817.5 cubic f e e t T o t a l b i a s (absolute) 14.9 cubic f e e t T o t a l b i a s ( r e l a t i v e ) 0.25 per cent Average b i a s per t r e e 0.04 cubic feet Standard e r r o r of estimate of 18.66 cubic f e e t decay volume i n i n d i v i d u a l trees (19.5 per cent) decay volume i n standing western hemlock trees.can be r e l i a b l y estimated from DBH and the presence of absence of c e r t a i n e x t e r n a l a b n o r m a l i t i e s which i n d i c a t e decay. Conks, large open scars and dead or broken tops are the most important e x t e r n a l i n d i c a t o r s of decay. An equation which includes DBH and the above a b n o r m a l i t i e s as independent v a r i a b l e s , permits the e s t i m a t i o n of decay volume i n i n d i v i d u a l western hemlock trees w i t h a standard e r r o r of estimate of 18.66 cubic f e e t or 19.5 per cent. Table 46. Estimated decay volume expressed as a percentage of t o t a l t r e e volume by DBH c l a s s e s f o r s e v e r a l e x t e r n a l abnormality groupings.1 E x t e r n a l a b n o r m a l i t i e s DBH (inches) n i l 1 2 3 1+2 1+3 2+3 1+2+3 Decay volume as per cent of gross tree volume 8 0.0 22.2 10.9 4.6 33.2 26. ,8 15.6 37.8 10 1.0 23.2 11.9 5.6 34.2 27. ,9 16.6 • 38.8 12 2.0 24.3 13.0 6.6 35.2 28. . 9 17.6 .: 39.9 14 3.0 25 .3 14.0 7 .6 36.2 29. ,9 18.6 40.9 16 4.0 26.3 15.0 8.7 37 .3 30. ,9 19.7 41.9 18 5.1 27 .3 16.0 9.7 38.3 32. ,0 20.7 42.9 20 6.1 28.3 17.0 10.7 39.3 33. ,0 21.7 44.0 22 7.1 29.4. 18.1 11.7 40.3 34. ,0 22.7 45 .0 24 8.1 30.4 19.1 12.8 41.4 35. ,0 23.7 46.0 26 9.2 31.4 20.1 13.8 42.4 36. 0 24.8 47.0 28 10.2 32.4 21.1 14.8 43.4 '••37. 1 25.8 48.0 30 11.2 33.4 22.2 15 .8 44.4 38. .1 26.8 49.1 32 12.2 34,5 :. 23.2 16.9 45 .4 39. ,1 27.8 • • 50.1 34 13.2 35.5 24.2 17 .9 46.5 40. ,1 . 28.8. 51.1 36 14.3 36.5 25.2 18.9 47.5 41. ,2 29.9 52.1 38 15.3 37 .5 26.3 19.9 . 48.5 42. ,2 30.9 53.2 40 16.3 38.6 27 .3 20.9 49.5 43. ,2 31.9 54.2, 42 17 .3 39,6 28.3 22.0 50.6 44. .2 32.9 55.2 44 18.4 40.6 29.3 23.0 51.6 45. ,2 34.0 56.2 46 19.4 41.6 30.3 24.0 52.6 46. ,3 35.0 .57 .2 48 20.4 42.6 31.4 25.0 53.6 47. ,3 36.0 58.3 50 21.4 43.7 32.4 26.1 54.6 48. ,3 37 .0 59.3 Decay volume percentage = -4.136 + .511DBH + 22.258C + 10.976LOS + 4.643T. 2 "1" i s conks ( 0 ) , " 2 m i s large open scars (LOS), "3" i s dead or broken tops (T) 108 CHAPTER V DEVELOPMENT OF LOG POSITION DECAY FACTORS S e l e c t i o n of Equation Form Examination of the p o s i t i o n of- the decay columns w i t h i n the trees showed that f o r a l l decayed trees the average column of- decay was s i t u a t e d i n the middle p o r t i o n of the trunk. Decay d i d not extend downwards to the ground l e v e l or upwards t o the poin t of m e r c h a n t a b i l i t y which, f o r t h i s study, was deemed to be a 4-inch top diameter i n s i d e bark. Table 26 shows that the average decay column began at 14.9 f e e t , reached maximum diameter at 25.1 feet and extended to a t o t a l height of .46.9 feet above ground l e v e l . The maximum diameter f o r t h i s average column was 8.9 inches. Of the 272 trees which were decayed, a t o t a l of 48 or 17 per cent had a second but much smaller decay column above the primary column. T*he l o c a t i o n of the main decay column suggests that logs i n various p o s i t i o n s w i t h i n the t r e e would not have the same decay volume or decay volume percentage. From the average l o c a t i o n of the r o t columns i t can be expected that logs i n the mid-section of the tree are the most d e f e c t i v e , w h i l e butt logs and top logs are r e l a t i v e l y l e s s decayed. A n a l y s i s of the i n d i v i d u a l 16-foot cut se c t i o n s showed t h i s to be the case (Table 47). Decay percentage increased from the butt logs to the t h i r d l o g , decreased from the f o u r t h to seventh l o g and then increased s l i g h t l y to the tree t i p . The t h i r d l og i n the tree was the most d e f e c t i v e averaging 21.4 per cent decay. However, the second l o g contained the l a r g e s t cubic foot volume of decay. Attempts were made to develop an a n a l y t i c a l technique that Table 47. Summary of basic, data by l o g p o s i t i o n f o r 369 western hemlock t r e e s . Log p o s i t i o n (numbered from ground) V a r i a b l e 1 2 3 . 4 5 6 7 8 9 10 11 • •" • . • • — • » • »y . . . . . , . Diameter ( i n s i d e 15.3 13.5 11.4 9.7 9.6 8.8 7.1 5.9 5.5 4.4 4.0 bark ( i n c h e s ) . Height 16.3 .31.6 47.0 61.0 75.5 91.9 107.8 123.9 141.0 157.3 171.0 above ground ( f t . ) Average gross 28.8 21.7 17.3 13.8 13.1 11.7 8.8 6.5 5.3 3.4 1.8 v o l . ( c . f . ) Average decay 4.1 4.3 3.7 2.5 1.6 1.0 0.6 0.5 0.8 0.6 0.0 v o l . ( c . f . ) Average decay 14C2 19 i 8 21'A 1811 12 j 2 11'. 7 6'.8 7 57 15.0 17; 6 00 v o l . (per cent of gross l o g v o l . ) Number of 369 369 361 316 212 140 96 54 20 7 1 logs 110 would y i e l d reasonable estimates of decay volumes f o r i n d i v i d u a l logs i n standing t r e e s , much i n the same manner that an equation was developed to estimate decay volume percentage i n the e n t i r e tree.' Phrased i n another• manner, attempts were made to r e d e f i n e the t r e e decay e s t i m a t i o n equation to permit the e s t i m a t i o n of decay volume f o r i n d i v i d u a l logs w i t h i n t r e e s . At f i r s t c o n s i d e r a t i o n , i t might seem l o g i c a l t o develop a f u n c t i o n to estimate l o g defect i n terms of the top diameter of the l o g . This i s not s u f f i c i e n t , however, because the p o s i t i o n of the log w i t h i n the t r e e i s an important c r i t e r i o n i n the determination of the amount of defect l i k e l y to be present i n any given l o g . A log w i t h a .small top diameter could o r i g i n a t e from the top of a large t r e e , the middle of a smaller t r e e or the butt of an even smaller t r e e . As pointed out e a r l i e r , each of the above p o s i t i o n s r e q u i r e s a separate decay l o s s f a c t o r . I t i s necessary, t h e r e f o r e , that any f u n c t i o n deve-loped must incorporate some measure of l o g p o s i t i o n as an independent v a r i a b l e . The manner i n which log p o s i t i o n i s i n d i c a t e d i s a l s o impor-t a n t . In order to provide maximum f l e x i b i l i t y , i t i s necessary that the equation be adaptable to provide estimates f o r logs of any given length. A measure which determines log p o s i t i o n r e l a t i v e to t o t a l height of the t r e e can be r e a d i l y used to provide such f l e x i b i l i t y . The simplest and probably most e f f i c i e n t expression i s h/H where"h'r i s height above ground of the top of a given log and "H" i s t o t a l tree h e i g h t . This f r a c t i o n can be used to s p e c i f y the exact p o s i t i o n of the top of a l o g i n any tree f o r which t o t a l height i s a v a i l a b l e . An a d d i t i o n a l measure needed to develop a p r e d i c t i n g equation i s the DBH of the t r e e . The hypothesis then can be s t a t e d that the I l l -defect percentage i n any log i s a f u n c t i o n of the t r e e DBH and log p o s i t i o n expressed as h/H. To t h i s must be added those e x t e r n a l i n d i c a t o r s which proved to be s i g n i f i c a n t i n the development of the tr e e decay f a c t o r s . U t i l i z a t i o n : o f the lo g p o s i t i o n i n d i c a t o r h/H permits the e s t i m a t i o n of percentage decay i n a tree to any given height. Results and D i s c u s s i o n M u l t i p l e c o r r e l a t i o n and r e g r e s s i o n analyses were used to consider those v a r i a b l e s which could be of.importance i n the e s t i m a t i o n of i n d i v i d u a l l og decay volume. Table 48 shows simple c o n - e l a t i o n c o e f f i c i e n t s obtained f o r s e v e r a l dependent and independent v a r i a b l e s . I n a d d i t i o n to s i g n i f i c a n t e x t e r n a l a b n o r m a l i t i e s , s e v e r a l t r a n s f o r -mations of h/H were included, some of which proved to be s t a t i s t i c a l l y s i g n i f i c a n t . P r e l i m i n a r y r e g r e s s i o n equations were developed from stepwise r e g r e s s i o n s o l u t i o n s u s i n g some of the s i g n i f i c a n t l y c o r r e l a t e d v a r i a b l e s (Table 49). Numerous other v a r i a b l e s , transformations and i n t e r a c t i o n s were considered i n a d d i t i o n to the ones presented i n Table 49, however, they were not s i g n i f i c a n t l y a s s o c i a t e d w i t h log p o s i t i o n decay. Table 50 shows a d d i t i o n a l r e g r e s s i o n equations based on grouped a b n o r m a l i t i e s plus s e v e r a l transformations of DBH and h/H which were included because of high simple c o r r e l a t i o n c o e f f i c i e n t s . S t a t i s t i c a l l y , the "best" p r e d i c t i n g equation i n Table 50 accounted f o r 51.8 per cent of the v a r i a b i l i t y of decay w i t h i n logs and had a standard e r r o r of 9.10 per cent. S e v e r a l of the equations i n Table 50 were used to estimate the decay volume w i t h i n the logs of the 369 sample trees i n the b a s i c data. Computer p r i n t o u t s of a c t u a l and estimated decay volume for each l o g were examined f o r accuracy and b i a s . Table 48. Simple c o e f f i c i e n t s of c o r r e l a t i o n f o r v a r i a b l e s considered f o r use i n development of l o g p o s i t i o n decay f a c t o r s . 2 V a r i a b l e X 1 X 2 X3 simple c o r r e l a t i o n c o e f f i c i e n t s (r) DBH (inches) .6113 .397 - .432 T o t a l height ( H ) ( f t . ) .452 .284 .322 Age (yrs.) .366 .321 -.324 S i t e index ( f t . ) -.074 . -.077 .099 Gross v o l . ( c . f . ) .674 .354 -.390 Merch. v o l . ( c . f . ) .430 .152 -.179 Echinodontium conks^ .032 .174 - .161 Fomes conks .347 .529 -.570 " B l i n d " conks .251 .408 - .442 "Other" conks - .013 - .007 .009 Small open scars .037 .091 - . 104 Medium open scars .122 .089 -.113 Large open scars .327 .120 -.128 Small c l o s e d scars .166 .100 -.106 Med. c l o s e d scars ,237 .074 -.086 Large c l o s e d scars .296 .108 - . 120 Table 48. cont'd. Simple c o e f f i c i e n t s of c o r r e l a t i o n f o r v a r i a b l e s / c o n s i d e r e d f o r use i n development of l o g p o s i t i o n decay f a c t o r s . V a r i a b l e x l x 2 x 3 Small f r o s t cracks s imp l e .118 c o r r e l a t i o n .079 c o e f f i c i e n t . -.086 Medium f r o s t cracks .015 .074 -.083 Large f r o s t cracks .117 .152 -.166 M i s t l e t o e -.042 -.025 .022 Rotten branches .054 .096 - . 109 Dead or broken tops • .006 .065 -.074 Forks -.044 - .021 .031 Crooks - .073 - .059 .060 Other .012 - .010 .000 Accum. gross v o l . ( c . f . ) .720 .420 -.357 Accum. merch v o l . ( c . f . ) .461 .203 -.143 Accum. height ( f t . ) .396 .356 --.189 Accum. h t . / t o t a l , h t . .161 .24-3 -.041 2 (Accum. h t . / t o t a l ht.) .165 .237 - .050 3 (Accum. h t . / t o t a l ht.) .168 .231 -.057 (DBH) 2 ( t o t a l ht.) .671 .339 -.372 A l l conks .337 .599 NA Med.+Large f r o s t cracks .043 .096 NA e x t e r n a l a b n o r m a l i t i e s assigned value of "1" i f present; "0" i f absent. Xj i s accumulated decay volume ( c . f . ) to a s p e c i f i e d height. X 2 i s accumulated decay volume as a percentage of gross tree volume, X3 i s accumulated merchantable volume as a percentage of gross tree volume. " r " values l a r g e r than 0.100 are s i g n i f i c a n t at p.05. :1 2 3 Table 49. Some p r e l i m i n a r y r e g r e s s i o n equations and s t a t i s t i c s f o r use i n e s t i m a t i o n of: per :cen decay volume to s p e c i f i e d heights (h) i n i n d i v i d u a l trees w i t h 1 t o 10 independent v a r i a b l e s . 1 Regression c o e f f i c i e n t s V a r i a b l e Constant term .6375 -.0497 -1.089 - 1.219 -5.177 .6783 .7288 .5949 .7429 -3.894 Fomes conks 21.91 20.48 21.36 17 .53 16.19 16.02 16.39 16.33 16.36 16.50 h . 1234 .1258 .1233 .0872 .1094 .1092 .1089 .1088 .1087 Echinodontium conks 12.38 17 .53 12.71 11.83 12.09 12.13 12.12 10.94 " B l i n d " conks 12.36 12.25 12.86 12.95 13.27 12.92 12.02 DBH (inches) .2824 .7577 .7057 .7052 .6972 0.622 T o t a l height ( f t . ) -.1648 - .1569 - .1526 - . 1618 . 1530 Large open scars 9.160 8.869 8.617 8.031 Small open scars 2.922 . 3';044 3.257 Large f r o s t cracks 4.125 4.276 Age (yrs.) .0207 C o e f f i c i e n t of determination (R 2) .280 .368 .422 .460 .488 .521 .531 .537 .543 .552 Standard e r r o r of estimate, %. 11.11 10.41 9.96 9.63 9.38 9.07 8.98 8.93 8.87 8.79 A l l v a r i a b l e s are s t a t i s t i c a l l y s i g n i f i c a n t at p.05, r e g a r d l e s s of the combinationsain which they are used; e x t e r n a l a b n o r m a l i t i e s assigned value of "1" i f present, "0" i f absent. Table 50. Some r e g r e s s i o n equations and s t a t i s t i c s f o r use i n e s t i m a t i o n of per cent decay volume to s p e c i f i e d heights (h) i n i n d i v i d u a l trees w i t h v a r i o u s groups and combinations of e x t e r n a l a b n o r m a l i t i e s . ^ Equation number and r e g r e s s i o n c o e f f i c i e n t s V a r i a b l e 1 2 3 4 5 6 7 8 Constant term 4.979 .5640 -5.626 -5.504 -5.840 -9.236 -9.383 -9.413 A l l conks 19.77 (DBH) 18.27 18.17 18.51 18.41 18.44 18.38 18.33 .0088 .0086 . .0079 .0081 .0084 .0083 .0083 h/H 12.29 12.27 12.18 28.60 28.73 28.79 Large open scars 8.948 8.743 8.733 8.610 8.264 Dead or broken tops (h/H) 2 2.813 2.906 2.881 2.845 -16.11 -16.25 -16 .32 Med. + large f r o s t 1.217 1.223 cracks Rotten branches 2.341 C o e f f i c i e n t s of • determination (R 2) .359 .;448 .499 .508 .513 .516 .517 .518 Standard e r r o r , % 10.5 9.73 9.27 9.19 9.15 9.12 9.11 9.10 a l l v a r i a b l e s are s t a t i s t i c a l l y s i g n i f i c a n t a t p.05, r e g a r d l e s s of the combinations i n which they are. used; e x t e r n a l a b n o r m a l i t i e s assigned value of "1" i f present; "0" i f absent. 116 A c t u a l standard e r r o r s of estimated log decay volume were obtained f o r each l o g p o s i t i o n by s o l u t i o n of the equation on page 101. Each e s t i -mating f u n c t i o n proved to be biased f o r c e r t a i n l o g p o s i t i o n s . The equation which combined best p r e c i s i o n w i t h l e a s t b i a s was equation No. 6 i n Table 50. ' This f u n c t i o n i s graphed f o r the 20-inch DBH c l a s s i n F i g ure .4 and tabulated f o r a l l . p o s s i b l e - a b n o r m a l i t y groupings by 2-inch DBH c l a s s e s from 8-50 inches and by lo g p o s i t i o n s from 10 to -100 per cent-of t o t a l t r e e height i n Appendix I . I f a wholly g r a p h i c a l procedure i s p r e f e r r e d , a c o r r e c t i o n f o r DBH other than 20 inches can be made using- Figure 4. P r e d i c t e d values from.the equation are compared w i t h a c t u a l values f o r each l o g p o s i t i o n i n Table 51. Standard e r r o r s of estimate which ranged from 13.7 cubic feet i n butt logs to 0.1 cubic feet i n top logs are a l s o given i n t h i s t a b l e . The equation has a r e l a t i v e l y large b i a s and low p r e c i s i o n i n the f i r s t 16-foot log i n the t r e e . Thereafter, however, b i a s i s much l e s s and p r e c i s i o n improves. Reasonable estimates of decay volume can be made w i t h t h i s equation f o r the f i r s t 32-foot l o g i n a tree but not f o r the f i r s t 16-foot l o g . Comparisons of decay percentages f o r lo g p o s i t i o n h/H equal to "1" (which are estimates of t o t a l decay percentage i n the t r e e ) , w i t h t o t a l decay percentages tabulated i n Table 46, are favorable (Appendix I I ) . Since these two estimates are derived from l e a s t squares procedures which were not conditioned to i d e n t i t y , t o t a l agreement cannot be expected. The most c o r r e c t values are those estimated from the t r e e decay equation ("A" group of Appendix I I , and Table 46). Therefore, Appendix II."revalues might be conditioned to i d e n t i t y w i t h Appendix I I "A"values. The f a c t that agreement i s c l o s e , however, i n d i c a t e s that both e s t i m a t i n g systems are mathematically s t a b l e and p o t e n t i a l l y Table 51. Summary of a c t u a l and estimated decay volumes by l o g p o s i t i o n w i t h i n t r e e s . Log p o s i t i o n (numbered from ground) V a r i a b l e 1 2 3 4 5 6 7 8 9 10 11 Top diameter i n s i d e bark 15.3 13.5 11.4 9.7 9.6 8.8 7 . 1 5.9 5.5 4.4 4. ,0 (inches) Log length ( f e e t ) 16.3 15.3 15.4 14.0 14.5 16.4 15. 9 16 .1 17 .1 16.3 13. ,7 Cumulative l o g length 16.3 31.6 47 .0 61.0 75.5 91.9 107 . 8 123.9 141.0 157 .3 171. ,0 ( f e e t ) Average gross v o l . / l o g 28.8 21.7 17 .3 13.8 13.1 11.7 8. 8 5.5 5.3 3.4 1. .8 ( c . f . ) Cumulative gross v o l . 28.8 50.5 67.8 81.6 94.7 106.4 115. 2 121.7 127.0 130.4 132. ,2 v.c . J- . ) Average decay v o l . / l o g 4.1 4.3 3.7 2.5 1.6 1.0 0. 6 0.5 0.8 0.6 0. ,0 ( c . f . ) Estimated decay v o l . / l o g 6.9 2.3 2.1 1.8 1.7 1.6 1. 2 . 0.8 0.6 0.2 0. ,0 ( c . f . ) Cumulative decay v o l . 4.1 8.4 12.1 14.6 16.2 17 .2 17 . 8 18.3 19.1 19.7 19. ,7 ( c . f . ) Estimated cumulative decay 6.9 9.2 11.3 13.1 14.9 16.5 17. 7 18.5 19.1 19.3 19. ,3 v o l . ( c . f . ) Average standard e r r o r of 13.7 8.2 7^2 5.3 4.1 3.5 2. 8 2.6 1.4 0.1 0. ,0 estimate of l o g v o l . . ( c . f . ) No. of logs 369 369 361 315 211 140 96 54 20 7 1 118 Figure 4- Relationship between estimated accumulated decay voiume percentage and relative height for 2 0 - i n c h DB-M-c lass trees for several external abnormal ity groupings with an adjustment for other D B H classes-35 f DBH to & CP CD 6 50 i o CJ c o ft) c o o o w. o u •o o o o D CO 40 30 -20 -10-h/H Estimated values obtained from equation No- 6, table 50-The first ordinate axis can be used to adjust for D B H classes other than 20 inches-119 u s e f u l as decay e s t i m a t i n g equations. Conclusion As would be expected i n t r e e s w i t h heart r o t caused by E. t i n c t o r i u m , logs from mid-height p o s i t i o n s were the most d e f e c t i v e . Analyses of m u l t i p l e c o r r e l a t i o n and r e g r e s s i o n show that the d i s t r i -b u t i o n of decay volume i n standing western hemlock trees can be e s t i -mated from a m u l t i p l e r e g r e s s i o n equation i n c o r p o r a t i n g as independent v a r i a b l e s t r e e DBH, t o t a l t r e e height, s p e c i f i e d merchantable height and the. presence or absence of the s i g n i f i c a n t decay i n d i c a t i n g e x t e r n a l a b n o r m a l i t i e s , conks, large open scars and dead or broken tops. Standard e r r o r s of estimate of decay volume ranged from 13.7 cubic feet i n butt logs to 0.1 cubic feet i n top logs. 120 CHAPTER VI DEVELOPMENT OF TAPER FUNCTION D e r i v a t i o n of Bas i c Function Attempts were made to de r i v e a mathematical f u n c t i o n which would permit the development of an equation to provide estimates of stem diameter i n s i d e bark at s p e c i f i e d heights i n terms of the t r e e parameters DBH and t o t a l h e i g h t. The f o l l o w i n g theory i s based on the assumption that t r e e form can be reasonably approximated by a quadratic p a r a b o l o i d although some, authors have stat e d otherwise (see page 5 1 ) . According to Newnham (1958)^ who studi e d the form and taper of western hemlock i n B r i t i s h Columbia, a quadratic p a r a b o l o i d i s a p p l i c a b l e to approximately 85 per cent of the t o t a l height of a t r e e . Only near the b u t t , which i s n e i l o i d , and the t i p , which i s c o n i c a l , does tree form d i f f e r s i g n i f i -c a n t l y from that of a quadratic p a r a b o l o i d I f a quadratic p a r a b o l o i d i s r o t a t e d on i t s c e n t r a l a x i s , the square of the diameter at any poi n t w i l l be p r o p o r t i o n a l to the d i s t a n c e from the point of diameter measurement to the poi n t of t r u n c a t i o n . Thus D 2 a H - 4.5 (1.1) where D i s DBH, H i s t o t a l tree height and denotes a l i n e a r r e l a t i o n -s h i p . S i m i l a r l y dob. 2 a H - 4.5 - L. (1.2) i i where dob. i s the diameter outside bark at point " i " and L. i s the 121 distance from the p o i n t of t r u n c a t i o n ( i . e . t r e e t i p ) to " i " . For convenience and p r a c t i c a b i l i t y i t i s b e t t e r to deal w i t h p o r t i o n s of t o t a l tree height r a t h e r than distances measured downward from the tree t i p . The r e l a t i o n s h i p dob. 2 a h. - 4.5 (1.3) J J where h. i s tree height measured from ground l e v e l to p o i n t " j " i s simply the inverse of formula 1.2. Formulae' 1.2 and 1.3 can be combined i n r a t i o form to 2 dob. h - 4.5 (1.4) _ a _ J D 2 H - 4.5 Formula 1.4 can be f u r t h e r s i m p l i f i e d to d 2 h. D 2 H on the b a s i s of the f o l l o w i n g assumptions: (a) except i n instances where h^ or H are s m a l l , the constant "4.5" can be e l i m i n a t e d without s i g n i f i c a n t l y changing the value of the r a t i o on the r i g h t hand side of formula 1.4. (b) diameter i n s i d e bark (d^) can be s u b s t i t u t e d for diameter outside bark (dob.) without s i g n i f i c a n t l y changing the value of the r a t i o on the l e f t hand side of formula 1.4. To s u b s t a n t i a t e the foregoing algebra and assumptions i t can be shown-that formula 1.5 i s a l i n e a r t r a n s f o r m a t i o n of a quadratic p a r a b o l o i d by rearranging the v a r i a b l e s to I—~ d. a D \ /h. ' (1.6) which i s of the quadratic form. 122 A f u n c t i o n of the form of formula 1.6 can be used to estimate diameters i n s i d e bark at s p e c i f i e d heights above the ground, w h i l e a simple transformation of formula 1.6 to h. a Hd 2/D 2 (1.7) f a c i l i t a t e s estimates of merchantable.heights f o r s p e c i f i e d upper stem diameters i n s i d e bark. Results and D i s c u s s i o n Attempts were made to f i t the curve form p o s t u l a t e d (formula 1.5, page 121) to the b a s i c data from the sample of 369 western hemlock trees and to t e s t the usefulness of the equation derived from both t h e o r e t i c a l and p r a c t i c a l viewpoints. Average diameters i n s i d e bark and heights f o r each s e c t i o n , together w i t h transformations and combinations are tabulated i n Table 52. C o r r e l a t i o n analyses were c a r r i e d out to determine to what 2 extent v a r i a b l e s other than h/H were a s s o c i a t e d w i t h (d/D) . The simple c o r r e l a t i o n c o e f f i c i e n t s d e rived are given i n Table 53.. As would be expected from the t h e o r e t i c a l d e r i v a t i o n , the v a r i a b l e most 2 h i g h l y c o r r e l a t e d w i t h (d/D) was h/H. This was followed c l o s e l y by exponentiation of h/H to the 1.5, 2nd and 3rd powers. Further exponen-t i a t i o n a l s o y i e l d e d s i g n i f i c a n t simple c o r r e l a t i o n c o e f f i c i e n t s , as di d some a r b i t r a r y combinations of v a r i a b l e s . P r e l i m i n a r y r e g r e s s i o n equations u t i l i z i n g a l l of these v a r i a b l e s , transformations and combinations were developed. Some equations were p l o t t e d and examined g r a p h i c a l l y f o r u s e f u l n e s s ; others were tested by computing estimated diameters i n s i d e bark and comparing them w i t h a c t u a l diameters for each s e c t i o n h e i g h t . Table 54 l i s t s 123 Table 52. Summary of average diameters i n s i d e bark (d) and heights (h) at va r i o u s cut se c t i o n s f o r 369 western hemlock t r e e s . No. of 0 obs. DBH ( i n . ) T o t a l height(H) ( f t . ) • h. . ( f t , ) d ( i n . ) (d/DBH)~ (h/H) 369 19.1 94.6 1.0 : 18.0 .8881 .0010 369 19.1 94.6 16.3 15.3 .6416 .1723 369 19.1 94.6 31.6 13.5 .4996 .3340 361 19.2 95.7 47.0 11.4" .3525 .4911 315 20.2 100.2 61.0 9.7 .2306 .6088 211 23.2 112.4 75.5 9.6 .17 12 .6726 140 26.8 124.5 91.9 8.8 .1078 .7331 96 28.6 134.2 107.8 7.1 .0616 .8033 54 31.8 144.9 123.9 5.9 .0344 .8551 20 35.4 158.8 141.0 5.5 .0241 .8879 7 39.6 172.0 157.3 4.4 .0123 .9145 1 55.1 178.0 171.0 4.0 .0053 .9607 124 .Table 53. Simple c o r r e l a t i o n c o e f f i c i e n t s f o r v a r i a b l e s considered f o r use i n development of a f u n c t i o n to estimate upper stem diameters(d)I. V a r i a b l e Upper stem diameter(d) (d/DBH)' DBH .519 1 - .067 T o t a l height(H) .472 -.049 Merch. height(h) -.533 -.855 h/H -.756 -.963 (h/H) 2 -.763 -.898 ( h / H ) 1 " 5 -.766 -.933 (h/H) 3 -.742 -.830 (h/H) 4 - .717 - .773 (h / K ) 5 -.692 - .727 (h/H) 1 0 -.610 - .595 ( h / H ) 1 5 -.573 -.542 ( h / H ) 2 0 - .555 -.518 ( h / H ) 1 ' 5 - ( h / H ) 2 0 ' -.274 - .538 (h/H) 1- 5-(h/H) 1 0 . -.239 -.513 (DBH)(H) -.510 - .059 DBH(H)(h/H) 1- 5-(h(H) 2 0) -.028 -.427 DBH(H)((h/H) 1- 5-(h/H) 1 0) .026 -.409 Hah/ID^-Oi/H) 2 0) -.161 -.514 ^ ( ( h A O ^ - a / H ) 2 0 ) -.065 -.444 (h/H) 1' 5-(h/H) 3 -.048 -.325 H((h/H) 1- 5-(h/H) 3) - .111 -.318 DBH ( ( h / H ) 1 - 5 - ( h / H ) 3 ) -.173 -.314 H 2 ( ( h / H ) 1 > 5 - ( h / H ) 3 ) .206 -.271 -1 J. :. " r " values l a r g e r than 0.100 are s i g n i f i c a n t at p.05 Table 54. Some p r e l i m i n a r y r e g r e s s i o n equations and s t a t i s t i c s f o r use i n e s t i m a t i o n of (d/DBH) 2 w i t h 1 to 9 independent v a r i a b l e s . 1 V a r i a b l e Regression c o e f f i c i e n t s Constant term .8253 .8561 .8715 .8830 .3959 .8983 .3807 .8862 .8824 h/H -.8875 -.8641 -1.114 -1.114--: -2.567 -2.830 -2.949 -3.216 -3.469 DBH((h/H) 1- 5-(h/H) 3) -.0160 -.0120 -.0148 - .0137 -.0281 . -.0329 -.0303 - .0418 ( h / H ) 1 ' 5 -.2378 1.527 4.201 5.375 5.871 6.626 7 .699 (h/H) 2 -.8090 -2.689 -3.685 -4.064 -4.627 -5.547 (h/H) 1 0 .1625 .2431 .2441 .4928 .0549 DBH(H)X (h/H) - ( h / H ) 1 U ) 383:io-3;' 384:10-A •'. 3 24.10 " 4 ; 178. DBH (inches) 20 ( h / H ) Z J DBH(H)((h/H) 1' 5-(h/H) 2 0) 949.10-3 .822.10" - .1779 4.113. - ."5415 -.110. C o e f f i c i e n t of d e t e r m i n a t i o n ( R 2 ) .928 . 944 .945 .947 , 948 ,949 .949 .949 .949 Standard e r r o r of estimate .0815 .0721 .0715 .0711 .0698 .0693 .0691 .0690 .0687 1 a l l v a r i a b l e s are s t a t i s t i c a l l y s i g n i f i c a n t a t p.05, re g a r d l e s s of the combinations i n which they are used. 126 equations developed from one such a n a l y s i s where a l l v a r i a b l e s included proved to be s t a t i s t i c a l l y s i g n i f i c a n t . , Comparisons of a c t u a l and estimated diameters f o r the simple 2 l i n e a r r e g r e s s i o n of (d/D) on h/H showed excessive bi a s and under-2 e s t i m a t i o n of diameters near tre e t i p s . The term (h/H) was added to the equation i n an attempt to remove t h i s b i a s . Although t h i s helped, i t d i d not completely e l i m i n a t e e s t i m a t i o n of zero or negative diameters near the top of t r e e s . Further m o d i f i c a t i o n s to the equation form were r e q u i r e d , the f i r s t being to a r t i f i c i a l l y r e s t r i c t the f u n c t i o n so that at 100 per cent of t o t a l t r e e height, zero diameter e s t i m a t i o n would be ensured. This was accomplished by f i t t i n g the data to the same equation form by l e a s t squares methods conditioned to s a t i s f y the above r e s t r i c -t i o n . C o n d i t i o n i n g c a l c u l a t i o n procedures followed were those recommended by Freese (1964). This c o n d i t i o n i n g e l i m i n a t e d zero and negative diameter e s t i m a t i o n , but u n f o r t u n a t e l y r e s u l t e d i n unacceptable p o s i t i v e b i a s i n t r e e diameters above 47 fee t i n height (see values from equation No. 1, Table 55). Subsequent unpublished t e s t s of t h i s equation form by Kozak and Smith (1967) f o r the commercial t r e e species of B r i t i s h Columbia showed t h a t , i n most cases, t h i s form was not biased. In view of the success of Kozak and Smith, and of the reasonable estimated diameters obtained f o r t h i s data from c o e f f i c i e n t s provided by them for western hemlock (see values from equation No. 2, Table 55), i t was assumed that computer programming e r r o r s were the source of the excessive b i a s . A f t e r attempts to discover programming e r r o r s proved f u t i l e , the stem a n a l y s i s sampling technique was examined and the reasons for bias became apparent. Data used by Kozak and Smith were c o l l e c t e d i n the d e c i l e Table 55. Comparisons of a c t u a l and estimated stem diameters i n s i d e bark at v a r i o u s tree heights f o r s e v e r a l e s t i m a t i n g equations. Average Average No. Equation numbers and average height a c t u a l d i a . of estimated diameters ( i n . ) ( f t . ) ( i n . ) obs. 1 2 3 4 1 I'..; 18.0 369 17.8 20.3 .17.8 17 .9 16.3 15.3 369 15.7 17.3 15.3 15.4 31.6 13.5 369 13.5 14.4 13.4 13.6 47 .0 11.4 361 11.4 11.6 11.2 11.4 61.0 9.7 315 10.1 9.9 9.6 9.8 75.5 9.6 211 10.3 9.9 9.4 9.5 9 it 9 8.8 140 10.3 9.4 9.7 8.9 107.8 7.1 96 9.3 8.2 7.2 7 .5 123.9 5.9 54 8.7 7.4 6.0 6.3 141.0 5.5 20 8.5 7 .0 5,3 5.4 157.3 4.4 7 8.3 6.6 4.6 3.3 171.0 4.0 1 7.7 5.8 3.4 -Weighted average standard e r r o r of 1.59 2.06 1.29 1.20 estimated diameters } d=DBHV 0.8812-1.283h/H+0.4018(h/H)2 2 d=DBHy 11152-2.057h/H+0.9046(h/H) see t a b l e 56, equation No.5. ;:see t a b l e 59. 128 system, where each tree was sectioned and measured i n ten equal p o r t i o n s above breast height, whereas data f o r t h i s study were c o l l e c t e d from s e c t i o n s of approximately 16-foot lengths. The f i x e d length sampling r e s u l t e d i n a l a r g e r number of observations at lower heights than at higher h e i g h t s . Table 52 shows that the number of s e c t i o n s and obser-v a t i o n s decreased from 369 i n the f i r s t three s e c t i o n s to 1 i n the l a s t s e c t i o n . In the d e c i l e sampling technique, an equal number of obser-v a t i o n s was obtained at each s e c t i o n and, i n the r e s u l t i n g analyses t h e r e f o r e , each s e c t i o n was accorded equal weight. In the f i x e d length sampling where the number of observations was l a r g e , the l e a s t squares s o l u t i o n provided a good curve f i t but as the number of observations d e c l i n e d , so d i d the goodness of f i t . In order to achieve comparable r e s u l t s w i t h the conditioned equation f o r data c o l l e c t e d on a f i x e d l ength format, weighting was necessary to a r t i f i c i a l l y make the number of observations equal at each p o i n t . This was accomplished by averaging the data values f o r each of the 13 s e c t i o n heights (Table 52). The conditioned equation f i t t e d to the data averages d i d not provide a s a t i s f a c t o r y curve f i t near the t r e e butts and to remedy t h i s , polynomial equations from the f i r s t to the f i f t h degree were f i t t e d (Table 56) and examined by comparison of a c t u a l and estimated values (Table 57). The f i f t h degree polynomial proved t o be the best f i t when graphed against the average data values (Figure 5 ) . Estimated diameters were c a l c u l a t e d from t h i s equation f o r each cut s e c t i o n i n each tr e e and the standard e r r o r of estimate of diameter i n s i d e bark i n inches was determined w i t h the formula on page 101. Average estimated diameters compared f a v o r a b l y w i t h average Figure 5- The relationship between (d/D) and h/H, showing a fifth degree polynomial ' curve fitted to average values of the basic data-Legend X average values OO 0-2 0-4 0-6 0-8 1-0 h /H 1 See table 56 for equation-130 Table 56. Regression polynomials 2 equations f o r e s t i m a t i o n of (d/DBH) f o r from degree one to f i v e . V a r i a b l e Regression c o e f f i c i e n t s f o r polynomials of degree 1 2 3 4 5 Constant term .81034 .88776 .87508 .88769 .89046 h/H -.88932 -1.37294 -1.14849 -1.77777 -2.23409 (h/H) 2 0.46073 -0.10388 3.01184 6.63776 (h/H) 3 0.36488 -4.49652 -14.18542 (h/H) 4 2.38232 12197729 (h/H) 5 -4.08533 a c t u a l diameters (see values from equation No. 3, Table 55) throughout the diameter range of the b a s i c data. The standard e r r o r of estimate, of 1.29 inches was lower than f o r previous equations. Further t e s t s f o r b i a s i n equation: No. 3 were made by d r v i d i n g the b a s i c data i n t o three DBH c l a s s groups and preparing separate estimates of s e c t i o n diameters f o r each group (Table 58). Residuals i n each group were l a r g e r than f o r the data as a whole and there was evidence of bia s according to tree s i z e as measured by DBH. A s l i g h t underestimation of diameter was noted f o r tr e e s l a r g e r than 22 inches DBH while s l i g h t overestimates were observed,for t r e e s between 14.1 and 22 inches DBH. Standard e r r o r s of estimated diameter were higher f o r the l a r g e s t DBH c l a s s group. The tendency to underestimate diameters- i n the l a r g e r tree s i z e s suggested that some i n t e r a c t i o n term i n v o l v i n g DBH and tre e height should be added to the e s t i m a t i n g equation to e l i m i n a t e b i a s a s s o c i a t e d 131 w i t h t r e e s i z e . Analyses by Bruce e_t a_l. (1967) of taper of red a l d e r i n d i c a t e d that i n t e r a c t i o n terms i n c o r p o r a t i n g DBH and height w i t h high ex p o n e n t i a t i o n removed b i a s a s s o c i a t e d w i t h DBH. T h e r e f o r e , v a r i a b l e combinations and exponents s i m i l a r to those used by Bruce et_ a_l. (1967) were s t u d i e d . Simple c o r r e l a t i o n c o e f f i c i e n t s c a l c u l a t e d are included i n Table 53. Two such i n t e r a c t i o n terms are included i n some of the m u l t i p l e r e g r e s s i o n equations i n Table 54. Although both terms were s t a t i s t i c a l l y s i g n i f i c a n t , they added l i t t l e to the usefulness of the equation from a p r e d i c t i n g view p o i n t . Table 55 (equation No. 4) includes estimated diameters from an equation (Table 59) developed by-procedures suggested by Bruce e_t a_l. (1967). Average a c t u a l and estimated diameters compare f a v o r a b l y except near the t i p s of l a r g e r t r e e s . The comparisons of the various taper f u n c t i o n s i n d i c a t e that estimates secured from the 5th degree polynomial equation are acceptable. The complications introduced by the use of high exponentiation and i n t e r -a c t i o n terms makes t h e i r use unwarranted. Diameters estimated from the polynomial equation are tabulated by 2-inch DBH c l a s s e s from 8 to 50 inches f o r d e c i l e s of height i n Appendix I I I . Conclusion Although reasonable estimates of upper stem diameters i n s i d e bark can be obtained from equations based on the assumption that t r e e form i s p a r a b o l o i d , more p r e c i s e estimates are f a c i l i t a t e d by expansion of the b a s i c p a r a b o l o i d f u n c t i o n to a 5th degree polynomial. The equation developed and tabulated enables estimates of upper stem diameters of western hemlock w i t h an average standard e r r o r of estimate of 1.29 132 Table 57. Comparisons of a c t u a l and estimated v a l u e s . o f (d/DBH) from the independent v a r i a b l e h/H f o r polynomials from degree one to f i v e . 2 2 S e c t i o n . (d/DBK) (d/DBH) estimated from polynomials No. a c t u a l 1 2 3. 4 5 1 . .888 .809 .886-; .874 ,885 .888 2 .642 .657 .665 .676 .650 .641 3 .500 .513 , .481 .493 .492 .501 4 .352 .373 .325 .329 .347 .352 5 .231 .269 .223 .220 .234 .231 6 .172 .212 .173 .167 .174 .168 7 .108 .153 .125 .117 .115 .110 8 .062 .096 .082 .075 .064 .063 9 .034 .050 .051 .045 .032 .035 10 " .024 .021 .032 .029 .017 .021 11 .012 -.003 .017 .017 .008 .013 12 .005 -.044 -.006 .000 .002 .004 13 .000 -.079 -.025 -.012 .007 .001 133 Table 58. The extent of b i a s i n the e s t i m a t i o n of stem diameters from 5^ . degree polynomial equation f o r s e v e r a l DBK c l a s s e s . . Approx. DBH c l a s s (inches)  height 7.5-14.0 14.1-22.0 22.1+ 7.5+ ( f t . ) ; a c t u a l diameter minus estimated diameter (inches) 1 -0.2 0.0 0.9 0.2 16 0.3 0.1 -0.4 0.0 31 0.4 0.1 -0.2 0.1 47 0.7 0.4 -0,5 0.2 61 1.2 0.3 -0.5 0.1 75 0.5 -0,4 0.1 92 0.5 -0.2 0.0 108 0.7 -0.2 0.0 124 - o . i 0.1 141 0.2 0.2 157 -0.1 -0.1 171 0.6 0.6 Average 0.88 1.09 1.60; 1.29 standard e r r o r of estimate i n inches No. trees 131 132 106 369 Table 59. E s t i m a t i n g equation f o r (d/DBH) i n c o r p o r a t i n g v a r i a b l e s and i n t e r a c t i o n s as suggested i n method proposed by Bruce et a_l. (1968). Independent v a r i a b l e Regression c o e f f i c i e n t Constant term 0.873968 DBH (inches) 0.001589 b ( f t . ) -0.000343 h/H -3.500720 (h/H) 2 -5.793200 ( h / H ) 1 * 5 7.984210 ( h / H ) 1 0 1.006370 ( h / H ) 2 0 -0.568393 (DBH) (H)((h/H)1'5-(h/H)2°) -0.000117 (DBH) ( H ) ( ( h / H ) 1 ' 5 - ( h / H ) 1 0 ) 0.000198 (DBH)((h/H) 1' 5-(h/H)3) -0.045472 135 inches,. More complicated f u n c t i o n s i n c o r p o r a t i n g i n t e r a c t i o n v a r i a b l e s and hi g h exponentiation do not s i g n i f i c a n t l y improve the p r e c i s i o n of estimates of upper stem diameters. 136 CHAPTER V I I ESTIMATION OF VOLUME AND VALUE OF SOUND AND DECAYED WOOD Est i m a t i o n of Tree and Stand Volumes and Values The r e l i a b i l i t y of estimates of tree volume and value depends on three major f a c t o r s : the gross tre e volume e s t i m a t i o n , the decay volume e s t i m a t i o n and the v a l u a t i o n or grading system f o r a s s e s s i n g t r e e q u a l i t y . Gross tre e volume e s t i m a t i o n i s probably the simplest and most p r e c i s e of the steps involved i n determining t r e e volume and value. Numerous gross tree volume equations are a v a i l a b l e . In B r i t i s h Columbia, equations f o r the commercial tre e species have been prepared by Browne (1962). These make use of Schumacher's b a s i c equation form (Bruce and Schumacher, 1950), but other equations are a l s o a v a i l a b l e (Smith and Breadon, 1964; Smith and Munro, 1965; Munro, 1967). Gross t r e e volume equations can be developed simply and e f f i c i e n t l y through the use of m u l t i p l e r e g r e s s i o n analyses on e l e c t r o n i c computers. Two such gross tr e e volume equations developed f o r the trees used i n t h i s study are l i s t e d i n Table 60. The most e f f i c i e n t decay f a c t o r s are those which can be expressed i n equation form and there f o r e incorporated i n f l e x i b l e computer a p p l i c a t i o n s . Most t a b l e s f o r the e s t i m a t i o n of decay i n tree s have been developed by a freehand g r a p h i c a l b a s i s and are the r e f o r e subject to personal b i a s . In the development of decay f a c t o r s by graphi-c a l methods i t i s impossible to assess a l l the combinations and i n t e r -a c t i o n s which a f f e c t decay i n t r e e s . I t i s only r e c e n t l y that mathematical methods have been a p p l i e d to develop func t i o n s f or e s t i m a t i n g decay 137 Table 60. Two equations f o r use i n e s t i m a t i o n of cubic foot tree volume between a 1-foot stump height and a.4-inch top diameter f o r western hemlock. Dependent v a r i a b l e Constant (DBH)2(H)/100 Log. DBH Log. H ndependent v a r i a b l e s R Tree v o l . ( c . f . ) 5.2619 .17838 .98 15.2 Log. t r e e v o l . -2.7024 1.8957 1.0612 .99 11.9 w i t h i n i n d i v i d u a l t r e e s . Equations such as those published by Aho (1966) which permit decay e s t i m a t i o n i n board and cubic f e e t f o r s e v e r a l t r e e species w i t h various abnormality and age c l a s s e s are extremely u s e f u l . The equation developed i n t h i s t h e s i s f o r western hemlock o f f e r s f l e x i -b i l i t y to the extent that i t can be used to estimate decay volumes f o r r e s i d u a l trees and f o r suspect trees w i t h a t o t a l of seven d i f f e r e n t combinations of three suspect a b n o r m a l i t i e s . An important but e a s i l y overlooked advantage of t h i s equation form which makes use of indepen-dent v a r i a b l e c l a s s i f i c a t i o n "present" or "absent" ( i . e . "1" or "0") i s the s i g n i f i c a n c e attached to the r e g r e s s i o n c o e f f i c i e n t s f o r each inde-pendent v a r i a b l e . Using the numerical values "1" to i n d i c a t e the presence of an e x t e r n a l abnormality and "0" to i n d i c a t e the absence means that each r e g r e s s i o n c o e f f i c i e n t i n the equation i s , i n r e a l i t y , the percent-age of gross t r e e volume decayed i f that abnormality i s present. The equation f o r decay i n western hemlock (Table 46) Per cent of gross tree volume decayed = -4.136 + .511DBH + 22.258C + 10.976LOS + 4.643T can be i n t e r p r e t e d as f o l l o w s : 138 a) Minimum per cent of gross cubic foot volume decayed, r e g a r d l e s s of e x t e r n a l a b n o r m a l i t i e s present, i s -4.136 + .511DBH ( I t f o l l o w s , t h e r e f o r e , that t h i s equation i s not u s e f u l f o r trees l e s s than 8.3 inches DBH). b) I f e x t e r n a l a b n o r m a l i t i e s are present, decay percentage must be increased from the minimum by 22.258 or 22 per cent f o r conks, 10.967 or 11 per cent f o r large open scars and 4.643 or 5 per cent f o r dead or broken tops. E x t e r n a l a b n o r m a l i t i e s other than the above do not warrant any percent-age deduction above the minimum as they are not included i n the equation. Equations expressed i n the above format are simple to i n t e r p r e t and can be a p p l i e d as general " r u l e s of thumb" f o r quick estimates on a reconnaissance b a s i s . In computer a p p l i c a t i o n s where i t i s d e s i r e d to provide estimates o f net volume d i r e c t l y , the gross volume f u n c t i o n and the decay volume f u n c t i o n can be combined i n t o one equation to y i e l d d i r e c t estimates of net t r e e volume. Of equal importance w i t h the e s t i m a t i o n of gross volume and decay volume i s the e s t i m a t i o n of tre e q u a l i t y (Gaines, 1964). The e s t i m a t i o n of tree value r e q u i r e s some system of c l a s s i f i c a t i o n of tre e q u a l i t y . Numerous q u a l i t a t i v e c l a s s i f i c a t i o n methods are a v a i l a b l e , however, to avoid b i a s a s s o c i a t e d w i t h personal judgement and to permit mathematical a n a l y s i s i t i s necessary that a q u a n t i t a t i v e q u a l i t y c l a s s system be developed. Smith _et a_l. (1961) presented s e v e r a l equations 139 which r e l a t e d t r e e q u a l i t y to such c h a r a c t e r i s t i c s as height to l i v e crown, l i v e crown widt h and length and branch s i z e . The l o g and t r e e grade committee of the S o c i e t y of American F o r e s t e r s (Lockard, 1961) has o u t l i n e d the general t o p i c s which need f u r t h e r research i n the development of t r e e and log grades. The s t u d i e s of O'Regan and Savin (1964), Csizmazia e_t aJL, (1966) and Dobie (1966) are e x c e l l e n t examples of progress being made i n t h i s f i e l d . A n a l y t i c a l procedures u s i n g comprehensive r e g r e s s i o n analyses f o r the determination of gross t r e e q u a l i t y c l a s s e s f o r I n t e r i o r Douglas f i r were developed by Csizmazia et_ a_l. (1966). Figure. 6 shows these t r e e q u a l i t y c l a s s e s and t h e i r r e l a t i o n s h i p to t r e e DBH and s i t e index. Dobie (1966) found that net t r e e value of c o a s t a l Douglas f i r could be estimated most e f f i c i e n t l y from combinations of DBH, b u t t log grade and crcwn c l a s s . In equation form, these q u a l i t y c l a s s i f i c a t i o n s can be coupled w i t h t r e e equations f o r gross volume and decay volume to provide estimates of value f o r i n d i v i d u a l t r e e s . Information u s e f u l for the determination of value on a stand b a s i s , as opposed to a t r e e b a s i s , can be obtained from Figures 1 and 2. R e l a t i v e numbers of trees free from decay or w i t h l e s s than s p e c i f i e d amounts of decay can be estimated from these f i g u r e s and such i n f o r m a t i o n may be u s e f u l i n determining marginal t r e e s i z e s and a l l o w a b l e decay s p e c i f i c a t i o n s f o r l o c a l areas. For example, of those trees w i t h conks, 50 per cent w i l l have more than o n e - t h i r d of t h e i r gross volume decayed, whereas of those trees w i t h e x t e r n a l a b n o r m a l i t i e s other than conks, only 18 per cent w i l l have more than o n e - t h i r d of gross volume decayed. Assess-ment of number of dead standing trees per acre may a l s o prove u s e f u l i n e s t i m a t i n g d e f e c t i v e volume and value on a stand b a s i s . Foster and 140 Figure 6- Gross tree value (quality) and D B H relationship by site index classes for British Columbia interior Douglas fir- ' JLto 20 22 24 26 28 30 32 34 36 D B H (inches) Source : Csizmazia efof{\9G6)-141 Foster (1952) found an e x c e l l e n t r e l a t i o n s h i p between stand defect and volume of dead trees per acre. Their equation was Y = 7.20 + 1.02X where: Y i s stand decay volume expressed as a per cent of gross stand volume, and X i s volume of dead trees per acre expressed as a percentage.of gross stand volume. Computer programs such as those developed by Henley and Hoopes (1967) f o r the c a l c u l a t i o n of saw log lumber recovery and value are u s e f u l i n the development of t r e e grades and q u a l i t y and value c l a s s e s . A d d i t i o n a l i n f o r m a t i o n may come from a e r i a l photography. •The use of low l e v e l h e l i c o p t e r photography holds promise i n d e t e c t i n g suspect and dead trees i n stands. The B r i t i s h Columbia Forest Service i s c u r r e n t l y engaged i n a c t i v e research regarding the usefulness of such photography f o r the assessment of decay and reported t h a t : " r e s u l t s are encouraging and warrant f u r t h e r study." ( 3 r i t i s h Columbia Department of Lands, Forests and Water Resources, 1967) . According to Boyce and Wagg (1953), development of r o t caused by F_. p i n i may be c y c l i c a l and numbers of i n f e c t e d and dead trees increase and decrease w i t h i n c r e a s i n g stand age. They s t a t e d : "Fomes p i n i i s somewhat pathogenic, commonly encroaching on the sapwood, r e s u l t i n g e i t h e r i n the death of the t r e e d i r e c t l y or, as seems more l i k e l y , reducing i t s v i g o r so that i t succumbs to competition. The most r a p i d l y growing trees are infecLed f i r s t , t h e i r growth i s reduced, and f i n a l l y they drop out of the stand. Meanwhile, new i n f e c -t i o n s are o c c u r r i n g i n the remaining t r e e s , and the process i s repeated." Trees severely i n f e c t e d or decayed by other f u n g i such as E. t i n c t o r i u m which are not pathogenic, are o f t e n weakened to such an 142 extent that they are removed from the stand by windbreak. I t i s conceivable that the use'of low l e v e l h e l i c o p t e r photography to detect trees and stands i n e a r l y stages of decay may enable f o r e s t e r s to develop management plans which provide f o r logging during low p o i n t s of decay c y c l e s , thus e l i m i n a t i n g excessive decay l o s s e s . E s t i m a t i o n of Log Volumes and Values A p p l i c a t i o n of t o t a l tree decay f a c t o r s such as those discussed e a r l i e r i n t h i s chapter can be m i s l e a d i n g and may cause erroneous values when a p p l i e d to i n d i v i d u a l logs. As i l l u s t r a t e d w i t h the trees i n t h i s study, the amount of decay i n butt and top logs would be overestimated w h i l e the amount of decay i n mid-section logs would be underestimated, i f the average tree decay f a c t o r were to be a p p l i e d to logs from each p o s i t i o n i n the t r e e . Where log q u a l i t y i s important, i t may be h i g h l y m i s l e a d i n g to s t a t e decay losses i n terms of a percentage of gross merchantable volume i n the t r e e . I n v e s t i g a t i o n s by B i e r , Foster and S a l i s b u r y (1946) and B i e r (1946) on S i t k a Spruce i n the Queen C h a r l o t t e Islands showed that high value, Grade No. 1 butt logs were a c t u a l l y among the l e a s t decayed. Decay percentages by volume were 7.2, 7.1, and 23.4 f o r Grade Nos. 1, 2 and 3 r e s p e c t i v e l y . However, s i m i l a r i n v e s t i g a t i o n s by Foster and Foster (1952, 1953) on western hemlock i n the Queen C h a r l o t t e Islands i n d i c a t e d that the average percentage of defect was greater i n Grade No. 1 logs than i n Grade No. 3 logs. They s t a t e d : " w i t h i n each diameter c l a s s and i n r e l a t i o n to gross volume, decay was found to be of greater s i g n i f i c a n c e i n Grade 3 than i n Grade 1 wood. On the b a s i s of the q u a l i t y of wood a f f e c t e d , however, decay was of equal, i f not greater, importance i n the b e t t e r grades. The average percentage of 143 "defect was greater i n Grade 1 than i n Grade 3 owing to the l a r g e r average diameter." The taper f u n c t i o n developed i n t h i s study i s designed so that estimates of diameter i n s i d e bark can be made at any height above ground p r o v i d i n g the DBH and t o t a l height of the tree are known. Pre-d i c t i o n of a s e r i e s of diameters at s p e c i f i e d i n t e r v a l s along the stem enables the c a l c u l a t i o n of gross volumes of i n d i v i d u a l l o g s . I t i s important to r e a l i z e , however, that volumes estimated from taper f u n c t i o n may be biased (Grosenbaugh, 1954). Taper fu n c t i o n s i n v o l v e the grouping and averaging of diameters whereas volume functions i n v o l v e the grouping or averaging of volumes. I t i s recommended, ther e f o r e , that i n the e s t i m a t i o n of gross volumes of i n d i v i d u a l logs, adjustments be made to c o r r e c t f o r p o s s i b l e volume b i a s introduced by the taper f u n c t i o n Since r e l i a b l e gross tre e volume f u n c t i o n s are r e a d i l y a v a i l a b l e f o r most species, i t i s l o g i c a l to adju s t volumes derived from the taper f u n c t i o n to equal those derived from the volume f u n c t i o n . The simplest method of adjustment i s to compute the gross volume of the tree to the standard of u t i l i z a t i o n of the tree volume f u n c t i o n by accumulating a l l log volumes estimated by the taper f u n c t i o n . This volume i s then compared w i t h the tree volume estimated from the volume f u n c t i o n and any d i f f e r e n c e i n the two volumes i s pro-rated on a percentage b a s i s over i n d i v i d u a l log volumes c a l c u l a t e d from the taper f u n c t i o n . This adjustment ensures that-the t o t a l volume c a l c u l a t e d from the taper f u n c t i o n w i l l equal the t o t a l volume c a l c u l a t e d from the volume f u n c t i o n . Such an adjustment, i f based on r e l i a b l e t r e e volume equation s a f e l y e l i m i n a t e s any volume bias present i n the taper f u n c t i o n . Furthermore, the need to prepare l o c a l i z e d taper f u n c t i o n s which are d i f f i c u l t and .expensive to d e r i v e , .is e l i m i n a t e d and at the same time, a r t i f i c i a l changes i n volume due to a r b i t r a r y s e l e c t i o n of l o g lengths cannot occur. Log volumes c a l c u l a t e d w i t h the a i d of a t a p e r f u n c t i o n should be reduced f o r estimated decay w i t h i n each l o g . The l o g p o s i t i o n decay f u n c t i o n i s designed so that decay estimates can be made f o r logs s i t u a t e d at any height i n a standing t r e e . E s t i m a t i o n of decay volumes to successive heights above ground f o l l o w e d by successive s u b t r a c t i o n s of estimated decay volumes, can provide estimates of decay volume w i t h i n s p e c i f i e d l og lengths. The expression of decay as a percentage of gross tree volume avoids the n e c e s s i t y of l o c a l i z a t i o n of decay f u n c t i o n s f o r d i f f e r e n t t r e e volume equations. As pointed out i n an e a r l i e r s e c t i o n , the l o g p o s i t i o n decay f u n c t i o n r e s u l t s i n unacceptably biased estimates of decay volume f o r b u t t logs s h o r t e r than 32 f e e t . This i s not a serious l i m i t a t i o n i n assess i n g h i g h q u a l i t y butt logs however, because such logs are u s u a l l y cut i n lengths of approximately 32 f e e t . B r i t i s h Columbia l o g grading r u l e s ( B r i t i s h Columbia Forest S e r v i c e , 1963) s p e c i f y that Grade No. 1 hemlock logs must be at l e a s t 26 inches i n diameter. For 32-foot butt logs and f o r logs of any length above a height of 32 f e e t , acceptable estimates of decay can be -made from the l o g p o s i t i o n decay f u n c t i o n . Adjustments of estimated l o g p o s i t i o n decay volumes should be made i n a s i m i l a r manner to the adjustments made f o r the taper f u n c t i o n volumes. The log p o s i t i o n decay f u n c t i o n and the tree decay f u n c t i o n are derived independently by l e a s t squares procedures and i t cannot, t h e r e f o r e , be expected that t o t a l tree decay volumes estimated from the two equations w i l l be i d e n t i c a l . Since t e s t s proved that the tree decay f u n c t i o n was p r a c t i c a l l y unbiased (Table 45), i t i s recommended that decay volume estimated from the l o g p o s i t i o n , f u n c t i o n be adjusted to equal decay volume estimated from the t r e e decay equation. Recommended c a l c u l a t i o n procedures f o r the e s t i m a t i o n of l o g p o s i t i o n gross and net volumes are i l l u s t r a t e d by example i n Appendix IV. In a s s i g n i n g a value or q u a l i t y c l a s s to i n d i v i d u a l logs i n t r e e s , i t i s necessary that some measure of l o g q u a l i t y be a v a i l a b l e . I t i s not necessary that l o g s i z e be one of the q u a l i t y parameters... log s i z e can be coupled with the q u a l i t y c l a s s i f i c a t i o n system i n the c o m p i l a t i o n w i t h diameter estimates from the taper f u n c t i o n . Q u a l i t y or value assigned a l s o depends on the methods of s c a l i n g . In B r i t i s h Columbia, where s e v e r a l methods of s c a l i n g are used, i t i s important to r e a l i z e that the f u n c t i o n s developed i n t h i s t h e s i s estimate volume of decay only. Such estimates are e q u i v a l e n t to cubic foot s c a l i n g to " c l o s e " u t i l i z a t i o n standards. R e v i s i o n - o f these f u n c t i o n s would be necessary i f estimates were re q u i r e d f o r "intermediate" u t i l i z a t i o n standards where s c a l i n g may be e i t h e r i n board fee t or cubic f e e t and deductions are permitted f o r waste and breakage i n a d d i t i o n to decay. Estimates of q u a l i t y i n standing trees should u t i l i z e such q u a n t i t a t i v e tree v a r i a b l e s as length of c l e a r b o l e , length of l i v e crown or branch s i z e . Csizmazia _et _ a l . (1966) reported that s i t e index, height to f i r s t l i v e limb and number of sides c l e a r on the f i r s t 16 f e e t of b o l e , were the tree v a r i a b l e s most s i g n i f i c a n t l y a s s o c i a t e d w i t h q u a l i t y expressed as gross d o l l a r value per gross cubic f o o t . Such v a r i a b l e s can be r e a d i l y r e l a t e d to e x i s t i n g B r i t i s h Columbia l o g grades ( B r i t i s h Columbia Fo r e s t S e r v i c e , 1963) f o r western hemlock which, i n a d d i t i o n to s i z e s p e c i f i c a t i o n s , have s t r i c t requirements concerning allowable h e a r t r o t percentages and number, s i z e and spacing of knots. For example, Grade No. 1 s p e c i f i c a t i o n s s t a t e c l e a r l y that " h a l f the net contents of the l o g must be c l e a r s " and that "knots are t o l e r a t e d only to the extent of a few well-spaced ones on the upper 30 per cent of one quadrant or on the upper 20 per cent of two quadrants on logs 36 f e e t and over i n length." Grade No. 2 s p e c i f i c a t i o n s permit any number of sound, t i g h t knots provided not l e s s than 20 per cent of the net contents of the l o g y i e l d c l e a r lumber. Grade No. 3 logs i n c l u d e those which c o n t a i n more than 33 1/3 per cent of t h e i r gross volume as sound.wood, but are lower i n grade than No. 2. The l o g p o s i t i o n decay f u n c t i o n f a c i l i t a t e s the e s t i m a t i o n of decay w i t h i n i n d i v i d u a l logs i n t r e e s . I f t h i s decay i s expressed as a percentage of gross volume of the l o g , a d d i t i o n a l measures of q u a l i t y regarding p e r m i s s i b l e amounts of decay i n logs could be developed. E s t i m a t i o n of C e l l u l o s e Quantity and Q u a l i t y i n Decayed Wood. In order to assess the p o s s i b l e value of decayed western hemlock wood f o r pulp, wood samples from three western hemlock trees near Blue R i v e r , B. C. w i t h t y p i c a l r o t columns caused by E. t i n c t o r i u m were s e l e c t e d f o r c e l l u l o s e determinations. Blocks approximately two inches square were obtained at i n t e r v a l s of two f e e t throughout the length of each t r e e , both i n s i d e and outside the decay column. Where p o s s i b l e , samples were taken the same number of r i n g s from p i t h . A l l sample blocks were c o l l e c t e d immediately a f t e r the tr e e s had been f e l l e d and allowed to a i r dry i n the sun. Upon r e t u r n 147 from the f i e l d , the samples were stored i n a c o l d chamber at o approximately 33 F u n t i l they were re q u i r e d f o r a n a l y s i s . A t o t a l of 21 of these wood blocks were s e l e c t e d f o r la b o r a t o r y analyses. The a c t u a l l o c a t i o n and number of samples chosen from each tree are shown i n Appendix V. Because the main o b j e c t i v e of the la b o r a t o r y analyses was to determine i f the decayed wood had undergone any s i g n i f i c a n t l o s s i n h o l o c e l l u l o s e or alpha c e l l u l o s e i n r e l a t i o n to the soundwood, samples were taken from decayed wood i n the intermediate to advance stages of decay, from t r a n s i t i o n zone wood and from soundwood. Laboratory procedures Each wood block was s p l i t i n t o pieces of approximately match-stick s i z e and a i r - d r i e d i n a normal l a b o r a t o r y atmosphere f o r two days. Each was then fed at a constant r a t e of speed i n t o a Wiley m i l l and ground to pass a 20-mesh screen. The wood meal was shaken by hand f o r 30 seconds on a 40-mesh screen and the 20 to 40-mesh and the 40+ mesh f r a c t i o n s ( h e r e a f t e r r e f e r r e d to as coarse and f i n e f r a c t i o n s , r e s p e c t i v e l y ) c o l l e c t e d s e p a r a t e l y i n glass p e t r i e d i s h e s . Both f r a c t i o n s were e q u i l i b r a t e d i n an atmosphere c o n t r o l l e d at 73°F (+ 0.5 6F) and 50 per cent (+ 2.0 per cent) r e l a t i v e humidity. The a c t u a l e q u i l i b r i u m moisture content (EMC) of the wood meal was determined by d r y i n g a p o r t i o n of each meal f r a c t i o n from decayed wood and soundwood to constant weight at 100°C. and s o l v i n g the formula: MC = meal weight at EMC - meal weight OP x 100% meal weight. OD where MC = moisture content i n per cent OD i s oven dry. 148 P o s s i b l e screening losses in.decayed wood were evaluated by expressing the OD weight of the coarse meal f r a c t i o n as a i percentage of the OD weight of both meal f r a c t i o n s f o r each wood sample. This p r o p o r t i o n was termed " p h y s i c a l y i e l d " . Chemical analyses f o r the determination of h o l o c e l l u l o s e and alpha c e l l u l o s e were c a r r i e d out i n r e p l i c a t i o n s of two on the co-arse meal f r a c t i o n s f o r each sample. The procedure f o r h o l o c e l l u l o s e determination was the c h l o r i t e d e i i g n i f i c a t i o n process of Wise et_ a l . (1946), as o u t l i n e d by Kennedy (1961) w h i l e alpha c e l l u l o s e determina-t i o n s were made f o l l o w i n g procedures suggested by E r i c k s o n (1962). Results and d i s c u s s i o n The p h y s i c a l y i e l d was c a l c u l a t e d to determine i f there was any d i f f e r e n c e i n the g r i n d i n g p r o p e r t i e s i n the Wiley M i l l between decayed and soundwood. The l i t e r a t u r e review i n d i c a t e d that decayed wood i s subject to excessive chipping and screening losses because of brashness. P h y s i c a l y i e l d was c a l c u l a t e d f o r each of 21 wood samples, 13 of which came from soundwood, 5 from decayed wood and 3 from t r a n s i t i o n zone wood. A n a l y s i s of variance (Table 61) i n d i c a t e d no s i g n i f i c a n t d i f f e r e n c e i n p h y s i c a l y i e l d between any of the wood types. Whether or not the g r i n d i n g p r o p e r t i e s of the wood from which these samples came would d i f f e r i n a commercial chipper i s not p o s s i b l e to determine, and i t would be dangerous to e x t r a p o l a t e on the b a s i s of the r e s u l t s obtained from t h i s t e s t . A n a l y s i s of variance of h o l o c e l l u l o s e content i n d i c a t e d a s i g n i f i c a n t d i f f e r e n c e between trees and between wood c o n d i t i o n (Table 62). Mean values f o r y i e l d s from each wood c o n d i t i o n were t e s t e d by Duncan's new m u l t i p l e range t e s t and the y i e l d of 149 Table 61. A n a l y s i s of va r i a n c e f o r p h y s i c a l y i e l d s from western hemlock wood w i t h v a r i o u s stages of heartrot:: catised by PiChinodontium t i n c t o r i u m . Source of DF Sum Mean Variance S i g . ! v a r i a t i o n . squares squares r a t i o s l e v e l Trees 2 10.303 5.15 0.33 NS Wood c o n d i t i o n 2 14.187 7 .093 0.46 /NS I n t e r a c t i o n 4 32.997 8.249 0.53 NS E r r o r 12 186.61 15.55 T o t a l 20 244.10 NS not s i g n i f i c a n t at p.05; Table 62. A n a l y s i s of va r i a n c e f o r h o l o c e l l u l o s e y i e l d s from wood of western hemlock w i t h v a r i o u s stages of h e a r t r o t caused by Echinodontium t i n c t o r i u m . ~ ... Source of DF Sum Mean Variance S i g . ! v a r i a t i o n squares squares r a t i o s l e v e l Trees 2 129.62 64.811 18.02 •JL. Wood c o n d i t i o n 2 144.65 72.326 20.10 I n t e r a c t i o n 4 12.973 3.2432 0.90 NS E r r o r 39 140.30 3.5975 T o t a l 47 427.55 * s i g n i f i c a n t a t p.05 NS not s i g n i f i c a n t at p.05 150 h o l o c e l l u l o s e from soundwood was found to be s i g n i f i c a n t l y higher a t p.05 than the y i e l d from decayed or t r a n s i t i o n zone wood. Although these y i e l d s were s t a t i s t i c a l l y s i g n i f i c a n t l y d i f f e r e n t they were l e s s than 4 per cent higher than the y i e l d s from decayed wood (Table 63). Table 63. Comparison of average p h y s i c a l y i e l d s and holo-and alpha c e l l u l o s e y i e l d s from western hemlock wood w i t h v a r i o u s stages of h e a r t r o t caused by Echinodontium t i n c t o r i u m . V a r i a b l e Decayed T r a n s i t i o n wood zone wood P h y s i c a l y i e l d (%) 73.75 74.33 75.51 H o l o c e l l u l o s e (%) 72.98 74.16 76.67 1 Alpha c e l l u l o s e ( % ) 47.32. 48.29 48.50 1 S i g n i f i c a n t l y d i f f e r e n t at p.05 from values shown f o r decayed wood and t r a n s i t i o n zone wood according to Duncan's new m u l t i p l e range t e s t . A n a l y s i s of variance of alpha c e l l u l o s e content (Table 64) i n d i c a t e d s i g n i f i c a n t d i f f e r e n c e s between trees but no s i g n i f i c a n t d i f f e r e n c e s between wood c o n d i t i o n . The i n t e r a c t i o n of t r e e s and wood c o n d i t i o n was s i g n i f i c a n t , i n d i c a t i n g that the r e l a t i v e order of alpha c e l l u l o s e y i e l d i n sound, t r a n s i t i o n zone and decayed wood was not c o n s i s t e n t from tree to t r e e . I t can be i n f e r r e d from t h i s a n a l y s i s that although c e l l u l o s e q u a l i t y as measured by alpha c e l l u l o s e y i e l d i s not s i g n i f i c a n t l y d i f f e r e n t i n sound, t r a n s i t i o n zone or decayed wood, the i n d i v i d u a l t r e e has some i n f l u e n c e on the q u a l i t y of c e l l u l o s e . I t may be p o s s i b l e that decay-causing f u n g i act Sound -wood Table 64. A n a l y s i s of va r i a n c e f o r alpha c e l l u l o s e y i e l d s from western hemlock wood w i t h v a r i o u s stages of h e a r t r o t caused by Echinodontium t i n c t o r i u m . Source of DF Sum Mean Variance S i g . l V a r i a t i o n squares squares r a t i o s leve I Trees 2 .40.986 20.493 9.45 Wood c o n d i t i o n 2 12.922 6.4609 ' 2.98 NS I n t e r a c t i o n 4 35.393 8.8481 4.08 E r r o r 33 71.526 2.1675 T o t a l 41 160.83 1 NS not s i g n i f i c a n t at p.05 * s i g n i f i c a n t at p.05 d i f f e r e n t l y on alpha c e l l u l o s e from tree to t r e e . I t i s important to consider how the measures of p h y s i c a l y i e l d , h o l o c e l l u l o s e and alpha c e l l u l o s e are expressed. I n t h i s study, each was expressed as a percentage of the oven-dry weight, of the wood sample analysed. I d e a l l y , y i e l d s should be expressed as a percentage of the o r i g i n a l weight of soundwood, a measure not a v a i l a b l e f o r the decayed m a t e r i a l used i n t h i s a n a l y s i s . As the y i e l d s are expressed here, the p o s s i b i l i t y that decayed wood may be lower i n s p e c i f i c g r a v i t y than soundwood i s masked. I f i t can be shown that the decayed wood has a lower s p e c i f i c g r a v i t y than the soundwood, then the y i e l d of c e l l u l o s e from the decayed wood i s reduced on the basis of y i e l d c a l c u l a t e d from an o r i g i n a l soundwood weight or gross volume. Since pulp y i e l d s from commercial d i g e s t e r s are l i m i t e d by volume of wood r a t h e r than weight of wood which can' be pulped at one time, i t i s necessary to show that 152 equal y i e l d s can be obtained from decayed wood on a volume b a s i s to prove that decayed wood can be used without y i e l d r e d u c t i o n . In an e f f o r t to estimate the amount of pulp y i e l d that might be l o s t due to the lower s p e c i f i c g r a v i t y of decayed wood, the s p e c i f i c g r a v i t y of s e v e r a l samples adjacent t o those used f o r chemical analyses was determined by water displacement. Results are summarized i n Table 65 and i n d i c a t e a s l i g h t increase i n s p e c i f i c g r a v i t y of decayed wood r a t h e r than a decrease as might be expected.^ Table 65. S p e c i f i c g r a v i t y of western hemlock wood i n f e c t e d w i t h v a r i o u s stages of h e a r t r o t caused by EEchinddofttlumttincfcorium. Wood type No. Obs. S p e c i f i c g r a v i t y (oven-dry volume) Sound sapwood 6 .431 Sound heartwood 4 .467 Decayed heartwood 6 .502 T r a n s i t i o n zone heartwood 2 .536 Although increases of s p e c i f i c g r a v i t y in tdecayed wood have been encountered by other i n v e s t i g a t o r s ( S c h e f f e r et a l . , 1941; Glennie and Schwartz,1950: H a r r i s and Wayman, 1956), no proven reasons f o r such a phenomenum e x i s t . H a r r i s and Wayman (1956) noted higher contents \ of ash, s i l i c a , and i r o n i n decayed western hemlock wood than i n \ ' soundwood. I t a l s o i s p o s s i b l e that i n response to fun g a l i n f e c t i o n , a d d i t i o n a l amounts of e x t r a c t i v e s are accumulated i n the i n f e c t e d 153 areas, thus c o n t r i b u t i n g to a higher s p e c i f i c g r a v i t y . On the b a s i s of these l i m i t e d i n v e s t i g a t i o n s , i t appears that h o l o c e l l u l o s e and alpha c e l l u l o s e y i e l d s from western hemlock wood decayed by E. t i n c t o r i u m should be p r a c t i c a l l y equivalent to y i e l d s obtained from equal volumes of soundwood. Conclusion Estimates of the d i s t r i b u t i o n of soundwood volume w i t h i n i n d i v i d u a l standing western hemlock tr e e s can be made from m u l t i p l e r e g r e s s i o n equations developed i n t h i s t h e s i s . Gross volumes of logs of s p e c i f i e d dimensions can be estimated from tre e taper and volume equations and estimates of decay volume can be made from tre e or l o g i ' p o s i t i o n decay equations. Estimates of log value can be made from equations s i m i l a r to those developed by Csizmazia (1966) and Dobie (1966). C h l o r i t e d e l i g n i f i c a t i o n experiments c a r r i e d out on samples from three trees i n d i c a t e that y i e l d s of h o l o c e l l u l o s e and alpha c e l l u l o s e from western hemlock wood decayed by E. t i n c t o r i u m are comparable to those obtained from equivalent volumes of soundwood. 154 CHAPTER V I I I SUMMARY AND SUGGESTIONS FOR FURTHER RESEARCH . . . The purpose of t h i s t h e s i s was to develop a n a l y t i c a l methods to determine the d i s t r i b u t i o n of soundwood volumes and values i n order that appropriate reductions f o r decay could be made f o r estimates of net volumes of logs of s p e c i f i e d s i z e s and grades. This was done by d e s c r i b i n g as completely as p o s s i b l e the d i s t r i b u t i o n of decay w i t h i n 369 i n d i v i d u a l western hemlock tre e s from the Yale P u b l i c Sustained Y i e l d U n i t . A l l analyses were c a r r i e d out on an I . B, M. 7044 computer. I n i t i a l summarization and analyses of the data r e q u i r e d a t o t a l of 15 computer programs, a l l but two of which were w r i t t e n by the author. Comprehensive analyses of the r e l a t i o n s h i p s of decay i n t r e e stems to a t o t a l of 19 d i f f e r e n t c l a s s e s of e x t e r n a l a b n o r m a l i t i e s showed that large open s c a r s , conks and dead or broken tops were the e x t e r n a l a b n o r m a l i t i e s most u s e f u l i n improving estimates of decay. M u l t i p l e r e g r e s s i o n equations which included p r o v i s i o n f o r three e x t e r n a l abnormality c l a s s e s were developed to estimate decay w i t h i n i n d i v i d u a l t r e e s . The f i n a l equation s e l e c t e d provided decay estimates w i t h a standard e r r o r of estimate of 18.66 cubic f e e t or 19.5 per cent i n i n d i v i d u a l t r e e s . A n a l y s i s of the d i s t r i b u t i o n of decay w i t h i n t r e e stems showed that the greatest volume of heartrot:. was concentrated i n the second and t h i r d 16-foot logs above the ground. Decay percentage increased from the butt l o g to the t h i r d l o g , then decreased to the seventh l o g and increased again i n higher logs. Regression equations 155 w i t h p r o v i s i o n -for r e c o g n i t i o n of s i g n i f i c a n t e x t e r n a l a b n o r m a l i t i e s were developed to describe percentages of decay volume to s p e c i f i e d percentages of t o t a l tree height. The f i n a l equation s e l e c t e d provided estimates of decay volume w i t h i n i n d i v i d u a l logs i n standing trees w i t h standard e r r o r s , of estimate ranging from 13.7 cubic f e e t (31.6 per cent) i n b u t t logs to 0.1 cubic f e e t (2.9 per cent) i n top l o g s . A mathematical f u n c t i o n was developed to describe the taper of western hemlock t r e e s . S e l e c t i o n of independent v a r i a b l e s was designed so that estimates of diameter i n s i d e bark at any s p e c i f i e d height could be made f o r trees of known DBH and t o t a l h e i g ht. A standard e r r o r of estimated diameter i n s i d e bark of 1.29 inches was obtained w i t h a 5 t h degree polynomial f u n c t i o n . A p p l i c a t i o n of the taper equation to estimate upper stem diameters i n s i d e bark enabled the c a l c u l a t i o n of gross volumes of logs from any s p e c i f i e d p o s i t i o n i n a t r e e . Combination of the l o g p o s i t i o n decay e s t i m a t i n g f u n c t i o n w i t h the t r e e taper f u n c t i o n provided an equation "package" which permitted e s t i m a t i o n / o f gross and net volumes of i n d i v i d u a l logs w i t h i n standing t r e e s . «, . • -A unique and u s e f u l f e a t u r e of the decay e s t i m a t i n g f u n c t i o n s i s the i n c o r p o r a t i o n of the independent v a r i a b l e c l a s s i f i c a t i o n "1" and "0" to denote the presence or absence, r e s p e c t i v e l y , of s p e c i f i e d e x t e r n a l a b n o r m a l i t i e s which i n d i c a t e decay. I n the system developed, the r e g r e s s i o n c o e f f i c i e n t f o r each e x t e r n a l abnormality i n the e s t i m a t i n g equations i s i n r e a l i t y , an estimate of the average ! ' \ percentage decay volume a s s o c i a t e d w i t h that abnormality. ! •  - \ The importance of r e c o g n i t i o n of e x t e r n a l a b n o r m a l i t i e s and I \ , i ' *• • t h e i r usefulness i n e s t i m a t i n g decay i n trees and stands are pointed out i n a new-graphical approach whereby the percentage of t r e e s i n a 156 stand wi t h more or l e s s than s p e c i f i e d amounts of decay can be estimated. C h l o r i t e _ d e l i g n i f i c a t i o n of samples of western hemlock wood i n f e c t e d w i t h E. t i n c t o r i u m i n d i c a t e d that: such wood may be u s e f u l f o r the production of pulp. H o l o c e l l u l o s e y i e l d s from decayed wood were reduced by about 4 per cent i n comparison w i t h y i e l d s from soundwood ,. and alpha c e l l u l o s e y i e l d s are unchanged. P o t e n t i a l h o l o c e l l u l o s e and alpha c e l l u l o s e q u a n t i t i e s a v a i l a b l e from wood decayed by E. t i n c t o r i u m warrant f u r t h e r i n v e s t i g a t i o n . In the f u t u r e i t may be necessary to develop methods to provide estimates of the p o r t i o n of volume of wood decayed by v a r i o u s f u n g i that i s s u i t a b l e f o r pulp manufacture. Although a n a l y t i c a l techniques have been developed i n t h i s study to describe the d i s t r i b u t i o n of soundwood volumes and values i n western hemlock, there are many areas where research can lead to improvement of these methods. The work i n i t i a t e d by Csizmazia et a l . (1966) should be continued and expanded f o r other species. The r e l a t i o n s h i p s of n a t u r a l pruning to p o s i t i o n of the decay column have not been i n v e s t i g a t e d . Most authors suggest that branch stubs are the most important source of i n f e c t i o n of E. t i n c t o r i u m i n western hemlock. Kimmey (1964) speculated that the n a t u r a l pruning encouraged by keeping stands f u l l y stocked would r e s u l t i n reduced amounts of decay. Stubs of branches pruned at e a r l y ages when branch heartwood has not formed i n a p preciable q u a n t i t i e s w i l l presumably heal q u i c k l y and minimize time of exposure to i n f e c t i o n . Although loss f a c t o r s are a v a i l a b l e f o r waste and breakage-associated w i t h decay ( B r i t i s h Columbia Forest S e r v i c e , 1966), the r e l a t i o n s h i p s of breakage to p o s i t i o n of the decay column have not been i n v e s t i g a t e d . The r e l a t i o n s h i p of bark thickness at d i f f e r e n t heights above the ground to decay p o s i t i o n s and amounts needs study. I n t e n s i v e studies s i m i l a r to those conducted on an 157 extensive b a s i s by Smith and Kozak (1967) on thickness and percentage of bark are needed. They noted, f o r example, that suppressed western hemlock trees and trees of low v i g o r had t h i n n e r bark than dominant and ccdominant t r e e s . I t i s p o s s i b l e that further, research might r e v e a l r e l a t i o n s h i p s between bark thickness and . i n f e c t i o n p o t e n t i a l . Studies reported by Hamilton (1967) i n d i c a t e d no d i f f e r e n c e i n proportions of r e s i d u a l , suspect and dead trees i n 5 d i f f e r e n t P.S.Y.U.'s, and i t i s t h e r e f o r e p o s s i b l e that r e s u l t s obtained from i n t e n s i v e a n a l y s i s of 369 t r e e s i n the Yale P.S.Y.U. may apply through-out much of the western hemlock in- the Cascade-Coast mountains i n B r i t i s h Columbia. Although f u r t h e r t e s t i n g may be r e q u i r e d to demon-s t r a t e the a p p l i c a b i l i t y of the r e s u l t s of t h i s study to western hemlock outside, the Yale P.S.Y.U., the methods developed h e r e i n may be used to d e f i n e the d i s t r i b u t i o n of soundwood volumes f o r any of the commercial tree species of B r i t i s h Columbia. A p p l i c a t i o n of improved methods of e s t i m a t i o n of the d i s t r i b u t i o n of soundwood volumes w i t h i n t r e e s should c o n t r i b u t e much to improved f o r e s t management, planning and b e t t e r u t i l i z a t i o n of i n d i v i d u a l trees and stands throughout B r i t i s h Columbia. -158 LITERATURE CITED Aho, E. 1966. Defect e s t i m a t i o n f o r Grand f i r , Engelmann spruce, Douglas f i r and western l a r c h i n the Blue Mountains of Oregon and Washington. U.S. Dept. A g r i c , Pac. N.W. For. and Rge. Exp. Sta., P o r t l a n d , Ore. pp. 26. Barnes, G. 1962. 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Mimeo. pp. 33. Spurr, S.H. 1952. Forest i n v e n t o r y . The Ronald Press, New York, pp. 475. Thomas, G.P. 1958. Studies i n f o r e s t pathology X V I I I : the occurr-ence of the Indian p a i n t fungus,.Echinodontium t i n c t o r i u m E. & E., i n B r i t i s h Columbia. For. B i o l . Div., Can. Dept. A g r i c , Ottawa, Ont. Pub. 1041. pp. 30. Thomas, G.P. and R.W. Thomas. 1954. Studies i n Forest Pathology XIV: Decay of Douglas f i r i n the c o a s t a l r e g i o n of B r i t i s h Columbia. Can. Jour. Bot. 32:630-653. T u r n b u l l , K.J.; L i t t l e , G.K. and G.E. Hoyer. 1963. Comprehensive tree volume t a b l e s . State of Wash. Dept. of Nat. Res., Olympia. 1 V o l . , v a r i o u s pagings. Waldie, R.-A. 1949. Decay losses i n western white spruce i n the Upper Fraser r e g i o n . Dom. Lab. For. Unpublished r e p o r t , pp. 62. Path., V i c t o r i a , B.C. Weir, R. and E.W. Hubert. 1918. A study of h e a r t - r o t i n western hemlock. U.S. Dept. A g r i c . B u i . 722. pp. 39. 168 Wise, L.E., Murphy, M. and A.A. D'Addieco. 1946. C h l o r i t e h o l o c e l -l u l o s e , i t s f r a c t i o n a t i o n and bearing on summative wood a n a l y s i s and on s t u d i e s on the h e m i c e l l u l o s e s . Paper Trade Jour. 122:35-43. Wright, W.G., 1927. Taper as a f a c t o r i n the measurement of standing timber. Can. For. Serv. B u i . 79. pp. 132. 169 APPENDIX I . Log P o s i t i o n Decay Fac t o r s f o r Western Hemlock. Basic e s t i m a t i n g equation: D^ = -9 .236+ IS .44C+ .0084DBH2+28 .60^+8 .733(L0S) + 2 .906T- 16 .11(J|) 2 where D^ = decay volume to height "h" as a per cent of gross tree volume i n cubic f e e t . b/H= f r a c t i o n of t o t a l tree height. C "1" i f one or more conks present: "0" i f conks absent. L0S= "1" i f one or more large open scars present; "0" i f . large open scars absent. T = "1" i f top dead or broken; "0" i f top not dead or broken. Suspect Class Key Suspect E x t e r n a l Abnormalities Present^ C l a s s conks. large open scars dead or broken top 0 : o 0 0 1 l 0 0 2 0 1 0 3 0 0 1 4 l 1 0 5 l 0 1 6 0 1 1 7 1 1 1 "0" i f abnormality absent: "1" i f abnormality present Log P o s i t i o n Decay Factors f o r Western Hemlock Trees: Suspect Class 0 F r a c t i o n of t o t a l height - h/H DBH ( i n c h e s ) .1 . 2 .3 Per .4 .5 .6 .7 cent of gross t r e e volume decayed • 8 .9 1.0 8 0.0 0.0 0.0 0.2 1.6 2. 7 3.4 3.9 4.0 4.0 10 0.0 0.0 0.0 0.5 1.9 3.0 3.7 4. 2 4.3 : 4.3 12 0. 0 0.0 0.0 0.8 2.2 3.3 4.1 4.5 4.7 4. 7 14 0.0 0.0 0.0 1.3 2.7 3. 8 4.5 5.0 5.1 5.1 16 0.0 0.0 0.0 1.8 3. 2 4.3 5.0 5.5 5.6 5.6 18 0.0 0.0 0. 6 2.3 3.8 4.3 5.6 6.0 6.2 6.2 20 0.0 0.0 1. 2 3-.0 4.4 5.5 6, 2 6.7 6.8 6. 8 22 0.0 0.0 1.9 3.7 5.1 6, 2 6.9 7.4 7.5 7.5 24 0.0 0.7 2. 7 4.4 5.9 6.9 7.7 8.2 8.3 8.3 26 0.0 1.5 3.6 5.3 6.7 7.8 8. 6 9.0 9. 1 9.1 28 0.0 2.4 4.5 6. 2 7.6 8.7 9.5 9.9 10.0 - 10.0 30 1.0 3.4 5.4 7. 2 8.6 9. 7 10.4 10.9 11.0 11.0 32 2.0 4.4 6.5 8. 2 9.6 10. 7 11.5 11. 9 12.0 12.0 34 3. 1 5.5 7. 6 (9.3 10.7 11.8 12.6 13.0 13.1 13. 1 36 4.3 6. 7 8.7 10.5 11.9 13.0 13.7 . 14.2 14.3 14.3 38 5.5 7.9 10.0 11. 7 13. 1 14.2 15.0 15.4 15.5 15.5 40 6.9 9.2 11.3 13,0 14.4 15.5 16.3 16. 7 16.8 16. 8 42 8.2 10. 6 12. 7 14.4 15.8 16.9 17. 7 •18. 1 18.2 18.2 44 9. 7 12.0 14.1 15. 8 17. 2 18.3 19.1 19.5 19.7 19. 7 46 11. 2 13.6 15. 6 17.3 18. 7 19. 8 20.6 21.0 .21.2 21.2 48 12. 7 15. 1 17.2 18.9 20.3 21.4 22.2 22. 6 22. 7 22. 7 50 14.4 16.8 18. 8 20. 6 22.0 23. 1 23. 8 24.3 24.4 24.4 Log P o s i t i o n Decay Factors f o r Western Hemlock Trees: Suspect Class 1 F r a c t i o n s of t o t a l height - h/H DBH . 1 .2 .3 .4 .5 .6 .7 .8 .9 .1.0 ( i n c h e s ) Per cent of gross t r e e volume decayed 8 12.4 14.8 16.9 18. 6 20.0 21. 1 21.9 22.3 22.4 22.4 10 12, 7 15. 1 17.2 18.9 20.3 21.4 22.2 : 22. 6 22.7 22. 7 12 13. 1 15.5 17.5 19. 3 20. 7 21. 8 22.5 23.0 23.1 23.1 14 . 13.5 15.9 18.0 19. 7 21.1 22.2 23.0 23.4 23.5 23.5 16 14.0 16.4 18.5 20. 2 21. 6 22. 7 23.5 23.9 24. 6 24. 6 18 -14.6 17.0 19.6 20. 8 22. 2 23.3 24.0 24.5 24.6 24.6 20 15.2 17.6 19. 7 21.4 22-. 8 23.9 24. 7 25. 1 25.2 25. 2 22 16.0 18.3 20.4 22. 1 23.5 24.6 25.4 25.8 25.9 25.9 24 16. 7 19.1 21.2 22.9 24.3 25.4 26. 2 26. 6 26.7 26. 7 26 17.6 19.9 22.0 23. 7 25. 1 26.2 27.0 27.4 27. 6 27.6 28 18. 5 20. 8 22.9 24. 6 26.0 27. 1 27.9 28.3 28.5 28. 5 30 19.4 21.8 23.9 25. 6 27.0 28. 1 28.9 29.3 29.4 29.4 32. 20. 5 22. 8 24.9' 26.6 28.0 29. 1 29.9 30.3 30.5 30.5 34 21. 6 25. 1 27.2 28.9 30.3 31.4 .32. 2 32.6 ' 32.7 32. 7 36 22. 7 25. 1 27.2 28.9 30.'3 31.4 32.2 32.6 32. 7 32. 7 38 24. 0 26.4 28.4 30'. 2 31.6 32: 6 33.4 33.9 34. 0 34.0 40 25 .'3 27. 7 • 29. 7 31.5 32.9 34.0 34. 7 35.2 35.3 35.3 42 26. 7 29.0 31.1 32. 8 34.2 35,3 36.1 36.5 36. 7 36.7 44 28.1 30.5 32.5 34.3 35.7 36. 8 37.5 38. 0 38. 1 38.1 46 29.6 32.0 34.0 35.8 37. 2 38.3 39.0 39.5 . 39.6 39.6 48 31.2 33.6 35.6 37.3 33. 8 39.8 40.6 41.1 41.2 41.2 50 32.8 35. 2 37.3 39.0 40.4 41.5 42.3 42, 7 42. 8 42.8 r-1 Log P o s i t i o n Decay Factors f o r Western Hemlock Trees: Suspect Class 2 F r a c t i o n s of t o t a l height - h/H DBH . 1 .2 .3 .4 .5 .6 . 7 .8 • .9 1.0 ( i n c h e s ) Per cent of gross t r e e volume decayed "8 2.7 .5: i ' 7.2 8.9 10.3 11.4 12. 2 12.6 12.7 12.7 10 3.0 5.4 7.5 9.2 10.6 l l i 7 12.5 12.9 13.0 13.0 12 3.4 5.8 7. 8 9.6 11.0 12. 1 12. 8 13.3 13.4 13.4 14 3.8 6. 2 8.3 10.0 11.4 12. 1 12.8 13,7 13.8 13.8 16 4.3 6.7 8.8 10.5 11.9 13.0 13.3 14.2 14.3 14.3 18 4.9 7.3 :.9. 3 11.1 12.5 13.6 .14.3 14. 8 14.9 14.9 20 5, 5 7.9 10.0 11.7 13.1 14. 2 15.0 - 15.4: 15.5 15.5 22 6.2 8. 6 10. 7 12.4 13.8 14; 9 15.7 16. 1 16.2 16.2 24 '."7.0 9.4 11.4 . 13.2 14.6 15; 7 16.4 16.9 17.0 17.0 26 7.9 10.2 12.3 14,0 15.4. 16; 5 17.3 17. 7 17. 8 17.8 28 8. 8 11.1 13. 2 14.9 16.3 17.4 18.2 18. 6 18.8 . 18.8 30 9.7 12.1 14.2 15.9 17,3 18.4 19.2 19.6 19.7 19. 7 32 10. 8 13. 1 14.2 15.9 17.3 18,4 19.2 19. 6 19.7 19. 7 34 11.9 14.2 16.3 18.0 19.4 20, 5 21.3 21. 7 21.9 21.9 36 13.0 15.4 17.5 19.2 20. 6 21. 7 22.5 22.9 23.0 23.0 38 14.3 16. 7 18.7 20.4 21.9 22,9 23.7 24. 2 24. 3 24.3 40' 15.6 18.0 20.0 21. 8 23. 2 24.3 25.0 . 25.5 25. 6 25. 6 42 17.0 19.3 21.4 23, 1 24.5 25, 6 26.4 26. 8 27.0 27.0 44 18.4 20.8 22. 8 24. 6 26.0 27. 1 2.7. 8 28.3 28.4 28.4 46 19.9 22.3 24.3 26. 1 27.5 28, 6 29.3 29. 8 29.9 29.9 48 21.5 23.9 25.9 27. 6 29.1 30, 1 30.9 31.4 31.5 31.5 50 23. 1 25.5 27. 6 29.3 30.7 31.8 32.6 33. 0 33. 1 33. 1 Log P o s i t i o n Decay F a c t o r s f o r . Western Hemlock Trees: Suspect c l a s s 3 F r a c t i o n s of t o t a l height - h/H DBH (i n c h e s ) . 1 .2 .3 Per .4 .5 .5 .7 cent of gross t r e e volume decayed • 8 .9 1.0 8 0.0 0.0 1.3 3. 1 4.5 5.6 6.3 6. 8 6.9 6.9 10 0.0 0.0 1.6 3.4 4. 8 5.9 6. 6 7.1. 7.2 7.2 12. 0..0 0.0 2.0 3.7 5. 1 6. 2 7.0 7.4 7.6 7,6 14 0.0 0.4 2.4 4.2 5.6 6.7 7.4 7.9 8.0 : 8,0 16 0.0 0.9 2.9 4.7 6.1 7.2 7.9 8.4 8,5 8.5 IS 0.0 1.5 3. 5 5.2 6. 7 7.7 8.5 9.0 9. 1 9.1 20 0.0 2.1 4.1 5.9 5.9 7.3 8.4 9.1 9.6 9.7 22 0.4 2.8 4.9 6.6 8.0 9. 1 9.8 10.3 10.4 10.4 24 1.2 3.6 5.6 7.4 8. 8 9.9 10.6 11.1 11.2 11.2 26 2.0 4.4 6.5 8. 2 9. 6 10. 7 11.5 12.8 12.9 12.9 28 2.9 5.3 7.4 9.1 10.5 11.6 12.4 12. 8 12.9 12.9 30 3.9 6.3 8.3 10. 1 11.5 12. 6 13.3 13.8 13.9 . 13.9 32 4.9 7.3 9.4 11.1 12.5 13.6 14.4 14.3 14.9 14.9 34 6.0 78.4 10. 5 12.2 13.6 14.7 15.5 15.9 16.0 16.0 36 7.2 9.6 11. 6 13.4 14.3 15.9 16.6 17.1 17.2 17.2 38 8.5 10.8 12.9 14. 6 16.0 17. 1 17.9 18.3 18.5 13.5 40 9.8 12.1 14.2 15.9 17.3 18.4 19.2 ' 19. 6 19.8 19.8 42 11. 1 13.5 15.6 17.3 18. 7 19.8 20.6 21.0 21.1 21.1 44 12.6 15.0 17.0 18. 7 20.1 21.2 22.0 22.4 22. 6 22.6 46 14.1 16.5 18.5 20.2 21.7 22. 7 23.5 24.0 24. 1 24.1 48 15. 7 18.0 20.1 21.8 23.2 24.3 25.1 25.5 25. 6 25.6 50 17.3 19.7 21.7 23.5 24.9 26.0 26. 7 27. 2 27.3 27.3 Log P o s i t i o n Decay Factors f o r Western Hemlock Trees: Suspect Class 4 F r a c t i o n of t o t a l height - h/H Dim .1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 ( i n c h e s ) Per cent of gross t r e e volume decayed 3 21.2 23.5 25. 6 27.3 28. 7 29. 8 30.6 31.0 31.2 31.2 10 21.5 . r '23.8 25.9 27. 6 29.0 30.1 30.9 31.3 31.5 31.5 12 21. 8 24. 2 26.3 28.0 29.4 30.5 31.3 31.7 . 31.8 31.8 14 22.3 24.7 26. 7 28.4 29. 8 30.9 31. 7 32. 1 32.3 32.3 16 22. 8 25.2 27. 2 28.9 30.4 31.4 32.2 32.6 32.8 32. 8 18 23.3 25. 7 27.8 29.5 30.9 32.0 32. 8 33.2 33.3 33.3 20 24.0 26.4 28. 4 30. 1 31.6 32. 6 33.4 33.9 34.0 34, 0 22 24.7 27.1 29. 1 30. 8 32.3 33.3 34. 1 34. 6 34. 7 34. 7 24 25.5 27. 8 29.9 31. 6 33.0 34. 1 34.9 35.3 35.4 35.4 26 26.3 28. 7 30. 7 32.5 33.9 35.0 35.7 36.2 36.3 36.3 28 27. 2 29.6 31. 6 33.4 34. 8 35.9 36. 6 37, 1 37.2 - 37.2 30 28.2 30.5 32.6 34. 3 35. 7 36. 8 37. 6 38.0 38.2 38. 2 32 29.2 31.6 33. 6 35.4 36. 8 37.9 38.6 39,1 39.2 39. 2 34 30.3 32. 7 34. 7 36.5 37.9 39.0 39. 7 40.2 40.3 40.3 36 31.5 33.9 35.9 37.6 39.1 40. 1 40.9 . 41.4 41.5 41.5 38 32. 7 35. 1 37.2 38.9 40.3 41.4 42. 1 42. 6 42. 7 42.7 40 34.0 36.4 38. 5 40. 2 41.6 42. 7 43.5 43.9 44.0 44. 0 42 35.4 37.8 39. 8 41.6 43.0 44. 1 44. 8 45.3 45.4 45.4 44 36. 8 39.2 41.3 43.0 44.4 45.5 46. 3 46.7 46. 8 46. 8 46 38.3 40.7 ". 42. 8 44.5 45.9 47,0 47. 8 48. 2 48.3 48.3 48 39.9 42.3 44.3 46. 1 47.5 48. 6 49.3 49.8 49.9 49.9 50 41. 6 43.9 46.0 47.7 49. 1 50.2 51.0 51.4 51,6 51. 6 Log P o s i t i o n Decay Factors f o r Western Hemlock Trees: Suspect Class 5 F r a c t i o n of t o t a l height - h/H DBH .1 .2 .3 - 4 • .5 .6 .7 .8 .9 1.0 (i n c h e s ) Per cent of gross t r e e volume decayed 8 15.3 17.7 19.8 21.5 22.9 24.0 24. 8 25.2 25.3_. 25,3 10 15.6 18.0 20. 1 21.8 23.2 24.3 25. 1 25.5 25. 6 25.6 12 16.0 18.4 20.4 22. 2 23. 6 24. 7 25.4 25.9 26.0 26.0 14 16.4 18.8 20.9 22.6 24.0 25.1 25.9 26.3 26.4 26.4 16 16.9 19.3 21.4 23.1 24.5 25.6 26.4 26. 8 26.9 26.9 18 17.5 19.9 22. 0 23.7 25. 1 26. 2 26.9 27.4 27.5 27.5 20 18.2 20.5 22. 6 24.3 25. 7 26. 8 27. 6 28.0 28.1 28. 1 22 18.9 21. 2 23.3 25.0 26.4 27.5 28.3 28. 7 28.9 28,9 24 19. 6 22.0 24.1 25.8 27. 2 28.3 29.1 29.5 29. 6 29. 6 26 20.5 22.8 24.9 26.6 28.0 29.1 29.9 30.3 30.5 30. 5 28 21.4 23. 7 25. 8 27.5 28.9 30.0 30. 8 31.2 31.4 31.4 30 22.3 24.7 26. 8 28.5 29.9 31.0 31. 8 32. 2 32.3 32.3 32 23.4 25.8 27. 8 29.5 31.0 32.0 32. 8 33.3 33.4 33.4 34 . 24.5 • 26.9 28.9 30.6 32.1 33.1 33.9 34.4 34.5 34.5 36 25.7 28.0 30. 1 31. 8 33. 2 34.3 35. 1 35.5 35.6 35.6 38 26.9 29.3 31.3 33.1 34.5 35.6 36.3 36. 8 36.9 36.9 40 28. 2 30.6 32.6 34. 4 35.8 36.9 37. 6 38. 1 38.2 38.2 42 29.6 31.9. 34.0 35. 7 37.1 38. 2 39.0 39.4 39.6 39.6 44 3.1.0: 33.4 35.4 37.2 38. 6 39. 7 40.4 40.9 41.0 41.0 46 32.5 . 34.9 36.9 38. 7 40. 1 41.2 41.9 : 42.4 42.5 42.5 48 34. 1 36.5 38.5 40.3 41.7 42.8 43.5 44.0 44.1 44. 1 50 35. 7 38.1 . 40.2 41.9 43.3 44.4 45.2 45. 6 45.7 45.7 Log P o s i t i o n Decay Factors f o r Western Hemlock Trees: Suspect Class 6 F r a c t i o n of t o t a l height - h/H DBH .1 . 2 .3 .4 .5 . 6 .7 .8 .9 1.0 (i n c h e s ) Per cent of gross t r e e volume decaye d 8 5. 6 8.0 10.1 11. 3 13.2, 14.3 15.1 15. 5 15. 6 15.6 10 5.9 8.3 . 10. 4 12.1 13.5 14.6 15.4 15.8 15;9 15.9 12 6.3 ' 8. 7 10,7 12.5 13.9 15.0 15.7 16.2 16.3 16.3 14 6.7 9. 1 11.2 12.9 14.3 15.4 16.2 16, 6 16.7 16.7 16 7.2 9.6 11. 7 13.4 14.8 15.9 16.7 17. 1 17.2 17.2 18 77.8 10.2 12. 2 14.0 15.4 16,5 17.2 17.7 17.8 17.8 20 8.5 10.8 12.9 14.6 16.0 17.1 17.9 18.3 18.. 4 18.4 22 9.2 XX. J 13.6 15.3 16. 7 17.8 18.6 19.0 19.1 19. 1 24 9.9 12,3 14. 4 16.1 17.5 18. 6 19.4 19. 8 19.9 19.9 26 10. 8 13. 1 15. 2 16.9 18.3 19.4 20. 2 20.6 20. 8 20.8 28 11. 7 14.0 "16. 1 17. 8 19.2 20. 3 21. 1 ' 21.5 21.7 21. 7 30 12.6 15.0 17.1 18. 8 20. 2 21.3 22.1 22. 5 22.6 22. 6 32 13. 7 16.1 18.1 19.8 21. 2 22. 3 23. 1 23.5 23.7 23. 7 34 14.8 17.2 19.2 20.9 22.4 23.4 24.2 24.7 24. 8 24. 8 36 15.9 18,3 20.4 22. 1 23.5 24. 6 25.4 25. 3 25.9 25.9 38 17.2 19,6 21.6 23.4 24. 8 25.9 26. 6 27. 1 27.2 27. 2 40 18.5 20.9 22.9 24. 7 26.1 27.2 27.9 28.4 28.5 28.5 42 19.9 22.2 24.3 26.0 27.4 28.5 29.3 29.7 29. 9 29.9 44 21.3 23. 7 25. 7 27.5 28. 9 30,0 30. 7 31.2 31.3 31.3 46 22.8 25. 2 27. 2 29.0 30.4 31.5 32. 2 32. 7 32.8 32. 8 48 24.4 26.8 28.8 30. 6 32, 0 33.1 33. 8 34.3 34.4 34.4 50 26.0 28.4 30.5 32.2 33, 6 34.7 35.5 35.9 36.0 36.0 Log P o s i t i o n Decay Factors f o r Western Hemlock Trees: Suspect Class 7 F r a c t i o n of t o t a l height - h/H DBH .1 .2 .3 .4 • .5 . 6 . 7 .8 .9 1.0 (inches) Per cent of gross t r e e volume de cayed 8 24. 1 26.5 28. 5 30. 2 31. 7 32. 7 33. 5 33.9 34.1 34. 1 10 24.4 26. 8 28. 8 30. 5 32. 0 33.0 33. 8 34. 2 34. 4 34. 4 12 24. 7 27. 1 29. 2. 30.9 32. 3 33. 4 34.2 34. 6 34. 7 34. 7 14 25. 2 27.6 29. 6 31.3 32. 8 33. 8 34. 6 35. 1 35.2 35. 2 16 25. 7 28. 1 30. 1 31.8 33.3 34. 3 35. 1 35. 6 35. 7 35. 7 18 26.3 28. 6 30. 7 32. 4 33. 8 34.9 35. 7 35. 1 36. 2 36, 2 20 26.9 29.3 31. 3 33.1 34. 5 35. 6 36. 3 36.8 36.9 36.9 22 27. 6 30. 0 32.0 33.8 35.2 36,3 37.0 37. 5 37.6 37. 6 24 28. 4 30. 7 32.8 34. 5 35.9 37. 0 37. 8 38, 2 38.4 38. 4 26 29. 2 31.6 33.6 35. 4 • 36.8 37.'9 38. 6 39. 1 39. 2 39. 2 28 30. 1 32. 5 34. 5 36.3 37. 7 38.8 39. 5 40. 0 40.1 40. 1 30 31. 1 33.4 35. 5 37. 2 38. 6 39, 7 40. 5 40.9 41.1 41. 1 32 32. 1 34.5 36. 5 38.3 39.7 40. 8 41.5 42.0 42. 1 42. 1 34 33. 2 35.6 37.6 39.4 40. 8 41.9 42.6 43. 1 43.2 43. 2 36 34.4 36. 8 38. 8 40.6 42,0 43. 1 43.8 44.3 44.4 44.4 38 35. 6 38.0 40. 1 41.8 43.2 44.3 45. 1 45. 5 45.6 45.6 40 36.9 39.3 41.4 43. 1 44.5 45.6 46.4 46.8 46.9 46.9 42 38.3 40. 7 42. 7 44. 5 45.9 47,0 47. 7 48.2 48. 3 48. 3 44 39. 7 42. 1 44. 2 45.9 47.3 48.4 49. 2 49.6 49.7 49,7 46 41.3 43. 6 45. 7 47.4 48. 8 49,9 50. 7 51.1 51.2 51. 2 48 42.8 45. 2 47.3 49.0 50.4 51.5 52.3 52.7 52.8 52.8 50 44.5 46.8 48.9 50.6 52.0 53.1 53.9 54.3 54,5 54. 5 Appendix I I . Comparison of estimated per cent of gross tree volume decayed from tre e decay equation (A) and l o g p o s i t i o n decay equation (B) f o r s e v e r a l suspect c l a s s e s . Suspect c l a s s DBH 0 1 2 3 (inches) A B A B A B A B 8 0.0 4.0 22.2 ' 22.4 10.9 12.7 4.6 6.9 10 1.0 4.3 23.2 22.7 11.9 13.0 5.6 7.2 12 2.0 4.7 24.3 23.1 13.0 13.4 6.6 7.6 14 3.0 5.1 25.3 23.5 14,0 13.8 7.6 8.0 16 4.0 5.6 26.3 24.0 15.0 14.3 8.7 3.5 18 5.1 6.2 27.3 24.6 16.0 14.9 9.7 9.1 20 6.1 6.8 28.3 25.2 17 .0 . .15.5 10.7 9.7 22 7.1 7.5 29.4 25.9 18.1 16.2 11.7 10.4 24 8.1 8.3 30.4 26.7 19.1 17 .0 12.8 11.2 26 9.2 9.1 31.4 27.6 20.1 17.8 13.8 12.0 28 10.2 10.0 32.4 28.5 21.1 18.8 14.8 12.9 30 11.2 11.0 33.4 29.4 22.2 19.7 15.8 13.9 32 12.2 12.0 34.5 30.5 23.2 20.8 16.9 14.9 34 13.2 13.1 35 .5 31.6 24.2 21.9 17 .9 16.0 36 14.3 14.3 36.5 32.7 25 .2 23.0 18,9 17 .2 38 15.3 15.5 37 .5 34.0 26.3 24.3 . 19.9 • 18.5 40 16.3 16.8 38.6 35.3 27 .3 25.6 20.9 19.8 42 17 .3 18.2 39.6 36.7 28.3 27.0 22.0 21.1 44 18.4 19.7 40.6 38.1 29.3 28.4 23.0 22.6 46 19.4 21.2 41.6 39.6 30.3 29.9 24.0 24.1 48 20.4 22.7 42.6 41.2 31.4 31.5 25.0 25.6 50 21.4 24.4 ' 43.7 42.8 32.4 33.1 26.1 27 .3 Appendix I I cont'd. Comparison of. estimated per cent of gross tree volume decayed from t r e e decay equation (A) and l o g p o s i t i o n decay equation (B) f o r s e v e r a l suspect c l a s s e s . Suspect c l a s s DBH 4 5. . 6 __7_ (inches) A B A B A 3 A, B .8 33.2 31.2 26.8 25.3 15.6 15.6 37 .8 34.1 10 34.2 31.5 27 .9 25 .6 16.6 15.9 38.8 34.4 12 35.2 31.8 28.9 26.0 17.6 16.3 39.9 34.7 14 36.2 32.3 29.9 26.4 18.6 16.7 : 40.9 35.2 16 37 .3 32.8 30.9 26.9 19.7 17 .2 41.9 ' 35.7 18 38.3 33.3 32.0 27 .5 20.7 17.8 42.9 36.2 20 39.3 34.0 33.0 28.1 21.7 18.4 44.0 36.9 22 40.34 34.7 34.0 28.9 22.7 19.1 45.0 37 .6 24 41.4 35.4 35 .0 29.6 23.7 19.9 46.0 = 38.4 26 42.4 36.3 36.0 30.5 24.8 20.8 47.0 39.2 28 43.4 37 .2 37.1 31.4 25.8 21.7 48.0 • 40.1 30 44.4 38.2 38.1 32.3 26.8 22.6 49.1 41.1 32 45.4 39.2 39.1 33.4 27.8 23.7 50.1 42.1 34 46.5 40; 3 40.1 34.5 28.8 24.8 51.1 . 43.2 36 47.5 41.5 41.2 35 .6 29.9 25.9 52.1 44.4 38 48.5 42.7 42.2 36.9 30.9 27 .2 53.2 45 .6 40 49.5 44.0 43.2 38.2 31.9 28.5 5412 46.9 42 50.6 45.4 44.2 39.6 32.9 29.9 55.2 48.3 44 51.6 46.8 45.2 41.0 34.0 31.3 56.2 49.7 46 52.6 48.3 46.3 42.5 3.5.0 32.8 . 57.2 51.2 48 53.6 49.9 47.3 44.1 36.0 34.4 58.3 52.8 50 54.6 51.6 48.3 45.7 37 .0 36.0 59.3 54.5 VO Appendix I I I . Taper Table f o r Western Hemlock: DBH (inch e s ) . 1 . 2 F r a c t i o n of t o t a l height - h/H .3 .4 .5 .6 Diameter i n s i d e bark ( d i b ) (in c h e s ) .7 . 8 .9 1.0 8 6. 8 6.3 5.8 *5.3 4. 7 3.9 3.0 2.0 1. 1 0.0 10 8. 5 7. 8 7.3 . 6. 6 5.9 4.9 3.8 ' 2.6 1.3 0.0 12 10. 2 9.4 8. 7 8.0 7.0 5.9 4.5 3. 1 1. 6 0.0 14 11.9 11.0 10. 2 9.3 8. 2 6.9 5.3 3. 6 1.8 o:o 16 13. 6 12. 5 11. 6 10. 6 9.4 7, 8 5.0 : 4.1 2. 1 0.0 18 15.3 14. 1 13.1 12. 0 10. 5 8. 8 6. 8 4. 6 2.4 0.0 20 17,0 15. 7 14. 6 13.3 11. 7 9.8 7.6 5. i : 2. 6 0.0 22 18. 7 17.3 16.0 14. 6 12.9 10.8 8. 3 5. 6 2.9 0.0 24 20.4 18.8 17. 5 15.9 14.1 11 .8 9.1 6. 1 3. 2 0.0 26 22. 1 20.4 18.9 17.3 15. 2 12. 7 •9.8 6. 6 3.4 0.0 28 23.8 22.0 20. 4 18. 6 16. 4 13. 7 10,6 7.2 3. 7 0.0 30 25.5 23.5 21.8 19.9 17. 6 14.7 11.3 •7.7' 3.9 0.0 32 27. 2 25. 1 23. 3 21.3 18. 7 15. 7 12. 1 8.2 4. 2 0.0 34 28.9 26. 7 24. 7 22. 6 19.9 16. 6 12,8 8. 7 ' 4.5 0.0 36 30. 6 28.2 26. 2 23.9 21.1 17.6 13.6 9.2 4. 7 0.0 38 32.3 29.8 27. 7 25. 2 22.3 18.6 14.4 9.7 .5.0 0.0 40 34.0 31.4 29. 1 26. 6 23.4 19.6 15.1 10. 2 5.3 0.0 42 35. 7 32.9 30. 6 27.9 24.6 20. 6 15.9 10.7 5.5 0.0 44 37.3 34.5 32.0 29. 2 25.8 21.5 16,6 11.2 5.8 0.0 46 39.0 36.1 33. 5 30. 6 26.9 22.5 17.4 11.7 6.0 0.0 48 40. 7 37.6 34.9 31.9 28. 1 23. 5 18.1 12.3 6.3 0.0 50 42.4 39.2 36.4 . 33. 2 29.3 24.5 18. 9 12.8 6. 6 0.0 Ba s i c equation: dib=DBH \j . 89046 - 2. 23409^ + 6.63776(g) 2 - 14. 18542(|) 3 + 12.97729(|) 4 - 4.08533(|) 5 by d e f i n i t i o n : when h=H dib=»0.0 Appendix IV. T a b u l a t i o n ( P a r t I ) and e x p l a n a t i o n ( P a r t I I ) of values derived during c a l c u l a t i o n sequence f o r the e s t i m a t i o n of gross and net cubic foot volumes by l o g p o s i t i o n w i t h i n a t r e e Given: Western hemlock tree and the f o l l o w i n g observations: DBH 1 6 inches T o t a l height 1 0 0 f e e t E x t e r n a l a b n o r m a l i t i e s 1 l a r g e open scar Required: E s t i m a t i o n of gross and net volume f o r each 20-foot s e c t i o n between a stump height of 1 foot and a top diameter i n s i d e bark of 4" inches. P a r t I: T a b u l a t i o n of c a l c u l a t e d ' v a l u e s . Column No. 1 2 3 4 5 6 7 8 9 10 11 12 Sec t i o n No. Length ( f e e t ) Cumulative length ( f e e t ) Diameter i n s i d e -bark (inches) b u t t top Gross (cubic unadj. volume feet) adj . Cumulative decay volume unadjusted % c . f . Decay (cubic unadj. volume feet) adj.. Net volume (cubic f e e t ) adjusted 1 1 1 16.0 16.0 1.40 1.36 ',-'.' - • _.. 1.36 2 20 21 16.0 12.5 22.48 21.63 6.7 3.41 3.41 3.59 18.04 3 20 41 12.5 10.6 14.65 14.09' 10.5 5.35 1.94 2.03 12.06 4 2.0 61 10.6 7 .8 9.45 9.09 13.0 6.62 1.27 1.33 7.76 5 20 81 7J8 4.1 4.24 4.0.8 14.2 7.23 0.61 0.64 3,44 8 :. 19. 100G 4.1 0.0 0.70 0.68 14.3 7 .28 0.05 0.05 0.63 TOTAL Explanation of t a b u l a t i o n of c a l c u l a t e d values . Explanation I d e n t i f i c a t i o n and sequence number of s e c t i o n s i n tree numbered i n order from ground to top. Length i n feet of each s e c t i o n Cumulative length i n feet from ground to top of s p e c i f i e d s e c t i o n number. Diameters i n s i d e bark i n inches at butt and top of s p e c i f i e d s e c t i o n . These diameters estimated through taper f u n c t i o n tabulated i n Appendix I I I . Gross cubic foot volumes c a l c u l a t e d by Smalian's formula from diameters estimated i n columns '"4" and "5".. F i r s t s e c t i o n volume c a l c u l a t e d as volume of a c y l i n d e r ; l a s t s e c t i o n volume c a l c u l a t e d as .4 times b a s a l area of butt of top s e c t i o n times length of t i p s e c t i o n . Gross cubic foot volumes adjusted to ensure that summation of s e c t i o n volumes are equivalent to t o t a l t r e e volume as estimated by tree volume f u n c t i o n ( t a b l e 46), T o t a l cubic f o o t t r e e volume = 5.2619 + .17838(DBH) 2H/100 = 50.93 cubic f e e t . Adjustment f a c t o r = 50.93/52.92 = 0.962. Adjusted gross cubic foot volumes = 0.962 times column "6" e n t r i e s . 184 Par t I I : E x p l a n a t i o n of t a b u l a t i o n of c a l c u l a t e d values (cont'd). Column Explanation no. 8 Cumulative unadjusted decay volume expressed as a percentage of t o t a l adjusted t r e e volume i n cubic f e e t . These f i g u r e s derived from l o g p o s i t i o n decay e s t i m a t i n g f u n c t i o n tabulated i n appendix I, 9> Cumulative unadjusted decay volumes i n cubic f e e t c a l c u l a t e d by m u l t i p l y i n g column "8" e n t r i e s by column "7" t o t a l entry, 10 Unadjusted decay volume i n cubic f e e t c a l c u l a t e d by successive s u b t r a c t i o n s of e n t r i e s i n column "9", 11 Cubic foot decay volumes adjusted to ensure that summation of s e c t i o n decay volumes i s equivalent to t o t a l t r e e decay volume as estimated by tree decay f u n c t i o n ( t a b l e 46), T o t a l t r e e decay•= 15 per cent of 50.93 ~ 7.64 cubic f e e t . Adjustment f a c t o r = 7.64/7/28 = 1.049. Adjusted decay volume - 1.049 times e n t r i e s i n column "10". 12 •, Net s e c t i o n volumes i n cubic f e e t c a l c u l a t e d by s u b t r a c t i n g column "11" e n t r i e s from column "7" e n t r i e s . 185 Appendix V: Tree stem and decay p r o f i l e s f o r three western hemlock trees w i t h h e a r t r o t caused by E. t i n c t o r i u m . 186 Stem and decay profile showing sample locations,tree No-22-196-Legend decayed wood • sample locations and numbers 10 15 20 Diameter inside bark (inches) 25 Stem and decay profile showing sample locations,tree N o U 35|-Diameter inside bark (inches) cay profile showing sample locations, tree-No- 22-138-Diameter inside bark (inches) 

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