UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

The evaluation of margo porosity in relationship to wood permeability of douglas fir (Pseudotsuga Menziesii… Chan, Cho-Kai 1972

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

Notice for Google Chrome users:
If you are having trouble viewing or searching the PDF with Google Chrome, please download it here instead.

Item Metadata

Download

Media
831-UBC_1972_A6_7 C33.pdf [ 11.52MB ]
Metadata
JSON: 831-1.0302207.json
JSON-LD: 831-1.0302207-ld.json
RDF/XML (Pretty): 831-1.0302207-rdf.xml
RDF/JSON: 831-1.0302207-rdf.json
Turtle: 831-1.0302207-turtle.txt
N-Triples: 831-1.0302207-rdf-ntriples.txt
Original Record: 831-1.0302207-source.json
Full Text
831-1.0302207-fulltext.txt
Citation
831-1.0302207.ris

Full Text

THE EVALUATION OF MARGO POROSITY IN RELATIONSHIP TO WOOD PERMEABILITY OF DOUGLAS - FIR [PSEUDOTSUGA MENZIESII (MIRB.) FRANCO] by CHO-KAI CHAN B . S c , CHUNG CHI COLLEGE, H.K. CHINESE UNIV., 1964 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n the Department o f F o r e s t r y We accept t h i s t h e s i s as conforming t o the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA APRIL, 1972 In presenting t h i s thesis i n p a r t i a l fulfilment of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t freely available for reference and study. I further agree that permission for extensive copying of t h i s thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. I t i s understood that copying or publication of t h i s thesis for f i n a n c i a l gain s h a l l not be allowed without my written permission. Department of The University of B r i t i s h Columbia Vancouver 8, Canada Date 19 7 ^ A B S T R A C T L o n g i t u d i n a l a i r p e r m e a b i l i t y measurements of Douglas-f i r [Pseudotsuga m e n z i e s i i (Mirb.) Franco] outer sapwood from three t r e e s of d i f f e r e n t seed sources and growth l o c a t i o n s were determined on microsections about 500-700 microns t h i c k , d r i e d by a i r - s e a s o n i n g and solvent-seasoning. The specimens were suc-c e s s i v e l y reduced i n leng t h from 3.6 to 0.4 cm. Darcy's law was found to be i n v a l i d w i t h respect t o specimen l e n g t h . Sapwood earlywood l o n g i t u d i n a l a i r p e r m e a b i l i t y was found to be a s e n s i t i v e barometer of seasoning e f f e c t on p i t a s p i r a t i o n . The o b j e c t i v e was t o determine where the v a r i a t i o n s i n margo p o r o s i t y were s i g n i f i c a n t , and hence a p p l i c a b l e t o problem of D o u g l a s - f i r p e r m e a b i l i t y . The diameters of earlywood margo openings were measured d i r e c t l y from e l e c t r o n micrographs of un-a s p i r a t e d (solvent-seasoned) p i t s . The margo measurement was assumed to represent one plane i n s t e a d of the a c t u a l three dimen-s i o n a l s t r u c t u r e , and the pores observed were the ones that con-t r o l l e d the r a t e of flow. Samples from the most, i n t e r m e d i a t e l y and l e a s t permeable specimens were s e l e c t e d and prepared f o r the e v a l u a t i o n of anatomical parameters of bordered p i t membranes (margo area and margo p o r o s i t y ) as r e l a t e d t o p e r m e a b i l i t y . The e f f e c t s of p i t a s p i r a t i o n , t r a c h e i d length, t o t a l number of p i t s per t r a c h e i d , number of t r a c h e i d s per square m i l l i m e t e r , and s p e c i f i c g r a v i t y on p e r m e a b i l i t y were a l s o assessed. P i t p a r t -i a l a s p i r a t i o n was found as the most important v a r i a b l e c o r r e l a t e d w i t h p e r m e a b i l i t y . I n an order of decreasing importance, p i t p a r t i a l a s p i r a t i o n , margo p o r o s i t y and s p e c i f i c g r a v i t y together accounted f o r 94 per cent of t o t a l v a r i a b i l i t y i n p e r m e a b i l i t y of solvent-seasoned earlywood. No s t a t i s t i c a l e v a l u a t i o n s were made to compare the three t r e e s w i t h respect t o t h e i r p e r m e a b i l i t y and the measured parameters. TABLE OF CONTENTS i v PAGE TITLE PAGE i ABSTRACT i i TABLE OF CONTENTS i v LIST OF TABLES v i LIST OF FIGURES v i i . ACKNOWLEDGEMENT v i i i INTRODUCTION 1 LITERATURE REVIEW 3 I . Concept and measurement of coniferous wood p e r m e a b i l i t y 3 I I . V a r i a b i l i t y of coniferous wood p e r m e a b i l i t y 7 A. Geographic v a r i a t i o n s 7 B. Wood zone v a r i a t i o n s 9 C. Growth zone v a r i a t i o n s 10 I I I . Coniferous wood s t r u c t u r a l f a c t o r s a f f e c t i n g p e r m e a b i l i t y 14 A. X y l a r y anatomy of D o u g l a s - f i r 14 1. S t r u c t u r a l components 14 2. V a r i a b i l i t y of t r a c h e i d dimensions 15 3. Bordered p i t - p a i r s of l o n g i t u d i n a l t r a c h e i d s 19 a) A key f a c t o r i n f l u e n c i n g flow 19 b) D e t a i l e d s t r u c t u r e 21 (1) P i t border 25 (2) Pinus-type p i t membrane 25 (a) Torus 26 (b) Margo 27 (c) Margo pore dimensions 29 c) P i t a s p i r a t i o n 34 B. Man i p u l a t i o n of coniferous wood p e r m e a b i l i t y by solvent-seasoning 39 V PAGE MATERIAL AND METHODS 42 I. Sample m a t e r i a l s 42 I I . P e r m e a b i l i t y specimens 43 I I I . P e r m e a b i l i t y apparatus and measurements 47 IV. Anatomical measurements 53 A. Tracheid l e n g t h and number of p i t s per t r a c h e i d 53 B. Percent p i t a s p i r a t i o n , r a d i a l w a l l thickness and number of t r a c h e i d s per square m i l l i m e t e r 53 C. P i t dimensions and margo p o r o s i t y 56 V. S t a t i s t i c a l analyses 59 RESULTS AND DISCUSSION 60 I. D o u g l a s - f i r sapwood bordered p i t s 60 A. General s t r u c t u r e 60 B. Margo p o r o s i t y 69 I I . E f f e c t of specimen l e n g t h on l o n g i t u d i n a l a i r p e r m e a b i l i t y 73 I I I . E f f e c t of t r a c h e i d dimensions and s p e c i f i c g r a v i t y pn l o n g i t u d i n a l a i r p e r m e a b i l i t y 81 IV. E f f e c t of p i t s t r u c t u r e on l o n g i t u d i n a l a i r p e r m e a b i l i t y 84 A. P i t a s p i r a t i o n and seasoning e f f e c t 84 B. Margo area and margo p o r o s i t y 90 CONCLUSIONS 92 LITERATURE CITED 93 APPENDIX I DEHYDRATION, INFILTRATION AND EMBEDDING 111 APPENDIX I I STAINING 113 APPENDIX I I I DEFINITIONS OF SYMBOLS 114 APPENDIX IV MARGO AREA CALCULATION 115 APPENDIX V THE ESTIMATION OF MARGO PORE SIZE 116 APPENDIX VI STATISTICAL AND DATA TABLES 123 v i LIST OF TABLES PAGE Table 1. Table 2. Table 3. Tabl e 4. Table 5. Table 6. Table 7. Table 8. Table 9. Table 10. Table 11. Survey o f D o u g l a s - f i r t r a c h e i d l e n g t h Survey o f margo pore s i z e d e terminations 17 31 Percentage o f u n a s p i r a t e d p i t s i n a i r - d r i e d sapwood o f 5 c o n i f e r o u s s p e c i e s (from P h i l l i p s , 1933) 36 E f f e c t o f seasoning on a s p i r a t i o n o f D o u g l a s - f i r earlywood i n t e r t r a c h e i d bordered p i t - p a i r s and l o n g i t u d i n a l a i r p e r m e a b i l i t y (from Meyer, 1971) 4 1 C h a r a c t e r i s t i c s o f t h r e e D o u g l a s - f i r wood specimens used i n the study 42 Average diameters o f p i t annulus, t o r u s and a p e r t u r e 60 Average margo pore areas and diameters 70 Summary o f t r a c h e i d dimensions o f D o u g l a s - f i r sapwood 81 Summary o f p e r m e a b i l i t y vs. s p e c i f i c g r a v i t y o f D o u g l a s - f i r sapwood 83 E f f e c t o f seasoning on a s p i r a t i o n o f Douglas-f i r o uter sapwood i n t e r t r a c h e i d bordered p i t -p a i r s and l o n g i t u d i n a l a i r p e r m e a b i l i t y 85 Percentage o f u n a s p i r a t e d p i t s and r a d i a l w a l l t h i c k n e s s 85 v i i LIST OF FIGURES PAGE Figure 1. Unaspirated coniferous bordered p i t - p a i r 22 Figure 2A. M i c r o s e c t i o n blank 45 B. P e r m e a b i l i t y sandwich 45 C. Sampling of r e p l i c a t i n g and embedding specimens 45 Figur e 3. Schematic diagram of l o n g i t u d i n a l a i r permea-b i l i t y apparatus 49 Figure 4. P e r m e a b i l i t y c e l l d e t a i l 51 Figure 5. Schematic diagram of p i t a s p i r a t i o n 55 Figur e 6. E l e c t r o n micrograph of t y p i c a l latewood p i t s 62 Fi g u r e 7. E l e c t r o n micrograph of t y p i c a l earlywood p i t s 64 Figure 8. E l e c t r o n micrograph of an unaspirated earlywood p i t from the solvent-seasoned outer sapwood of IC t r e e 67 Figure 9. E l e c t r o n micrograph of unaspirated p i t s from the outer sapwood of I I t r e e 72 Figure 10. R e l a t i o n s h i p between log a r i t h m of l o n g i t u d i n a l a i r p e r m e a b i l i t y and specimen l e n g t h of D o u g l a s - f i r sapwood 75 A. CC t r e e 75 B. IC t r e e 77 C. I I t r e e 79 Figure 11. E l e c t r o n micrograph of earlywood p i t s from the outer sapwood of D o u g l a s - f i r showing the d i f f e r e n t degree of a s p i r a t i o n as a r e s u l t of seasoning 88 A C K N O W L E D G E M E N T v i i i The author wishes t o thank God f o r the opportunity to study i n the F a c u l t y of F o r e s t r y of the U n i v e r s i t y of B r i t i s h Colum-• l i i a t/ and t o acknowledge the s u p e r v i s i o n and guidance o f f e r e d by Dr. J . W. Wilson, Professor, 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 over the past years at t h i s U n i v e r s i t y . G r a t e f u l acknowledgement i s made to Dr. R. W. Meyer, Western Forest Products Laboratory, Vancouver, f o r the valuable counsel and k i n d a s s i s t a n c e i n a l l phases of the study. A s p e c i a l debt of g r a t i t u d e i s owed t o the Western Forest Products Labora-t o r y , Vancouver, as w e l l as t o the F a c u l t y of F o r e s t r y of the U n i v e r s i t y of B r i t i s h Columbia, f o r t h e i r f i n a n c i a l a s s i s t a n c e and f o r the extensive use of the former's f a c i l i t i e s and equip-ment. The c o n s t r u c t i v e c r i t i c i s m s and h e l p f u l suggestions o f f e r e d by the author's committee are much appreciated. P a r t i c u l a r thanks are due t o Dr. W. G. Warren, Miss A. Hej j a and Mr. J . Hejjas f o r t h e i r advice on s t a t i s t i c a l analyses and computer programming, the former w i t h regard t o the e s t i m a t i o n of margo pore s i z e . A p p r e c i a t i o n i s extended t o Mrs. A. Bramhall and Mrs. 0. E. Ferguson f o r t h e i r a s s i s t a n c e i n the p r e p a r a t i o n of m i c r o s l i d e s used i n anatomical measurements; a l s o t o Dr. G. Bramhall f o r h i s h e l p f u l counsel. i x L ast, but not the l e a s t , the encouragement and patience of my w i f e , Anna, i s deeply appreciated. I N T R O D U C T I O N 1 Several f i e l d s of wood u t i l i z a t i o n (e.g. wood pre-s e r v a t i o n , wood seasoning, dimensional s t a b i l i z a t i o n and pulping) are concerned e i t h e r d i r e c t l y or i n d i r e c t l y w i t h the movement of l i q u i d s , gases or vapours through wood. In other words, the p e r m e a b i l i t y of wood plays an important r o l e i n a f f e c t i n g process-i n g time and product q u a l i t y , which are i n v a r i a b l y r e l a t e d t o cost f a c t o r s . A b a s i c knowledge of wood p e r m e a b i l i t y i s t h e r e f o r e e s s e n t i a l f o r a proper understanding of these f i e l d s of wood u t i l i z a t i o n , and f o r t h e i r r a t i o n a l d e v e l o p m e n t S i g n i f i c a n t s t r i d e s have been made i n understanding the mechanisms of flow through wood and the r e l a t i o n s h i p of flow to the minute wood s t r u c t u r e . I t i s c l e a r l y seen t h a t p e r m e a b i l i t y depends on an i n t e r a c t i o n of s e v e r a l f a c t o r s and th a t no one approach be i t p h y s i c a l , chemical or anatomical, t o the e x c l u s i o n of the others, w i l l l e a d t o an understanding of the phenomenon ( B a i l e y , 1964). The various- f l u i d flow passageways i n coniferous woods are l i m i t e d w i t h t h e i r simple and homogeneous s t r u c t u r e . F l u i d f l o w along the g r a i n must be p r i m a r i l y through the predominant, l o n g i t u d i n a l t r a c h e i d s , and the bordered p i t - p a i r s connecting them thus provide the p o t e n t i a l passageways f o r i n t e r t r a c h e a l f l u i d flow. Since .the p e r f o r a t e d p i t membrane was demonstrated by s e v e r a l i n v e s t i g a t o r s ( B a i l e y , 1913, a,b; Cote and Krahmer, 1962; 2 Kishima, 1965; and L i e s e , 1956), i t has been g e n e r a l l y assumed tha t most of the l o n g i t u d i n a l f l u i d flow occurs through the margo pores of coniferous bordered p i t s . Therefore, margo p o r o s i t y should have a profound i n f l u e n c e on p e r m e a b i l i t y . But no research t o date has demonstrated the r e l a t i o n s h i p between margo p o r o s i t y and p e r m e a b i l i t y d i r e c t l y . The present study was undertaken t o determine the r e -l a t i v e i n f l u e n c e of margo p o r o s i t y and s e v e r a l other anatomical f a c t o r s (margo area, t r a c h e i d l e n g t h , number of p i t s per t r a c h e i d , per cent p i t a s p i r a t i o n , number of t r a c h e i d s per square m i l l i m e t e r and s p e c i f i c g r a v i t y ) on l o n g i t u d i n a l a i r p e r m e a b i l i t y of Douglas-f i r sapwood. Measurements of r e l a t i v e p e r m e a b i l i t i e s of earlywood and latewood were obtained by preparing microsections across the growth i ncr ement. LITERATURE REVIEW 3 I . C o n c e p t and measurement of coniferous wood p e r m e a b i l i t y The movement of f l u i d s (penetration) through the c a p i l l a r y s t r u c t u r e of wood can be a t t a i n e d by the use of one of two mech-anisms t h a t f o l l o w d i f f e r e n t laws and vary i n e f f e c t i v e n e s s through d i f f e r e n t s t r u c t u r e s , namely, (1) d i f f u s i o n , and (2) p e r m e a b i l i t y (Ellwood and Thomas, 1968; Stamm, 1967). The former i s a spon-taneous movement of a substance i n t o another from a higher con-c e n t r a t i o n zone to a zone of lower c o n c e n t r a t i o n under a m o t i v a t i o n which i s always from w i t h i n (Stamm, 1967). I t p r i m a r i l y depends upon the d e n s i t y of wood (Ellwood and Thomas, 1968). The l a t t e r , p e r m e a b i l i t y , i s the f l u i d c o n d u c t i v i t y of wood as a porous medium, r e f l e c t i n g i t s c a p a c i t y t o be permeated by f l u i d under a pressure gradient (Fogg, 1968). This mechanism can be more r a p i d than d i f f u s i o n and provides more opportunity f o r c o n t r o l of depth of pe n e t r a t i o n : a n d r e t e n t i o n of the penetrant and i s l a r g e l y indepen-dent of de n s i t y (Ellwood and Thomas, 1968). A l l p e r m e a b i l i t y t h e o r i e s and equations o r i g i n a t e from Darcy's (1856) famous law, a f t e r the formulator, Henri P. - G. Darcy, a French h y d r a u l i c engineer. He i n v e s t i g a t e d flow c h a r a c t e r i s t i c s of sand f i l t e r s i n connection w i t h the p u b l i c fountains i n D i j o n . His law i n f l u i d dynamics s t a t e s t h a t the v e l o c i t y of flow of a l i q u i d through a porous medium due t o d i f f e r e n c e i n pressure, i s p r o p o r t i o n a l t o the pressure gradient i n the d i r e c t i o n of flow, and i s expressed as f o l l o w s : k = AAP where k = the p e r m e a b i l i t y constant, Q = f l u i d f low r a t e , L = specimen length, A = c r o s s - s e c t i o n a l area of specimen, and A P = pressure drop across the specimen. Coniferous wood p e r m e a b i l i t y can be determined by measurements usi n g e i t h e r l i q u i d f low or gas flow, but sin c e gas flow i s not complicated by the decreasing flow r a t e and other anomalous be-haviour t h a t c h a r a c t e r i z e s l i q u i d flow, i t i s much simpler t o measure (Comstock, 1967). T h e o r e t i c a l l y , gas and l i q u i d permea-b i l i t i e s are fun c t i o n s of the permeated wood and t h e r e f o r e should be independent of i n e r t , nonswelling, permeating f l u i d s (Com-stock, 1965). However, they were reported t o be not i d e n t i c a l (Comstock, 1967; Resch and Ecklund, 1964; Smith, 1963). The gas p e r m e a b i l i t y value of a wood sample i s g e n e r a l l y higher than the value of l i q u i d p e r m e a b i l i t y . The d i f f e r e n c e was b e l i e v e d t o be due to the combined e f f e c t of s l i p flow encountered w i t h gas (Comstock, 1967, 1968), and three major f a c t o r s , namely menisci e f f e c t s , t r a n s p o r t a t i o n of d e b r i s , and movement of t o r i which predominate i n l i q u i d f low (Ellwood and Thomas, 1968). The former i s r e s p o n s i b l e f o r higher measured gas p e r m e a b i l i t y values than 5 the t r u e p e r m e a b i l i t y of wood, whereas the l a t t e r f a c t o r s introduce hindrances i n the l i q u i d flow through wood. The d i r e c t r e l a t i o n s h i p between gas and l i q u i d p e r m e a b i l i t y i n wood was revealed f i r s t by Comstock (1967). He concluded that under c o n d i t i o n s of equal s w e l l i n g , s l i p - c o r r e c t e d gas permeabi-l i t y was no d i f f e r e n t than the l i q u i d p e r m e a b i l i t y . I n other words, wood p e r m e a b i l i t y i s a c h a r a c t e r i s t i c of the wood i t s e l f , and i s independent of the permeating f l u i d used t o measure i t . Assuming laminar flow through the c a p i l l a r y s t r u c t u r e of wood, the l i q u i d p e r m e a b i l i t y of wood can be adequately expressed i n the modified form of Darcy's law which in c l u d e s the e f f e c t of f l u i d v i s c o s i t y : K _ Q M — AAP where k = s p e c i f i c or tru e p e r m e a b i l i t y (darcy), 3 Q = flow r a t e (cm / s e c ) , L = specimen l e n g t h (cm), <3? — v i s c o s i t y ( c e n t i p o i s e ) , 2 A = flow area (cm ), and AP = pressure drop (atm.). The above equation i s only v a l i d f o r an incompressible f l u i d (Fogg, 1968), but has a l s o been employed f o r gas p e r m e a b i l i t y c a l c u l a t i o n s by many i n v e s t i g a t o r s before and a f t e r Comstock*s 6 (1967) f i n d i n g . Taking i n t o account the c o m p r e s s i b i l i t y of the gas, the s u p e r f i c i a l gas p e r m e a b i l i t y , kg (Scheidegger, 1960) can be c a l c u l a t e d according to Darcy's law kQ = K g AAPp where P = the absolute pressure at which the flow, Q, i s measured, and p = the mean absolute pressure i n the specimen. Klinkenberg (1941) deri v e d the f o l l o w i n g expression f o r gas p e r m e a b i l i t y w i t h c o r r e c t e d s l i p flow: kg = k (1 _ P where b = = constant f o r a given sample, C = constant ^ 1 , X = mean f r e e path of the gas, and r 6 = rad i u s of pores . The above expression has been a p p l i e d t o wood by Comstock (1967). 7 I I . V a r i a b i l i t y of coniferous wood p e r m e a b i l i t y A. Geographic v a r i a t i o n s D o u g l a s - f i r i s d i s t r i b u t e d n a t u r a l l y i n p a r t s of B r i t i s h Columbia (Canada) as w e l l as C a l i f o r n i a , Oregon and Washington (Western U n i t e d ' S t a t e s ) , where i t occurs i n the c o a s t a l region,, and i n the mountains. The geographical and e c o l o g i c a l i s o l a t i o n s between c o a s t a l and i n t e r i o r forms are d e f i n i t e (Frothingham, 1909; Haddock, et a l . , 1967; L i t t l e , 1953). A s e r i e s of s i g n i -f i c a n t d i f f e r e n c e s i n morphology between c o a s t a l and i n t e r i o r populations were i n d i c a t e d by Tusko (1963). He concluded t h a t there are s u f f i c i e n t grounds to recognize two subspecies w i t h i n the province of B r i t i s h Columbia. These are ssp. m e n z i e s i i , c o a s t a l D o u g l a s - f i r , and ssp. glaucescens ( B a i l l y ) Schw., i n t e r i o r or Rocky Mountain D o u g l a s - f i r . Anatomical d i f f e r e n c e s of both types of the wood cannot normally be d i s t i n g u i s h e d (Krahmer, 1961), but they have been found to d i f f e r i n s t r e n g t h p r o p e r t i e s and ease of t r e a t a b i l i t y (Panshin and DeZeeuw, 1970). The i n f l u e n c e of geographic o r i g i n on p e r m e a b i l i t y of Douglas-f i r was discussed by s e v e r a l i n v e s t i g a t o r s (Blew, 1961; Bramhall, 1966, 1967, 1971; C r a i g , 1963; E r i c k s o n and Estep, 1962; M i l l e r , 1961; M i l l e r and Graham, 1963). I t i s w e l l e s t a b l i s h e d through these i n v e s t i g a t i o n s t h a t the p e r m e a b i l i t y , e s p e c i a l l y of h e a r t -wood, from the two d i f f e r e n t regions i s remarkably d i f f e r e n t , w i t h the i n t e r i o r type g e n e r a l l y possessing much lower p e r m e a b i l i t y . 8 Bramhall (1966) showed that the p e r m e a b i l i t y of D o u g l a s - f i r heartwood from 26 areas of B r i t i s h Columbia, which v a r i e d from extremely r e f r a c t o r y t o moderately permeable, i s r e l a t e d to the reg i o n of growth. He a l s o depicted a r e l a t i o n s h i p between the annual p r e c i p i t a t i o n of the area of growth and the p e r m e a b i l i t y , because samples from d r i e r areas showed lower p e r m e a b i l i t i e s than those from s i t e s w i t h higher r a i n f a l l . He concluded t h a t geo-graphic o r i g i n i s the most important f a c t o r i n f l u e n c i n g the p e r m e a b i l i t y of D o u g l a s - f i r heartwood. 9 B. Wood zone v a r i a t i o n s Many i n v e s t i g a t o r s ( B a i l e y , 1913a; B a i l e y , 1966; Bramhall, 1967, 1971; Bramhall and Wilson, 1971; Comstock, 1968; Fogg, 1968; G r i f f i n , 1919, 1924; Krahmer and Cote, 1963) reported t h a t higher sapwood p e r m e a b i l i t i e s of most species are found i n the n a t u r a l (green) c o n d i t i o n . The wood p r e s e r v a t i o n i n d u s t r y has long been aware of the sapwood-heartwood d i f f e r e n c e i n per-m e a b i l i t y . This i s e s p e c i a l l y t r u e i n D o u g l a s - f i r and other resinous s p e c i e s . Krahmer and Cote (1963) revealed t h a t p i t as-p i r a t i o n , o c c l u s i o n and i n c r u s t a t i o n g e n e r a l l y a s s o c i a t e d w i t h the t r a n s f o r m a t i o n of sapwood i n t o heartwood, are e f f e c t i v e i n reducing the c a p i l l a r y s i z e of the bordered p i t - p a i r s and thus c o n t r i b u t e t o the lower p e r m e a b i l i t y of heartwood. The a i r per-m e a b i l i t y r a t i o of unextracted, e a r l y sapwood to l a t e heartwood f o r D o u g l a s - f i r was 34:1 (Krahmer and Cote, 1963). They a l s o found t h a t e x t r a c t i o n of heartwood w i t h hot water, ethanol and ethanol-benzene improved the p e r m e a b i l i t y , but the p e r m e a b i l i t y of e x t r a c t e d heartwood d i d not equal that of the unextracted sap-wood. Bramhall and Wilson (1971) observed that earlywood permea-b i l i t i e s of c o a s t a l D o u g l a s - f i r heartwood were 10 to 100 times higher than t h a t of i n t e r i o r type f o r s e v e r a l d r y i n g methods. However, p e r m e a b i l i t y of e i t h e r sapwood or heartwood latewood specimens was about the same (0.2 darcy) f o r each d r y i n g method t e s t e d , and the h i g h earlywood p e r m e a b i l i t i e s recorded a f t e r low s u r f a c e - t e n s i o n d r y i n g were e n t i r e l y r e s t r i c t e d t o the sapwood. 10 C. Growth zone v a r i a t i o n s Weiss (1912) was probably the e a r l i e s t i n v e s t i g a t o r i n r e c o g n i z i n g higher p e r m e a b i l i t y f o r dry latewood than t h a t of earlywood. He a m p l i f i e d Tiemann's theory (1910) by suggesting that the s t i f f e r and t h i c k e r - w a l l e d latewood t r a c h e i d s check more than the earlywood t r a c h e i d s , thus accounting f o r the higher latewood p e r m e a b i l i t y . G r i f f i n (1919) observed the same phenome-non, but explained that earlywood p i t a s p i r a t i o n i s the r e s p o n s i b l e f a c t o r f o r t h i s e f f e c t . By v i r t u e of i t s l a r g e r t r a c h e i d s , greater number of p i t s per t r a c h e i d ( P h i l l i p s , 1933; Thomas and Scheld, 1967), and s i z e of the p i t s (Thomas and S c h e l d , 1967), earlywood w i t h p i t s i n the unaspirated c o n d i t i o n should be much more per-meable than latewood. A f t e r d r y i n g the greater number of unas-p i r a t e d latewood p i t s should r e s u l t i n greater p e r m e a b i l i t y there as the latewood p i t possesses a more r i g i d p i t membrane t o r e s i s t a s p i r a t i o n ( P h i l l i p s , 1933). The high latewood p e r m e a b i l i t y of d r i e d wood has been shown by s e v e r a l i n v e s t i g a t o r s ( E r i c k s o n et a l . , 1937; H a r r i s , 1953; Osnach, 1961; Scarth, 1928; Teesdale, 1914). In s t u d i e s of flow passageways, Buro and Buro (1959a) found no c o n s i s t e n t d i f f e r e n c e i n Scots pine between earlywood and l a t e -wood, whereas•Erickson and B a l a t i n e c z (1964) noted t h a t u s u a l l y a greater number of latewood t r a c h e i d s i n D o u g l a s - f i r were permeated. Comstock (1968) claimed that the h i s t o r y of the wood p r i o r t o d r y i n g i s important i n t h i s r e l a t i o n s h i p . 11 Formal attempts to measure r e l a t i v e earlywood and latewood p e r m e a b i l i t i e s have only been made i n recent years, because of the t e c h n i c a l problems a s s o c i a t e d w i t h making these measurements. P a r t i t i o n i n g the l o n g i t u d i n a l gas.^permeability of small wood blocks into'earlywood and latewood components was done by s e a l i n g the exposed, s e l e c t e d components of growth zones on the ends of blocks w i t h p a r a f f i n by Buro and Buro (1959b) or r e s i n by Osnach (1961). Considerable v a r i a t i o n s were found i n t h e i r r e s u l t s . A x i a l gas p e r m e a b i l i t y of D o u g l a s - f i r microsections across the growth increment was i n i t i a l l y determined by Bramhall and Wilson (1971). They found t h a t w i t h i n the growth increment of i n t e r i o r D o u g l a s - f i r , the last-formed latewood and f i r s t - f o r m e d earlywood were more permeable, i n d i c a t i n g t h a t the f i r s t - f o r m e d earlywood has p e r m e a b i l i t y c h a r a c t e r i s t i c s more r e l a t e d t o latewood than earlywood. They showed t h a t latewood p e r m e a b i l i t y of e i t h e r sap-wood or heartwood was about 0.2 darcy f o r s e v e r a l d r y i n g methods. The above observation suggested t h a t the latewood margo was of s t i f f e r nature and r e s i s t s a s p i r a t i o n , t h e r e f o r e , no s i g n i f i c a n t change i n latewood p e r m e a b i l i t y i s experienced as a r e s u l t of con-v e n t i o n a l d r y i n g techniques or i n p h y s i o l o g i c a l sapwood-heartwood conversion. They a l s o observed the l e a s t earlywood p e r m e a b i l i t y i n a i r or oven-dried i n t e r i o r heartwood, wh i l e h i g h earlywood p e r m e a b i l i t i e s were e n t i r e l y r e s t r i c t e d to t h a t sapwood t r e a t e d by low s u r f a c e - t e n s i o n d r y i n g techniques. On the other hand, repo r t s on the i n f l u e n c e of s p e c i f i c g r a v i t y on p e r m e a b i l i t y are c o n f l i c t i n g ; probably s p e c i f i c g r a v i t y i t s e l f does not a f f e c t p e r m e a b i l i t y but r a t h e r f a c t o r s r e l a t e d to s p e c i f i c g r a v i t y are i n v o l v e d (Benvenuti, 1963). Obviously v a r i a t i o n s i n s p e c i f i c g r a v i t y are expressions of changes i n c e l l u l a r dimensions and arrangements. Percentage of latewood i s a gross expression of these changes (Lassen and Okkonen, 1969). D i f f e r e n c e s i n s p e c i f i c g r a v i t y , e i t h e r w i t h i n a s i n g l e species or between d i f f e r e n t species d i d not show a corresponding v a r i a b i l i t y i n permeability!. (Craig, 1963; E r i c k s o n and Estep, 1962; Koran, 1964; M i l l e r , 1961). This i s a t t r i b u t a b l e t o the f a c t t h a t p e r m e a b i l i t y i s more dependent on the arrangement and frequency of p i t t i n g than on the p r o p o r t i o n of v o i d spaces i n the wood ( M i l l e r , 1961; Resch and Ecklund, 1964). However, Blew (1961) found a r e l a t i o n s h i p between s p e c i f i c g r a v i t y and per-m e a b i l i t y i n c o a s t a l D o u g l a s - f i r . Benvenuti (1963) a l s o concluded th a t s p e c i f i c g r a v i t y was the best s i n g l e i n d i c a t o r of d i f f e r e n c e s i n p e r m e a b i l i t y between t r e e s ( l o b l o l l y pine, Pinus taeda L.) and w i t h i n the sapwood of s i n g l e t r e e s ; based on the a t t r i b u t e of l a r g e r t r a c h e i d and fewer a s p i r a t e d p i t s i n latewood. Bramhall (1967) noted t h a t the p o i n t of gr e a t e s t p e r m e a b i l i t y w i t h i n an increment was not tha t of greatest s p e c i f i c g r a v i t y , and a simple c o r r e l a t i o n between s p e c i f i c g r a v i t y and l o n g i t u d i n a l gas-permea-b i l i t y might be f o r t u i t o u s . 13 Buro and Buro (1959a) noted t h a t width of the growth i n -crements had no e f f e c t on p e r m e a b i l i t y . The same a p p l i e s f o r the r e l a t i o n s h i p between the growth r a t e and p e r m e a b i l i t y . 14 I I I . Coniferous wood s t r u c t u r a l f a c t o r s a f f e c t i n g p e r m e a b i l i t y A. X y l a r y anatomy of D o u g l a s - f i r 1. S t r u c t u r a l components The Xylem of D o u g l a s - f i r i s a t y p i c a l coniferous wood t i s s u e . I t has a comparatively simple, r e g u l a r s t r u c t u r e c o n s i s t i n g p r i m a r i l y of l o n g i t u d i n a l t r a c h e i d s , arranged r e g u l a r l y i n r a d i a l rows, w i t h both parenchyma and t r a c h e i d s forming the x y l a r y rays. X y l a r y rays are of two types, namely, u n i s e r i a t e and f u s i f o r m . The l a t t e r contain: a transverse r e s i n c a n a l . The only other l o n g i t u d i n a l l y o r i e n t e d s t r u c t u r e s i n D o u g l a s - f i r are e p i t h e l i a l c e l l s forming the l o n g i t u d i n a l r e s i n canals and the l o n g i t u d i n a l parenchyma. The l o n g i t u d i n a l t r a c h e i d s , which con-s t i t u t e more than 90% of the wood volume (Isenberg, 1963), are of demonstrated s i g n i f i c a n c e i n l o n g i t u d i n a l p e r m e a b i l i t y . The arrangement of l o n g i t u d i n a l t r a c h e i d s provides f o r stepwise, l a t e r a l f l u i d movement i n the t a n g e n t i a l d i r e c t i o n through the bordered p i t p a i r s (Cote, 1963). The l o n g i t u d i n a l r e s i n canal i s a l s o a p o s s i b l e pathway f o r l o n g i t u d i n a l f l u i d movement, but p r o p o r t i o n -a l l y much l e s s s i g n i f i c a n t than t r a c h e i d s , thus i t does not appear t o be e f f e c t i v e (Hunt and G a r r a t t , 1967). On the other hand, the rays c o n t r i b u t e t o l a t e r a l f l u i d movement i n the r a d i a l d i r e c -t i o n ( Erickson and B a l a t i n e c z , 1964). 15 2. V a r i a b i l i t y of t r a c h e i d dimensions Richardson (1964) pointed out t h a t d i r e c t e f f e c t s of c l i m a t i c v a r i a b l e s are of l i t t l e s i g n i f i c a n c e i n determining u l t i m a t e c e l l s i z e i n c o n i f e r s . I n d i r e c t i n f l u e n c e s may be im-p o r t a n t . w i t h respect to w a l l t h i c k n e s s and lumen diameter but the major determinants of t r a c h e i d l e n g t h are unknown. Probably the genotypic component of the phenotype plays an important r o l e . A d i r e c t r e l a t i o n s h i p between t r a c h e i d l e n g t h and d i s t a n c e from the p i t h was reported i n D o u g l a s - f i r , white f i r and noble f i r (Anderson, 1951). This r e l a t i o n s h i p i s independent of height i n t r e e , p r o v i d i n g the t r a c h e i d s are l o c a t e d somewhat above ground l e v e l . The s h o r t e s t t r a c h e i d s were found near the p i t h ; outward from the p i t h , t r a c h e i d l e n g t h increased r a p i d l y , then more slow l y w i t h a tendency to l e v e l o f f (Anderson, 1951; Lee and Smith, 1916). Wellwood and Smith (1962) reported t h a t lengths of t r a c h e i d s of 16 D o u g l a s - f i r t r e e s i n c r e a s e as r i n g age i n c r e a s e s . Tracheids near the t r e e baset.'were sh o r t e r than those at higher l e v e l s at p o i n t s e q u i d i s t a n t from the p i t h (Ander-son, 1951; Lee and Smith, 1916; Shepard and B a i l e y , 1914). W i t h i n a growth increment, a t a given l e v e l i n the t r e e , the latewood t r a c h e i d s are g e n e r a l l y considered t o be longer than the earlywood t r a c h e i d s (Chalk, 1930; K r i b s , 1928; Lee and Smith, 1916). How-ever, Gerry (1915) found t h a t the l a r g e s t t r a c h e i d s of D o u g l a s - f i r are i n the e a r l i e s t earlywood and s h o r t e s t i n the l a s t l a y e r s of 16 latewood. Data a v a i l a b l e on the t r a c h e i d l e n g t h of c o a s t a l and i n t e r i o r D o u g l a s - f i r are summarized i n Table 1. Several i n v e s t i g a t o r s (Krahmer, 1961; Lee and Smith, 1916; Meyer, 1971) concluded that c o a s t a l D o u g l a s - f i r appears t o produce a t r a c h e i d averaging s l i g h t l y longer than t h a t growing i n the i n t e r i o r . The r e s u l t s of Koran (1964) showed th a t i n t e r i o r D o u g l a s — f i r t r a c h e i d l e n g t h was not an important f a c t o r i n determining a i r p e r m e a b i l i t y or creosote r e t e n t i o n . Any minor i n f l u e n c e which t r a c h e i d l e n g t h might have had was masked by the e f f e c t of more important f a c t o r s . On the other hand, Meyer (1971) suggested that s h o r t e r t r a c h e i d s and a s m a l l e r number of p i t s per t r a c h e i d render wood r e l a t i v e l y l e s s permeable. F l e i s c h e r (1950) revealed .that t r a c h e i d s i n the per-meable (c o a s t a l ) heartwood were l a r g e r and had l a r g e r lumina than those i n the r e f r a c t o r y ( c o a s t a l ) heartwood. For a l l Douglas-f i r samples measured, Krahmer (1961) noted t h a t the permeable woods had a s i g n i f i c a n t l y l a r g e r average lumen s i z e of 40.32 microns r a d i a l l y , and 35.61 microns t a n g e n t i a l l y , whereas i n r e f r a c t o r y woods the width of t r a c h e i d s was 27.96 microns r a d i a l l y and 26.69 microns t a n g e n t i a l l y . Penhallow (1907) r e a l i z e d t h a t the c e l l w a l l s of Douglas-f i r are about 2.4 microns t h i c k i n the earlywood and 8.4 microns t h i c k i n the latewood, i . e . , they are some three times as t h i c k i n the latewood as i n the earlywood. Later, P h i l l i p s (1933) 17 TABLE 1. SURVEY OF DOUGLAS-FIR TRACHEID LENGTH Wood Growth (mm) Tracheid Length Type Zone Zone Min. Ave. Max. Source Remark Coastal SW*,HW* EW* LWf 0.34 4.46 8.60 Lee & Smith (1916) 8550 t r a c h e i d s measured at 171 p o i n t s ( i n -crements ) i n a s i n g l e t r e e . C o a s t a l SW,HW EW,LW • — — 3.44 — — I I 500 measure-ments made from 10 increments. Coast a l I I n — 4.43 — I I I I Mountain ( i n t e r i o r ) I I I I — 3.06 — I I I I Mountain ( i n t e r i o r ) I I n — 4.18 — I I H Permeable ( c o a s t a l ) HW EW,LW 5.06 5.59 6.16 Krahmer (1961) 180 t r a c h e i d s measured Refr a c t o r y (mountain) HW EW, LW 3.19 3.68 4.09 I I 200 t r a c h e i d s measured I n t e r i o r True SW EW,LW 4.14 Koran (1964) 20 t r a c h e i d s measured I n t e r i o r Outer HW I I — 4.11 — II • i I n t e r i o r Included SW n — 4.15 — II I I I n t e r i o r Included SW n — 3.48 — II I I I n t e r i o r Inner HW I I — 3.03 — II I I C o a s t a l SW EW" — 4.94 — Meyer (1971) 45 t r a c h e i d s measured I n t e r i o r SW EW — 3.49 — I I * SW = sapwood HW = heartwood EW = earlywood LW — latewood 18 s t a t e d t h a t i n most cases a very d i r e c t c o r r e l a t i o n e x i s t e d be-tween c e l l w a l l thickness and the percentage of unaspirated p i t s . He found t h a t B r i t i s h - g r o w n D o u g l a s - f i r xylem w i t h 6-micron-thick r a d i a l w a l l s was 79% aspirated, whereas Canadian-grown D o u g l a s - f i r xylem w i t h 11-micron-thick r a d i a l w a l l s was only 47% a s p i r a t e d . 19 3. Bordered p i t - p a i r s of l o n g i t u d i n a l t r a c h e i d s a) A key f a c t o r i n f l u e n c i n g flow The v a r i e t y of f l u i d flow passageways are l i m i t e d i n coniferous woods w i t h t h e i r simple and homogeneous s t r u c t u r e . F l u i d f low along the g r a i n must be p r i m a r i l y through the predominant, l o n g i t u d i n a l t r a c h e i d s , and the bordered p i t -p a i r s connecting them thus provide the p o t e n t i a l passageways f o r i n t e r t r a c h e a l f l u i d flow. Tiemann's (1910) hypothesis t h a t l i q u i d s pass through m i c r o s c o p i c a l s l i t s i n the seasoned wood c e l l w a l l s during pressure impregnation was disproved by B a i l e y (1913a), who showed t h a t although s l i t s may occur i n the t r a c h e i d w a l l s during d r y i n g the primary w a l l s remain unruptured, and a l s o demonstrated th a t small carbon p a r t i c l e s suspended i n l i q u i d pass through the membranes of bordered p i t s ( B a i l e y , 1913b). Since the o r i g i n a l work of B a i l e y (1913,a,b) and subsequently of Cote and Krahmer (1962), Kishima (1965) and L i e s e (1956) demonstrated that the p i t membrane contains p e r f o r a -t i o n s , i t has been g e n e r a l l y accepted that the flow of f l u i d s from t r a c h e i d t o t r a c h e i d takes place through the bordered p i t s . In a d d i t i o n , the dependence of f l u i d flow on the a v a i l a b i l i t y of p i t s has been s u b s t a n t i a t e d by a number of i n v e s t i g a t o r s ( B a l a t i n e c z , 1963; Buro and Buro, 1959a; Cote, 1958; Cote and Krahmer, 1962; E r i c k s o n and B a l a t i n e c z , 1964; Krahmer and Cote, 1963; L i e s e , 1965; Resch and Ecklund, 1964; Sebastian, e_t a l . , 1965; Smith and Lee, 1958; Stamm, 1963; Stamm and Wagner, 1961). 20 Despite a number of experimental f a c t s which support the theory t h a t p i t s are the major paths f o r flow, Preston (1959) has expressed the opposite o p i n i o n t o e x p l a i n the l o c a t i o n of water-borne p r e s e r v a t i v e s w i t h i n the c e l l w a l l . Based on the presence of p r e s e r v a t i v e s a l t s w i t h i n the c e l l w a l l s revealed by the e l e c t r o n microscope, he suggested t h a t f a r greater flow i s l i k e l y t o occur through the system of more numerous, f i n e c a p i -l l a r i e s i n the c e l l w a l l s . His hypothesis was supported by B a i l e y (1964), but no new evidence was a v a i l a b l e . Probably the presence of s a l t s i n the c e l l w a l l as a r e s u l t of d i f f u s i o n a f t e r t r e a t -ment i s a more l i k e l y e x p l a n a t i o n as pointed out by Nicholas (1966) and Tamblyn (1960). Stamm (1946) regarded these c a p i l l a r i e s as being too small and tortuous t o permit s u b s t a n t i a l l i q u i d flow. Furthermore, Stamm (1967) i n d i c a t e d t h a t the passage of l i q u i d s through the c e l l w a l l i n comparison w i t h p i t s i s n e g l i g i b l e as the average diameter of openings i n bordered p i t s (0.06 micron) i s 75 times greater than t h a t of the t r a n s i e n t openings i n water swollen c e l l w a l l (0.0008 micron). 21 b) D e t a i l e d s t r u c t u r e The s t r u c t u r e and p h y s i o l o g i c a l behaviour of bordered p i t s has been n o t i c e d f o r a long time ( B a i l e y , 1913b, 1915; Russow, 1883; Sachs, 1887; Sanio, 1873). Since the advent of the e l e c t r o n microscope much more became known about bordered p i t s t r u c t u r e ( B a i l e y , 1957; Ei c k e , 1954; Frey-Wyssling and Bosshard, 1953; Harada and Mi y a z a k i , 1952; L i e s e , 1956, 1965; L i e s e and Hartmann-Fahnenbrock, 1953) and about t h e i r ontogeny (Fengel, 1966; Frey-Wyssling, et a l . , 1956). Bordered p i t s and t h e i r membranes, which are c r i t i c a l s t r u c t u r e s f o r f l u i d flow i n c o n i f e r s , have r e c e i v e d a d i s p r o p o r t i o n a t e l y l a r g e share of a t -t e n t i o n i n the era of e l e c t r o n microscopy of wood. This i s appro-ximately equivalent t o the p e r i o d beginning around 1947 or 1948 and extending t o the present (Cote, 1967). The IAWA (1964) d e f i n i t i o n of a bordered p i t i s as f o l l o w s : a recess i n the secondary w a l l of a tracheary element, together w i t h i t s e x t e r n a l c l o s i n g membrane, which i s overarched by the secondary c e l l w a l l , c a l l e d the p i t border. The p i t c a v i t y i s d e f i n e d as the e n t i r e space w i t h i n a p i t from the membrane t o the lumen; the space between the p i t membrane and the overarching p i t border i s c a l l e d the p i t chamber, and the opening i n the border i s the p i t aperture. An i n t e r c e l l u l a r p a i r i n g of two bordered p i t s makes a bordered p i t - p a i r as depicted i n Figure 1. p i t border p i t aperture annulus (membrane rim) Figure 1. Unaspirated Coniferous bordered p i t - p a i r c 23 A review of the l i t e r a t u r e revealed no systematic study of the s i z e and number of bordered p i t s i n D o u g l a s - f i r . Marts (1955), making use of phase microscopy i n h i s examination of D o u g l a s - f i r earlywood p i t membranes, s t a t e d t h a t the approximate dimensions of the bordered p i t s photographed are as f o l l o w s : border diameter 23 microns, torus diameter 11 microns, and aperture diameter 7 microns. F i f t e e n earlywood p i t s of each sample (per-meable and r e f r a c t o r y ) were measured d i r e c t l y from r a d i a l wood se c t i o n s w i t h a l i g h t microscope by Krahmer (1961). He published no average dimensions but reported t h a t the diameters of bordered p i t s t r u c t u r e s showed no r e l a t i o n s h i p t o the p e r m e a b i l i t y of D o u g l a s - f i r heartwood. Krahmer and Cote (1963) found t h a t the diameter of D o u g l a s - f i r p i t borders were about 18 microns, and the torus about 10 microns across. Meyer (1971) found t h a t the average number of bordered p i t s per earlywood t r a c h e i d i s much greater i n the c o a s t a l than the i n t e r i o r D o u g l a s - f i r sapwood. The former contained over twice as many p i t s per t r a c h e i d as the l a t t e r , 144 vs. 65. Based on the a v a i l a b l e evidence, he suggested t h a t the number of p i t s per t r a c h e i d together w i t h t r a c h e i d l e n g t h plays an important r o l e i n coniferous wood p e r m e a b i l i t y . By means of an i n d i r e c t method, P h i l l i p s (1933) gave an average number of p i t s per earlywood t r a -c h e i d and latewood t r a c h e i d , 92 and 8 r e s p e c t i v e l y f o r D o u g l a s - f i r grown i n England. Krahmer (1961) observed t h a t hexagonal earlywood t r a c h e i d s are predominant i n the cross s e c t i o n of permeable Douglas-24 f i r heartwoods, with a radial wall capable of supporting a double row of bordered pits, while the tracheids in refractory heartwoods are more square in cross section with a single row of bordered pits on the radial wall. (1) P i t border The absence of notable d i f f e r e n c e s i n the s t r u c t u r e of p i t border between specie s , genera, or f a m i l i e s of gymnosperms, caused L i e s e (1965) t o regard t h i s p a r t of the p i t as a s t a b l e f e a t u r e . The inner p a r t of the p i t border has been found f o r c o a s t a l and i n t e r i o r D o u g l a s - f i r t o be fre e i of a warty l a y e r (Liese and Hartmann-Fahnenbrock, 1953), so t h a t warts should have no i n f l u e n c e on the s e a l i n g e f f e c t of the t o r u s . (2) Pinus-type p i t membrane B a i l e y ' s (1913b) concept of a p e r f o r a t e d d i v i d i n g membrane w i t h a c e n t r a l , c i r c u l a r , thickened torus was supported by the r e s u l t s of Li e s e and Hartmann-Fahnenbrock (1953). The p i t membrane i s the e s s e n t i a l component of a bordered p i t - p a i r P r i n c i p a l d i f f e r e n c e s between species e x i s t p r i m a r i l y w i t h regard t o the p i t membrane (Comstock, 1968). According to the number and d e n s i t y of m i c r o f i b r i l s w i t h i n the margo and the presence or absence of a w e l l def i n e d thickened t o r u s , L i e s e (1965) proposed the f o l l o w i n g f i v e b a s i c types of p i t membranes: (1) Pinus-type, (2) Araucaria-type, (3) Thujopsis-type, (4) Gnetum-type, and (5) Cycas-type. Since D o u g l a s - f i r i s a member of the Pinaceae, only p i t membranes of the Pinus-type are considered i n d e t a i l here L i e s e (1965) defined the Pinus-type p i t membrane as one w i t h a 26 d e f i n i t e , thickened torus supported by a moderately dense margo w i t h f a i r l y l a r g e openings. The general s t r u c t u r e of the torus and margo of both c o a s t a l and i n t e r i o r D o u g l a s - f i r appeared t o be the same (Liese and Hartmann-Fahnenbrock, 1953). (a) Torus The torus i s d e f i n e d as the c e n t r a l thickened p a r t of the p i t membrane, where the m i c r o f i b r i l s are e s s e n t i a l l y o r i e n t e d i n a c i r c u l a r p a t t e r n (Krahmer and Cote, 1963), c o n s i s t i n g of middle l a m e l l a and two primary w a l l s . I t i s g e n e r a l l y regarded as imperforate and nonpermeable (Frey-Wyssling et a l . , 1956; L i e s e , 1965). Whenever the torus i s d i s -p laced from i t s middle p o s i t i o n as a r e s u l t of pressure d i f f e r e n c e s on opposite sides of the p i t , or of surface t e n s i o n forces a c t i n g during the d r y i n g of wood above the f i b e r s a t u r a t i o n p o i n t ( E r i -ckson, et a l . , 1938; G r i f f i n , 1919, 1924; P h i l l i p s , 1933), i t covers the p i t aperture e n t i r e l y and thus e f f e c t i v e l y blocks the movement of f r e e l i q u i d s . Jayme, et al_. (1960) have suggested t h a t the torus w i t h i t s r a d i a t i n g f i b r i l s i s an a r t i f a c t created by d r y i n g s t r e s s e s . However, L i e s e (1965), Thomas (1967), and Tsoumis (1965) pointed out the e x i s t e n c e of a torus i n unaspirated p i t s . Furthermore, the absence of a torus i n a s p i r a t e d p i t membranes of gymnosperm f a m i l i e s other than the Pinaceae a l s o speak against t h i s hypothesis ( L i e s e , 1965). 27 Stone (1939) concluded th a t the e f f e c t i v e s e a l i n g of p i t s by a s p i r a t i o n i n heartwood t r a c h e i d s of i n t e r i o r D o u g l a s - f i r was i n h i b i t e d by the roughly surfaced t o r u s . However, many D o u g l a s - f i r heartwood a s p i r a t e d p i t s observed i n the study of Krahmer and Cote (1963) w i t h the e l e c t r o n microscope d i d show a very t i g h t s e a l between the torus and the aperture margin. (b) Margo The margo (meaning the edge, or margin; Frey-Wyssling, 1959) i s the unthickened, p e r f o r a t e d p a r t of the membrane between the edge of the p i t border and the torus (Esau, 1967; L i e s e , 1965; Panshin and DeZeeuw, 1970) c o n s i s t i n g of r a d i -a t i n g and i n t e r t w i n i n g m i c r o f i b r i l l a r strands arranged i n a t h r e e -dimensional network. The r a d i a t i n g strands arranged i n a p r e -f e r e n t i a l l y r a d i a l p a t t e r n from the torus to the annulus or membrane r i m ( J u t t e and S p i t , 1963), are u s u a l l y l a r g e r i n d i a -meter than the i n t e r t w i n i n g randomly-oriented m i c r o f i b r i l l a r strands (Thomas, 1969). The formation of the l a r g e r a d i a l l y - o r i e n t e d ( r a d i a t i n g ) m i c r o f i b r i l l a r strands of the margo can be explained by the f o l l o w i n g two hypotheses: ( i ) By aggregation of e x i s t i n g primary w a l l m i c r o f i b r i l s (Brown and Baker, 1970; Jayme, et a l . , 1960) ( i i ) By d e p o s i t i o n of an a d d i t i o n a l l a y e r of m i c r o f i b r i l s on the e x i s t i n g primary w a l l (Thomas, 1968, 1970). 28 In the study o f the u l t r a s t r u c t u r e o f l o n g i t u d i n a l t r a c h e i d bordered p i t membranes o f southern p i n e s p e c i e s , Thomas (1969) observed t h a t the p a r t o f the margo near the t o r u s i s c o n s i d e r a b l y more open than the outer p o r t i o n . Margo d e n s i t y (the number o f margo m i c r o f i b r i l s ) v a r i a t i o n seems t o be c o n t r o l l e d by the number o f s m a l l , randomly-oriented m i c r o f i b r i l a r s t r a n d s throughout the margo. The latewood margo d e n s i t y was c o n s i s t e n t l y h i g h e r than earlywood. A d e f i n i t e decrease i n the number o f margo m i c r o f i b r i l l a r s t r a n d s w i t h i n c r e a s i n g age o f the wood was d e t e c t e d . He suggested t h a t enzyme a c t i v i t y p e r -s i s t i n g deep i n the xylem r e g i o n may be r e s p o n s i b l e f o r the de-cr e a s e . Thomas a l s o observed t h a t i n c r u s t a t i o n s capable o f a l t e r -i n g margo p o r o s i t y were not noted on earlywood p i t membranes o f the sapwood zone, whereas heavy i n c r u s t a t i o n s were found on l a t e -wood p i t membranes r e g a r d l e s s o f l o c a t i o n . On the other hand, i n D o u g l a s - f i r , no remarkable d i f f e r e n c e s between sapwood and heartwood p i t s as w e l l as between heartwood samples r a t e d permeable, semipermeable or r e f r a c t o r y t o c r e o s o t e p e n e t r a t i o n were r e v e a l e d by Krahmer and Cote (1963). Only very few h e a v i l y i n c r u s t e d p i t membranes c o u l d be observed. The presence o f i n c r u s t a t i o n s on the h e a r t -wood and i n c l u d e d sapwood p i t membranes o£ i n t e r i o r D o u g l a s - f i r was regarded as a c r i t i c a l f a c t o r p r o h i b i t i n g p e n e t r a t i o n by Koran (1964). Sebas t i a n , Cote and Skaar (1965) b e l i e v e d t h a t i n c r u s t a t i o n may s t i f f e n the margo m i c r o f i b r i l s and consequently 29 reduce a s p i r a t i o n . N i c h o l a s (1966) i n d i c a t e d t h a t i n c r u s t a t i o n s can a l t e r p e r m e a b i l i t y by: ( i ) r e d u c i n g the s i z e o f margo pores, ( i i ) improving t o r u s s e a l i n p i t a s p i r a t i o n , and ( i i i ) p r o v i d i n g hydrophobic s u r f a c e s which can i n f l u e n c e a i r blockage"when water permeates wood. (c) Margo-.pore dimensions Krahmer and Cote (1963) i n d i c a t e d t h a t pores may range i n s i z e from s e v e r a l microns down to a few angs-troms i n an i n d i v i d u a l margo. The extremely s m a l l diameter o f these pores compared w i t h t r a c h e i d diameter means t h a t they con-s t i t u t e v i r t u a l l y the whole of the r e s i s t a n c e of softwoods t o f l u i d f l o w (Smith, 1963). Since i n c r u s t a t i o n s are r a r e l y d e p o s i t e d on D o u g l a s - f i r p i t membranes (Krahmer and Cote, 1963), i f a s p i r -a t i o n i s absent, or i f the s e a l i s d e f i c i e n t , the n a t u r a l v a r i a -t i o n i n margo d e n s i t y can be important i n a l t e r i n g p e r m e a b i l i t y ( N i c h o l a s , 1966). However, P e t t y and Preston (1969) suggested t h a t the one-component system (margo pores) may be a f a l s e assum-p t i o n . P e t t y (1970) i n d i c a t e d t h a t two s t r u c t u r a l components a f f e c t the flow r a t e , namely the margo pores and the t r a c h e i d lumina. L o n g i t u d i n a l flow through c o n i f e r o u s wood thus i n v o l v e s two components i n s e r i e s . In f a c t , the margo pore s i z e has been q u a n t i f i e d by a number o f i n v e s t i g a t o r s employing d i r e c t and 30 i n d i r e c t m e a s u r i n g t e c h n i q u e s . T h e s e a r e s u m m a r i z e d i n T a b l e 2, a n d a c o n s i d e r a b l e amount o f v a r i a t i o n i n p o r e s i z e i s o b v i o u s l y -s e e n . N i c h o l a s ;.(1966) s u g g e s t e d t h a t t h r e e f a c t o r s c o u l d e a s i l y l e a d t o t h e o b s e r v e d v a r i a t i o n . T h e s e a r e : ( i ) s t r u c t u r a l d i f f e r e n c e o f p i t membranes among g e n e r a a n d s p e c i e s c o n t r i b u t e s t o t h e o b s e r v e d v a r i a t i o n , ( i i ) d i f f e r e n t m e a s u r i n g t e c h n i q u e s b a s e d on c e r t a i n a s s u m p t i o n s h a v e v a r y i n g e f f e c t s o n a c c u r a c y , a n d ( i i i ) t h e c o n d i t i o n o f t h e p i t membrane ( a s p i r a t e d a n d u n a s -p i r a t e d ) a t t h e t i m e o f m e a s u r e m e n t i s i m p o r t a n t . P e t t y ( 1 9 7 0) n o t e d t h a t t h e c a p i l l a r y p r e -s s u r e a n d f i l t r a t i o n m e t h o d s p r o v i d e a n i n d i c a t i o n o f t h e s i z e d i s t r i b u t i o n o f p o r e r a d i i w h i l e t h e f l o w m e t h o d a l l o w ' t h e t o t a l number o f p o r e s t o b e e s t a b l i s h e d . He i n d i c a t e d t h a t t h e c a l c u -l a t e d v a l u e s o f p o r e numbers p u b l i s h e d s o f a r a p p e a r t o b e much s m a l l e r t h a n m i g h t be e x p e c t e d f r o m e x a m i n a t i o n o f e l e c t r o n m i c r o -g r a p h s o f p i t membranes. Thomas a n d N i c h o l a s ( 1 9 6 6) p o i n t e d o u t t h a t t h e s i z e o f t h e o p e n i n g s m e a s u r e d d i r e c t l y f r o m e l e c t r o n m i c r o g r a p h s ' o f a s p i r a t e d p i t s may b e o v e r e s t i m a t e d b e c a u s e t h e f i n e m i c r o f i b r i l s t r a n d s a r e d i f f i c u l t t o d e t e c t . The u s e o f a s o l v e n t - e x c h a n g e d r y i n g t e c h n i q u e (Thomas a n d N i c h o l a s , 1968) p r e v e n t s p i t a s p i r a t i o n a n d t h u s a l l o w s a more e x a c t , u n a l t e r e d margo f o r d i r e c t m e a s u r e m e n t . As t h e r e i s no d e f i n i t e i n f o r m a t i o n o n t h e d e p t h o f s p a c e o c c u p i e d b y t h e margo s t r a n d s , t h e p r i m a r y 31 TABLE 2. Survey of margo pore size determinations Assumptions Techniques Investigators Species Part of Wood Margo Pore Dimensions Assumed that the pores observed are the ones that control the rate of flow. I. Direct electron . microscopic measurements Liese & Hartmann-Fahnenbrock (1953) i Abies alba, Larix decidua, Picea abies, Pinus nigricans var. calabrica approximately 180 filaments per p i t ; each filament i s 0.03 jam i n diameter. Krahmer & Cote (1963) Pseudotsuga menziesii i sapwood & heartwood distance between margo strands less than 0.1 to 1.0 um Sebastian, Cote & Skaar < (1965) l Picea glauca I sapwood & heartwood average distance between margo strands i s 0.66 um Petty & Puritch (1970) Abies grandis sapwood 0.09 - 0.12 um i n radius Assumed that there i s no a t t r a c t i o n between the p i t membrane and f i l t r a t i n g p a r t i c l e s . I I . Indirect f i l -t r a t i o n measurements: from observation of the f i l t r a t i o n of aqueous suspensions containing p a r t i c l e s of known size during passage through wood. Frenzel (1929) , Pinus s y l v e s t r i s 0.072 - 0.144 umin diameter 1 Liese (1956) ! Abies alba, Larix decidua,• excelsa,. Pinus s y l v e s t r i s , ; Pseudotsuga menziesii 0.13 - 0.20 um i n diameter Balatinecz (1963) * Pseudotsuga menziesii 0.20 - 0.40 um i n diameter Liese & Bauch (1964) Abies nordmanniana Thuja occidentalis Thuja p i i c a t a sapwood II II 0.205 um -j 0.165 um -J maximum diameters 0.182 um -1 Liese (1965) Pinus s y l v e s t r i s i 500 m i c r o f i b r i l s per margo Megraw (1967) i Picea glauca • Picea sitchensis 80% of flow through pores >0.075 um 90% of flow through pores >0.047 um 50% of flow through pores >0.075 um 75% of flow through pores >0.047 p i 97% of flow through pores >0.009 um Assumed that the model used represents the wood structure, (i) the resistance to flow resides en-t i r e l y i n the margo pores I I I . Indirect flow rate measurements Derivation of equi-valent pore r a d i i from:-A. combining pressure permeability and electro-osmotic flow data Stamm (1929) Chamaecyparis nootkatensis Picea sitchensis Pseudotsuga menziesii (Mountain) Thuja p l i c a t a a i r - d r i e d heartwood II II H 0.068 - 0.164 um i n radius 0.098 - 0.164 um i n radius 0.068 - 0.123 um i n radius 0.105 - 0.184 um i n radius TABLE 2. (cont'd) 32 ( i ) ( c o n t ' d ) B. the flow r a t e of a i r through wood under pressure at d i f f e r -ent r e l a t i v e humid-i t i e s Stamm (1935) Pinus monticola heartwood 0.028 um, average ra d i u s C. a i r p e r m e a b i l i t y of wood at d i f f e r e n t moisture contents Stamm (1946) Pinus monticola 0.073 um average ra d i u s D. data f o r overcoming the surface t e n s i o n of water. Stamm (1952) Pseudotsuga m e n z i e s i i Pinus e l i o t t i i ; sapwood II 0.42 um average ra d i u s 11.00 um average ra d i u s E. measurements of the pressure r e q u i r e d to d i s p l a c e a i r -l i q u i d or l i q u i d -l i q u i d menisci from the pores. Stamm & Wagner (1961) Yao & Stamm (1967) Stamm, C l a r y & E l l i o t t (196E Stamm (1970a) Stamm (1970b) Picea s i t c h e n s i s Pseudotsuga m e n z i e s i i Pseudotsuga m e n z i e s i i Pseudotsuga m e n z i e s i i Pinus ponderosa heartwood heartwood heartwood sapwood heartwood s^apwood heartwood 0.094 - 0.150 um i n rad i u s 0.2 - 0.4 um i n radius 0.01 - 0.52 um i n rad i u s maximum r a d i i 0.20 um (never-dried);0.17um(dried & resoaked) 0 i035um(never-dried);0.025um( " " ) 0.46um ( " " );0.30um ( " " ) 0.047um( " " );0.027um( " " ) F. measurements of mercury uptake (mercury impreg-n a t i o n method) Clermont (1963) Pseudotsuga m e n z i e s i i sapwood heartwood 0.2-2.4um(air-«ScOven-dried) i n radius 0.4-4.4um(solvent-dried) i n radius 0.2-2.2um(air-,oven-& solvent dried) i n radius G. measurements of the gaseous permeabi-l i t y of dry wood. Sebastian, Cote & Skaar (1965) Comstock (1967) Picea glauca Tsuga canadenis sapwood heartwood sapwood & he a r t -wood. 0.7-2.5um i n radius 0.8-4.8um i n radius 0.380-1.010um(N 2data) i n radius 0.653-1.360um(He data) i n radius ( i i ) l o n g i t u d i n a l flow through coniferous tfood i n v o l v e s 2 com-ponents (margo pores & t r a c h e i d lumina) i n s e r i e s H. a combination of gaseous and l i q u i d P e t t y & Preston (1969) Pseudotsuga m e n z i e s i i sapwood heartwood 1.04-1.07um i n rad i u s 0.70-0.83um i n rad i u s p e r m e a b i l i t y mea-surements Petty (1970) Picea s i t c h e n s i s sapwood 0.14um average radius I. measurements of gaseous permeabi-l i t y at various mean pressures. Petty & P u r i t c h (1970), Abies grandis sapwood 0.12um(air-dried), average radius 0.09um(solvent-dried), average radius l a r t i f a c t f o r the d i r e c t measurement of margo pore s i z e u t i l i z i n g t r a n s m i s s i o n e l e c t r o n micrographs i s t o assume the margo as being i n one plane i n s t e a d of f i l l i n g a c t u a l three-dimensional space. 34 (c) P i t a s p i r a t i o n In Pinaceae, during a i r - d r y i n g or h e a r t -wood formation, as the c e l l u l o s i c margo m i c r o f i b r i l l a r strands are p l i a b l e , the torus of a bordered p i t - p a i r i s f r e q u e n t l y d i s -placed t o block one of the apertures. This phenomenon i s defined as p i t a s p i r a t i o n (IAWA, 1964). On the other hand, the p i t s of many other species i n the Cupressaceae, Podbcarpaceae and Taxaceae, without a torus e s s e n t i a l f o r the s e a l i n g of the p i t aperture, remain unaspirated even i n the case of normal d r y i n g of f r e s h wood (Liese and Bauch, 1967b). Cote and Krahmer (1962) noted t h a t i f warts are present, as w i t h hemlocks, they could hinder the e f f e c t i v e s e a l i n g of the torus.. Frey-Wyssling ahd'-Muhlethaler (1965) i n d i c a t e d t h a t the main purpose of torus s e a l i n g i n p i t a s p i r a t i o n i s t o exclude t r a c h e i d s of o l d e r annual r i n g s from the water conduction system. L i e s e and Bauch (1967b) proposed th a t those wood species w i t h t o r i incapable of c l o s i n g or without any torus would be exposed t o greater p h y s i o l o g i c a l danger. In surveying p i t a s p i r a t i o n , P h i l l i p s (1933), Stone (1939) and other workers used t a n g e n t i a l l o n g i t u d i n a l s e c t i o n s where Kishima and Hayashi (1962) as w e l l as Meyer (1971) employed cross s e c t i o n s , because they found that counting l a r g e r numbers of c e l l s was p o s s i b l e i n the same l i m i t e d area of micro-s c o p i c view when the l a t t e r was used. In a d d i t i o n , the i d e n t i f i -c a t i o n of the t r a n s i t i o n a l zone between earlywood and latewood 35 could a l s o be achieved i n one and the same s l i d e . The only-shortcoming which could not be avoided on any s e c t i o n i s t h a t the small areas counted might not be s u f f i c i e n t t o o b t a i n represen-t a t i v e r e s u l t s of the p a r t s of wood s t u d i e d . With respect t o the degree of a s p i r a t i o n , Kishima and Hayashi (1962) counted incompletely a s p i r a t e d p i t s as unaspirated p i t s unless the t o r i were completely adhered to the p i t borders, whereas Meyer (1971) d i s t i n g u i s h e d them as p a r t -i a l l y a s p i r a t e d . P a r t i a l p i t a s p i r a t i o n has been recognized as incomplete p i t a s p i r a t i o n i n the past (Comstock and Cote, 1968; Stone, 1939; Thomas and N i c h o l a s , 1966). As there i s no com-p a r i s o n determined between the magnitude of f l u i d flow through p a r t i a l l y a s p i r a t e d p i t - p a i r s and unaspirated p i t - p a i r s , Meyer (1971) i n d i c a t e d t h a t any deductive use of t h i s phenomenon i s precluded. P h i l l i p s (1933) conducted a comprehensive study of p i t a s p i r a t i o n on f i v e species of Pinaceae. He found th a t p i t s of green heartwood were already a s p i r a t e d , and no s i g n i -f i c a n t d i f f e r e n c e e x i s t e d between heartwood and a i r - d r i e d sapwood. The average percentage of unaspirated p i t s per t r a c h e i d i n e a r l y -wood as w e l l as latewood of a i r - d r i e d sapwood i s shown i n Table. 3. He revealed three s a l i e n t features about the p a t t e r n of occurrence of a s p i r a t i o n i n coniferous sapwood. F i r s t l y , i n green wood some 36 p i t s are a s p i r a t e d even when considerable f r e e water i s present. Secondly, the number of a s p i r a t e d p i t s g r a d u a l l y increases w i t h l o s s of moisture down t o the v i c i n i t y of the f i b e r s a t u r a t i o n p o i n t when n e a r l y a l l the earlywood p i t s become a s p i r a t e d . T h i r d l y , a c e r t a i n p r o p o r t i o n of the latewood p i t s i n dry wood were found i n unaspirated s t a t e . He a s c r i b e d the greater tendency of l a t e -wood p i t s t o r e s i s t a s p i r a t i o n t o the greater p i t membrane r i g i d -i t y . TABLE 3. Percentage of unaspirated p i t s i n a i r - d r i e d sapwood of 5 coniferous species (from P h i l l i p s , 1933) Species Average Percent of P i t s Unaspirated Springwood (Earlywood) Summerwood (Latewood) L a r i x decidua 1 29 Picea excelsa 7 31 Pinus n i g r a 1 40 var. c a l a b r i c a Pinus s y l v e s t r i s 2 66 Pseudotsuga m e n z i e s i i 1 25 L i e s e and Bauch (1967a) observed the same phenomena:iin Pinus and Picea and gave a more d e t a i l e d e x p l a n a t i o n . They i n d i c a t e d t h a t w i t h the i n c r e a s i n g thickness of p i t membrane and a simultaneous trend towards a lens-shaped c o n f i g u r a t i o n of 37 the torus towards the latewood, the adhesion forces r e q u i r e d f o r a s p i r a t i n g the p i t s become greater, i n as much as even the high s u r f a c e t e n s i o n of water i s not s u f f i c i e n t t o b r i n g about a s p i r a t i o n of many of the p i t s i n latewood t r a c h e i d s . F u r t h e r -more, the t i g h t e r margo t e x t u r e i n latewood p i t s , t h e i r small diameter and the c o n f i g u r a t i o n of the p i t chamber c o n t r i b u t e to t h e i r s t i f f n e s s . The amount of adhesion fo r c e necessary f o r p i t a s p i r a t i o n i s dependent on p i t membrane s t r u c t u r e . P h i l l i p s (1933) a l s o noted t h a t the occurrence of t h i c k c e l l w a l l s was i n v e r s e l y c o r r e l a t e d w i t h p i t a s p i r a t i o n , but he gave no explana-t i o n . As e a r l y as i n 1891, Strassburger noted the phenomenon of reducing coniferous wood p e r m e a b i l i t y a f t e r a i r - d r y i n g and t r a c e d i t t o p i t a s p i r a t i o n . B a i l e y (1913b) ob-served the v a l v e - l i k e a c t i o n of the torus and considered a s p i r a -t i o n as a f a c t o r i n preventing permeation and h i s concept was supported by G r i f f i n (1919, 1924). She noted t h a t the lowland ( c o a s t a l ) D o u g l a s - f i r w i t h a greater number of unaspirated p i t s i s more permeable than the mountain ( i n t e r i o r ) grown t r e e . Sub-sequently, a number of i n v e s t i g a t o r s (Bramhall, 1967, 1971; Bram-h a l l and Wilson, 1971; Meyer, 1971; Sebastian et a l . , 1965; Wardrop and Davies, 1961) described the i n f l u e n c e of p i t a s p i r a t i o n upon coniferous wood p e r m e a b i l i t y . 38 Since, deposits were absent i n the bordered p i t s of D o u g l a s - f i r heartwood, Krahmer and Cote (1963) concluded that p i t a s p i r a t i o n alone was r e s p o n s i b l e f o r reduced p e r m e a b i l i t y . Sebastian et_ al_. (1965) proved t h a t e x t r a c t i v e s are l e s s important, i n p e r m e a b i l i t y r e d u c t i o n than p i t a s p i r a t i o n as i n c r u s t a t i o n can occur i n white spruce sapwood p i t membranes p r i o r t o the marked d i f f e r e n c e i n p e r m e a b i l i t y a s s o c i a t e d w i t h heartwood formation. Recently, a mathematical r e l a t i o n between percent p i t a s p i r a t i o n and sapwood earlywood l o n g i t u d i n a l gas p e r m e a b i l i t y of Douglas-f i r has been"demonstrated by Meyer (1971). He a l s o i n d i c a t e d that gas flow i s most pronounced when fewer than 80 t o 90% of the p i t s are a s p i r a t e d . 39 B. Man i p u l a t i o n of coniferous wood p e r m e a b i l i t y by s o l v e n t -seasoning B a i l e y (1913b) suggested t h a t a s p i r a t i o n i s a r e s u l t of the r e c e s s i o n of an a i r - w a t e r i n t e r f a c e i n t o the p i t . L a t e r , (1916) he found t h a t the pressure r e q u i r e d to f o r c e a i r i n t o wood saturated with- sap, g l y c e r i n e , a c e t i c a c i d , acetone or a l c o h o l , was d i r e c t l y p r o p o r t i o n a l t o the surface t e n s i o n . Subsequently, many workers (Erickson and Crawford, 1959; G r i f f i n , 1919; H a r r i s , 1953; Hart and Thomas, 1967; Kishima and Hayashi, 1962; Liese 1, 1965; L i e s e and Bauch, 1966, 1967a,b; P h i l l i p s , 1933) regarded p i t a s p i r a t i o n as a surface t e n s i o n - r e l a t e d phenomenon. I t has been shown tha t by removal of water i n wood p r i o r t o d r y i n g using organic s o l v e n t s of low surface t e n s i o n and s w e l l i n g power, p i t a s p i r a t i o n i s markedly a l l e v i a t e d and p e r m e a b i l i t y improved i n s e v e r a l coniferous species ( E r i c k s o n and Crawford, 1959; L i e s e and Bauch, 1967a; Meyer, 1971; P h i l l i p s , 1933). This was confirmed by the st u d i e s of Thomas and Nicholas (1966) on pentane-dried wood, and they were the f i r s t t o d e p i c t bordered p i t membranes i n the unaspirated s t a t e . I n 1969, Thomas employed s p e c i a l i z e d low surface t e n s i o n methods, s p e c i f i c a l l y solvent-exchange, c r i t i c a l - p o i n t and f r e e z e - d r y i n g techniques t o e f f e c t i v e l y prevent p i t a s p i r a t i o n . He i n d i c a t e d that the surface t e n s i o n of the f i n a l evaporating l i q u i d i s important only w i t h regard t o p i t a s p i r a t i o n and does not a l t e r margo s t r u c t u r e t o 40 any n o t i c e a b l e degree. For Pinus-type p i t membrane of e a r l y -wood, i t was found t h a t surface t e n s i o n of 26 dynes/cm i s ade-quate f o r a s p i r a t i o n (Liese and Bauch, 1967b), whereas p i t s i n latewood t r a c h e i d s showed a d i f f e r e n t behaviour due t o t h e i r d i f f e r e n t anatomical f e a t u r e s . However, Comstock (1968) proved th a t there i s no s i n g l e c r i t i c a l surface t e n s i o n f o r the evapora-t i n g l i q u i d below which a s p i r a t i o n of p i t s does not occur, but t h a t p i t a s p i r a t i o n depends on other p r o p e r t i e s of the evaporating l i q u i d , such as s w e l l i n g a b i l i t y , i n a d d i t i o n t o i t s surface t e n s i o n . He revealed that the c o n c e n t r a t i o n of s o l v e n t i n the wood would change as d r y i n g progressed and could be q u i t e d i f f e r -ent at the p o i n t where most a s p i r a t i o n occurs (about f i b e r s a t u r a -t i o n p o i n t ) than i t was o r i g i n a l l y ; the r i g i d i t y of the membrane and adhesion of the torus t o the p i t border could be a l t e r e d by the water-solvent mixtures. The a c t u a l amount of a s p i r a t i o n t h a t took place during seasoning of D o u g l a s - f i r xylem from an alcohol-benzene mixture was measured by Meyer (1971:); as shown i n Table 4. He concluded t h a t solvent-seasoning proved e f f e c t i v e , but a s i g n i f i c a n t number of p i t s s t i l l became a s p i r a t e d , probably due t o the choice of s o l v e n t system used. 41 TABLE 4. E f f e c t s of seasoning on a s p i r a t i o n of D o u g l a s - f i r earlywood i n t e r t r a c h e i d bordered p i t - p a i r s and l o n g i t u d i n a l a i r p e r m e a b i l i t y (from Meyer, 1971) Coast Sapwood I n t e r i o r Sapwood A i r Seasoning Solvent Seasoning A i r Seasoning Solvent Seasoning % A s p i r a t e d not a v a i l -able 34 93 55 % Unaspirated II II 38 6 29 % P a r t i a l l y A s p i r a t e d •i II 28 1 17 P e r m e a b i l i t y (darcys) 1.05 8.00 0.05 1.10 42 MATERIALS AND METHODS I. Sample materials Wood sectors were taken from two 16-year-old Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] trees growing side-by-side i n a provenance t r i a l at the University of B r i t i s h Columbia Re-search Forest (Haney, B.C.). These trees were grown from seeds representing coastal (Enumclaw, Washington) and i n t e r i o r (Salmon Arm, B.C.) provenances. In addition, one i n t e r i o r (Kamioops, B.C.) -grown tree was sampled to include wood from a d i f f e r e n t growth area. These three trees represent wood from coastal and i n t e r i o r seed sources grown i n a coastal environment and from an i n t e r i o r seed source grown i n i n t e r i o r conditions. They were designated as CC, IC and II to indicate seed source and growth area, respectively. A 5-inch-thick disk was cut from each tree about four feet above the ground. The freshly sawn disks were label l e d , placed i n separate polythene bags and stored i n the freezer (-10°C) u n t i l required. Further c h a r a c t e r i s t i c s of the above three wood sectors are given i n Table 5. TABLE 5. Characteristics of three Douglas-fir wood specimens used i n the study Code Seed Source Growth Location Diam. Inside Bark Age II Kamioops, B. C. (Interior or mountain type) Kamioops, B. C. 4.8 i n . 26 yr. IC Salmon Arm, B. C. (Interior or mountain type) Haney, B. C. 4.7 i n . 16 yr. CC Enumclaw, Wash. (Coastal or low-land type) Haney, B. C. 5.3 i n . 16 yr. 43 I I . P e r m e a b i l i t y specimens A block 3/4 x 3 x 2 - i n . i n t a n g e n t i a l , r a d i a l and l o n g i -t u d i n a l d i r e c t i o n s was cut from each of the -.three green d i s k s . The f i r s t two complete increments from the cambium on each sample block were then sectioned i n the green c o n d i t i o n w i t h a s l i d i n g microtome according to the c u t t i n g o r i e n t a t i o n ( i . e . g r a i n d i r e c -t i o n p a r a l l e l t o the k n i f e edge, s l i c e angle 10°) recommended by Kennedy and Chan (1970). This method not only reduced c e l l w a l l deformations, but a l s o r e s u l t e d i n the ease of s e c t i o n i n g . S e r i a l t a n g e n t i a l s e c t i o n s of 500 um nominal thickness f o r latewood and 700 um f o r earlywood were c o l l e c t e d across each annual increment and these were maintained i n saturated c o n d i t i o n at a l l times. Each m i c r o s e c t i o n blank was d i v i d e d i n t o three p a r t s , y i e l d i n g two 7 x 40 mm matched specimens f o r seasoning treatments, and a c e n t r a l p o r t i o n f o r s p e c i f i c g r a v i t y determination, as shown i n Figure 2A. Due t o increment width and curvature no d i s c r e t e l a t e -wood s e c t i o n s were obtained from the i n t e r i o r sample ( I I ) , so the t h i r d increment from the cambium of t h i s m a t e r i a l was a l s o sectioned t o i n c r e a s e the number of observations. An a i r - s e a s o n i n g treatment was done to induce p i t a s p i r a t i o n . L a b e l l e d specimens were h e l d between two s t a i n l e s s s t e e l screens, suspended to provide v e n t i l a t i o n . They were d r i e d t o constant weight at room temperature (^26°C). An solvent-seasoning t r e a t -44 Figure 2A. M i c r o s e c t i o n blank a. Grain d i r e c t i o n b. Air-seasoned i b1. Solvent-seasoned c. S p e c i f i c g r a v i t y F i g u r e 2B. P e r m e a b i l i t y sandwich a. P l e x i g l a s s blocks b. P e r m e a b i l i t y specimen ( r a d i a l surface) c. Scotch double-coated tape Figu r e 2C. Sampling of r e p l i c a t i n g and embedding specimens a. P e r m e a b i l i t y specimen ( t a n g e n t i a l surface) b. Sawn piece c. R e p l i c a t i n g d. Embedding a 40 mm" Figure 2A 20mm ,-"4 -a •a 36mm Figure 2B Figure 2C 46 ment was done to l i m i t p i t a s p i r a t i o n . Specimens of each pro-venance were marked w i t h an i n d e l i b l e p e n c i l and e x t r a c t e d w i t h acetone i n a Soxhlet e x t r a c t o r f o r four hours. They were then solvent exchanged i n the Soxhlet e x t r a c t o r w i t h pure isopentane f o r another s i x hours, during which two changes of solvent were made. This was followed by d r y i n g t o constant weight at room temperature. A f t e r seasoning, a l l specimens ( a i r - and solvent-seasoned) were s t o r e d i n a d e s i c c a t o r over 1 D r i e r i t e 1 (anhydrous calcium su l p h a t e ) , u n t i l needed. Treated specimens were fastened between p l e x i g l a s s blocks w i t h Scotch double-coated tape as shown i n Figure 2B, t o h o l d them r i g i d l y f o r i n s e r t i o n i n t o the permea-b i l i t y apparatus. Before f a s t e n i n g , care was taken t o ensure p e r f e c t l o n g i t u d i n a l alignment w i t h the wood g r a i n , determined by g e n t l y t e a r i n g the specimen along an edge. The trimmed pieces were saved f o r anatomical s t u d i e s . The dimensions of each per-m e a b i l i t y specimen were recorded. A l l the 'permeability sandwiches' were st o r e d i n a d e s i c c a t o r over ' D r i e r i t e ' , u n t i l r e g u i r e d . 47 I I I . P e r m e a b i l i t y apparatus and measurements A schematic diagram of the apparatus used f o r a i r permea-b i l i t y measurement and d e t a i l s of the p e r m e a b i l i t y c e l l are i l l u s t r a t e d i n Figures 3 and 4. The apparatus o r i g i n a l l y deve-loped by Bramhall (1970) was modified t o a l l o w measurement of low flow r a t e s by u s i n g water i n s t e a d of a i r i n the flow tubes. Low pressure d i f f e r e n t i a l s were measured by u s i n g water r a t h e r than mercury i n the manometer. The b a s i c c o n s t r u c t i o n remained unchanged, except t h a t the two ends of the bank of flowmeters were connected w i t h two containers of equal s i z e t o provide water r e s e r v o i r s f o r the flowmeters. In the present study, d r i e d a i r (passed through ' D r i e r i t e ' ) was admitted t o the specimen chamber through the base of the c e l l , and a i r passing through the specimen was conducted through the upper brass plug t o the 'donor' water r e s e r v o i r . This pressed the water t o one of a bank of flowmeters f o r measurement. Pre-ssure d i f f e r e n t i a l was a p p l i e d and c o n t r o l l e d by means of a vacuum pump and mercury manostat, and was measured w i t h a water mano-meter b r i d g i n g the specimen. Water f o r the system was prepared by degassing under vacuum f o r one-half hour. Degassing was has-tened and made more complete by p l a c i n g the vacuum f l a s k i n the tank of an u l t r a s o n i c c l e a n e r . A p a i r of p l e x i g l a s s b locks fastened w i t h only Scotch double-coated tape was placed i n the p e r m e a b i l i t y c e l l and used f o r 48 F i g u r e 3. Schematic diagram o f l o n g i t u d i n a l a i r permeable apparatus a. A i r flow d i r e c t i o n b. D r i e r i t e c. C o t t o n wool d. Water manometer e. S a f e t y v i a l f . N i t r o g e n tank (high p r e s s u r e ) g. N i t r o g e n flow d i r e c t i o n h. P e r m e a b i l i t y sandwich i . P e r m e a b i l i t y c e l l j . Vacuum pump k. Thermometer 1. Water flow d i r e c t i o n m. Degassed water n. Donor water r e s e r v o i r o. Mercury manostat P. "I P'. C a l i b r a t e d flowmeters P"._ q. Bead r . A i r l e a k s. S a f e t y f l a s k t . Degassed water u. Recei v e r water r e s e r v o i r 49 50 Figure 4. P e r m e a b i l i t y c e l l d e t a i l a. A i r i n l e t b. Nylon net c. P l e x i g l a s s b locks d. High pressure n i t r o g e n e. Nylon net f. A i r o u t l e t g. Brass plug h. Brass sleeve • f Specimen j • Rubber l i n i n g k. Scotch double-coated tape 1. Brass base 51 F i g u r e 4. 52 leakage d e t e c t i o n b e f o r e each s e t o f p e r m e a b i l i t y measurements. Absence o f leakage i n the apparatus was ensured i f no flow was recorded i n the flowmeters. A ' p e r m e a b i l i t y sandwich' was then i n s e r t e d i n the p e r m e a b i l i t y c e l l t o determine a i r flow r a t e a t approximately 5 cm Hg p r e s s u r e d i f f e r e n t i a l f o r the l o n g e s t specimen l e n g t h (average 3.6 cm). A f t e r a flow measurement was recorded, the ' p e r m e a b i l i t y sandwich' was reduced i n l e n g t h w i t h a microsaw (Bramhall and McLauchlan, 1970). The sawn end o f the p e r m e a b i l i t y specimen, i n a ' p e r m e a b i l i t y sandwich', was trimmed w i t h a r a z o r blade, i t s l e n g t h measured, and another s e t o f p e r -m e a b i l i t y measurements was taken. Pressure d i f f e r e n t i a l a c r o s s the specimen was reduced i n p r o p o r t i o n t o the decrease i n s p e c i -men l e n g t h . 53 IV. Anatomical measurements Measurements were made on the most and l e a s t permeable specimens from each t r e e . A specimen of intermediate permeabi-l i t y was a l s o i n c l u d e d as a f u r t h e r t e s t of the e f f e c t of ana-t o m i c a l f a c t o r s on p e r m e a b i l i t y . The anatomical features b e l i e v e d t o have the greatest i n f l u e n c e on p e r m e a b i l i t y were evaluated using l i g h t and e l e c t r o n microscopic methods. S p e c i f i c g r a v i t y of the c e n t r a l wood s t r i p taken from the corresponding green t a n g e n t i a l s e c t i o n (Figure 2A) was determined by the maximum-moisture-content method (Smith, 1954; Stamm, 1964). A. Tracheid l e n g t h and number of p i t s per t r a c h e i d . Pieces trimmed:1 from the p e r m e a b i l i t y specimens were macerated i n 50:50 g l a c i a l a c e t i c a c i d : 30% hydrogen peroxide at 60°C f o r 10 h r . The macerated elements were then t e m p o r a r i l y mounted i n 10% aqueous g l y c e r i n e s o l u t i o n on m i c r o s l i d e s f o r study. L o n g i t u d i n a l t r a c h e i d l e n g t h and number of p i t s per t r a c h e i d were determined d i r e c t l y using a Reichert Visopan micro-scope. An average of 100 t r a c h e i d s were measured f o r each s p e c i -men as t a b u l a t e d i n Table VI-3. B. Percent p i t a s p i r a t i o n , r a d i a l w a l l t h i c k n e s s and number of t r a c h e i d s per square m i l l i m e t e r . A small piece of wood taken from the c e n t r a l p o r t i o n of the f i r s t sawn piece of each p e r m e a b i l i t y specimen (Figure 2C) 54 was embedded i n L u f f s Epon f o l l o w i n g the usual dehydration steps (See Appendix I ) . Approximately f i f t y 1 urn-thick s e r i a l cross s e c t i o n s were cut from each embedded block w i t h a diamond k n i f e mounted on a Porter-Blum MT-2 ultramicrotome. The s e c t i o n s were s t a i n e d w i t h a l k a l i n e methylene blue and mounted f o r l i g h t microscopy (See Appendix I I ) . The embedding r e s i n was l e f t i n place so th a t the p o s i t i o n of the t o r i a t the time of embedding could be determined (Meyer, 1971). In order t o reduce the p o s s i b i l i t y of repea€edly counting the same p i t i n s e r i a l cross s e c t i o n s , only those bordered p i t -p a i r s d i s p l a y i n g two open apertures were recorded according to the scheme shown i n Figure 5. Each p i t - a s p i r a t i o n value f o r a i r - or solvent-seasoned m a t e r i a l given i n Table VI-4 i s based on 100 t o 1,300 observations on p i t membrane p o s i t i o n at 500X m a g n i f i c a t i o n . These were obtained from 16 t o 50 s e c t i o n s per specimen, depending on the number of u s e f u l s e c t i o n s obtained. The number of p i t membranes observed per s e c t i o n v a r i e d , depending on whether or not the s e c t i o n passed through h e a v i l y p i t t e d t r a c h e i d - o v e r l a p areas of a specimen. Average thickness of the common r a d i a l w a l l of two adjacent l o n g i t u d i n a l t r a c h e i d s at the outermost and innermost margins of 8 cross s e c t i o n s f o r each p e r m e a b i l i t y specimen were determined by measuring d i r e c t l y under the l i g h t microscope (Table VI-5). Unaspirated P a r t i a l l y A s p i r a t e d A s p i r a t e d F i g u r e 5. Schematic diagram of p i t a s p i r a t i o n a. P i t aperture b. P i t chamber c. Middle l a m e l l a d. Margo e. Torus f. P i t border 56 Number of t r a c h e i d s per square m i l l i m e t e r cross s e c t i o n f o r each p e r m e a b i l i t y specimen was obtained by m u l t i p l y i n g r a d i a l and t a n g e n t i a l counts of t r a c h e i d s per m i l l i m e t e r (Table VI-6). C. P i t dimension and margo p o r o s i t y Two r a d i a l s p l i t s were made on each of the f i r s t sawn pieces as shown i n Figure 2C. The s p l i t r a d i a l surfaces were r e p l i c a t e d according to the d i r e c t carbon method o u t l i n e d by Cote, Koran and Day (1964), w i t h the exception t h a t chromium was used f o r shadowcasting. B r i e f l y , the air-seasoned specimens were shadowcasted w i t h chromium a t an angle of approximately 30° t o the h o r i z o n t a l t o increase the c o n t r a s t of a s p i r a t e d p i t membranes, t h i s was followed by evaporating carbon over the shadowed surfaces at an angle of approximately 75° t o the h o r i -z o n t a l w h i l e r o t a t i n g the specimens. I n order t o reduce margo damage by heat r a d i a t i o n , shadowcasting was not a p p l i e d t o some solvent-seasoned specimens, but no s i g n i f i c a n t improvement was found. As most p i t membranes of the solvent-seasoned specimens were i n the unaspirated p o s i t i o n , r e p l i c a s formed by evaporating only carbon over the non-shadowed surfaces provided good c o n t r a s t i n e l e c t r o n micrographs. A p a r a f f i n backing l a y e r was a p p l i e d t o p r o t e c t the carbon r e p l i c a during the removal of wood. The r e p l i c a s were cleaned by h y d r o l y s i n g the wood w i t h 72% s u l p h u r i c a c i d and 1:1 57 10% chromic / 10% n i t r i c a c i d . Unfortunately, the specimens by n e c e s s i t y were t h i n n e r than d e s i r a b l e . As the r e s u l t , the hot p a r a f f i n wax e a s i l y penetrated the wood t i s s u e , and p a r t l y i n -h i b i t e d the h y d r o l y s i s step. Extra e f f o r t working under a d i s s e c t i n g microscope was r e q u i r e d t o completely remove a l l p a r t i a l l y hydrolyzed wood from the r e p l i c a s . This was e s p e c i a l l y t r u e f o r t h i n n e r latewood specimens. The e l e c t r o n microscopic examination was done on an H i t a c h i HU-11E e l e c t r o n microscope, o p e r a t i n g at 100KV. I n d i v i d u a l bordered p i t s of l o n g i t u d i n a l t r a c h e i d s were photographed on Kodak 4489 e l e c t r o n microscope f i l m (Estar t h i c k base) at 4,000 X m a g n i f i c a t i o n . Diameters of p i t a n n u l i , t o r i , apertures and margo strands were measured d i r e c t l y from e l e c t r o n micrographs enlarged t o approximately 10,300 X (Tables VI-7A t o 7D), and margo areas (Table VI-7E) were then c a l c u l a t e d (See Appendix I V ) . The d i -mensions of margo openings were determined by a random-dot g r i d method. A 10 x 10 i n . c l e a r p l a s t i c sheet w i t h 500 randomly arranged dots was placed over the e l e c t r o n micrographs. Only the t a n g e n t i a l and r a d i a l diameters of those margo openings en-countered w i t h dots were measured. Where a dot was d i r e c t l y over a margo strand, the opening clockwise to the strand was measured. Values are l i s t e d i n Table VI-8.,,• These measurements were analyzed by Dr. W. G. Warren (See Appendix V), t o d e t e r -mine mean s i z e of margo openings (Tables VI-9, 10). 59 V. S t a t i s t i c a l analyses Regression analyses (Table VT-11) were conducted t o study the r e l a t i v e i n f l u e n c e of each of the measured v a r i a b l e s (Xi) on l o n g i t u d i n a l a i r p e r m e a b i l i t y (Y perm) f o r each of nine d i f -f e r e n t c a t e g o r i e s as f o l l o w s : (1) a l l t r e e s a l l data, (2) a l l t r e e s solvent-seasoned, (3) a l l trees air-seasoned, (4) a l l earlywood, (5) a l l latewood, (6) a l l t r e e s solvent-seasoned earlywood, (7) CC data, (8) IC data, and ( 9 ) ' I I data. Best r e g r e s s i o n equations were s e l e c t e d u s i n g a backward e l i m i n a t i o n technique (Table VI-12). The t e s t e d v a r i a b l e s were as f o l l o w s : Y perm = weighted mean of p e r m e a b i l i t y values of the three longer specimen lengths (darcys), X t l = l o n g i t u d i n a l t r a c h e i d l e n g t h (mm), X ca = p i t s completely a s p i r a t e d (%), X pa = p i t s p a r t i a l l y a s p i r a t e d {%), —} X ua = p i t s unaspirated (%), X t n = number of t r a c h e i d s per square m i l l i m e t e r , X sg = s p e c i f i c g r a v i t y , 2 X mp = margo p o r o s i t y or estimated margo pore s i z e (um ), and X ma = margo area (um 2). 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 independent v a r i a b l e s used i n es t i m a t i n g l o n g i t u d i n a l a i r p e r m e a b i l i t y were computed as shown i n Table VI-13A t o E. The estimated percent cumulative frequency d i s t r i b u t i o n of estimated margo pore s i z e f o r the p i t s of the three t r e e s (171 data s e t s ) was obtained. Of these, only maximum and minimum margo pore s i z e s of the p i t s i n the f i r s t increment next t o the cambium of each t r e e were presented i n Table VI-14 and Figure VI-1. 60 RESULTS AND DISCUSSION I. D o u g l a s - f i r sapwood bordered p i t A. General s t r u c t u r e From the e l e c t r o n microscopic examination of the bor-dered p i t s , no notable d i f f e r e n c e s were found i n the general s t r u c t u r e of p i t border, torus and margo f o r c o a s t a l and i n t e r i o r D o u g l a s - f i r sapwood (Figures 6 and 7). Average values of the measurements summarized from Table VI-7A to C are t a b u l a t e d i n the f o l l o w i n g t a b l e . TABLE 6. Average diameters of p i t annulus, torus and aperture Diameters (um) C C Tree I C Tree I I Tree LW EW LW EW EW P i t annulus 13.80 17.67 11.40 16.12 16.95 P i t torus 5.08 8.19 5.94 7.64 8.49 P i t aperture 4.55 6.02 3.51 4.91 5.61 Latewood p i t dimensions were apparently smaller than those of earlywood, but no s t a t i s t i c a l e v a l u a t i o n has been made f o r the p i t dimensions. The inner p a r t of the p i t border was f r e e of a warty l a y e r and the p i t membrane was Pinus-type w i t h smoothly surfaced to r u s , which agree w i t h previous f i n d i n g s ( L i e s e , 1965; L i e s e 61 Figure 6. E l e c t r o n micrograph of t y p i c a l latewood p i t s from the outer sapwood of three D o u g l a s - f i r t r e e s , w i t h i n c r u s t e d and unaspirated p i t membranes; d i r e c t carbon r e p l i c a , pre-shadowed w i t h chromium; magni-f i c a t i o n 4,800X A. II11A B. CC11S C. IC24S 62 63 Figure 7. E l e c t r o n micrograph of t y p i c a l earlywood p i t s from the outer sapwood of three D o u g l a s - f i r t r e e s w i t h unaspirated p i t membranes; d i r e c t carbon r e p l i c a , pre-shadowed w i t h chromium; m a g n i f i c a t i o n 4,800X A. CC15S B. IC15S C. II33S 64 65 and Hartmann-Fahnenbrock, 1953). Unaspirated margos were e v i -d e n t l y three dimensional networks c o n s i s t i n g of r a d i a l l y - o r i e n t e d ( r a d i a t i n g ) and randomly-oriented ( i n t e r w i n i n g ) m i c r o f i b r i l l a r strands. The average diameters of i n d i v i d u a l r a d i a t i n g and i n t e r -wining strands were the same w i t h a value of 0.05 micron (Figure 8 and Table VI-7D). However, the r a d i a t i n g s trand u s u a l l y appeared to be l a r g e r than the i n t e r w i n i n g s trand as a r e s u l t of micro-f i b r i l l a r aggregation (Jayme, Hunger, and Fengel, 1960; Brown and Baker, 1970) or a p p o s i t i o n (Thomas, 1968, 1970). F o l l o w i n g i s a summary of f i n d i n g s of the u l t r a s t r u c -t u r e of l o n g i t u d i n a l t r a c h e i d bordered p i t membranes i n the D o u g l a s - f i r sapwood. (1) The p a r t of the margo near the torus i s more open than i s the outer p o r t i o n . (2) The margo d e n s i t y (the number of margo m i c r o f i b r i l s ) v a r i a -t i o n seems t o be c o n t r o l l e d by the number of randomly-oriented m i c r o f i b r i l l a r strands throughout the margo. (3) The latewood margo d e n s i t y i s c o n s i s t e n t l y higher than earlywood. These f i n d i n g s are s i m i l a r t o those of Thomas (1969) f o r south-ern pine. The average earlywood p i t margo areas i n the sapwood samples of CC, IC, and I I trees were 134.87, 115.43, and 143.53 square microns, r e s p e c t i v e l y (Table VI-7E). 66 Figure 8. E l e c t r o n micrograph of an earlywood p i t from the solvent-seasoned outer sapwood of IC t r e e ; p i t membrane was unaspirated; arrows A and B denote equal diameters of r a d i a t i n g and i n t e r w i n i n g m i c r o f i b r i l l a r strands, arrow C denotes aggregation of r a d i a t i n g strands; d i r e c t carbon r e p l i c a , preshadowed w i t h chromium; m a g n i f i c a t i o n 9,800X JU m 67 68 Examination of the p i t membranes showed th a t i n c r u s -t a t i o n s capable of a l t e r i n g margo p o r o s i t y were noted on both a s p i r a t e d and unaspirated latewood p i t membranes of the outer sapwood zone, but absent on earlywood p i t membranes regardless of provenance (Figure 6). The nature of the deposited m a t e r i a l was not i n v e s t i g a t e d i n t h i s study. As i t d i d e x i s t on specimens a f t e r both a i r - and solvent-seasoning, i t i s probable t h a t t h i s m a t e r i a l was not a cold-water-soluble or acetone-isopentane - / _ r -s o l u b l e e x t r a c t i v e . 69 B. Margo p o r o s i t y Review of the l i t e r a t u r e i n d i c a t e d that margo pore s i z e i n D o u g l a s - f i r sapwood p i t s where earlywood and latewood were not separated, had been q u a n t i f i e d by s e v e r a l i n v e s t i g a t o r s employing d i r e c t and i n d i r e c t measuring techniques (Clermont, 1963; Krahmer and Cote, 1963; Petty and Preston, 1969; Stamm, 1952, 1970a). Margo pore diameters ranging from 0.1 t o 4.4 microns were reported. Studies of margo p o r o s i t y were confined t o i n c r u s t a -t i o n - f r e e earlywood p i t membranes. An i n t e n s i v e e l e c t r o n mi-cr o s c o p i c i n v e s t i g a t i o n and an elaborate random-dot-grid d i r e c t measuring technique were a p p l i e d t o determine mean s i z e and t o o b t a i n a frequency d i s t r i b u t i o n of s i z e s f o r each t r e e . As the p r o b a b i l i t y f o r random dots t o h i t l a r g e r margo openings was higher, the measurements of those openings recorded were mostly l a r g e r margo pores, thereby causing a s i z e - b i a s e d sampling. An estimate of the a c t u a l average pore area as opposed t o the observed average (Tables VI-9 and 10) was determined by W.G. Warren (see Appendix V). The combined averages of observed and estimated margo pore areas, as w e l l as margo pore diameters, are given i n the f o l l o w i n g t a b l e . 70 TABLE.7. Average margo pore areas and diameters Combined Averages CC Tree IC Tree I I Tree Observed margo pore area (um2) 0.1820 0.2152 0.0917 Observed margo pore diameter * (um) 0.48 0.52 0.34 Estimated margo pore area (um2) 0.0344 0.0280 0.0186 Estimated margo pore diameter * (um) 0.20 0.19 0.15 The observed margo pore area and diameter were higher than the estimated values, the I I t r e e possessing the s m a l l e s t margo pore area and diameter. The above margo pore diameters agree w i t h previous f i n d i n g s (Table 2). Estimated percent cumulative f r e -quency d i s t r i b u t i o n s of maximum and minimum margo pore areas of the p i t s i n the f i r s t increment next t o the cambium of each t r e e are shown i n Table VI-14 and Figure VI-1. The v a r i a b i l i t y of margo p o r o s i t y w i t h i n growth increments appeared t o be as l a r g e as the v a r i a b i l i t y among growth increments and a l s o between tr e e s (Figures 7 and 9). The diameter was c a l c u l a t e d from the combined average by assuming the margo pore t o approximate a c i r c u l a r shape. 71 Figure 9. E l e c t r o n micrograph of unaspirated p i t s from the outer sapwood of I I t r e e ; d i r e c t carbon r e p l i c a , preshadowed w i t h chromium; m a g n i f i c a t i o n , 4,800X A. I I 11A B. I I 13S C. I I 14S D. I I 15S E. I I 25S F I I 33S 72 73 I I . E f f e c t of specimen len g t h on l o n g i t u d i n a l a i r p e r m e a b i l i t y M i c r o s e c t i o n s of wood were used i n t h i s study, i n order t o observe d i f f e r e n c e s between earlywood and latewood. Figures 10A to C show the r e l a t i o n s h i p between the log a r i t h m of p e r m e a b i l i t y and specimen l e n g t h . The solvent-seasoned earlywood p e r m e a b i l i t y of a l l three D o u g l a s - f i r t r e e s appears t o be e s s e n t i a l l y constant as specimen l e n g t h decreases, but a drop occurs a t the sh o r t e s t lengths. A tendency f o r an increase i n solvent-seasoned l a t e -wood p e r m e a b i l i t y i s noted i n CC and IC specimens as the specimen leng t h shortened. On the other hand, the air-seasoned permea-b i l i t y of d i f f e r e n t specimens gives d i f f e r e n t patterns as specimen le n g t h decreases. I n general, no apparent l i n e a r negative r e l a -t i o n s h i p was found between the log a r i t h m of p e r m e a b i l i t y and specimen l e n g t h . Such asnegative r e l a t i o n s h i p has been confirmed by s e v e r a l i n v e s t i g a t o r s (Buro and Buro, 1959b; Siau, 1972; Sucoff, et a l . , 1965). However, some d e v i a t i o n s have a l s o been observed regarding t h i s l e n g t h e f f e c t (Ameniya, 1962; Bramhall, 1971; Sebastian, et a l . , 1965). Bramhall (1971) modified Darcy's equation so the f u n c t i o n of specimen l e n g t h could be more p r e c i s e l y recognized. He reported t h a t f o r D o u g l a s - f i r , Darcy's law was only v a l i d f o r permeable sapwood specimens, but i n v a l i d f o r l e s s permeable specimens under steady-state c o n d i t i o n s . He i n d i c a t e d t h a t p e r m e a b i l i t y of the l e s s permeable specimens decreased s i g n i f i c a n t l y as specimen len g t h was reduced from 3.5 cm t o 0.5 cm. He a l s o suggested t h a t a p h y s i c a l 74 F i g u r e 10A. R e l a t i o n s h i p between lo g a r i t h m of l o n g i t u d i n a l a i r p e r m e a b i l i t y and specimen len g t h of CC D o u g l a s - f i r sapwood. K.0 CC11AL • CC11SL D CC14AE • CC14SE A CC15AE • CC15SE 75-xo. u 10.0 A I I "A • A • ' A 5.0 • A • • • • - O G A O o 0 0 • O • 1.0 • • - • • • 0.5 -A • A A A D A A A 0.1 ; I 1 I i i . 1 i 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4. Specimen l e n g t h (cm). F i g u r e 10A 76 F i g u r e 10B. R e l a t i o n s h i p between l o g a r i t h m o f l o n g i t u d i n a l a i r p e r m e a b i l i t y and specimen lerjgth o f IC D o u g l a s - f i r sapwood* 0 IC11AL • IC11SL q, IC13AE • IC13SE A IC15AE • IC15SE 15.0 10.0 5.0 A A CO >1 o u g (1) a, l . o 0.5 o o o $ k A A 0.1 J I I 1 1 1 1 1 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.< S p e c i m e n l e n g t h (cm) F i g u r e 10B 78 F i g u r e IOC. R e l a t i o n s h i p between l o g a r i t h m o f l o n g i t u d i n a l a i r p e r m e a b i l i t y and specimen l e n g t h o f I I D o u g l a s - f i r sapwood O II14AE • II14SE d I H 5 A E • II15SE A II16AE A II16SE 15.0 10.0 5.0 to >i u u ,<8 1.0 u CD ft 0.5 0.1 — MM o A A A" A" • • — • • # 9 • • — • - i • • — A -o O O O o • • • • — O O • • A A A — A — A A I A i -A 1 1 1 1 1 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4. Specimen len g t h (cm) Figure ilOC. 80 model i n which the number of conducting t r a c h e i d s decreases e x p o n e n t i a l l y w i t h depthsof p e n e t r a t i o n provided a l o g i c a l ex-p l a n a t i o n of the r e s u l t s . On the other hand, Meyer (1971) showed t h a t the p r o b a b i l i t y of occurrence of f l u i d - f i l l e d e a r l y -wood t r a c h e i d s of D o u g l a s - f i r decreases e x p o n e n t i a l l y w i t h specimen l e n g t h when specimen len g t h i s expressed w i t h terms of numbers of e f f e c t i v e conducting t r a c h e i d s . 81 I I I . E f f e c t of t r a c h e i d dimensions and s p e c i f i c g r a v i t y on l o n g i t u d i n a l a i r p e r m e a b i l i t y Tracheid dimensions and s p e c i f i c g r a v i t y , two of the impor-t a n t q u a l i t i e s of wood, are i n f l u e n c e d by a l a r g e number of complex and i n t e r - r e l a t e d f a c t o r s , such as r a t e of growth, number of r i n g s from p i t h , and height w i t h i n the t r e e (Wellwood and Smith, 1962). The f o l l o w i n g t a b l e summarizes the t r a c h e i d dimensions of the specimens used. TABLE 8. Summary of t r a c h e i d dimensions of D o u g l a s - f i r sapwood Type Growth Zone Ave. Tracheid Length (mm) No.of P i t s per Trach-e i d No. of . Trach-e i d Obser-ved No. of Trach-eids per mm2 No.of Ob-se r v a t i o n s CC t r e e LW 2.65 17.30 224 1169 32 EW 2.38 48.55 415 748 64 IC t r e e LW 2.38 12.55 325 1610 48 EW 2.07 33.18 279 1132 48 I I t r e e LW — — — — EW 2.81 83.93 546 1163 80 The t r a c h e i d s measured were from the increments, 15-16, 15-16 and 24-26 r i n g s from p i t h , r e s p e c t i v e l y f o r CC, IC and I I t r e e s . Latewood t r a c h e i d s are longer, w i t h a smaller number of p i t s per t r a c h e i d , than those of earlywood. The t r a c h e i d s of CC t r e e appear t o be longer and have more p i t s per t r a c h e i d than those of IC t r e e . But the longest t r a c h e i d s , i n a d d i t i o n t o the highest 82 number of p i t s per t r a c h e i d , d i d not render the earlywood of I I t r e e r e l a t i v e l y more permeable. I t s i n f l u e n c e was t h e r e f o r e probably masked by the e f f e c t of more important f a c t o r s . The r e g r e s s i o n analyses showed th a t t r a c h e i d l e n g t h ( X t l ) 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 p e r m e a b i l i t y (Yperm) (Table VI-12 and 13). The smaller number of t r a c h e i d s per square m i l l i m e t e r means l a r g e r average t r a c h e i d lumen s i z e . The summary i n Table 8 i n -d i c a t e s t h a t latewood t r a c h e i d lumen s i z e i s smaller than e a r l y -wood. On the other hand, the earlywood t r a c h e i d lumen s i z e s i n decreasing order are CC t r e e , IC t r e e and I I t r e e . F l e i s c h e r (1950) and Krahmer (1961) i n d i c a t e d t h a t the p e r m e a b i l i t y of D o u g l a s - f i r was r e l a t e d t o t r a c h e i d lumen s i z e . A s i g n i f i c a n t negative c o r r e l a t i o n between number of t r a c h e i d per square m i l l i -meter (Xtn) and p e r m e a b i l i t y (Yperm) i s shown i n Table VI-13. In other words, the l a r g e r t r a c h e i d lumen s i z e renders wood more permeable. The averages of l o n g i t u n d i n a l a i r p e r m e a b i l i t y and the corresponding s p e c i f i c g r a v i t y of the three D o u g l a s - f i r t r e e s are t a b u l a t e d i n the f o l l o w i n g t a b l e . 83 TABLE 9. Summary of p e r m e a b i l i t y vs. s p e c i f i c g r a v i t y of D o u g l a s - f i r sapwood, Pe r meab i 1 i ty (darcys) S p e c i f i c g r a v i t y C C Tree I C Tree I I Tree A D S D A D S D A D S D LW EW LW EW LW EW LW EW LW " EW LW EW 1.43 0.61 0.45 0.27 1.25 0.61 9.78 0.27 0.91 0.67 0.56 0.40 1.01 0.67 7.17 0.40 — 0.75 0.33 — 7.66 0.33 V a r i a t i o n of s p e c i f i c g r a v i t y e x i s t s among the three D o u g l a s - f i r t r e e s , probably due t o provenance e f f e c t as concluded by Haigh (1961). The p e r m e a b i l i t y of air-seasoned D o u g l a s - f i r sapwood i s higher f o r the specimens of higher s p e c i f i c g r a v i t y w i t h i n the same t r e e . The reverse i s t r u e f o r the solvent-seasoned specimens. Table VI-12 and 13 i n d i c a t e t h a t s p e c i f i c g r a v i t y (Xsg) i s an important v a r i a b l e h i g h l y and n e g a t i v e l y c o r r e l a t e d w i t h p e r m e a b i l i t y (Y perm) i n four of the nine c a t e g o r i e s analyzed. Although the foregoing r e p o r t s (Blew, 1961; C r a i g , 1963; E r i c k s o n and Estep, 1962; Koran, 1964; M i l l e r , 1961) on the i n f l u e n c e of s p e c i f i c g r a v i t y on p e r m e a b i l i t y were c o n f l i c t i n g , the r e s u l t s of analyses l i s t e d i n Tables VI-12 and 13 demonstrate t h a t s p e c i f i c g r a v i t y i s a good i n d i c a t o r of d i f f e r e n c e s i n a i r p e r m e a b i l i t y of D o u g l a s - f i r earlywood and latewood. 84 IV. E f f e c t of p i t s t r u c t u r e on l o n g i t u d i n a l a i r p e r m e a b i l i t y A. P i t a s p i r a t i o n and seasoning e f f e c t , The s i g n i f i c a n t i n f l u e n c e of p i t a s p i r a t i o n on l o n g i -t u d i n a l p e r m e a b i l i t y of D o u g l a s - f i r was c l a r i f i e d r e c e n t l y by Meyer (1971). He concluded t h a t sapwood earlywood l o n g i t u d i n a l a i r p e r m e a b i l i t y was a s e n s i t i v e barometer of the e f f e c t of seasoning c o n d i t i o n s on p i t a s p i r a t i o n (Table 4 ) . The r e s u l t s obtained i n t h i s i n v e s t i g a t i o n l e a d t o a s i m i l a r c o n c l u s i o n . P i t membrane p o s i t i o n was l i n k e d w i t h l o n g i t u d i n a l a i r permea-b i l i t y and could be used t o e x p l a i n the earlywood p e r m e a b i l i t y of a l l three D o u g l a s - f i r t r e e s , but t h i s was not the case i n latewood. I t was shown t h a t n e a r l y a l l the earlywood p i t s ob-served were a s p i r a t e d i n air-seasoned sapwood w h i l s t a c e r t a i n p r o p o r t i o n of the latewood p i t s remained unaspirated (Table 10). The higher percentage of unaspirated p i t s was respon-s i b l e f o r the greater latewood p e r m e a b i l i t y i n air-seasoned s t a t e . The reduced a s p i r a t i o n was probably due to a more r i g i d s t r u c t u r e (higher margo d e n s i t y and presence of i n c r u s t a t i o n s ) and t o the sma l l e r dimensions of latewood p i t s . Tracheid w a l l t h i c k n e s s i s c o r r e l a t e d w i t h the r e s i s -tance t o a s p i r a t i o n as shown i n Table 11. The above phenomenon was f i r s t recognized by P h i l l i p s (1933). This can be explained TABLE 10. E f f e c t of seasoning on a s p i r a t i o n of D o u g l a s - f i r outer sapwood i n t e r t r a c h e i d bordered p i t - p a i r s and l o n g i t u d i n a l a i r p e r m e a b i l i t y C C Tree •I C Tree I I Tree A D S D A D S D A D S D LW EW LW EW LW EW LW EW LW EW LW EW Yo A s p i r a t e d 72.03 9.9.78 15.80 5.86 52.14 97.65 12.50 3.67 not a v a i l -a b le 98.60 not a v a i l -able 1.39 Yo Unaspirated LI.69 .0.03 65.39 66.39 20.51 0.43 66.86 68.63 II 0.34 II 80.90 Yc P a r t i a l l y A s p i r a t e d L6.28 0.19 18.81 27.75 27.35 1.92 20.64 27.70 II 1.06 II 17.71 Perm e a b i l i t y (darcys) 1.43 0.45 1.25 9.78 0.91 0.56 1.01 7.17 II 0.75 II 7.66 TABLE 11. Pe srcentage of unaspirated p i t s and r a d i a l w a l l t hickness C C Tree I C Tree I I Tree A D S D A D S D A D S D LW EW LW EW LW EW LW EW LW EW LW EW Vo Unaspirated Radial Wall Thickness(um) LI.69 4.20 0.03 1.45 65.39 4.00 66.39 1.50 20.51 4.13 0.43 1.87 66.86 4.33 68.63 1.93 0.34 2.00 80.90 1.96 86 as a r e s u l t of a simultaneous increase of w a l l thickness and p i t membrane s t i f f n e s s . The acetone-isopentane solvent system used i n t h i s study appeared t o be more e f f e c t i v e i n preventing p i t a s p i r a t i o n than the ethanol-benzene system employed by Meyer (1971). P i t a s p i r a -t i o n was markedly a l l e v i a t e d by the former solvent system, but a s i g n i f i c a n t number of p i t s s t i l l became a s p i r a t e d i n the l a t t e r (Tables 4 and 10). Figures 10A t o C show tha t the p e r m e a b i l i t y of earlywood a f t e r solvent-seasoning was much improved i n a l l three D o u g l a s - f i r t r e e s , but t h a t of latewood was h a r d l y changed. By means of solvent-seasoning technique, a s p i r a t i o n was more e f f e c t i v e l y prevented i n earlywood p i t s (Table 10), which, i n a d d i t i o n t o t h e i r l a r g e r p i t dimensions and higher margo p o r o s i t y , a l s o more p i t s per t r a c h e i d and l a r g e r t r a c h e i d s , probably r e -s u l t e d i n the higher p e r m e a b i l i t y . The degree of a s p i r a t i o n was the only observable u l t r a s t r u c -t u r a l d i f f e r e n c e among earlywood p i t s as depicted i n Figure 11. Nicholas (1966) reported t h a t p i t s w i t h lower d e n s i t y margos (simultaneously w i t h lower s t r e n g t h of p i t membrane) i n v a r i a b l y were more t i g h t l y a s p i r a t e d . I n other words higher margo p o r o s i t y (lower margo density) should r e s u l t i n a higher percentage of a s p i r a t e d p i t s . The above statement needs f u r t h e r study. 87 Figure 11. E l e c t r o n micrograph of earlywood p i t s from the outer sapwood of D o u g l a s - f i r showing the d i f f e r e n t degree of a s p i r a t i o n as a r e s u l t of seasoning; d i r e c t carbon r e p l i c a , pre-shadowed w i t h chromium; m a g n i f i c a t i o n , 4,800X A. Unaspirated p i t , CC15S B. P a r t i a l l y a s p i r a t e d p i t , IC15A C. Completely a s p i r a t e d p i t , showing an i n p r i n t of aperture, IC15A 89 P a r t i a l p i t a s p i r a t i o n , noted i n the past as incomplete p i t a s p i r a t i o n (Stone, 1939; Kishima and Hayashi, 1962; Comstock and Cote, 1968; Thomas and N i c h o l a s , 1966), was found t o be the most important v a r i a b l e r e l a t e d to p e r m e a b i l i t y i n m u l t i p l e r e -g r e s s i o n analyses, except i n the " a l l t r e e s solvent-seasoned" category (Table VI-12). I t i s evident i n Table VI-13A t h a t both percentages of p a r t i a l l y a s p i r a t e d p i t - p a i r s and unaspirated p i t -p a i r s were h i g h l y c o r r e l a t e d w i t h p e r m e a b i l i t y , but the former y i e l d e d a higher p o s i t i v e c o r r e l a t i o n . The a c t u a l reason f o r t h i s phenomenon i s unknown. P a r t i a l l y a s p i r a t e d p i t s may pro-vide an e f f i c i e n t flow path or might be a s e n s i t i v e measure of o v e r - a l l p i t c o n d i t i o n . Any deductive use of p a r t i a l p i t a s p i r a -t i o n r e q u i r e s a f u r t h e r determination of the magnitude of gas flow through p a r t i a l l y a s p i r a t e d p i t - p a i r s i n comparison w i t h unaspirated p i t - p a i r s . As expected, a negative c o r r e l a t i o n was found between percentage of completely a s p i r a t e d p i t s and per-m e a b i l i t y . 90 B. Margo area and margo p o r o s i t y Krahmer (1961) i n d i c a t e d t h a t both permeable and r e -f r a c t o r y D o u g l a s - f i r woods have bordered p i t s t r u c t u r e s o f the same diameter. In other words, margo areas of the bordered p i t - p a i r s showed no r e l a t i o n s h i p t o p e r m e a b i l i t y . T h i s was a l s o the case i n the presen t study. Table VI-13E i n d i c a t e s t h a t margo p o r o s i t y (Xmp) as w e l l as margo area (Xma) were 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 p e r m e a b i l i t y (Y perm). Smith and Banks (1971) i n d i c a t e d t h a t the geometry o f the d i s t a n c e between the to r u s and the i n t e r i o r o f the border o f the p i t s t r u c t u r e r a t h e r than t h a t o f the margo c o n t r o l l e d the flow i n grand f i r (Abies  g r a n d i s ) . Margo area and margo p o r o s i t y c o u l d be i n c l u d e d i n the m u l t i p l e r e g r e s s i o n analyses o n l y f o r the solvent-seasoned e a r l y -wood o f a l l t r e e s due t o l i m i t e d sample s i z e . The s o l v e n t -seasoned earlywood was the b e s t m a t e r i a l f o r margo p o r o s i t y d e t e r m i n a t i o n , as i t p r o v i d e d u n a s p i r a t e d and i n c r u s t a t i o n - f r e e p i t membranes. The b e s t e q u a t i o n t o d e s c r i b e the r e l a t i o n s h i p o f v a r i o u s independent v a r i a b l e s t o p e r m e a b i l i t y was determined as: Yperm = 6.5814 + 0.1700Xpa - 7.3824Xsg + 6.8406Xmp SEE = 0.7295 R = 0.9436** DF = 8 91 A l l s i x independent v a r i a b l e s ( X t l , Xpa, Xtn, Xsg, Xmp and Xma) used i n r e g r e s s i o n a n a l y s i s accounted f o r 97.18 per cent of the t o t a l v a r i a b i l i t y i n p e r m e a b i l i t y . P i t p a r t i a l a s p i r a t i o n (Xpa) was the most important s i n g l e v a r i a b l e i n f l u e n c i n g p e r m e a b i l i t y (Y perm). I t alone accounted f o r 73.38 per cent o f the t o t a l v a r i a b i l i t y i n p e r m e a b i l i t y . In order of d e c r e a s i n g importance, the v a r i a b l e s s e l e c t e d i n the above equation, were p a r t i a l p i t a s p i r a t i o n (Xpa), margo p o r o s i t y (Xmp) and s p e c i f i c g r a v i t y (Xsg). Although t h e r e was not a s i g n i f i c a n t simple c o r r e l a t i o n between margo p o r o s i t y and p e r m e a b i l i t y (Table VI-13E), p i t p a r t i a l a s -p i r a t i o n and margo p o r o s i t y t o g e t h e r accounted f o r 90.27 per cent o f the t o t a l v a r i a b i l i t y i n p e r m e a b i l i t y . The i n c l u s i o n o f margo p o r o s i t y i n the r e g r e s s i o n e q u a t i o n f o r s o l v e n t - d r i e d earlywood i s e s p e c i a l l y s i g n i f i c a n t , s i n c e p a r t i a l p i t a s p i r a t i o n and s p e c i f i c g r a v i t y were the two v a r i a b l e s r e t a i n e d by the r e g r e s s i o n a n a l y s i s program f o r each o f the nine c a t e g o r i e s o f data t e s t e d (Table VI-12). Th e r e f o r e , when the s e v e r a l anatomical f a c t o r s b e l i e v e d t o i n f l u e n c e p e r -m e a b i l i t y a re measured and t e s t e d t ogether f o r t h e i r j o i n t e f f e c t on p e r m e a b i l i t y , the importance o f p i t membrane geometry as w e l l as p i t membrane p o s i t i o n becomes r e a d i l y apparent. 92 CONCLUSION 1. The dimensions of p i t annuli, t o r i and apertures as well as margo porosity appeared to be d i f f e r e n t between ear l y -wood and latewood, whereas marked differences were not noted between p i t s of d i f f e r e n t trees. 2. Incrustations capable of a l t e r i n g margo porosity were observed only on latewood p i t membranes. 3. The v a r i a b i l i t y of earlywood margo porosity within growth increments appeared to be as large as the v a r i a b i l i t y among growth increments and also between trees. 4. Solvent-seasoned earlywood permeability was a function of p a r t i a l p i t aspiration, margo porosity and s p e c i f i c gravity, i n decreasing order of importance, while the influence of tracheid dimensions was masked by the e f f e c t of the above more important factors. 5. Acetone-isopentane solvent system used i n solvent-seasoning appeared to be e f f e c t i v e i n the prevention of p i t a s p i r a t i o n . 6. The longitudinal a i r permeability of outer sapwood Douglas-f i r specimens dried by solvent-seasoning and air-seasoning disobeyed Darcy's law with respect to specimen length. 93 L I T E R A T U R E C I T E D Ameniya, S. 1962. Research on wood p r e s e r v i n g treatment. I I I . Measuring the p e n e t r a t i o n f a c t o r o f a few softwoods i n the f i b e r d i r e c t i o n . Jour, o f the Jap. Wood Res. S o c , 8 (2): 81-86. Anderson, E. A. 1951. T r a c h e i d l e n g t h v a r i a t i o n i n c o n i f e r s as r e l a t e d t o d i s t a n c e from p i t h . Jour. F o r e s t r y , 49 ( 1 ) : 38-42. B a i l e y , I.W. 1913 a. The p r e s e r v a t i v e treatment o f wood. I. The v a l i d i t y o f c e r t a i n t h e o r i e s concerning the p e n e t r a t i o n o f gases and p r e s e r v a t i v e s i n t o seasoned wood. F o r e s t r y Q u a r t e r l y , 11: 5-11. . 1913 b. The p r e s e r v a t i v e treatment of wood. I I . The s t r u c t u r e o f the p i t membranes i n the t r a c h e i d s o f c o n i f e r s and t h e i r r e -l a t i o n o f the p e n e t r a t i o n o f gases, l i q u i d s , and f i n e l y d i v i d e d s o l i d s i n t o green and seasoned wood. F o r e s t r y Q u a r t e r l y , 11: 12-20. . 1915. The e f f e c t o f s t r u c t u r e o f wood upon i t s p e r m e a b i l i t y . The t r a c h e i d s o f c o n i f e r o u s timbers. Amer. R a i l . Eng. Assoc. P r o c , 16: 835-853. . 1916. The s t r u c t u r e o f bordered p i t s o f c o n i f e r s and i t s b e a r i n g upon the t e n s i o n h y p o t h e s i s o f the ascent o f sap i n p l a n t s . Bot. Gaz. 61: 133-142. . 1957. The s t r u c t u r e o f the p i t membranes i n the t r a c h e i d s o f c o n i f e r s . Holz a l s Roh-und Werkstoff, 15 (5): 210-213. A u s t r a l i a CSIRO, T r a n s l . No. 3639. 94 B a i l e y , P . J . 1964. The p e r m e a b i l i t y o f s o f t w o o d s . J o u r , o f t h e I n s t , o f Wood S c i . , 12: 44-55. . 1966. P h y s i c a l s t u d i e s i n r e l a t i o n t o -the p e r m e a b i l i t y o f t h e xylem o f D o u g l a s - f i r . Ph. D. T h e s i s , U n i v . o f Leeds. B a l a t i n e c z , J . J . 1963. The i n f l u e n c e o f m o r p h o l o g i c a l f a c t o r s upon l i q u i d f l o w i n D o u g l a s - f i r wood under p r e s s u r e . M.F. T h e s i s , U n i v . o f Washington. B e n v e n u t i , R.R. 1963. An i n v e s t i g a t i o n o f methods o f i n c r e a s i n g t h e p e r m e a b i l i t y o f l o b l o l l y p i n e . M. Sc. T h e s i s , U n i v . o f N o r t h C a r o l i n a . Blew, J.O. 1961. R e s u l t s o f p r e s e r v a t i v e t r e a t m e n t o f D o u g l a s - f i r from d i f f e r e n t a r e a s . Amer. Wood P r e s . A s s o c . P r o c , 57: 200-212. B r a m h a l l , G. 1966. P e r m e a b i l i t y o f D o u g l a s - f i r heartwood from v a r i o u s a r e a s o f growth i n B.C. B. C. Lumberman, 50 ( 1 ) : 98-102. . 1967. L o n g i t u d i n a l p e r m e a b i l i t y w i t h i n D o u g l a s - f i r [Pseudotsuga  m e n z i e s i i ( M i r b . ) Franco] growth i n c r e m e n t s . M. Sc. T h e s i s , U n i v . o f B r i t i s h C olumbia. . 1970. The v a l i d i t y o f Darcy's l a w i n t h e a x i a l p e n e t r a t i o n o f wood. Ph. D. T h e s i s , S t a t e U n i v . C o l l e g e o f F o r e s t r y a t S y r a c u s e U n i v . . 1971. The v a l i d i t y of Darcy's law i n the a x i a l p e n e t r a t i o n of wood. Wood S c i . and Tech., 5: 121-134. , and T. A. McLauchlan. 1970. The p r e p a r a t i o n of microsections by sawing. Wood and F i b e r , 2 (1): 67-69. , and J . W. Wilson. 1971. A x i a l gas p e r m e a b i l i t y of D o u g l a s - f i r microsections d r i e by various techniques. Wood S c i . , 3 (4): 223-230. Brown, F. L., and H. M. Baker. 1970. Scanning e l e c t r o n microscopy of mature D o u g l a s - f i r e a r l y wood i n t e r t r a c h e i d p i t t i n g . Wood and F i b e r , 2(1): 52-64. Buro, A., and E. A. Buro. 1959 a. The routes by which l i q u i d s penetrate i n t o wood of Pinus s y l v e s t r i s . Holzforschung, 13(3): 71-77. U. S. Forest Serv., T r a n s l . No. FPL624. . 1959 b. Studies on the p e r m e a b i l i t y of pine wood. Holz a l s Roh-und Werkstoff, 17(12): 461-474. U. S. Forest Serv., T r a n s l . No. FPL623. Chalk, L. 1930. Tracheid l e n g t h , w i t h s p e c i a l reference to S i t k a spruce (Picea s i t c h e n s i s C a r r . ) . F o r e s t r y , 4: 7-14. Clermont, L.P. 1963. Pore s i z e d i s t r i b u t i o n i n D o u g l a s - f i r . P r o j e c t 0-384-2. Progress Report No. 7. Can. Dept. Forest. R. D. 96 Comstock, G . L . 1965. Longi tudinal permeabi l i ty of green eastern hemlock. For . Prod. J o u r . , 15(10): 441-449. 1 9 6 7 . Longi tudinal permeabi l i ty of wood to gases and non-swell ing l i q u i d s . For . Prod. J o u r . , 17(10): 41-46. 1968. Phys ica l and s t r u c t u r a l aspects of the l o n g i t u d i n a l permeabi l i ty of wood. Ph. D. Thes is , State Univ. College of Forestry at Syracuse Univ. , and W. A . Cote, J r . 1968. Factors a f f e c t i n g permeabi l i ty and p i t a s p i r a t i o n i n coniferous sapwood. Wood S c i . and Tech . , 2(4): 279-291. Cote, W. A . 1958. E lec tron microscope studies of p i t membrane s t ruc ture . Implicat ions i n seasoning and preservat ion of wood. For . Prod. J o u r . , 8(10): 296-301. J r . 1963. S t r u c t u r a l factors a f f e c t i n g the permeabi l i ty of wood. Proc. 4th C e l l u l o s e Conf . , Jour , of Polymer S c i . : Part C, Polymer Symposia, No.2: 231-242. . 1967. His tory of wood u l t r a s t r u c t u r e research. In: His tory of Wood Science. Wood S c i . and Tech . , 1(3): 178-180. , Z . Koran, and A . C. Day. 1964. Repl ica techniques for e lec tron microscopy of wood and paper. TAPPI, 47(8): 477-484. 97 , and R. L. Krahmer. 1962. The p e r m e a b i l i t y of coniferous p i t s demonstrated by e l e c t r o n microscopy. TAPPI, 45(2): 119-122. C r a i g , D. W. 1963. The p e r m e a b i l i t y of D o u g l a s - f i r heartwood from various geographic sources i n the State of Washington. M. Sc. Thesis, Univ. of Washington. Darcy, H.P.G. 1856. Les fontaines publiques de l a v i l l e de D i j o n . V i c t o r Dalmont, P a r i s . ( C i t e d by P. J . B a i l e y , 1966). Eicke, R. 1954. A c o n t r i b u t i o n t o the s t r u c t u r e of the bordered p i t i n c o n i f e r s . Ber. Deut. Bot. Ges., 67: 6/7: 123-7. U.S.D.A., For. S e r v i c e , FPL, Madison, Wis. T r a n s l . No. 284. Ellwood, E.L., and R. C. Thomas. 1968. Pe r m e a b i l i t y of wood i n r e l a t i o n t o i t s s t r u c t u r e and p e n e t r a b i l i t y by f l u i d s . Impregnated f i b r o u s m a t e r i a l s , IAEA, Vienna, pp. 19-33. E r i c k s o n , H.D., and J . J . B a l a t i n e c z . 1964. L i q u i d flow paths i n t o wood usi n g p o l y m e r i z a t i o n techniques — D o u l g a s - f i r and styrene. For. Prod. Jour., 14(7): 293-299. , and R. J . Crawford. 1959. The e f f e c t of s e v e r a l seasoning methods on the pe r m e a b i l i t y of wood to l i q u i d s . Amer. Wood Pres. Assoc. P r o c , 55: 210-219. , and E. M. Estep. 1962. Per m e a b i l i t y of D o u l g a s - f i r heartwood from western Washington. For. Prod. Jour., 12(7): 313-324. 98 , H. Schmitz, and R. A. Gortner. 1937. The p e r m e a b i l i t y of wood t o l i q u i d s and f a c t o r s a f f e c t i n g the r a t e of flow. Univ. Minn., Agr. Expt. Sta. Tech. B u i . 122. . 1938. D i r e c t i o n a l p e r m e a b i l i t y of seasoned wood t o water and some f a c t o r s which a f f e c t i t . Jour. Agr. Res., 56(10): 711-746. Esau, K. 1967. Plant Anatomy, 2nd ed. John Wiley and Sons, Inc. N.Y. Fengel, D. 1966. Development an d . u l t r a s t r u c t u r e of bordered p i t s i n Pinaceae. Svensk Pap p e r s t i d . , 69(7): 232-241. T r a n s l . Can. Dept. Forest. R.D., ODF TR48. F l e i s c h e r , H.O. 1950. An anatomical comparison of r e f r a c t o r y and e a s i l y t r e a t e d Doulgas - f i r heartwood. Amer. Wood Pres. Assoc. P r o c , 46: 152-157. Fogg, P.J. 1968. L o n g i t u d i n a l a i r p e r m e a b i l i t y of southern pine wood. Ph. D. Thesis, L o u i s i a n a State U n i v e r s i t y . F r e n z e l , P. 1929. Uber d i e Porengrossen E i n i g e r P f l a n z l i c h e r Zellmembranen. P l a n t a , 8: 642-665. (C i t e d by R. A. Megraw, 1967). Frey-Wyssling, A. 1959. Die p f l a n z l i c h e Zellwand. Springer - Ve r l a g , B e r l i n . ( C i t e d by K. Esau, 1967). 99 , and H.H. Bosshard. 1953. Uber den Feinbau der S c h l i e Bhaute i n H o f t u p f e l n . Holz a l s Roh-und Werkstoff, 11: 417-420. (C i t e d by J . Bauch, W. L i e s e and F. Scholz, 1968). , H.H. Bosshard, and K. Muhlethaler. 1956. Die submikroskopische Entwicklung der H o f t u p f e l . [The submicroscopic development of the bordered p i t ] . P l a n t a , 47(2): 115-126. (Ger., Engl. sum.). , and K. Muhlethaler. 1965. U l t r a s t r u c t u r a l P l a n t Cytology. E l s e v i e r P u b l i s h i n g Co. N.Y. Frothingham, E.H. 1909. D o u l g a s - f i r : A study of the P a c i f i c coast and Rocky Mountain forms. U.S.D.A.., For. S e r v i c e , Washington, D.C, C i r c u l a r 150. Gerry, E. 1915. F i b e r measurement s t u d i e s : l e n g t h v a r i a t i o n s , where they occur and t h e i r r e l a t i o n t o the s t r e n g t h and uses of wood. S c i . , 61(1048): 179. G r i f f i n , G.J. 1919. Bordered p i t s i n D o u g l a s - f i r : A study of the p o s i t i o n of the torus i n mountain and lowland specimens i n r e l a t i o n t o creosote p e n e t r a t i o n . Jour. F o r e s t r y , 17(7): 813-822. . 1924. Further note on the p o s i t i o n of the t o r i i n bordered p i t s i n r e l a t i o n t o p e n e t r a t i o n of p r e s e r v a t i v e s . Jour. F o r e s t r y , 22(6): 82-83. Haddock, P.G., J . Walters, and A. Kozak. 1967. Growth of c o a s t a l and i n t e r i o r provenances of D o u g l a s - f i r [Pseudotsuga m e n z i e s i i (Mirb.) Franco] at Vancouver and Haney i n B r i t i s h Columbia. F a c u l t y of F o r e s t r y , Univ. of B.C., Research Papers No.79. 100 Haigh, R. W. 1961. The e f f e c t of provenance and growth r a t e on s p e c i f i c g r a v i t y and summerwood percentage of young D o u g l a s - f i r . B.S.F. Thesis, Univ. of B r i t i s h Columbia. Harada, H., and Y. Mi y a z a k i . 1952. The e l e c t r o n microscopic observation of the c e l l w a l l of c o n i f e r t r a c h e i d s . Jour. Jap. F o r e s t r y S o c , 34: 350. H a r r i s , J.M 1953. Heartwood formation i n Pinus r a d i a t a (D. Don). Nature, 172 (4377): 552. Hart, C A . and R. J . Thomas. 1967. Mechanism of bordered p i t a s p i r a t i o n as caused by c a p i l l a r i t y . For. Prod. Jour., 17(11): 61-68 . Hunt, G.M., and G.A. G a r r a t t . 1967. Wood p r e s e r v a t i o n . 3rd ed. McGraw-Hill Book Co., N.Y. I n t e r n a t i o n a l A s s o c i a t i o n of Wood Anatomists. 1964. M u l t i l i n g u a l g l o s s a r y of terms used i n wood anatomy (Engl. vers i o n ) . Isenberg, I.H. 1963. The s t r u c t u r e of wood. In: The chemistry of wood, e d i t e d by B.L. Browning. I n t e r s c i e n c e P u b l i s h e r s , N.Y. Jayme, G., G. Hunger, and D. Fengel. 1960. The e l e c t r o n microscope p i c t u r e of c e l l u l a r m i c r o s t r u c t u r e of c l o s e d and unclosed p i t s i n coniferous woods. Holzforschung, 14(4): 97-105. U.S.D.A., For. S e r v i c e , FPL, Madison, Wis. T r a n s l . No.424. 101 J u t t e , S.M., and B.J. S p i t . 1963. The submicroscopic s t r u c t u r e of bordered p i t s on the r a d i a l w a l l s of t r a c h e i d s i n Parana pine, K a u r i and European spruce. Holzforschung, 17(6): 168-175. Kaye, G.I., and N. Lane. 1967. A one-step method f o r o r i e n t i n g t i s s u e during embedding i n p l a s t i c . S t a i n Technology, 42(6): 318-319. Kennedy, R.W., and C.K. Chan. 1970. T e n s i l e p r o p e r t i e s of microsections prepared by d i f f e r e n t microtomy techniques. Jour, of the I n s t , of Wood S c i . , 25:39-42. Kishima, T. 1965. Review on the bordered p i t s t r u c t u r e of coniferous wood and the l i q u i d p e n e t r a t i o n . Wood Res., 34: 10-12. , and S. Hayashi. 1962. Ort the c l o s u r e of bordered p i t - p a i r s i n coniferous t r a c h e i d s . Wood Res., 27: 22-39. T r a n s l . Can. Dept. F i s h e r i e s and F o r e s t r y , OOFF TR6. Klinkenberg, L . J . 1941. The p e r m e a b i l i t y of porous media t o l i q u i d s and gases. D r i l l i n g Prod. P r a c t . , pp. 200-213. Koran, Z. 1964. A i r p e r m e a b i l i t y and creosote r e t e n t i o n i n D o u g l a s - f i r . For. Prod. Jour., 14(4): 159-166. Krahmer, R.L. 1961. Anatomical features of permeable and r e f r a c t o r y D o u l g a s - f i r . For. Prod. Jour., 11(9): 439-441. , and W. A. Cote, J r . 1963. Changes i n coniferous wood c e l l s a s s o c i a t e d w i t h heartwood formation. TAPPI, 46(1): 42-49. 102 K r i b s , D.A. 1928. Length of t r a c h e i d s i n jack pine i n r e l a t i o n t o t h e i r p o s i t i o n i n the v e r t i c a l and h o r i z o n t a l axes of the t r e e . Univ. Minn., Agr. Expt. Sta. Tech. B u i . 54. Lassen, L.E., and E.A. Okkonen. 1969. Sapwood thickness of D o u g l a s - f i r and f i v e other western softwoods. U.S.D.A., For. S e r v i c e , FPL, Madison, Wis. Res. Paper No.124. Lee, H.N., and E.M. Smith. 1916. D o u g l a s - f i r f i b e r , w i t h s p e c i a l reference t o le n g t h . F o r e s t r y Q u a r t e r l y , 14: 671-695. L i e s e , W. 1956. Fine s t r u c t u r e of bordered p i t s i n coniferous woods. I n t e r n a t i o n a l Conference on E l e c t r o n Microscopy, Proc. 550-554. London. A u s t r a l i a CSIRO, T r a n s l . No. 3621. . 1965. The f i n e s t r u c t u r e of bordered p i t s i n softwoods. In C e l l u l a r U l t r a s t r u c t u r e of Woody P l a n t s , ed. by W. A. Cote, J r . , pp. 271-290. Syracuse Univ. Press. , and J . Bauch. 1964. About the p e n e t r a b i l i t y of the bordered p i t s of c o n i f e r s . Die Naturwissen Schaften 21:516. Great B r i t a i n For. Prod. Res. Lab., T r a n s l . No. 124. . 1966. On the c l o s u r e of bordered p i t s i n c o n i f e r s . Jour. Wood S c i . and Technol., Quart. Rev. (Cite d by W. L i e s e and J . Bauch, 1967 b ) . . 1967 a. On the cl o s u r e of bordered p i t s i n c o n i f e r s . Wood S c i . and Tech., 1 ( 1 ) : 1-13. 103 . 1967 b . The e f f e c t o f d r y i n g o n t h e l o n g i t u d i n a l p e r m e a b i l i t y o f sapwood o f gymnosperms. ( S o u v e n i r f o r i n a u g u r a t i o n o f l a b o r a t o r i e s , I n d i a n P l y w o o d I n d . Res. A s s . ) . T r a n s l . Can. Dept. F o r e s t . R.D., ODF TR318. , and M. H a r t m a n - F a h n e n b r o c k . 1953. E l e c t r o n m i c r o s c o p e i n v e s t i g a t i o n s o f t h e b o r d e r e d p i t s o f c o n i f e r s . B i o c h i m i c a e t B i o p h y s i c a A c t a , 1 1 ( 2 ) : 190-198. A u s t r a l i a CSIRO, T r a n s l . No. 2220 . L i t t l e , E .L. J r . 1953. Check l i s t o f n a t i v e a n d n a t u r a l i z e d t r e e s o f U n i t e d S t a t e s ( i n c l u d i n g A l a s k a ) . A g r i c u l t u r a l handbook No. 41, F o r e s t S e r v i c e , W a s h i n g t o n , D. C. L u f t , J . 1961. Improvements i n epoxy r e s i n embedding methods. J o u r . B i o p h y s . B i o c h e m . C y t . , 9: 409-414. M a r t s , R.O. 1955. Some s t r u c t u r a l d e t a i l s o f D o u g l a s - f i r p i t membranes by p h a s e c o n t r a s t . F o r . P r o d . J o u r . , 5 ( 5 ) : 381-382. Megraw, R. A. 1967. A h y d r o d y n a m i c p a r t i c u l a t e a p p r o a c h t o p i t membrane p o r e s i z e d i s t r i b u t i o n . F o r . P r o d . J o u r . , 1 7 ( 1 1 ) : 29-38. Meyer, R.W. 1971. I n f l u e n c e o f p i t a s p i r a t i o n on e a r l y w o o d p e r m e a b i l i t y o f D o u g l a s - f i r . Wood a n d F i b e r , 2 ( 4 ) : 328-339. M i l l e r , D.J. 1961. P e r m e a b i l i t y o f D o u g l a s - f i r i n O r e g o n . F o r . P r o d . J o u r . , 1 1 ( 1 ) : 14-16. 104 , and R.D. Graham. 1963. T r e a t a b i l i t y of D o u g l a s - f i r from western United States. Amer. Wood Pres. Assoc. Proc., 59: 218-222. Nic h o l a s , D.D. 1966. St r u c t u r e and chemical composition of the p i t membrane i n r e l a t i o n t o the p e r m e a b i l i t y of l o b l o l l y pine (Pinus taeda L ) . Ph. D. Thesis, North C a r o l i n a State Univ. Osnach, N.A. 1961. On the p e r m e a b i l i t y of wood. Derev. Prom., 10(3): 11-13. T r a n s l . Can. Dept. F o r e s t . R.D., ODF TR99. Panshin, A.J., and C. DeZeeuw. 1970. Textbook of wood- technology. V o l . 1. McGraw-Hill, N.Y. Penhallow, D.P. 1907. Anatomy of Gymnosperms, Boston. (Ci t e d by H. N. Lee and E. M. Smith, 1916). P e t t y , J.A. 1970. Pe r m e a b i l i t y and s t r u c t u r e of the wood of S i t k a spruce. Proc. Roy. Soc. Lond. B. 175: 149-166. , and R. D. Preston. 1969. The dimensions and number of p i t membrane pores i n c o n i f e r wood. Proc. Roy. Soc. Land. B. 172: 137-151. , and G.S. P u r i t c h . 1970. The e f f e c t s od d r y i n g on the s t r u c t u r e and p e r m e a b i l i t y of the wood of Abies grandis. Wood S c i . and Tech., 4: 140-154. P h i l l i p s , E.W.J. 1933. Movement of the p i t membrane i n coniferous woods, w i t h s p e c i a l reference t o p r e s e r v a t i v e treatment. F o r e s t r y 7: 109-120. 105 Preston, R.D. 1959. The f i n e s t r u c t u r e of wood w i t h s p e c i a l reference t o timber impregnation. Record of the 1959 Ann. Conv. of the B r i t . Wood Pres. Assn. pp. 31-57. Resch, H., and B. A. Ecklund. 1964. Pe r m e a b i l i t y of wood e x e m p l i f i e d by measurements on redwood. For. Prod. Jour., 14(5): 199-206. Richardson, S.D. 1964. The e x t e r n a l environment and t r a c h e i d s i z e i n c o n i f e r s . In the Formation of Wood i n Forest Trees, ed. by M. H. Zimmermann. Academic Press, N.Y. pp. 367-388. Russow, E. 1883. Zur Kenntniss des Holzes, i n s o n d e r h e i t des Coniferenholzes. Bot. C e n t r a l b l a t t , V o l . V I I I . ( C i t e d by I . W. B a i l e y , 1913 b ) . Sachs, J . 1887. Vorlesungen Uber P f l a n z e n - P h y s i o l o g i e . 2nd ed. L e i p z i g . ( C i t e d by I . W. B a i l e y , 1913 b ) . Sanio, C. 1873. Anatomie der gemeinen K i e f e r (P. s y l v e s t r i s ) . J . Wiss. Bot., 9: 50-126. (C i t e d by J . Bauch, W. Li e s e and F. Scholz, 1968). Scarth, G.W. 1928. The s t r u c t u r e of wood and i t s p e n e t r a b i l i t y . Paper Trade Jour., Apr. 16, pp. 228-233. Scheidegger, A.E. 1960. The physics of flow through porous media. Revised e d i t i o n . Univ. of Toronto Press, Canada. 106 Sebastian, L.P., W. A. Cote, J r . , and C.Skaar. 1965. R e l a t i o n s h i p of gas phase p e r m e a b i l i t y t o u l t r a s t r u c t u r e of white spruce. For.Prod. Jour., 15(9): 394-404. Shepard, H.B., and I.W. B a i l e y . 1914. V a r i a t i o n i n l e n g t h of coniferous f i b e r s . Proc. Soc. Amer. For., 9:4. Siau, J.F. 1972. The e f f e c t of specimen l e n g t h and impregnation time upon the r e t e n t i o n of o i l s i n wood. Wood S c i . 4 ( 3 ) : 163-170. Smith, D.M. 1954. Maximum moisture content method f o r determining s p e c i f i c g r a v i t y of small wood samples. U. S. FPL, Madison, Wis. Rept. No. 2014. Smith, D.N. 1963. The p e r m e a b i l i t y of wood t o l i q u i d s and gases. Paper presented at 5th FAO Conf. on Wood Tech., Madison, Wis., Sept., 1963. , and E. Lee. 1958. The l o n g i t u d i n a l p e r m e a b i l i t y of some hardwoods and softwoods. Great B r i t a i n Dept. S c i . of Indus. Res., For. Prod. Res. Spec. Rept. 13. H.M.S..O. London. Smith, D.N.R., and W.B. Banks. 1971. The mechanism of flow.of gases through coniferous wood. Proc. Roy. Soc. Lond. B. 177: 197-223. Stamm, A.J. 1929. The c a p i l l a r y s t r u c t u r e of softwoods. Journ. A g r i . Res., 38(1): 23-67. 107 . 1935. The e f f e c t of changes i n the e q u i l i b r i u m r e l a t i v e vapor pressure upon the c a p i l l a r y s t r u c t u r e of wood. U. S. Forest S e r v i c e , FPL, Rept. No. R 1075. _ . 1946. Passage of l i q u i d s , vapors, and d i s s o l v e d m a t e r i a l s through softwoods. U,S.D.A. Tech. B u i . 929. . 1952. Surface p r o p e r t i e s of c e l l u l o s i c m a t e r i a l . In Wood Chemistry, ed. by L. E. Wise and E. C. Jahn, 2nd e d i t i o n , V o l . 2: 769-792. Reinhold Pub. Corp., N.Y. . h963. P e r m e a b i l i t y of wood t o f l u i d s . For. Prod. Jour., 13(11): 503-507. . 1964. Wood and C e l l u l o s e Science. Ronald Press Co., N.Y. . 1967. Movement of f l u i d s i n wood. Part I : Flow of f l u i d s . Wood S c i . and Tech., 1(2): 122-141. _ . 1970 a. Maximum e f f e c t i v e p i t pore r a d i i of the heartwood and sapwood of 6 softwoods as a f f e c t e d by d r y i n g and resoaking. Wood and F i b e r , 1 ( 4): 263-269. . 1970 b. V a r i a t i o n s of maximum t r a c h e i d and p i t pore dimensions from p i t h t o bark f o r Ponderosa pine and redwood before and a f t e r d r y i n g determined by l i q u i d displacement. Wood S c i . and Tech., 4:81-96. 108 • , S. W. C l a r y , and W.J. E l l i o t . 1968. E f f e c t i v e r a d i i of lumen and p i t pores i n softwood. Wood S c i . , 1 ( 2 ) : 93-101. , and E. Wagner. 1961. Determining the d i s t r i b u t i o n of i n t e r s t r u c t u r a l openings i n wood. For. Prod. Jour., 11(3) : 141-144. Stone, C D . 1939. A study on the bordered p i t s of D o u g l a s - f i r w i t h reference t o the p e r m e a b i l i t y of wood t o l i q u i d s . Ph. D. Thesis, Univ. of Washington, S e a t t l e . Strasburger, E. 1891. Uber den Bau und d i e V e r r i c h t u n g der L e i t u n g s -bahnen i n den Pflangen. H i s t o l o g i s c h e B e i t r a g e H I I I , Jena. (C i t e d by G. Bramhall, 1970). Sucoff, E.I., P.Y.S. Chen, and R.L. Hossfeld. 1965. Pe r m e a b i l i t y of unseasoned xylem of northern white cedar. y For. Prod. Jour. 15(8): 321-324. Tamblyn, N. 1960. Pen e t r a t i o n of chemicals i n t o wood. 5th World For. Congress, S e a t t l e , Washington. Teesdale, C H . 1914. R e l a t i v e r e s i s t a n c e of various c o n i f e r s t o i n j e c t i o n w i t h creosote. U.S.D.A. B u i . No. 101. Thomas, R.J. 1967. The s t r u c t u r e of the p i t membranes i n long l e a f p i n e : An e l e c t r o n microscope study. Amer. Wood Pres. Assoc. Proc. 63: 20-29. . 1968. The development and u l t r a s t r u c t u r e of the bordered p i t membrane i n the southern y e l l o w pines. Holzforschung, 22(2)j 38-44. 1 . 1969. The u l t r a s t r u c t u r e of southern pine bordered p i t membranes as revealed by s p e c i a l i z e d d r y i n g techniques. Wood and F i b e r , 1 ( 2): 110-123. . 1970. O r i g i n of bordered p i t margo m i c r o f i b r i l s . Wood and F i b e r , 2(3): 285-288. , and D. D. N i c h o l a s . 1966. P i t membrane s t r u c t u r e i n l o b l o l l y pine as i n f l u e n c e d by so l v e n t exchange d r y i n g . For. Prod. Jour., 16(3): 53-56. . 1968. The u l t r a s t r u c t u r e of the p i n o i d p i t i n southern y e l l o w pine. TAPPI, 51(2): 84-88. , and J.L. Scheld. 1967. The d i s t r i b u t i o n and s i z e of the i n t e r t r a c h e i d p i t s i n eastern hemlock. Forest S c i . 13(1): 85-89. Tiemann, H.B. 1910. The p h y s i c a l s t r u c t u r e of wood i n r e l a t i o n to i t s p e n e t r a b i l i t y by p r e s e r v a t i v e f l u i d s . Amer. R a i l . Eng. & Mainten. of Way Assoc. B u i . 120 (App. D): 359-375. Tsoumis,G. 1965. L i g h t and e l e c t r o n microscopic evidence on the s t r u c t u r e of the membrane of bordered p i t s i n t r a c h e i d s of c o n i f e r s In C e l l u l a r U l t r a s t r u c t u r e of Woody P l a n t s , ed. by W. A. Cote, J r . , pp. 305-317. Syracuse Univ. Press. Tusko, F.F. 1963. A study of v a r i a b i l i t y i n c e r t a i n D o u g l a s - f i r populations i n B r i t i s h Columbia. Ph. D. Thesis, Univ. of B r i t i s h Columbia. Wardrop, A.B., and G.W. Davies. 1961. Morphological f a c t o r s r e l a t i n g t o the p e n e t r a t i o n o l i q u i d s i n t o wood. Holzforschung, 15(5): 129-141. Weiss, H.F. 1912. Str u c t u r e of commercial woods i n r e l a t i o n t o the i n j e c t i o n of p r e s e r v a t i v e s . Amer. Wood Pres. Assoc. Proc. 8: 185-197. Wellwood, R.W. and J.G.H. Smith. 1962. V a r i a t i o n i n some important q u a l i t i e s of wood from young Douglas f i r and hemlock t r e e s . Univ. of B r i t i s h Columbia, Fac. of F o r e s t r y . Res. Pap. No. 50, 15pp. Yao, J . and A.J. Stamm. 1967. V a l i d i t y of determining p i t pore s i z e s i n softwoods surface t e n s i o n r e s i s t a n c e w i t h flow r a t e . For. Prod. Jour., 17(2): 33-40. I l l APPENDIX I . DEHYDRATION, INFILTRATION AND EMBEDDING The wood specimen was dehydrated stepwise i n a v i a l u s i n g acetone and propylene oxide at room temperature according to the f o l l o w i n g schedule: Dehydrating Reagents Time i n each change No. of changes 50% acetone aqueous s o l u t i o n 15 min. 1 70% acetone aqueous s o l u t i o n 15 min. 1 95% acetone aqueous s o l u t i o n 60 min. 1 100% acetone 15 min. 3 100% propylene oxide 20 min. 3 Specimens i n the f i n a l change of 100% propylene oxide were i n f i l t r a t e d by passing through the L u f f s (1961) Epon s e r i e s i n propylene oxide, u n t i l pure Epon was reached. I n f i l t r a t i o n Reagents Time 1:1 L u f f s Epon/propylene oxide 60 min. 2:1 L u f f s Epon/propylene oxide 60 min. 100% L u f f s Epon overnight For embedding, a s m a l l , coded paper l a b e l was i n s e r t e d i n t o a BEEM capsule which was d r i e d i n an oven f o r one hour at 60°C. Thereafter, the capsule was f i l l e d h a l f f u l l w i t h f r e s h L u f f s Epon. P o s i t i o n i n g of i n d i v i d u a l specimens i n capsules was done by using a minuten p i n and a small s t i f f paper d i s c (Kaye and Lane, 1967) as i l l u s t r a t e d i n Figure I - l . F i n a l c u r i n g was done at 60°C f o r 36 hours. gure I - l . I l l u s t r a t i o n of p o s i t i o n i n g of wood specimen i n 'BEEM' capsule f i l l e d ;w/~jjj with,Epon The p a r t i a l assembly ready f o r lowering i n t o the embedding medium::> The completed assembly ready f o r c u r i n g , the d i s c f l o a t s on the l i q u i d L u f t ' s Epon.-"^  No.15 "miauten. p i n (Clay-Adams, Cat.No.E.81) S t i f f paper d i s c (6mm i n diameter) Wood specimen BEEM capsule L u f t 1 s Epon a. b. c. d. e. 113 APPENDIX I I STAINING S e r i a l cross s e c t i o n s of Epon embedded m a t e r i a l f o r l i g h t microscopy were pi c k e d up on a cover s l i p and a i r -d r i e d f o r s e v e r a l minutes. They were then s t a i n e d i n the f o l l o w i n g , f i l t e r e d S o l u t i o n : Methylene blue c h l o r i d e 1 gm. Sodium borate 1 gm. D i s t i l l e d water t o make 100 ml. The f o l l o w i n g technique c o n s i s t e n t l y gave sharp s t a i n -i n g f o r p i t torus and middle l a m e l l a . 1. Flood or immerse dry embedded se c t i o n s on cover s l i p s i n the above s o l u t i o n f o r 45 minutes. 2. Wash thoroughly i n s e v e r a l changes of d i s t i l l e d water t o remove excess s t a i n . 3. Dry s t a i n e d s e c t i o n s i n a i r . 4. Mount i n permount. 5. Cure f o r approximately 12 hours i n an oven at 60°C. 114 APPENDIX I I I . DEFINITIONS OF SYMBOLS Symbol D e f i n i t i o n A Air-seasoned. a Radius of a s p i r a t e d area (um). CC D o u g l a s - f i r sapwood from a c o a s t a l seed source grown i n c o a s t a l environment. CV C o e f f i c i e n t of v a r i a t i o n . DF Degrees of freedom. E Earlywood. IC D o u g l a s - f i r sapwood from an i n t e r i o r seed source grown i n c o a s t a l environment. L Latewood. Len Specimen le n g t h (cm). N Number of observations. P Diameter of p i t annulus (um). p Radius of p i t annulus (um). AP> Pressure d i f f e r e n t i a l (cm Hg). Perm " L o n g i t u d i n a l a i r p e r m e a b i l i t y (darcys). R M u l t i p l e c o r r e l a t i o n c o e f f i c i e n t , r Simp«le c o r r e l a t i o n c o e f f i c i e n t . S Solvent-seasoned. SD Standard d e v i a t i o n . SEE Standard e r r o r of estimate. T Diameter of p i t torus (um). t Radius of p i t torus (um). Xf Estimated margo pore area (um 2). Xg Observed margo pore area (um 2). X t l L o n g i t u d i n a l t r a c h e i d l e n g t h (mm). Xca P i t completely a s p i r a t e d Xpa P i t p a r t i a l l y a s p i r a t e d Xua P i t unaspirated (%). Xtn Number of t r a c h e i d s per square m i l l i m e t e r . Xsg S p e c i f i c g r a v i t y . Xmp Estimated margo pore area (um 2). Xma Margo area (um 2). Yperm Weighted mean of p e r m e a b i l i t y values of the f i r s t three longer specimen lengths (darcys). o" f 2 An estimate of the variance of the a c t u a l d i s t r i b u t i o n . / a f The square root of ^ f 2 . n 3.1416. 115 APPENDIX IV. MARGO AREA CALCULATION Figure IV-1. Diagrammatic, r a d i a l view of a bordered p i t a = radius of a s p i r a t e d area (um) p = radius of p i t annulus (um) t =? radius of p i t torus (um) 1 5 • • Assume t = — P , a = — p 5 5 .*. p = 2t , a = — ( 2 t ) = — T, where T = torus diameter. o o I . P a r t i a l l y a s p i r a t e d margo area (um2) = [na2-nt2] x % p a r t i a l l y a s p i r a t e d = I I [ ( | T ) 2 - ( ^ T ) 2 ] X % p a r t i a l l y a s p i r a t e d o z 9 9 = — IT. T x % p a r t i a l l y a s p i r a t e d 54 2 I I . Unaspirated margo area (um ) = [ n P 2 - n t 2 ] x % unaspirated = n [(j P)? - (j T ) 2 ] x % unaspirated = ^ n [ P 2 - T 2] x % unaspirated I I I . T o t a l margo area a v a i l a b l e t o flow (xna ) = 1 + 11 9 ? 1 2 o = — IT T x % p a r t i a l l y a s p i r a t e d + — n [P -T z] x % unaspirated. 116 APPENDIX V. THE ESTIMATION OF MARGO PORE SIZE BY W. G. WARREN* Attempts t o describe the data i n terms of s i z e - b i a s e d sampling from a standard d i s t r i b u t i o n were uns u c c e s s f u l . Several standard forms i n c l u d i n g lognormal, W e i b u l l , negative exponential, gamma and beta were considered. Various aspects of s i z e - b i a s e d sampling from such d i s t r i b u t i o n s were i n v e s t i g a t e d and w i l l be reported independently. They do not appear a p p l i c a b l e to the data i n question. The e m p i r i c a l technique f i n a l l y chosen f o r handling these data i s described below. I t i s assumed that the p r o b a b i l i t y d e n s i t y f u n c t i o n of fx pore s i z e i s f ( x ) w i t h d i s t r i b u t i o n f u n c t i o n F(x) =/ f ( t ) d t . Under the method of sampling, w i t h the p r o b a b i l i t y of an i n d i v i d u a l ' s s e l e c t i o n being p r o p o r t i o n a l t o i t s s i z e , we s h a l l have an ob-served d i s t r i b u t i o n whose d e n s i t y , g ( x ) , i s r e l a t e d t o the a c t u a l d e n s i t y by: g(x) = k x f (x) (1) where k may be determined from the f a c t that g ( t ) dt = 1 Thus f (x) dx -1 (2),say. * Research s c i e n t i s t , Biometrics s e c t i o n , Western Forest Products Laboratory, Vancouver, B. C. 117 Let us denote the variance of the a c t u a l d i s t r i b u t i o n by: 2 /"° 2 ° f = J o (x-U f) f(x) dx (3) and the mean of the observed d i s t r i b u t i o n by: /-OO U g = Jo X g ^ d X ^ Then, as i s w e l l known 2 , Ug = u f + af / u f (5) To complete the n o t a t i o n , l e t the d i s t r i b u t i o n f u n c t i o n of the observed d i s t r i b u t i o n be: G(x) = g ( t ) dt (6) I t f o l l o w s t h a t : )dt _ F(x) y* SM d t = y x f i t f * f (7) and thus ^O X ^ H Let the e m p i r i c a l d i s t r i b u t i o n f u n c t i o n of the observed d i s t r i -b u t i o n be: G * ( x ) defined from: where the sample i s of s i z e n, Suppose that we t r a c k the p o i n t s ( i Jby some curve as an \ i n + 1 / estimate of G(x), say G° (x). We may then approximate the i n t e g r a l : 118 g(x) by t a k i n g a succession of values of x, say 8 , 2 8 , 3 8 , 4 8 dx x o ( 5 small) so t h a t 8 ^  = i 8 , and use G 0 ( 8 . + 1 ) - G ° ( 5 . ) /8 t o approximate g(8 ^ +8/2), and f i n a l l y form the sum:. i = 1 5 ( 5 ± + 5/2) (10) The sum can be assured f i n i t e by e x t r a p o l a t i n g the t r a c k i n g f u n c t i o n t o a t t a i n u n i t y f o r some f i n i t e value of x . I t then seems reasonable t o estimate u^ by 1 / S . F u r t h e r , weronay estimate the d i s t r i b u t i o n f u n c t i o n F(x) by: 1. 2 G° ( t . + 1 ) - G°U.) S i , 8± <x 6 ( s ± + 8 /2) which can be conveniently achieved, computationally, by s t o r i n g the p a r t i a l sums obtained i n the c a l c u l a t i o n of S. The estimate of the d i s t r i b u t i o n f u n c t i o n may be used to provide estimates of any other property, e.g. p e r c e n t i l e s , higher order moments e t c . , 2 however to o b t a i n an estimate of the variance, <rf , i t would seem more convenient t o s u b s t i t u t e i n equation (5). Thus, ^2 o f = "I x - 77 I (ID where x i s the mean of the observations. In p r a c t i c e i t was found very d i f f i c u l t t o t r a c k the data w i t h some r a t i o n a l f u n c t i o n . 119 The polynomial r a t i o : P (x) = ax + bx 1+cx +bx (12) (p(0) = 0, p(x) — 1 as x •—- « ) was s u c c e s s f u l f o r some data s e t s , but the standard n o n - l i n e a r l e a s t squares f i t computer package could not be r e l i e d on t o y i e l d an acceptable s o l u t i o n , even w i t h f a i r l y good i n i t i a l es-timates. Note t h a t t o behave as a d i s t r i b u t i o n f u n c t i o n i t i s re q u i r e d that a, b, c > 0, otherwise p(x) may c o n t a i n a zero f o r x yo, be non-monotonic f o r x>o or become i n f i n i t e f o r f i n i t e p o s i t i v e x , sometimes w i t h i n the range of the data. Therefore t o be c e r t a i n of t r a c k i n g the data, the "curve" chosen c o n s i s t e d of s t r a i g h t l i n e segments between successive data p o i n t s . This r e q u i r e s some e l a b o r a t i o n . Let x_^  denote the i 1 " * 1 order s t a t i s t i c of the observations. Because of the l i m i t a -t i o n s of measuring there may be s e v e r a l , say r , observations w i t h the same value, i . e . x . = x = x . , . In such cases the data p o i n t was chosen as: The f i n a l l i n e segment was obtained by extending the l i n e between the l a s t two data p o i n t s , obtained as j u s t described, u n t i l i t i n t e r s e c t e d the l i n e y = 1. Since i t i s convenient.ato take 5 = 1 the a b s c i s s a f o r t h i s i n t e r s e c t i o n p o i n t was a p p r o p r i a t e l y rounded. 120 The estimates, as given by the computer program w r i t t e n t o the above p r e s c r i p t i o n , are presented i n Table 1. The f o l l o w i n g i n -formation i s given. ( i ) ID: This r e f e r s t o a s e r i a l number between 1 and 171 and i s simply an i n t e r n a l coding t o enable quick, unique i d e n t i f i c a t -i o n of the data s e t . ( i i ) Code: This i s a l e t t e r number combination such as II1-4 1, CC2-7 9 e t c . The f i r s t p a r t i n d i c a t e s the source of the m a t e r i a l and the f i n a l number the photograph w i t h i n that source. There are three cases i n the II1-5 s e r i e s , and one under CC1-4 s e r i e s , where independent estimates have been obtained from the same photograph. In other cases the same code number was given t o a d i f f e r e n t photographs, i . e . a s e r i e s of photographs from a source was sampled at one time and a second s e r i e s from the same source at a l a t e r time, but the same s e r i a l numbers were used. This one reason f o r the a d d i t i o n a l ID number. ( i i i ) N: The number of pores measured on the photo. ( i v ) X : The mean of the observations. I f the major and minor g axes of a pore are a, b then the observation was taken as Ft ab. To o b t a i n a c t u a l dimensions t h i s should be d i v i d e d by 4 and d i v i d e d by the appropriate m a g n i f i c a t i o n f a c t o r , the same f o r a l l ob-se r v a t i o n s from one photo but v a r y i n g s l i g h t l y f o r d i f f e r e n t photo's. (v) x f : The value of 1/S obtained as described above. This i s an estimate of the a c t u a l average pore s i z e as opposed t o the observed average above. The m a g n i f i c a t i o n f a c t o r and the d i v i s o r 4 (1 of ( i v ) ) are a l s o r e q u i r e d here t o o b t a i n a c t u a l dimensions. ( v i ) ^ ^ : An estimate of the variance as obtained from equation (11). ( v i i ) : The square root of the q u a n t i t y described i n ( v i ) . ( v i i i ) c v . : 'o^ expressed as a percentage of x^. * * The data of Table V - l are summarized i n Table V-2. The four cases where independent estimates were obtained from the same * photograph are bracketed. I n Table V-2 the data are summarized by code, the s e r i e s obtained a t d i f f e r e n t times being kept separate and a l s o combined. Tabulated are the maximum, minimum and average of the s e v e r a l x ^ values f o r each s e t , and a l s o of the c v . values. For completeness the number of photos i n the set i s a l s o recorded. Table V - l (See Table VI-9) Table V-2 (See Table VI-10) 122 This t a b u l a t i o n reveals a r a t h e r d i s t u r b i n g f e a t u r e . The x ^  estimates from the two s e r i e s of the code are, when a v a i l a b l e , g e n e r a l l y very d i f f e r e n t (greater d i f f e r e n c e s than could be accounted f o r by the v a r i a b l e m a g n i f i c a t i o n f a c t o r ) . On the other hand the four cases where we have independent estimates from the same photograph show good agreement. I t must be con-cluded t h e r e f o r e , t h a t t h e - d i f f e r e n c e s r e f l e c t sampling e r r o r s consequent on a h i g h l y v a r i a b l e p o p u l a t i o n (or t h a t a photograph i s , f o r some reason, a t y p i c a l ) . A c c o r d i n g l y the only d i s c r i m i -n a t i o n we can make w i t h any confidence i s between groups I I I - 4 , I I I - 5 and I I I - 6 on one hand and a l l remaining groups on the other ( i n s u f f i c i e n t data f o r ICl - 3 ) although a f i n e r o r d e r i n g i s perhaps p o s s i b l e . The i n t r o d u c t i o n of c.v. adds to the p i c t u r e ; f o r example CC1-4 and IC2-7 have low and high variances i n r e l a t i o n t o t h e i r r e s p e c t i v e means. This may be a c h a r a c t e r i s t i c of the group. 123 APPENDIX V I . STATISTICAL AND DATA TABLES Table VI-1. Data f o r l o n g i t u d i n a l a i r p e r m e a b i l i t y Code Len AP Perm Code Len AP Perm (cm) (cmHg) (darcys) (cm) (cmHg) (darcys) CC 3.61 5.93 2.13 CC 3.63 5.93 1.67 11 3.05 5.68 1.78 11 3.15 5.73 1.48 AL 2.53 5.01 1.91 SL 2.62 5.01 1.36 2.03 3.63 2.38 2.13 3.65 2.28 1.58 3.43 2.12 , 1.67 3.09 3.08 1.14 2.84 2.62 1.18 2.81 3.16 0.73 2.20 1.77 0.71 2.07 3.28 0.47 1.64 1.97 0.48 1.57 3.32 CC 3.58 5.97 0.68 CC 3.66 5.59 12.08 14 3.07 5.76 0.98 14 3.12 5.32 11.81 AE 2.59 5.01 0.47 SE 2.60 4.56 11.45 2.04 3.57 0.65 2.07 3.32 11.41 1.61 3.43 0.63 1.61 2.87 10.87 0.98 2.90 0.26 1.16 2.47 9.08 0.65 2.21 0.26 0.69 1.86 7.49 0.46 1.64 0.9.1 0.48 1.36 5.17 CC 3.66 5.97 0.46 CC 3.62 5.59 9.58 . 15 3.12 5.65 0.47 15 3.15 5.30 9.75 AE 2.66 4.95 0.45 SE 2.65 4.56 9.86 2.16 3.68 0.44 2.09 3.32 10.26 1.66 3.34 0.40 1.63 3.12 10.23 1.13 2.89 0.34 1.18 2.58 9.12 0.68 2.17 0. 50 0.68 1.93 6.08 0.45 1.62 1.43 0.44 1.34 4.51 124 Table VI-1 (cont'd) Code Len AP Perm (cm) (cmHg) (darcys) CC 3.60 5.97 0.96 22 3.10 5.73 0.82 AL 2.58 5.02 0.82 2.15 3.26 1.08 1.68 3.17 0.96 1.25 2.67 1.22 0.77 2.13 1.81 0.45 1.64 1.23 CC 3.63 6.64 0.32 25 3.16 5.73 0.29 AE 2.64 5.01 0.29 2.16 3.00 0.38 1.68 2.81 0.34 1.23 2.57 0.39 0.76 1.93 1.22 0.46 1.51 0.54 CC 3.62 6.68 0.51 27 3.14 5.80 0.42 AE 2.62 5.05 0.37 2.06 2.89 0.79 1.62 2.68 0.44 1.16 2.63 0.42 0.70 1.91 0.33 0.37 1.45 0.51 Code Len AP Perm (cm) (cmHg) (darcys) CC 3.67 5.97 1.23 22 3.20 5.73 0.93 SL 2.68 5.03 1.00 2.17 3.23 1.48 1.73 3.14 1.24 1.26 2.69 1.32 0.77 2.07 1.16 0.46 1.65 2.38 CC 3.67 6.43 7.55 25 3.21 5.61 6.79 SE 2.72 4.71 6.67 2.17 2.94 6.62 1.70 2.61 6.32 1.25 2. 32 6.15 0.77 1.66 5.78 0.46 1. 39 2.76 CC 3.63 6.39 10.43 27 3.13 5.42 10.54 SE 2.63 4.64 10.22 2.15 2.54 10.79 1.67 2.37 10.45 1.22 2.21 10.11 0.74 1.59 9.03 0.29 0.90 7.25 Table VI-1 (cont'd) Code Len AP Perm (cm) (cmHg) (darcys) IC 3.62 5.87 1.27 11 3.12 5.77 1.24 AL 2.63 5.01 1.28 1.21 2.78 1.98 0.75 2.07 2.02 0.48 1.05 1.46 IC 3.63 6.08 0.72 13 3.16 5.74 0.48 AE 2.61 5.06 0.51 1.20 2.98 0.96 0.74 2.04 0.53 0.47 1.12 0.66 IC 3.64 5.91 1.21 15 3.16 5.45 0.88 AE 2.65 5.01 0.69 1.05 2.35 0.58 0.75 2.07 0.24 0.44 1.09 0.35 Code Len AP Perm (cm) (cmHg) (darcys) IC 3.63 5.82 0.98 11 3.19 5.77 0.82 SL 2.74 5.05 0.82 1.26 2.71 1.61 0.74 2.08 1.38 0.51 1.03 2.09 IC 3.62 6.02 4.69 13 3.19 5.77 4.65 SE 2.74 5.02 4.60 1.24 2.77 5.28 0.75 2.08 4.14 0.47 1.08 4.84 IC 3.62 5.72 8.71 15 3.10 5.52 8.49 SE 2.60 4.56 8.19 1.15 2. 03 7.81 0.64 1.82 4.66 0.47 0.96 4.68 Table VI-1 (cont'd) Code Len AP Perm (cm) (cmHg) (darcys) IC 3.67 6.56 0,76 21 3.16 5.77 0.65 AL 2.65 5.03 0.76 2.13 4.49 0.74 1.63 2.89 0.67 1.27. 2.57 0.59 0.84 1.99 0.51 0.57 1.48 0.56 IC 3.66 6.73 0.77 24 3.14 5.80 0.72 AL 2.59 5.03 0.72 2.13 4.19 0.66 1.60 2.97 0.61 1.30 2.60 0.60 0.84 2.04 0.60 0.51 1.41 0.50 3.65 7.06 0.42 27 3.16 5.74 0.34 AE 2.62 5.02 0.34 2.10 3.37 0.34 1.61 3.06 0.30 1.20 2.52 0.27 0.79 2.07 0.26 0.52 1.45 0.37 Code Len AP Perm :(cm) (cmHg) (darcys) IC 3.64 6.61 0.75 21 3.19 5.85 0.74 SL 2.69 5.01 0.82 2.18 4.25 0.90 1.65 2.86 0.84 1.30 2.52 0.65 0.85 2.01 0.55 0.56 1.45 0.52 IC 3.68 6.75 1.32 24 3.19 5.82 1.63 SL 2.69 5.01 1.49 2.16 4.22 2.13 1.60 2.95 1.45 1.22 2.58 1.00 0.81 2.05 1.33 0.53 1.40 1.01 IC 3.64 6.59 8.18 27 3.12 5.40 8.46 SE 2.62 4.56 8.31 2.09 3.19 7.77 1.65 2.73 8.07 1.19 2.19 7.27 0.83 1.83 5.13 0.50 1.25 4.71 127 Table VI-1 [cont'd) Code Len AP Perm (cm) (cmHg) (darcys) I I 3.57 5.82 1.25 14 3.10 5.76 1.25 AE 2.59 5.18 1.31 2.17 4.33 1.12 1.68 3.96 0.83 1.19 3.23 0.67 0.73 2.93 0.64 0.46 2.52 0.81 I I 3.58 5.94 0.85 15 3.09 5.68 0.82 AE 2.63 5.18 0.83 2.20 4.28 0.79 1.71 4.19 0.63 1.22 3.29 0.57 0.74 2.92 0.39 0.55 2.49 0.42 I I 3.60 5.78 0.45 16 3.11 5.67 0.54 AE 2.66 5.17 0.34 2.20 4.31 0.55 1.68 3.96 0.39 1.19 3.27 0.34 0.73 2.89 0.31 0.47 2.47 0.35 I I 3.64 6.76 0.48 25 3.19- 5.72 0.71 AE 2.69 5.42 0.64 2.18 5.15 0.75 1.65 4.81 0.66 1.21 4.16 0.48 0.77 4.08 0.36 0.51 3.77 0.34 I I 3.66 5.93 0.53 33 3.18 5.74 0.51 AE 2.69 5.15 0.40 2.18 4.34 0.47 1.68 4.06 0.39 1.20 3.26 0.34 0.74 2.86 0.28 0.52 2.45 0.34 Code Len AP Perm (cm) (cmHg) (darcys) I I 3.57 5.85 6.91 14 3.10 5.62 7.13 SE 2.63 5.14 7.22 2.19 4.24 7.51 1.68 3.82 6.74 1.17 3.21 5.98 0.70 2.86 4.46 0.49 2.46 3.13 I I 3.58 5.71 9.18 15 3.15 5.65 9.13 SE 2.67 5.11 8.57 2.19 4.19 8.93 1.65 3.76 8.53 1.18 3.12 8.01 0.73 2.75 7.29 0.47 2. 38 3.71 I I 3.60 5.51 7.77 16 3.09 5.49 8.05 SE 2.61 5.15 7.89 2.15 4.10 8.63 1.62 3.71 8.72 1.12 3.05 8.46 0.65 2.69 4.17 0.46 2.39 .2.63 I I 3.57 5.72 9.20 25 3.09 5.62 7.74 SE 2.62 5.12 6.57 2.17 4.28 7.19 1.68 3.97 6.59 1.20 3.15 7.98 0.75 2.78 4.27 0.50 2.41 3.18 I I 3.60 5.70 7.39 33 3.20 5.64 6.64 SE 2.69 5.09 6.31 2.15 4.18 6.46 1.66 3.69 6.95 1.16 3.08 7.39 0.71 2.64 5.82 0.43 2.17 4.22 128 Table VI-2 Percent p o s i t i o n i n the r i n g and s p e c i f i c g r a v i t y of p e r m e a b i l i t y specimens Code Percent P o s i t i o n S p e c i f i c G r a v i t y CC11 L 69.55 .5823 CC14 E 27.73 .2314 CC15 E 9.64 .3020 CC22 L 76.79 .6311 CC25. E 52.16 .3377 CC27 E 22.39 .2252 IC11 L 69.82 .6622 IC13 E 51.58 .6198 IC15 E 19.91 .2778 IC21 L 93.10 .6629 IC24 L 63.40 .6725 IC27 E 16.30 .3107 1114 E 74.25 .3585 1115 E 49.25 .2995 1116 E 18.50 .3458 1125 E 8.95 .3325 1133 E 48.81 .3139 Table VI-3. Tracheid l e n g t h and number of p i t s per t r a c h e i d of per m e a b i l i t y specimens Tracheid length (mm) N No. of P i t s Per Tracheid uoae Min. Ave. Max. S.D. Min. Ave. Max. S.D. e c u L 1.31 2.64 3.92 0.57 112 6 19.45 50 8.36 CC14 E 1.21 2.34 3.25 0.50 82 32 56.80 90 14.07 CC15 E 0.88 2.37 3.46 0.49 105 21 51.19 89 14.74 CC22 L 0.98 2.65 3.69 0.63 112 3 15.15. 25 6.49 CC25 E 0.56 2.46 3.42 0.61 112 3 35.40 72 14.21 CC27 E 1.06 2.34 3.46 0.55 116 9 50.82 95 18.76 IC11 L 1.58 2.56 3.42 0.41 105 5 12.51 25 4.41 IC13 E 0.90 2.32 3.19 0.54 84 5 17.58 ,32 5.63 IC15 E 1.00 2.00 2.88 0.34 83 15 41.47 68 11.02 IC21 L 1.25 2.30 3.38 0.46 108 6 11.53 23 3.93 IC24 L 0.38 2.27 3.23 0.59 112 2 13.62 38 5.97 IC27 E 0.52 1.89 2.82 0.42 112 12 40.48 84 12.93 1114 E 1.58 3.11 4.00 0.45 105 35 73.72 126 19.32 1115 E 1.58 2.76 3.58 0.48 112 43 92.80 166 22.12 1116 E 2.00 2.89 3.96 0.41 112 35 97.37 180 24.68 1125 E 1.56 2.59 3.50 0.41 112 45 86.28 131 20.91 1133 E 1.52 2.68 3.60 0.47 105 11 69.48 118 25.11 130 Table VI-4. P i t membrane p o s i t i o n s recorded f o r air-seasoned and solvent-seasoned D o u g l a s - f i r p e r m e a b i l i t y specimens. Code N % Asp. P i t % Unasp. P i t % P a r t . Asp. P i t CC11AL 99 66.67 9.09 24.24 11SL 179 10.61 70.95 18.44 14AE 788 99.11 0.13 0.76 14SE 253 4.35 61.26 34.39 15AE 764 100.00 0.00 0.00 15SE 312 6.73 60.58 32.69 22AL ;.168 77.38 14.29 8.33 22SL 219 21.00 59.82 19.18 25AE 645 100.00 0.00 0.00 25SE 228 3.51 84.21 12.28 27AE 496 100.00 0.00 0.00 27SE 294 8.84 59.52 31.63 IC11AL 205 44.88 18.05 37.07 11SL 182 7.69 69.23 23.08 13AE 231 93.94 1.30 4.76 13SE 194 6.70 74.74 18.56 15AE 808 100.00 0.00 0.00 15SE 666 2.55 61.11 36.34 2 IAL 182 54.40 2 3.08 22.53 21SL 233 4.72 82.40 12.88 24AL 49 57.14 20.41 22.45 24SL 239 25.10 48.95 25.94 27AE 1313 99.01 0.00 0.99 27SE 1028 1.75 70.04 28.21 II14AE 215 96.74 0.93 2.33 14SE 446 1. 57 81.84 16.59 15AE 556 99.64 0.00 0.36 15SE 370 1.62 74.32 24.05 16AE 914 ,97.70 0.55 1.75 16SE 503 1.39 76.94 21.67 25AE 835 98.92 0.24 0.84 25SE 368 1.09 85.05 13.86 33AE 720 100.00 0.00 0. 00 33SE 476 1.26 86.34 12.39 131 Table VI-5. Average r a d i a l w a l l thickness of D o u g l a s - f i r p e r m e a b i l i t y specimens Code N Ave. R a d i a l W all Thickness (um) CC11AL 8 4.00 11SL 8 4.40 14AE 8 1.60 14SE 8 1.60 15AE 8 1.00 15SE 8 0.80 22AL 8 4.40 22SL 8 3.60 25AE 8 2.20 25SE 8 2.40 27AE 8 1.00 27SE 8 1.20 IC11AL 8 4.40 11SL 8 4.60 13AE 8 2.40 13SE 8 2.40 15AE 8 1.60 15SE 8 1.60 21AL 8 4.00 21SL 8 4.40 24AL 8 4.00 24SL 8 4.00 27AE 8 1.60 27SE 8 1.80 II14AE 8 2.40 14SE 8 2.40 15AE 8 2. 20 15SE 8 2.20 16AE 8 1.80 16SE 8 1.60 25AE 8 1.80 25SE 8 1.60 33AE 8 1.80 33SE 8 2.00 132 Table VI-6. Average t r a c h e i d diameter and number of t r a c h e i d s per square m i l l i m e t e r Code N Ave. Rad.Trach- Ave. Tang.Trach- Ave. No. o ^ T r a c h -e i d Diam. e i d Diam. (um) eids per mm (vim) CC11AL 8 27.20 33.00 1114 CC11SL 8 27.20 34.80 1056 CC14AE 8 36.80 34.40 789 CC14SE 8 38.40 35.20 739 CC15AE 8 38.40 40.00 651 CC15SE 8 38.40 36.20 719 CC22AL 8 24.00 34.00 1225 CC22SL 8 22.40 34.80 1282 CC25AE 8 33.60 36.80 808 CC25SE 8 33.60 33.60 885 CC27AE 8 40.00 35.20 710 CC27SE 8 36.80 40.00 679 IC11AL 8 21. 20 28.80 1637 IC11SL 8 22.40 26.80 1665 IC13AE 8 28.80 28.00 1240 IC13SE 8 28.80 27.20 1276 IC15AE 8 32.00 33.60 930 IC15SE 8 35.20 32. 00 887 IC21AL 8 20.80 27.20 1767 IC21SL 8 20.00 28.00 1785 IC24AL 8 24.00 28.80 1446 IC24SL 8 25.00 29.40 1360 IC27AE 8 27.20 28.80 1276 IC27SE 8 28.80 29.40 1181 II14AE 8 27.58 28.75 1261 II14SE 8 28.05 28.39 1255 II15AE 8 30.49 27.67 1185 II15SE 8 30.20 27.55 1201 II16AE 8 33.35 29.37 1020 II16SE 8 34.49 28.76 1008 II25AE 8 34.96 25.34 1128 II25SE 8 35.02 24.95 1144 II33AE 8 30.49 26.97 1216 II33SE 8 32.01 25.85 1208 133 Table VI-7A. Average diameters of p i t a n n u l i of s o l v e n t -seasoned D o u g l a s - f i r p e r m e a b i l i t y specimens Code N Min.(um) Ave.(um) Max.(um) S.D. C V . CC11SL 5 11.41 12.53 13.10 0.669 5.34 CC14SE 9 15.85 17.65 19.07 1.253 7.10 CC15SE v'3 17.89 18.01 18.19 0.161 0.89 CC22SL 1 15.07 15.07 15.07 0.0 0.0 CC25SE 15 12.86 16.20 17.73 1.290 7.96 CC27SE 14 16.25 18.84 21.62 1.361 7.23 IC11SL 7 11.46 12.16 13.10 0.565 4.64 IC13SE 5 12.28 14.54 16.90 1.870 12.86 IC15SE 29 15.34 17. 38 19.17 0.953 5.48 IC21SL 2 9.56 9.97 10.39 0.587 5.88 IC24SL 4 10.39 12.08 13.53 1.329 11.00 IC27SE 16 14.66 16.44 18.72 1.271 7.73 II14SE 8 13.95 15.21 16.71 0.877 5.77 II15SE 19 15.65 17.04 18.47 0.882 5.18 II16SE 15 14.73 17.11 19.29 1. 305 7.62 II25SE 20 16.18 17.91 19.75 1.041 5.81 II33SE 23 14.63 17.48 19.21 1.058 6.05 134 Table VI-7B. Average diameters of p i t t o r i of solvent-seasoned D o u g l a s - f i r p e r m e a b i l i t y specimens Code N Min.(um) Ave.(um) Max.(um) S.D. C V . CC11SL 5 5.11 5.98 6.70 0.602 10.07 CC14SE 9 6.96 8.16 9.41 0.811 9.93 CC15SE 3 7.89 8.36 8\ 77 0.444 5.31 CC22SL 1 5.18 5.18 5.18 0.0 0.0 CC25SE 15 6.01 7.74 8.94 0.724 9.35 CC27SE 14 7.12 8.50 10.49 0.720 8.47 IC11SL 5 5.16 5.84 6.36 0.463 7.93 IC13SE 5 5.58 6.78 7.57 0.919 13.55 IC15SE 29 7.12 8.21 9.76 0.673 8.19 IC21SL 2 4.73 5.50 6.28 1.096 19.91 IC24SL 3 5.15 6.49 7.16 1.158 17.85 IC27SE . 16 6.72 7.94 8.72 0.567 7.13 II14SE 8 7.15 7.99 9.61 0.807 10.10 II15SE 19 7.41 8.52 9.31 0.484 5.69 II16SE 15 . 7.16 8.84 9.95 0.816 9.23 II25SE 20 8.00 8.87 10.15 0.654 7.37 II33SE 23 7.00 8.27 9.16 0.583 7.05 135 Table VI-7C. Average diameters of p i t apertures of s o l v e n t -seasoned D o u l g a s - f i r p e r m e a b i l i t y specimens Code N Min.(um) Ave.(um) Max.(um) S.D. C.V. CC11SL 1 4.15 4.15 4.15 0.0 0.0 CC14SE 8 4.59 6.11 6.96 0.844 13.80 CC15SE 3 5.64 5.83 5.98 0.175 3.00 CC22SL 1 4.95 4.95 4.95 0.0 0.0 CC25SE 15 4.48 5.94 7.15 0.691 11.64 CC27SE 14 4.66 6.20 8.24 0.915 14.75 IC11SL 1 3.26 3.26 3.26 0.0 0.0 IC13SE 3 3.72 4.21 5.02 0.709 16.85 IC15SE 14 3.99 5.28 5.82 0.577 10.91 IC21SL 1 3.30 3.30 3.30 0.0 0.0 IC24SL 1 3.96 3.96 3.96 0.0 0.0 IC27SE 12 4.59 5.25 5.91 0.445 8.46 II14SE 1 3.63 3.63 3.63 0.0 0.0 II15SE 3 4.03 4.45 4.71 0.367 8.25 II16SE 1 5.14 5.14 5.14 0.0 0.0 II25SE 3 4.24 4.57 4.88 0.320 7.01 II33SE 4 4.85 5.27 5.71 0.413 7.82 Table VI-7D. Average r a d i a l l y o r i e n t e d and randomly o r i e n t e d m i c r o f i b r i l diameters of solvent-seasoned D o u l g a s - f i r earlywood p e r m e a b i l i t y specimens R a d i a l l y Oriented M i c r o f i b r i l Randomly Oriented M i c r o f i b r i l Diameter (um) Diameter (um) Code N Min. Ave. Max. S. D. C. V. Min. Ave. Max. S. D. C. V. CC14SE 20 0.04 0.05 0.06 0.005 10.31 0.04 0.05 0.06 0.005 10.90 CC15SE 10 0.04 0.05 0.06 0.005 9.43 0.05 0.05 0.06 0.004 8.11 CC25SE 55 0.04 0.05 0.05 0.003 . 5.93 0.04 0.05 0.05 0.005 10.62 CC27SE 40 0.04 0.05 0.06 0.004 7.74 0.04 0.05 0.05 0.005 9.88 IC13SE 25 0.04 0.05 0.06 0.004 8.59 0.04 0.05 0.06 0.005 10.00 IC15SE 65 0.04 0.05 0.07 0.005 9.42 0.04 0.05 0.07 0.006 11.02 IC27SE 25 0.04 0.05 0.06 0.006 11.25 0.04 0.05 0.06 0.005 10.28 II14SE 25 0.04 0.05 0.06 0.005 10.99 0.04 0.05 0.05 0.005 10.77 II15SE 25 0.04 0.05 0.06 0.005 10.99 0.04 0.05 0.05 0.005 10.87 II16SE 10 0.04 0.05 0.05 0.003 6.45 0.05 0.05 0.05 0.000 0.11 II25SE 20 0.04 0.05 0.06 0.003 66.49 0.04 0.05 0.05 0.003 6.28 II33SE 35 0.04 0.05 0.06 0.004 7.70 0.04 0.05 0.06 0. 005 9.86 137 Table VI-7E. Average margo areas of solvent-seasoned D o u g l a s - f i r earlywood p e r m e a b i l i t y specimens Code 2 Ave. Margo Area (um ) 2 Combined Area (um ) CC14SE 127.53 < CC15SE 132.30 136.67 134.87 i CC25SE CC27SE 142.99 IC13SE 101.34 IC15SE 123.42 115.43 IC27SE 121.54 II14SE 113.15 II15SE 134.29 II16SE 138.73 143.53 II25SE 166.79 II33SE 164.69 Table VI-8. Average r a d i a l and t a n g e n t i a l margo pore r a d i i of solvent-seasoned D o u g l a s - f i r earlywood p e r m e a b i l i t y specimens R a d i a l Pore R a d i i (um) Tangential Pore R a d i i (um) ID Code N Min. Ave. Max. S.D. C V. Min. Ave. Max. S.D. C. V. 30 CC14SE 65 .027 .325 1.033 .260 80.014 .054 .138 .326 .073 53.412 31 II 62 .027 .360 1.033 .250 69.440 .027 .161 .435 .100 62.212 35 II 93 .049 .324 1.299 .255 78.675 .049 .159 .441 .076 47.569 36 II 47 .072 .272 .531 .138 50.751 .024 .124 .290 .068 54.631 37 " 68 .049 .299 1.176 .239 79.860 .049 .137 . 368 .064 46.942 38 II 84 .049 .284 1.225 .244 86.059 .025 .129 .441 .079 61.344 39 II 74 .049 .205 .878 .157 76.842 .049 .105 .341 .060 57.613 40 II 47 .024 .207 .922 .178 86.193 .024 .103 .218 .058 55.756 41 II 53 .074 .295 .931 .190 64.355 .025 .124 .294 .072 57.712 42 II 63 .049 .247 .927 .206 83.185 .024 .119 .317 .075 63.217 43 II 73 .048 .219 .918 .185 84.568 .024 .107 . 362 .079 73.681 44 CC15SE 80 .049 .294 .858 .187 63.535 .049 .153 . 368 .085 55.411 45 II 70 .025 .239 .980 .173 72.360 .025 .114 .343 .072 62.567 46 " 52 .074 .322 .784 .215 66.715 .025 .140 . 343 .089 63.820 5 CC25SE 52 .024 .415 1.179 .328 79.071 .024 .137 .330 .085 61.898 6 II 51 .023 . 358 1.019 .303 84.481 .023 .150 .417 .095 63.295 7 II 54 .024 .471 1.509 .339 72.056 .024 .122 .259 .065 53.125 8 II 51 .024 .518 1.321 .409 78.908 .024 .158 .401 .098 61.990 47 II 53 .025 .254 1.084 .254 100.149 .025 .114 .320 .068 59.917 48 II 47 .025 . 208 .837 .161 77.624 .025 .115 .320 .083 72.610 49 II 29 .049 .188 .419 .119 63.459 .025 .092 .246 .052 56.460 50 II 76 .025 .484 1.478 .428 88.424 .025 .149 .394 .102 68.248 51 II 68 .025 .225 .665 .156 69.433 .025 .110 .296 .068 61.528 52 II 67 .025 .181 .665 .148 82.196 .025 .087 .271 .055 62.620 53 II 50 .025 . 301 .985 .268 89.143 .025 .114 .296 .093 81.446 54 " 50 .025 .226 1.078 .194 85.690 .025 .112 . 319 .072 64.242 55 61 .025 .229 .858 .176 77.176 .025 .106 .319 .074 69.795 56 i t 65 .024 .196 .756 .153 77.918 .024 .095 .220 .054 57.407 57 II 69 .024 . 332 1.184 .304 91.611 .024 .123 . 338 .075 60.940 Table V I - 8 ( c o n t ' d ) 9 CC27SE 44 .098 .777 1.863 .474 60.944 .049 .211 .466 .107 50.834 10 II 44 .072 .536 1.683 .417 77.721 .048 .179 .457 .102 57.166 11 II 49 .049 .450 1.029 .243 53.918 .025 .169 .392 .087 51.546 12 II 62 .048 .173 .673 .117 67.952 .024 .108 .337 .065 60.190 58 II 74 .024 .185 .683 .121 65.573 .024 .100 .244 .055 55.304 59 II 77 .049 .301 1.103 .245 81.140 .025 .151 .417 .109 72.316 60 II 93 .025 .593 1.863 .520 87.656 .025 .228 .662 .178 77.759 61 II 94 .024 .254 .927 .191 75.141 .024 .134 . 537 .110 81.968 62 II 102 .025 .290 1.863 .290 100.064 .025 .142 .515 .106 74.829 63 II 92 .024 . 555 2.000 .478 86.097 .024 .209 .683 .162 77.271 64 II 65 .024 .286 1.304 .251 87.825 .024 .124 .338 .079 63.486 65 II 70 .025 . 335 1.422 .318 94.763 .025 .133 .294 .077 57.390 66 II 47 .049 .291 1.512 .268 92.285 .024 .109 .244 .059 54.393 67 II 68 .025 .239 1.275 .231 96.594 .025 .093 .319 .068 73.224 175 IC13SE 28 .073 .294 .922 .221 75.109 .024 .101 .194 .058 57.175 34 IC15SE 45 .054 .377 1.141 .295 78.125 .054 .141 .380 .074 52.778 13 II 46 .059 .485 1.176 .290 59.746 .059 .178 .353 .089 50.305 14 II 46 .024 .230 .793 .164 71.372 .024 .099 .264 .066 66.668 15 II 71 .024 .357 1.214 .246 68.882 .024 .125 .340 .077 61.626 16 II 72 .024 .323 1.058 .221 68.490 .024 .116 .288 .065 55.884 17 II 62 .024 . 347 1.442 .344 99.162 .024 .116 .288 .071 61.398 18 II 61 .048 .319 1.514 .240 75.198 .024 .128 .409 .085 66.157 19 II 58 .024 .203 1.010 .162 79.948 .024 .107 .337 .069 64.060 20 II 63 .072 .237 1.106 .204 85.915 .024 .104 .337 .075 72.032 21 II 79 .048 .373 1.538 .288 77.223 .048 .169 .385 .083 48.979 68 II 24 .025 .200 .739 U 6 4 82.147 .025 .084 .296 .064 76.184 69 II 56 .049 .521 1.505 .412 78.944 .024 .143 .364 .099 69.215 70 » 56 .024 .317 .966 .293 92.410 .024 .148 .652 .124 83.783 71 II 64 .024 .201 .732 .158 78.755 .024 .089 .244 .059 65.909 72 II 61 .025 .263 1.275 .252 95.776 .025 .128 .490 . .124 97.000 73 » 60 .024 .288 1.238 .261 90.542 .024 .116 .316 .082 70.879 74 II 50 .025 .274 .931 .236 86.163 .025 .129 .466 .105 81.551 75 II 68 .024 .343 1.739 .385 112.275 .024 .125 .435 .107 85.066 76 II 68 .024 .316 1.135 .261 82.543 .024 .128 . 314 .086 67.034 77 II 70 .024 .403 1.268 .330 81.899 .024 .161 .439 .103 64.291 78 II 55 .024 .442 1.505 .402 90.883 .024 .161 .364 .104 64.467 79 II 58 .024 .378 1.268 .316 83.693 .024 .156 .512 .123 78.802 80 II 68 .024 . 224 .878 .206 92.007 .024 .113 .415 .103 90.816 Rl II r 4 f i "1 _ 7fiR . 09 5 . 1 If, . 392 . 104 58-9 59 Table VI-8 (cont'd) 82 IC15SE 55 .024 .275 .732 .202 73.246 .024 .130 .537 .100 76.645 83 II 45 .024 .191 .634 .162 85.118 .024 .105 .293 .074 70.776 84 II 62 .024 .436 1.401 .377 86.587 .024 .159 .507 .114 71.781 85 II 44 .024 .249 .878 .199 79.961 .024 .116 .244 .074 63.240 86 n 75 .024 .398 1.171 .295 74.075 .024 .153 .406 .107 69.687 87 IC27SE 36 .025 .398 1.275 .368 92.470 .025 .142 .392 .101 71.195 88 II 42 .024 .240 .829 .208 86.448 .024 .109 .317 .078 71.577 89 " 48 .025 .523 1.773 .431 82.363 .025 .168 .468 .126 74.884 90 II 40 .024 .459 1.262 .392 85.298 .024 .132 .413 .107 81.100 91 II 42 .024 .296 .874 .255 86.078 .024 .121 .388 .096 79.019 92 II 33 .025 .836 1.422 .437 52.262 .025 .178 .417 .097 54.801 93 II 45 .025 .269 .985 .256 95.181 .025 .112 .369 .099 88.123 94 II 48 .025 .551 1.576 .418 75.993 .025 .159 .567 .108 67.678 95 II 73 .025 .434 1.626 . 376 86.735 .025 .169 .443 .115 67.944 96 II 65 .049 .623 1.626 .447 71.873 .025 .218 .591 .136 62.429 97 it 69 .024 .569 1.707 .463 81.288 .049 .207 .439 .122 58.895 98 II 48 .025 .227 .784 .179 78.988 .025 .105 .294 .066 62.743 99 II 53 .024 .550 1.562 .437 79.426 .024 .141 .342 .082 58.108 100 n 57 .024 .348 1.739 .355 102.041 .024 .135 .386 .091 67.270 101 II 28 .049 .644 1.373 .442 68.587 .025 .205 .417 .129 62.746 102 II 56 .025 .434 1.527 .394 90.767 .025 .146 .443 .105 71.880 22 II14SE 30 .046 .179 .486 .116 65.049 .046 .098 .185 .038 38.583 23 n 40 .046 .116 .278 .061 52.457 .046 .067 .139 .024 35.614 24 II 54 .023 .191 .972 .174 90.854 .023 .083 .231 .045 53.971 25 II 54 .023 .267 .833 .192 71.962 .023 .113 .347 .085 75.472 26 II 25 .023 .170 .556 .120 70.478 .023 .066 .139 .038 57.212 103 II 51 .025 .165 .735 .158 95.338 .025 .068 .221 .046 68.472 104 II 41 .024 .183 .966 .171 93.451 .024 .076 .266 .055 71.974 105 II 48 .024 .111 .338 .081 72.967 .024 .053 .121 .028 52.215 106 n 41 .024 .095 .463 .104 109.441 .024 .048 .195 .038 78.813 107 II 29 .025 .149 .441 .107 71.814 .025 .056 .147 .040 71.332 108 II 24 .025 .134 . 343 .091 68.332 .025 .068 .147 .033 48.382 109 II 24 .024 .053 .097 .029 55.024 .024 .034 .097 .017 50.632 110 n 26 .024 .066 .121 .029 44.620 .024 .044 .097 .025 56.457 141 O r ^ v o c N C O O c N C T i r ^ H ^ ^ v o i n c N v o c N c n c n c < o c O r - -CO ro m vo vo ro a ^ v o c N v o r o u j ^ O L n c N v o H r ^ r - i v o c o c o h H H O n C 0 r | H ( N ( D ^ ^ r ^ c N O m o r ^ r ^ v o v o c r i i n r o o c r i c o c o c N C O c r i i n H c N v o v o H r o L n o j v o o o c o r M C N i n c M ^ ^ r ^ c n c o c N r o i n i n o i v o v o v o v o r ^ v o i n ^ r ^ i n i n i n c n i n u n i n L n k O L O L n v o i n r ^ H v o H r o m o c M ^ v o r ^ m o o m i n i n i n ' ^ ' v o v o i n L n v o i n c M r ^ ^ f T i C O r o H O O r o r o r ^ c N c n c n i ^ v o o ^ c n c n v o ^ ^ ^ r o ^ r o ^ ^ i ^ ^ ^ c N ^ C N r v j r o ^ ^ r o ' ^ ' ^ r o o o o o o o o o o o o o o o o o o o o o o o M m o o o M h O ^ i i i H O i n o i r o ^ r o c N C M r o c M ' s J ' m ' * o o o o o o o o o o o o vo co i n ^ v o c r i C O C N i ^ o v o r ^ O H r ^ v o H i n o i H c T i r N i H O C D ^ r o r o o o D c y i c N c n ^ r ^ c N ^ c n c o c n r ^ < N H r ~ -M ( N H H ( N H ( N 0 1 ( N f > ) r l H ( N H H r H H H H O i f O r H H cn CM ro ro CN VO O tn CM c M ' * v o r ^ c M c n c M r ^ ' « t c N ' * r ^ C N I - I H H I - I O I - I I - I I - I C M O J H r ^ ^ c o c M c n i n H C M r ^ c M C O H ' * ' = l , H C M O ' N t , i n c o L n o v o r ^ v o v o v o i n r o o o c n c o r ^ i n ^ i n i n v o c o v o v o c o r ^ v o o o o o o o o o o o o o o o o o o o o o o o O v o r o r - r ^ c O ' ^ c o m c r i L n r o o o o o o o o o o o o o ^ o o r o ^ ^ r o r o r o i n ^ i n i n L n ^ t n i n r o ^ i n i n L n i n C M C M C M C M C M C M C N C N C N C M C M C M C M C N C M C M C N C N C M C N C M C M o o o o o o o o o o o o o o o o o o o o o o i n i n ^ i n i n ^ m i n ^ ^ f i n i n C M C N C M C M C M C M C M C M C M C M C M C M o o o o o o o o o o o o v o c M O O c o i n v o o c M C M C N C M c o v o H i n o r ~ - v o c M v o c n i H H i H C M r ^ O L n < H c n r H C M < T i , ^ v o i n r ~ > c M v o c M t s - - r ^ O r ^ r o c M r o i D C T i i n ^ c N r ^ c M v o v o i n c M r ^ C O O v o c r i C N v o r o ( N O c O ( , ^ ( J > o ^ ^ f ^ o o ^ ^ c r i L n o o i n r o H c n i n ^ o i n r o c o •H CO i n v o r o y 3 H C O i H r - ~ O C M i n r o ^ r ^ i n G o r o i ^ c n i n ^ ^ c N O o o i n L n r o c M r o o r - -v o r ^ r ^ o r ^ v o r ^ v o r - ^ ^ v o v o c M r ^ c o v o v o c o r ^ v o v O ' v J ' o t ^ H H C T i r o r ^ k O c n r ^ r ^ r ^ c M v o c o i n i n c o t n c r i m v o r ^ v o H o ^ c o N i n c o ^ o o c o o c o ^ m ^ i n c n H ^ f f i H ' * O H C o r a o v o c N O r - ' i n c n v O i H v o o o v O r H O O c n H c r i r o H H O H H O r H H H O O O r H O O O i H O O H O O c n v o c M c n ^ c N O ^ m c o c M H H O O O O O O O O O O O < T i C M ^ r ^ i n H C M ^ r o ^ o o o v o o ^ o o > i r - - C M C O r ~ - i > O O c n H C M O r o v o r o ^ o ^ v o o o c r i v o r ^ c N r o c n c O r H ' N l 1 ^ v o r o c o ^ r o i n L n c o c M ^ r o v o c M i n c M ^ i n r o i n s l ' H C M ^ f l O ^ H C v i r j i n ' ^ o i r o o v o c n r o c ? i C M v o r - - H , N t , r o ^ r c r i r o k o c o o i c n c n c o o r o c n c n i n n c M i n c n c M r ^ a ^ c n O r H L O i n H v o r o c n v o i n i H C N c o o < T i o > c n < j ^ o D c n c M 0 3 i n r - -H H i H H H O r H r H C M H t H r H O O O O i H O H r H H O " v f r o ^ r o L n ^ i H v o c M O c n m C N O O v O i H r - r - - r - - C O O > i r O i H r o H - O O H O O O O O H H H s f o i n ^ ^ n n c i i n ^ i n t n i r i ^ i n i n n ^ f m i n i r i i n C M C N C N C M C M C M C M C N C M C M C M C M C M C M C N C M C M C M C N C N C M C N O O O O O O O O O O O O O O O O O O O O O O m i n ^ f i n i r i ' ^ i r i i n ^ ^ ' i n i n C M C N C N C N O J C M C N C M C M C M C M C M O O O O O O O O O O O O c M i n c o c N ^ r ^ r ^ ^ c O i H c n r o t ^ r ~ v o c o r o ^ H O > D O n o O v D ^ i ^ ^ H ^ L O k D r - C ^ r o m ^ f m r o r o ^ f L n ^ l ' v o L n m co m co vo .H H H H C M r o ^ r ^ c o c r i H C M r o ^ t < i n v o r ^ c o c M ' * i n o > i O H r o C M C M C M H r H H r H H H r H H C M C M C M H C M C M C M i H H i H H H H r H . - H i - H r H i - H . H i - l . - - I H v o r ^ o o c n O H C M o o ^ i n ^ o r ^ C M C M C M C M r o r o r o r o r o r o r o r o r - H r H r H r H H H H H H r - H r - I H Table VI-8 (cont'd) 138 II25SE 60 .024 .248 .976 .188 76.052 .024 .115 .341 .066 57.150 139 » 52 .025 .131 . 539 .111 85.075 .025 .083 .294 .066 79.183 140 30 .024 .185 1.171 .218 117.718 .024 .086 .244 .069 79.611 141 71 .025 .521 1.642 .399 76.581 .025 .180 .466 .117 65.227 142 75 .025 .412 1.397 .365 88.514 .025 .157 .490 .118 75.482 143 70 .049 .251 .907 .165 65.682 .025 .098 .245 .053 54.007 144 » 64 .025 .343 1.348 .307 89.551 .025 .124 .466 .088 71.173 145 » 67 .024 .216 1.019 .187 86.948 .024 .105 .316 .069 65.723 146 53 .025 .248 1.520 .274 110.262 .024 .094 . 319 .066 69.750 147 59 .025 .351 1.127 .252 71.611 .025 .135 . 392 .098 72.264 148 » 85 .025 .290 .784 .217 74.881 .025 .127 .392 .090 70.754 149 » 62 .025 . 336 1.127 .263 78.059 .025 .141 .343 .078 55.250 150 » 55 .049 .323 1.659 .289 89.283 .024 .110 .415 .077 69.960 151 » 77 .024 .431 1.561 . 390 90.380 .024 .136 .585 .104 76.213 152 43 .024 .457 1.488 .410 89.871 .024 .173 .488 .140 80.919 153 62 .025 .229 .784 .166 72.581 .025 .106 .294 .065 61.187 154 49 .049 .367 1.220 .295 80.313 .024 .164 .366 .095 57.888 155 68 .049 .310 1.220 .223 72.045 .024 .141 .341 .076 53.631 156 » 76 .098 .274 .829 .184 67.121 .049 .118 .268 .049 41.013 157 81 .049 .283 1.268 .221 78.184 .024 .112 .293 .064 57.440 158 II33SE 56 .025 .183 .588 .149 81.664 .025 .090 .221 .047 52.939 159 69 .025 .280 1.471 .312 111.466 .025 .108 .368 .076 70.531 160 73 .049 .385 1.324 .316 82.128 .025 .138 .417 .101 73.389 161 67 .025 . 349 1.176 .287 82.178 .025 .126 .392 .092 72.841 162 » 67 .049 .326 .980 .253 77.753 .025 .138 .417 .088 63.437 163 47 .049 .317 .735 .208 65.542 .025 .135 .319 .076 56.235 164 » 55 .049 .400 1.379 .327 81.723 . 025 .161 .591 .118 73.317 165 » 44 .025 .293 .887 .225 76.785 .025 .143 .345 .086 60.530 166 » 33 .025 .120 .394 .101 84.318 .025 .073 . 222 .045 60.988 167 42 .025 .266 .936 .214 80.685 .025 .132 .443 .093 70.790 168 69 .049 .341 .837 .203 59.489 .025 .151 .443 .090 59.453 169 » 48 .025 .168 .394 .101 60.078 .025 .099 .-296 .056 57.012 170 58 .049 . 397 1.527 .323 81.289 .049 .178 .443 .103 57.754 171 63 .025 .380 1.084 .289 76.086 .025 .155 .296 .074 47.763 172 68 .025 .346 1.379 .310 89.527 .025 .114 .271 .070 61.937 143 Table VI-9 (Table V - l ) . Observed and estimated margo pore areas of solvent-seasoned D o u g l a s - f i r sapwood earlywood p e r m e a b i l i t y specimens ID Code P r i n t N X g 0 Xf / \ 0 C V . No. (pm2) (um2) a f 30 CC1-4 1 65 0.175567 0.039402 614.97 24.80 186 31 CC1-4 1 62 0.217450 0.038516 789.96 28.11 216 35 CC1-4 1 93 0.193339 0.050509 1249.43 35.35 168 36 CC1-4 2 47 0.124180 0.041565 630.47 25.11 141 37 CC1-4 3 68 0.158641 0.052384 964.00 31.05 142 38 CC1-4 4 84 0.157127 0.038567 791.91 28.14 175 39 CC1-4 5 74 0.086901 0.023034 259.81 16.12 167 40 CC1-4 6 47 0.082359 0.022669 243.67 15.61 162 41 CC1-4 7 53 0.136414 0.034746 611.80 24.73 171 42 CC1-4 8 63 0.123831 0.025033 436.79 20.90 199 43 CC1-4 9 73 0.107307 0.017340 286.43 16.92 228 44 CC1-5 1 80 0.167363 0.048851 1002.68 31.67 156 45 CC1-5 2 70 0.107795 0.026288 371.08 19.26 176 46 CC1-5 3 52 0.184088 0.044214 1071.06 32.73 178 5 CC2-5 1 52 0.231822 0.024386 1021.80 31.97 292 6 CC2-5 2 51 0.233796 0.030821 1361.79 36.90 257 7 CC2-5 3 54 0.216425 0.030126 1133.70 33.67 249 8 CC2-5 4 51 0.345519 0.028324 1814.79 42.60 335 47 CC2-5 1 53 0.126477 0.020893 374.62 19.36 225 48 CC2-5 2 47 0.099274 0.015943 225.61 15.02 229 49 CC2-5 3 29 0.063214 0.021088 150.86 12.28 141 50 CC2-5 4 76 0.337038 0.032080 1661.36 40.76 308 51 CC2-5 5 68 0.095950 0.020263 260.44 16.14 193 52 CC2-5 6 67 0.064622 0.013978 120.21 10.96 190 53 CC2-5 7 50 0.167827 0.015992 412.34 20.31 308 54 CC2-5 - 8 50 0.110510 0.018022 288.67 16.99 227 55 CC2-5 9 61 0.106810 0.017469 270.30 16.44 226 56 CC2-5 10 65 0.072647 0.020750 190.18 13.79 158 57 CC2-5 11 69 0.178114 0.030736 831.69 28.84 219 9 CC2-7 1 44 0.619834 0.111159 9792.78 98.96 214 10 CC2-7 2 44 0.409162 0.065851 4231.62 65.05 228 11 CC2-7 3 49 0.271482 0.063557 2288.72 47.84 181 12 CC2-7 4 62 0. 070890 0.028130 225.14 15.00 123 58 CC2-7 1 74 0.070220 0.020274 .178.83 13.37 157 59 CC2-7 2 77 0.187884 0.030349 828.02 28.78 228 60 CC2-7 3 93 0.657030 0.044814 4751.64 68.93 370 61 CC2-7 4 94 0.150625 0.023438 526.48 22.94 233 62 CC2-7 5 102 0.197833 0.026600 788.85 28.08 254 63 CC2-7 6 92 0.571612 0.043807 4083.52 63.90 347 64 CC2-7 7 65 0.154193 0.023268 559.32 23.65 237 65 CC2-7 8 70 0.189326 0.025038 712.42 26.69 256 66 CC2-7 9 47 0.122237 0.034432 533.94 23.11 160 67 CC2-7 10 68 0.102124 0.018719 270.39 16.44 211 144 Table VI-9 (cont'd) ID Code P r i n t N Xf / \ C V . No. (um2) (Um2) fff 175 IC1-3 3 28 0.126308 0.026369 474.57 21.78 195 34 IC1-5 1 45 0.207378 0.045487 844.07 29.05 189 13 IC1-5 2 46 0.320035 0.075986 1548.84 39.36 179 14 IC1-5 3 46 0.092987 0.021011 283.06 16.82 185 : 15 IC1-5 4 71 0.173108 0.033038 833.35 28.87 206 16 IC1-5 5 72 0.154170 0.026627 635.67 25.21 219 17 IC1-5 6 62 0.186714 0.026119 785.12 28.02 248 18 IC1-5 7 61 0.177237 0.043570 1090.10 33.02 175 :.19 IC1-5 8 58 0.093311 0.026835 333.90 18.27 157 20 IC1-5 9 63 0.112126 0.026142 420.73 20.51 182 21 IC1-5 10 79 0.245770 0.054063 1939.97 44.05 188 68 IC1-5 1 24 0.075372 0.013686 143.37 11.97 212 69 IC1-5 2 56 0.316547 0.029786 1538.16 39.22 310 70 IC1-5 3 56 0.233401 0.017993 711.63 26.68 346 71 IC1-5 4 64 0.071814 0.015134 151.50 12.31 194 72 IC1-5 5 61 0.179282 0.014586 416.04 20.40 336 73 IC1-5 6 60 0.145655 0.024036 526.42 22.94 225 74 IC1-5 7 50 0.174332 0.026024 668.43 25.85 239 75 IC1-5 8 68 0.240566 0.014983 620.56 24.91 388 76 IC1-5 9 68 0.171976 0.021471 593.31 24.36 265 77 IC1-5 10 70 0.276550 0.028340 1242.33 35.25 296 78 IC1-5 11 55 0.317183 0.031082 1601.40 40.02 303 79 IC1-5 12 58 0.268531 0.026246 1123.07 33.51 304 80 IC1-5 13 68 0.127115 0.015372 303.36 17.42 270 81 IC1-5 14 53 0.399318 0.037798 2366.58 48.65 309 82 IC1-5 15 55 0.147650 0.019274 436.99 20.90 258 83 IC1-5 16 45 0.090922 0.014967 200.78 14.17 225 84 IC1-5 17 62 0.309832 0.026815 1393.39 37.33 325 85 IC1-5 18 44 0.115098 0.020964 348.52 18.67 212 86 IC1-5 19 75 0.261695 0.019673 911.97 30.20 351 87 IC2-7 1 36 0.276744 0.026144 1134.68 33.68 310 88 IC2-7 2 42 0.115384 0.018560 317.38 17.82 228 89 IC2-7 3 48 0.389866 0.032444 2076.23 45.57 341 90 IC2-7 4 40 0.299675 0.021633 1083.15 32.91 359 91 IC2-7 5 42 0.160171 0.019559 495.26 22. 25 268 92 IC2-7 6 33 0.564062 0.041811 3781.72 61.50 353 93 IC2-7 7 45 0.159164 0.019583 464.19 21.54 267 94 IC2-7 8 48 0.378825 0.039603 2281.37 47.76 293 95 IC2-7 9 73 0.320270 0.036934 1777.09 42.16 277 96 IC2-7 10 65 0.560557 0.048242 4197.06 64.78 326 97 IC2-7 11 69 0.513266 0.049447 4085.23 63.92 308 98 IC2-7 12 48 0.101788. 0.021266 296.56 17.22 195 99 . IC2-7 13 53 0.328851 0.030327 1592.67 39.91 314 100 IC2-7 14 57 0.205862 0.019254 659.67 25.68 311 101 IC2-7 15 28 0.504157 0.036140 2929.34 54.12 360 102 IC2-7 16 56 0.285981 0.019171 868.60 29.47 373 145 Table V I - 9 (cont'd) I D Code P r i n t No. N x g 2 (um ) X f (um2) /\ 2 f / \ f C V . 22 I I I - 4 1 30 0.061107 0.022977 190.71 13.81 128 23 I I I - 4 2 40 0.026342 0.012560 37.68 6.14 105 24 I I I - 4 3 54 0.066015 0.016311 176.48 13.28 175 25 I I 1 - 4 4 54 0.125879 0.017790 418.57 20.46 246 26 I I 1 - 4 5 25 0.042760 0.013246 85.10 9.22 149 103 I I 1 - 4 1 51 0.051182 0.009924 70.91 8.42 2 04 104 I I 1 - 4 2 41 0.065766 0.012859 124.91 11.18 203 105 I I I - 4 3 48 0.022194 0.008378 21.25 4.61 128 106 I I 1 - 4 4 41 0.024652 0.005901 19.54 4.42 178 107 I I I - 4 5 29 0.034362 0.009299 40.36 6.35 164 108 I I I - 4 6 24 0.033977 0.013649 48.05 6.93 122 109 I I 1 - 4 7 24 0.006185 0.004948 1.19 1.09 51 110 I I I - 4 8 26 0.010012 0.006185 4.35 2.08 79 1 I I I - 5 1 72 0.041120 0.012713 67.59 8.22 149 2 I I I - 5 2 45 0.047175 0.011746 90.58 9.52 174 3 I I I - 5 3 48 0.034851 0.009109 51.04 7.14 168 4 I I I - 5 4 32 0.049117 0.009269 69.13 8.31 207 27 I I 1 - 5 5 44 0.038648 0.009278 55.04 7.42 178 125 I I I - 5 15 104 0.023772 0.008733 23.19 4.82 131 28 I I I - 5 6 47 0.021562 0.007802 23.37 4.83 133 122 I I I - 5 12 58 0.023068 0.009684 22.45 4.74 118 29 I I I - 5 7 67 0.049640 0.016975 120.70 10.99 139 124 I I I - 5 14 53 0.058057 0.014458 152.01 12.33 174 111 I I I - 5 1 84 0.046727 0.018969 107.98 10.39 121 112 I I 1 - 5 2 68 0.096333 0.019416 258.64 16.08 199 113 I I 1 - 5 3 51 0.037668 0.015919 61.15 7.82 117 114 I I 1 - 5 4 39 0.042676 0.013817 69.06 8.31 145 115 I I 1 - 5 5 63 0.020185 0.008867 17.38 4.17 113 116 I I 1 - 5 6 37 0.025591 0.006440 21.09 4.59 171 117 I I I - 5 7 47 0.018554 0.007701 15.34 3.92 119 118 I I 1 - 5 8 56 0.019488 0.007689 15.71 3.96 124 119 I I I - 5 9 61 0.033497 0.010453 41.72 6.46 148 120 I I I - 5 10 60 0.063005 0.020353 150.34 12.26 145 121 I I I - 5 11 66 0.041138 0.014273 66.41 8.15 137 123 I I I - 5 13 40 0.015138 0.008482 9.78 3.13 89 126 I I 1 - 6 1 33 0.045007 0.007329 47.82 6.92 227 127 I I 1 - 6 2 58 0.017661 0.008314 13.46 3.67 106 128 I I I - 6 3 46 0.012836 0.006698 7.55 2.75 96 129 I I I - 6 4 53 0.031118 0.014562 41.75 6.46 107 130 I I 1 - 6 5 35 0.015859 0.007785 10.89 3.30 102 131 I I I - 6 6 34 0.012299 0.006745 6.88 2.62 91 132 I I I - 6 7 41 0.011366 0.006127 5.56 2.36 92 133 I I I - 6 8 54 0.018791 0.006944 14.25 3.77 131 134 I I I - 6 9 45 0.015039 0.008090 9.93 3.15 93 135 I I I - 6 10 66 0.039667 0.014039 63.54 7.97 135 136 I I I - 6 11 57 0.038230 0.009083 45.85 6.77 179 137 I I I - 6 12 59 0.034554 0.013697 49.48 7.03 123 146 Tabl e VI-9 (cont'd) ID Code P r i n t No. N Xg 2 (um ) xf 2 (um ) /\ 2 °f /\ * f C V . 138 II2-5 1 60 0.117906 0.025461 415.69 20.39 191 139 II2-5 2 52 0.047722 0.011150 70.62 8.40 181 140 II2-5 3 30 0.084164 0.012040 153.37 12.38 245 141 II2-5 4 71 0.386798 0.042772 2548.43 50.48 284 142 II2-5 5 75 0.301807 0.024486 1176.03 34.29 337 143 II2-5 6 70 0.089893 0.032848 324.53 18.01 132 144 II2-5 7 64 0.202062 0.022996 713.16 26.70 279 145 II2-5 8 67 0.097794 0.016330 239.57 15.48 223 146 II2-5 9 53 0.115701 0.015451 268.26 16.38 255 147 II2-5 10 59 0.199851 0.025903 780.36 37.93 259 148 II2-5 11 85 0.156911 0.029027 642.90 25.36 210 149 II2-5 12 62 0.198169 0.026961 799.42 28.27 252 150 II2-5 13 55 0.163236 0.028174 672.04 25.92 219 151 II2-5 14 77 0.274123 0.025390 1115.33 33.40 313 152 II2-5 15 43 0.396240 0.031362 2021.02 44.96 341 153 II2-5 16 62 0.098808 0.021843 291.15 17.06 188 154 II2-5 17 49 0.255396 0041023 1553.15 39.41 229 155 II2-5 18 68 0.166686 0.041785 921.72 30.36 173 156 II2-5 19 76 0.118620 0.050375 607.16 24.64 116 157 II2-5 20 81 0.131160 0.033004 572.14 23.92 172 158 II3-3 1 56 0.062524 0.018310 140.21 11.84 155 159 II3-3 2 69 0.152081 0.016340 384.13 19.60 288 160 II3-3 3 73 0.248006 0.038182 1387.51 37.25 234 161 II3-3 4 67 0.201124 0.027658 830.91 28.83 250 162 II3-3 5 67 0.191849 0.033737 923.83 30. 39 216 163 II3-3 6 47 0.162750 0.030565 699.73 26.45 210 164 II3-3 7 55 0.269601 0.046689 1767.39 42.04 219 165 II3-3 8 44 0.159795 0.033949 725.52 26.94 193 166 II3-3 9 33 0.034070 0.009876 40.58 6.37 157 167 II3-3 10 42 0.16309 5 0.024873 583.84 24.16 236 168 II3-3 11 69 0.192337 0.051906 1237.84 35.18 164 169 II3-3 12 48 0.060399 0.019389 135.03 11.62 145 170 II3-3 13 58 0.284210 0.059453 2269.19 47.64 195 171 II3-3 14 63 0.217792 0.047198 1367.33 36.98 190 172 II3-3 15 68 0.175811 0.026863 679.48 26.07 235 Table VI-10 (Table V-2). Summary of observed and estimated margo pore areas of solvent-seasoned D o u l g a s - f i r sapwood earlywood p e r m e a b i l i t y specimens Code T o t a l No. of P i t s Xg (um2) Xf (um2) C V . 1 s T o t a l No. of Pores Min. Ave. Max. Min. Ave. Max. Min. Ave. Max. CC14SE CC15SE CC25SE CC27SE 11 3 15 14 0.0824 0.1078 0.0632 0.0702 0.1421 0.1531 0.1633 0.2696 0.2175 0.1841 0.3455 0.6570 0.0173 0.0263 0.0140 0.0187 0.0349 0.0398 0.0227 0.0400 0.0524 0.0489 0.0321 0.1112 141 156 141 123 177 170 237 228 228 178 335 370 729 202 843 981 IC13SE IC15SE IC27SE 1 29 16 0.1263 0.0718 0.1018 0.1263 0.1961 0.3228 0.1263 0.3993 0.5640 0.0264 0.0137 0.0186 0.0264 0.0275 0.0300 0.0264 0.0760 0.0494 195 157 195 195 251 305 195 388 373 28 1695 783 II14SE II15SE II16SE II25SE II33SE 13 22 12 20 15 0.0062 0.0151 0.0114 0.0477 0.0341 0.0439 0.0385 0.0244 0.1802 0.1717 0.1259 0.0963 0.0450 0.3962 0.2842 0.0049 0.0064 0.0061 0.0112 0.0099 0.0118 0.0119 0.0091 0.0279 0.0323 0.0230 0.0204 0.0146 0.0504 0.0595 51 89 91 116 145 148 145 123 229 205 246 207 227 341 288 487 1242 581 1259 859 Table VI-11. Data f o r reg r e s s i o n analyses Y perm X t l Xca Xpa Xua Xmp P T Code (darcy) (mm) (X100%) (X100%) (X100%) Xtn Xsg (um^) (um) (um) CC11AL 1.97 2.64 .6667 .2424 .0909 1114 .5823 CC11SL 1.56 2.64 .1061 .1844 .7095 1056 .5823 CC14AE 0.63 2.34 .9911 .0076 .0013 789 .2314 CC14SE 11.88 2.34 .0435 .3439 .6126 739 .2314 .0349 17.65 8.16 CC15AE 0.46 2. 37 1.0000 . 0000 .0000 651 .3020 CC15SE 9.68 2.37 .0673 .3269 .6058 719 .3020 .0398 18.01 8.36 CC22AL 0.89 2.65 .7738 .0833 .1429 1225 .6311 CC22SL 0.93 2.65 .2100 .1918 .5982 1282 .6311 CC25AE 0.31 2.46 1.0000 .0000 . 0000 808 .3377 CC25SE 7.15 2.46 .0351 .1228 .8421 885 .3377 .0227 16.20 7.74 CC27AE 0.40 2.34 1.0000 .0000 .0000 710 .2252 CC27SE 10.42 2. 34 .0884 . 3163 .5952 679 .2252 .0400 18.84 8.50 IC11AL 1.26 2.56 .4488 .3707 .1805 1637 .6622 IC11SL 0.90 2.56 .0769 .2308 .6923 1665 .6622 IC13AE 0.49 2.32 .9394 .0476 .0130 1240 .6198 IC13SE 4.66 2.32 .0670 .1856 .7474 1276 .6198 .0264 14.54 6.78 IC15AE 0.82 2.00 1.0000 .0000 .0000 930 .2778 IC15SE 8.55 2.00 .0255 .3634 .6111 887 .2778 .0275 17.38 8.21 IC21AL 0.72 2.30 .5440 .2253 .2308 1767 .6629 IC21SL 0.76 2.30 .0472 .1288 .8240 1785 .6629 IC24AL 0.75 2.27 .5714 .2245 .2041 1446 .6725 IC24SL 1.36 2.27 .2510 .2594 .4895 1360 .6725 IC27AE 0.38 1.89 .9901 .0099 .0000 1276 .3107 IC27SE 8.30 1.89 .0175 .2821 .7004 1181 .3107 .0300 16.44 7.94 II14AE 1.26 3.11 .9674 .0233 .0093 1261 .3585 II14SE 7.04 3.11 .0157 .1659 .8184 1255 .3585 .0118 15.21 7.99 II15AE 0.84 2.76 .9964 .0036 .0000 1185 .2995 II15SE 9.06 2.76 .0162 .2405 .7432 1201 .2995 .0119 17.04 8.52 Table VI-11. (cont'd) Y perm -Xtl Xca Xpa Xua Xmp P T Code (darcy) (mm) (XI00%) (X100%) (XI00%) Xtn Xsg (um2) (um) (um) II16AE 0.46 2.89 .9770 .0175 .0055 1020 . 3458 II16SE 7.88 2.89 .0139 .2167 .7694 1008 .3458 .0091 17.11 8.84 II25AE 0.69 2.59 .9892 .0084 .0024 1128 .3325 II25SE 7.35 2.59 .0109 .1386 .8505 1144 .3325 .0279 17.91 8.87 II33AE 0.50 2.68 1.0000 .0000 .0000 1216 .3139 II33SE 6.96 2.68 .0126 .1239 .8634 1208 .3139 .0323 17.48 8.27 Table VI-12. Selected r e g r e s s i o n equations Regression Equations SEE R or r C a l c u l a t e d DF 1. A l l t r e e s a l l data Yperm = 7.5858 + 2.3460X_ - 0.1082X - 17.7 303X t l ca sg Yperm = 2.0458 + 0.4778X - 3.3205X pa sg Yperm = 11.7783 - 2.9125XJ_n + 0.1319X - 0.2983X,. t l ua t n 1.7671 1.4177 1.9267 0.8946 ic ic 0.9312 ** 0.8732 30 31 30 2. A l l t r e e s solvent-seasoned Yperm = 14.9585 - 20.9123X sg 1.0836 ic ic 0.9590 15 3. A l l t r e e s air-seasoned Yperm = 0.4849 + 0.2046X pa 0.2783 ic ic 0.7660 15 4. A l l earlywood Yperm = 1.0390 + 0.4812X pa 1.6110 ic ic 0.9239 22 5. A l l latewood Yperm = 4.6094 + 0.2138X - 6.4700X pa sg 0.1939 ** 0.9115 7 6. A l l t r e e s solvent-seasoned earlywood Yperm = 6.5814 + 0.1700X - 7.3824X + 6.8406X pa sg mp 0.7295 ic ic 0.9436 8 7. A l l CC tr e e s Yperm = 0.4287 + 0.5911X pa 1.4834 ic ic 0.9498 10 Table VI-12. (cont'd) Regression Equations SEE R or r C a l c u l a t e d DF 8. A l l IC trees Yperm = -0.0911 + 0.6108X pa 1.2556 ** 0.9185 10 9. A l l I I tr e e s Yperm = 0.9672 + 0.4011X pa 1.3989 it ic 0.9340 8 T a b l e VI-13A. 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 independent v a r i a b l e s used i n e s t i m a t i n g l o n g i t u d i n a l a i r p e r m e a b i l i t y f o r a l l t r e e s a l l data (N=34, DF=32) X t l X ca X pa X ua t n X sg Yperm x t l 1.00 X ca 0. 22 1.00 X pa 0.09 - 1.00 X ua 0.28 - - 1.00 t n 0.10 -0.22 -0.25 -0.13 1.00 X sg 0. 02 -0.39* -0.34* -0.31 0.76** 1.00 Yperm -0.02 -0.53** 0.92** 0.80** -0.37* -0.44** 1.00 153 T a b l e V I - 1 3 B . 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 i n d e p e n d e n t v a r i a b l e s u s e d i n e s t i m a t i n g l o n g i t u d i n a l a i r p e r m e a b i l i t y f o r a l l t r e e s s o l v e n t - s e a s o n e d a n d a i r - s e a s o n e d (N=17, DF=15) A l l t r e e s s o l v e n t - s e a s o n e d / 1 X t l X p a X t n X s g Y p e r m x t l 1.00 X p a 0.13 1.00 t n 0.13 - 0 . 6 2 * * 1.00 X s g 0.02 - 0 . 8 2 * * 0.77** 1.00 Y p e r m -0.09 0.86** - 0 . 7 8 * * - 0 . 9 6 * * 1.00 A l l t r e e s a i r - s e a s o n e d X t l X p a X t n X s g Y p erm x t l 1.00 X p a 0.23 1.00 t n 0.07 0.63** 1.00 X s g 0.02 0.76** 0.75** 1.00 Y p e r m 0. 38 0.77** 0.33 0.43 1.00 154 Table VI-13C. 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 independent v a r i a b l e s used i n e s t i m a t i n g l o n g i t u d i n a l a i r p e r m e a b i l i t y f o r a l l latewood and a l l earlywood (N=10, DF=8) A l l latewood X t l X pa X 4 -t n X sg Yperm x t l 1.00 X pa 0.22 1.00 X 4 -t n -0.59 -0.29 1.00 X sg -0.73* -0.39 0.80** 1.00 Yperm 0.45 0.75* -0.66* -0.72* 1.00 A l l earlywood X t l X pa X t n X sg Yperm x t l 1.00 X pa 0.09 1.00 X 4 -t n 0.30 -0.12 1.00 X sg 0.09 -0.22 0.54* 1.00 Yperm -0.03 0.92** -0.16 -0.19 1.00 155 Tabl e VT-13D. 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 independent v a r i a b l e s used i n e s t i m a t i n g l o n g i t u d i n a l a i r p e r m e a b i l i t y f o r a l l CC, IC and I I data A l l CC data (N=12, DF=10) X t l X pa X 4 -t n X sg Yperm x t l 1.00 X pa -0.36 1.00 X 4 -t n 0.95** -0.33 1.00 X sg 0.99** -0.34 0.95** 1.00 Yperm -0.44 0.95** -0.41 -0.44 . 1.00 A l l IC data (N=12, DF=10) X t l X pa t n X sg Yperm x t l 1.00 X pa -0.33 1.00 X 4 -t n 0.70* -0.40 1.00 X sg 0.88** -0.42 0.79** 1.00 Yperm -0.46 0.92** -0.54 -0.53 1.00 A l l I I data (N=10, DF=8) X t l X pa X 4 -t n X sg Yperm x t l 1.00 X pa 0.09 1.00 t n 0.19 -0.17 1.00 X sg 0.67* -0.02 -0.16 1.00 Yperm 0.01 0.93** 0.01 -0.05 1.00 156 Table VI-13E. Correlation c o e f f i c i e n t s for independent variables used i n estimating longitudinal a i r permeability for a l l trees solvent-seasoned earlywood (N=12, DF=10) X t l X pa X 4 -tn X sg X mp X ma Yperm x t l 1.00 X pa 0.19 1.00 X 4 -tn 0.34 -0.36 1.00 X sg 0.09 -0.61* 0.59* 1.00 X mp 0.64* -0.16 -0.57 -0.27 1.00 X ma 0.21 0.12 -0.11 -0.48 0.20 1.00 Yperm 0.22 0.73** -0.75** -0.84** 0.40 0.15 1.00 157 Table VI-14. Frequency d i s t r i b u t i o n s o f maximum and minimum estimated margo pore areas Code Maximum Minimum ID Xf(um^) C u l . F r e q . {%) ID Xf (W) C u l . F r e q . ( % ) CC 37 .0024 13.4 43 .0023 32.0 14 . 0240 33.1 .0230 85.4 SE .0480 68.0 .0460 94.3 .0720 82.6 .0690 95.7 .0960 91.1 .0920 97.3 .1200 93.3 .1150 98.3 .1440 94.5 .1380 98.6 .1680 95.6 .1610 99.1 .1920 96.1 .1840 99.3 .2160 96.7 .2070 99.4 .2400 97.7 .2300 99.5 .4800 99.6 .3450 99.8 .7200 99.7 .4002 99.9 .8520 99.9 1.2282 100.0 1.2792 100.0 IC 81 .0024 44.2 68 .0024 45.8 15 .0240 82. 5 .0240 92.0 SE .0480 87.9 . 0480 95.8 .0720 89.9 .0720 96.9 .0960 91.5 .0960 98.0 .1200 93.0 .1200 98.4 .1440 94.0 .1440 99.2 .1680 95.0 .1680 99.3 .1920 95.1 .1920 99.5 .2160 95.9 .2160 99.5 .2400 96.5 .2400 99.6 .4800 98.8 . 3120 99.7 .7200 99.2 .3600 99.9 .9600 99.8 . 3816 100.0 1.0320 99.9 2.8560 100.0 158 T a b l e VI-14 (cont'd) Maximum Minimum Code ID X f ( u m 2 ) C u l . F r e q . (%) ID X f ( u m 2 ) C u l . F r e q . (%) I I 22 .0021 22.0 109 .0023 73.1 14 .0210 71.7 .0046 86.8 SE .0420 83.8 .0069 91.5 .0630 93.2 .0092 94.5 .0840 97.2 .0115 96.9 .1050 97.9 .0138 98.0 .1260 98.6 . 0161 98.5 .1470 99.1 .0184 99.0 .1680 99.3 .0207 99.5 .1890 99.5 .0230 100.0 .2100 99.6 .2877 99.9 . 3402 100.0 159 Figure VI-1. Percent cumulative frequencies of maximum and minimum estimated margo pore areas Legend Code ID Margo pore area 0 CC14SE 37 maximum• • CC14SE 43 minimum-• IC15SE 81 maximum. • IC15SE 68 minimum A II14SE 22 maximum; • II14SE 109 minimum.- . Percent Cumulative Frequencies 4^  U l o o -i w 1-Ol O O 00 VO o o o . o O Q _ > 11 do. UJ) dP •o EH 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            data-media="{[{embed.selectedMedia}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
https://iiif.library.ubc.ca/presentation/dsp.831.1-0302207/manifest

Comment

Related Items