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UBC Theses and Dissertations

Growth increment, chemical composition and cellulose ultrastructure of Douglas-Fir stem wood formed under… Kim, Chung Tae 1976

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GROWTH INCREMENT, CHEMICAL COMPOSITION AND CELLULOSE ULTRA-STRUCTURE OF DOUGLAS-FIR STEM WOOD FORMED UNDER A R T I F I C I A L LONGITUDINAL COMPRESSIVE LOADING by CHUNG TAE^KIM B . S c . , . S e o u l N a t i o n a l U n i v e r s i t y , K o r e a , 1964 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n t h e F a c u l t y o f F o r e s t r y We a c c e p t t h i s t h e s i s a s c o n f o r m i n g t o t h e r e q u i r e d s t a n d a r d THE UNIVERSITY OF B R I T I S H COLUMBIA A u g u s t , 1976 <f) Chung Tae Kim 1976 In present ing t h i s t he s i s in p a r t i a l f u l f i l m e n t o f the requirements f o r an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree that the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r reference and study. I f u r t h e r agree that permiss ion for ex ten s i ve copying of t h i s t he s i s f o r s c h o l a r l y purposes may be granted by the Head of my Department or by h i s r ep re sen ta t i ve s . It i s understood that copying or p u b l i c a t i o n of t h i s t he s i s f o r f i n a n c i a l gain s h a l l not be al lowed without my w r i t t e n permis s ion. Department of The Un i v e r s i t y of B r i t i s h Columbia 2075 Wesbrook P l a c e Vancouver, Canada V6T 1W5 ABSTRACT A D o u g l a s - f i r stem was a r t i f i c i a l l y s u b j e c t e d t o l o n g i -t u d i n a l c ompressive l o a d e q u i v a l e n t t o an e s t i m a t e d g r e e n w e i g h t o f i t s crown. The wood s u b s e q u e n t l y formed under the l o a d was compared w i t h t h a t produced b e f o r e t r e a t m e n t and above t h e p o i n t o f l o a d i n g a f t e r seven growing seasons f o l l o w -i n g t r e a t m e n t . The r a t e o f i n c r e m e n t a l growth was c o n s i d e r -a b l y r e d u c e d i n b o t h volume and w e i g h t , w h i l e wood d e n s i t y somewhat i n c r e a s e d . H o l o c e l l u l o s e and a l p h a - c e l l u l o s e y i e l d s i n c r e a s e d and l i g n i n c o n t e n t d e c r e a s e d . A h i g h e r h o l o c e l l u -l o s e c r y s t a l l i n i t y and a s m a l l e r c e l l u l o s e m i c r o f i b r i l a n g l e were o b s e r v e d . These changes were immediate and more ap p a r e n t i n t h e f i r s t 2 y e a r s a f t e r t r e a t m e n t , t h e n t h e r e was a r e c o v -e r y t o s e e m i n g l y normal growth i n c r e m e n t s . The r e c o v e r y was confounded w i t h p o s s i b l e e f f e c t s of t h e changed wood d i s t r i -b u t i o n d u r i n g t h e 2 c o n s e c u t i v e y e a r s i m m e d i a t e l y f o l l o w i n g t r e a t m e n t . There were marked d i f f e r e n c e s i n t h e res p o n s e s o f i n c r e -m e n t a l growth zones and a l s o a t d i f f e r e n t h e i g h t s i n t h e l o a d e d stem w i t h r e s p e c t t o t h e p o i n t o f l o a d i n g . The d i f -f e r e n c e s c o u l d be e x p l a i n e d by t h e e x p e c t e d magnitude o f a p p l i e d s t r e s s and r e s u l t a n t s t r a i n . I t was c o n c l u d e d t h a t the l o n g i t u d i n a l c o m p r e s s i v e s t r e s s due t o t r e e w e i g h t , t o a l a r g e e x t e n t , i n f l u e n c e s wood forma-t i o n and plays a role l i m i t i n g stem growth, es p e c i a l l y i t s volume. Stem form and the d i s t r i b u t i o n a l patterns for wood cha r a c t e r i s t i c s within a stem are b a s i c a l l y shaped by the stress. i v TABLE OF CONTENTS 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 1.0 INTRODUCTION 1 2.0 LITERATURE REVIEW 3 2.1 E f f e c t s o f M e c h a n i c a l F o r c e s on Wood F o r m a t i o n 3 2.2 V a r i a b i l i t y i n Wood Che m i c a l and U l t r a -s t r u c t u r a l P r o p e r t i e s W i t h i n a Douglas-F i r Stem 10 2.2.1 Growth in c r e m e n t and wood zone l e v e l s . 10 2.2.2 I n c r e m e n t a l growth zone l e v e l 13 2.2.3 Abnormal wood 16 2.2.4 Summary and t h e t r e e used f o r t h e s t u d y 16 3.0 MATERIALS AND METHODS 18 3.1 E x p e r i m e n t a l Tree and L o a d i n g 18 3.2 Wood Sample P r e p a r a t i o n s f o r C h e m i c a l A n a l y s e s 19 3.3 P r o c e d u r e s 21 3.3.1 H o l o c e l l u l o s e and a l p h a - c e l l u l o s e ... 21 3.3.2 L i g n i n 24 3.3.3 C r y s t a l l i n i t y o f t h e c h l o r i t e h o l o c e l l u l o s e 25 3.3.4 M i c r o f i b r i l a n g l e 26 V Page 4 . 0 OBSERVATIONS AND DISCUSSION 2 7 4 . 1 Growth Increment B e f o r e L o a d i n g 2 7 4 . 2 Wood F o r m a t i o n A f t e r L o a d i n g 3 0 4 . 2 . 1 Growth i n c r e m e n t w i d t h and d e n s i t y .. 3 1 4 . 2 . 2 C h e m i c a l c o m p o s i t i o n 3 7 4 . 2 . 3 C r y s t a l l i n i t y and m i c r o f i b r i l a n g l e .. 4 6 4 . 3 About t h e Experiment 5 2 5 . 0 CONCLUSIONS AND PRACTICAL APPLICATION 5 5 6 . 0 LITERATURE CITED 5 6 APPENDIX (Sample s i z e f o r t h e d e s i r e d p r e c i s i o n i n s e l e c t e d h o l o c e l l u l o s e and l i g n i n p r o c e d u res) 6 2 / v i LIST OF TABLES / Page Table 1. Wood sample positions i n the stem. .... 20 " 2. Growth increment weight i n the compressed Douglas-fir stem before and afte r loading. 36 " 3. Chemical composition of the com-pressed Douglas-fir stem wood before and after loading. 38 " 4. Analysis of variance and Duncan's multiple range te s t for the chemical composition data, and chemical composition of growth zones and heights before and a f t e r loading. 39 " 5. C r y s t a l l i n i t y of the compressed Douglas-fir stem wood before and after loading. 47 " 6. Duncan's multiple range t e s t for the c r y s t a l l i n i t y data, and c r y s t a l l i n i t y of growth zones and heights before and afte r loading. 48 " 7. Average r a d i a l growth at breast height for the 180 young Douglas-fir trees at Univ. of B.C. Research Forest for the years 1960-71. 54 v i i LIST OF FIGURES Page Figure 1. Diagram showing mechanical forces acting on the stayed stem. 6 " 2. Variation i n growth increment width at d i f f e r e n t stem heights before loading, with reference to cardinal directions. 2 8 " 3. Variation i n incremental growth zone density at d i f f e r e n t stem heights before and a f t e r loading, with reference to cardinal d i r e c t i o n s . 29 " 4. Growth increment width at d i f f e r -ent stem heights before and after loading. 32 " 5. Incremental growth zone density at d i f f e r e n t stem heights before and afte r loading,^with reference to cardinal d i r e c t i o n s . 34> " 6. M i c r o f i b r i l angle of incremental growth zone at d i f f e r e n t stem heights before and afte r loading, with reference to cardinal directions. 50 v i i i ACKNOWLEDGEMENT The a u t h o r w i s h e s t o e x p r e s s h i s g r a t i t u d e t o Dr. L. P a s z n e r who p r o v i d e d s u p e r v i s i o n and s u g g e s t i o n s f o r t h i s s t u d y . Mr. L. Adamovich i n i t i a t e d a p r o j e c t f o r the t o p i c and s u p p l i e d wood samples. Drs. R. W. Wellwood and J . H. G. S m i t h , and Mr. L. Adamovich a r e g r a t e f u l l y acknowledged f o r t h e i r v a l u a b l e a d v i c e and r e v i e w o f t h i s t h e s i s . S t a t i s t i -' c a l a n a l y s e s and p r o c e s s i n g the X-ray d a t a f o r m i c r o f i b r i l a n g l e d e t e r m i n a t i o n s were made p o s s i b l e by t h e a s s i s t a n c e o f Dr. A. Kozak and h i s a s s i s t a n t s . The t e c h n i c a l a s s i s t a n c e o f Mr. G. Bohnenkamp i s much a p p r e c i a t e d . Mr. R. G. B u t t e r s , Department o f M e t a l l u r g y , k i n d l y h e l p e d w i t h X-ray machine. The generous h e l p o f the s t a f f a t t h e Western F o r e s t P r o d u c t s L a b o r a t o r y , Department o f the Environment i s a l s o a p p r e c i a t e d : Dr. R. M. K e l l o g g i n making the l i t e r a t u r e on m e c h a n i c a l f o r c e s - wood f o r m a t i o n r e a d i l y a v a i l a b l e , Dr. M. L. M. E l - O s t a , now i n Egypt, w i t h m i c r o f i b r i l a n g l e measurements, and o t h e r members i n v a r i o u s ways. S p e c i a l thanks i s extended t o the a u t h o r ' s w i f e , Won-ok, f o r her e n t h u s i a s t i c h e l p t h r o u g h o u t the a n a l y s e s and en-couragement d u r i n g t h e g r a d u a t e program. 1 1.0 INTRODUCTION Tree's own w e i g h t has been r e c o g n i z e d by e a r l i e r w o r k ers as a m e c h a n i c a l f o r c e which may i n f l u e n c e wood f o r m a t i o n and i t s d i s t r i b u t i o n i n the stem and as a p o s s i b l e cause o f growth s t r e s s e s i n t h e t r e e . Meanwhile, t h e r e have been numerous d i s c u s s i o n s f o r and a g a i n s t i t s s i g n i f i c a n c e as a f a c t o r con-t r o l l i n g t r e e growth. I n s u p p o r t o f t h e m e c h a n i s t i c t h e o r y , a f t e r r e v i e w i n g the l i t e r a t u r e on t h e t h e o r i e s o f stem form development, L a r s o n (27) s t a t e d t h a t , "From t h e s t a n d p o i n t o f s t r e n g t h r e q u i r e m e n t s and s u p p o r t f u n c t i o n , t h e m e c h a n i s t i c t h e o r y p r o v i d e s a r e a l i s t i c i n t e r p r e t a t i o n t h a t has s u r v i v e d ex-p e r i m e n t a l s t u d y r e a s o n a b l y w e l l . " , and t h a t " I t i s e v i d e n t t h a t the stem must be c o n s t r u c t e d s u f -f i c i e n t l y s t r o n g t o w i t h s t a n d not o n l y i t s own w e i g h t but a l s o t h e w e i g h t of i c e and snow, and the f o r c e s of t h e wind i m p r i n g i n g on the stem." A l t h o u g h a few s t u d i e s , done m o s t l y i n t h e e a r l i e r y e a r s by u s i n g t h e t e c h n i q u e o f a r t i f i c i a l c o m p r essing over t h e stem, have r e p o r t e d the i n f l u e n c e o f t h e i r t r e a t m e n t s on t r e e • growth (27,46), t h e i r e x p e r i m e n t a l r e s u l t s a r e c o n t r a d i c t o r y . F u r t h e r m o r e , t h e r e i s t o the w r i t e r ' s knowledge no r e p o r t a v a i l a b l e on t h e i n f o r m a t i o n about th e wood c h e m i c a l o r u l t r a s t r u c t u r a l c h a r a c t e r i s t i c s r e l a t e d t o t h e c o m p r e s s i o n . E x p e r i m e n t a l o b s e r v a t i o n s of r e a c t i o n wood f o r m a t i o n i n stems and branches s u b j e c t e d t o changes i n t h e i r normal o r i e n t a t i o n t o t h e d i r e c t i o n o f g r a v i t a t i o n a l f o r c e (52) suggest t h a t wood f o r m a t i o n may be r e g u l a t e d by g r a v i t y due t o t r e e weigh't. 2 R e c e n t l y the mechanics of l i v i n g t r e e s have been s t u d i e d as a f i e l d o f t r e e s c i e n c e . Tree mechanics i s concerned w i t h a b r o a d spectrum o f t r e e s t a t i c s , s t r e n g t h and dynamics. U l t i m a t e l y , t h e s e r e l a t e t o the e a r t h ' s g r a v i t a t i o n a l e f f e c t s on t r e e s t a b i l i t y and may have a d e c i s i v e i n f l u e n c e on the p h y s i o l o g i c a l and b i o c h e m i c a l response o f l i v i n g t r e e s . The g r o s s s t r u c t u r a l a r c h i t e c t u r e o f t r e e s i s b e l i e v e d t o be t h e d i r e c t r e s u l t of t r e e mechanics. F o r a p r o j e c t i n i t i a t e d by Adamovich and W a l t e r s (1) i n 1965, w i t h t h e purpose o f s t u d y i n g t h e mechanics o f s t a n d i n g c o n i f e r o u s t r e e s , D o u g l a s - f i r t r e e s were l o a d e d w i t h a w e i g h t e q u i v a l e n t t o t h e e s t i m a t e d g r een w e i g h t o f t h e i r crowns t o e v a l u a t e t h e r o l e o f t r e e w e i g h t i n t h e wood s t r e n g t h and c h e m i c a l p r o p e r t i e s . S i n c e p h y s i o l o g i c a l and b i o c h e m i c a l r e -sponses t o t h e l o a d i n g a r e h i g h l y confounded and complex, i t was l o g i c a l t o seek the t r e e ' s response i n the o b s e r v a b l e changes i n wood a n a t o m i c a l , p h y s i c a l and c h e m i c a l c h a r a c t e r -i s t i c s . P r e l i m i n a r l y , a m i c r o s c o p i c a l e x a m i n a t i o n o f the wood formed under the l o a d was r e p o r t e d ( 2 4 ) . The p r e s e n t paper w i l l d e s c r i b e t h e changes i n c h e m i c a l c o m p o s i t i o n and u l t r a s t r u c t u r e o f a D o u g l a s - f i r stem wood formed under the l o a d . These i n c l u d e h o l o c e l l u l o s e , a l p h a - c e l l u l o s e and l i g -n i n c o n t e n t s , c r y s t a l l i n i t y and m i c r o f i b r i l a n g l e . Data o f growth i n c r e m e n t w i d t h and d e n s i t y a re a l s o p r e s e n t e d f o r a d d i t i o n a l i n f o r m a t i o n on t h e t r e e . 3 2.0 LITERATURE REVIEW 2.1 E f f e c t s of M e c h a n i c a l F o r c e s on Wood F o r m a t i o n There are s e v e r a l m e c h a n i c a l f o r c e s w h i c h may i n f l u e n c e wood f o r m a t i o n i n t h e stem, such as b e n d i n g by wind a c t i o n , c o mpression by t r e e ' s own we i g h t and t h e a d d i t i o n a l w e i g h t o f snow and i c e , and growth s t r e s s e s . Among t h e s e f o r c e s , t r e e w e i g h t and w i n d a r e m a i n l y concerned w i t h p a r t i c u l a r r e f e r -ence t o c o n i f e r o u s t r e e stems. A l t h o u g h a v e r y c o n s i d e r a b l e amount o f work on t h e s u b j e c t has been r e p o r t e d , t h e s u b j e c t i s so complex t h e o r e t i c a l l y and t e c h n i c a l l y t h a t t h e w r i t e r i s u n d o u b t e d l y not q u a l i f i e d t o r e v i e w i t c r i t i c a l l y . More-o v e r , some o f t h e p u b l i s h e d works a r e c o n t r a d i c t o r y , i n c o n -c l u s i v e and sometimes c o n f u s i n g . Schwendener ( 4 4 ) , e a r l y i n 1874, i n t r o d u c e d t h e mechan-i s t i c t h e o r y of stem form development t h a t t h e response o f t r e e t o t h e bend i n g s t r e s s e s o r i g i n a t e d by wind d e t e r m i n e s stem form. T h i s i n t r o d u c t o r y p r o p o s a l has been c r i t i c i z e d , m o d i f i e d and d e v e l o p e d by f o l l o w i n g i n v e s t i g a t o r s . S i n c e t h e work done i n t h e e a r l y y e a r s was not a v a i l a b l e t o t h e w r i t e r , some h i s t o r i c a l developments on t h e m e c h a n i s t i c t h e o r y a re summarized from t h e comprehensive r e v i e w c o m p i l e d by L a r s o n (27) : i ) The w e i g h t o f t r e e i t s e l f was f i r s t r e c o g n i z e d by 4 Metzger (1893) as a v e r t i c a l mechanical force, s t i l l believing the wind to be a governing factor on the assumption that the stem i s a beam of uni-form resistance to bending. i i ) Hohenadl (1922) claimed, contrary to Metzger, that stem form i s primarily established by the tree weight and regarded the stem as a beam of uniform resistance to the compression exerted by i t s own weight. i i i ) Subsequent investigators of Hohenadl's propo-sa l maintained that tree weight may contribute only a minor part to stem form variations. The d e f i n i t e role of these mechanical forces i n influencing wood formation and, subsequently, i t s d i s t r i b u t i o n i n the stem, has not been determined, despite the numerous contro-versies. Nevertheless, the early contributions seem to indicate that stem form i s affected by complex variables and tree weight i s not an exclusively dominant factor. In l a t e r years, studies on the stem form - mechanical forces re l a t i o n s h i p have been directed mostly to wind. Jacobs (19,20), who was the f i r s t to study experimentally the e f f e c t of wind swaying on stem development, reported that wind sway was an important factor i n determining the d i s t r i b u t i o n of r a d i a l increment on the lower part of stem. Comparing free-swaying trees with stayed trees with guy-wires attached at the middle part of t h e i r stems, he found increased diameter 5 growth a t t h e lower l e v e l i n the f r e e - s w a y i n g t r e e s and above guys i n t h e s t a y e d t r e e s , and reduced r a d i a l i n c r e m e n t o v e r t h e s t a y e d stem p a r t . H i s o b s e r v a t i o n s on t h e e f f e c t o f wind t o s t i m u l a t e growth o f the lower stem have been c o n f i r m e d by L a r s o n (28) and B u r t o n and Smith ( 6 ) . I n t h e i r s t u d i e s e v a l -u a t i n g t h e e f f e c t o f w i n d , i t has been m a i n t a i n e d t h a t the p r e v e n t i o n o f wind caused r e d u c t i o n i n r a d i a l i n c r e m e n t o f the lower stem. However, the r e s u l t s o f t h e i r e x p e r i m e n t s r e q u i r e c a r e -f u l i n t e r p r e t a t i o n , s i n c e t h e e x p e r i m e n t a l t r e e s were exposed t o n o t m e r e l y wind l o a d i n g and no wind t r e a t m e n t (the s t a y e d t r e e s were used f o r a c o n t r o l ) , but a l s o c o m p l e t e l y d i f f e r e n t k i n d s o f m e c h a n i c a l f o r c e s . The f r e e - s w a y i n g t r e e s r e c e i v e g e o t r o p i c s t i m u l i as w e l l when t h e y a re d i s p l a c e d from t h e i r normal v e r t i c a l o r i e n t a t i o n . I n f a c t , t h e m e c h a n i c a l f o r c e s a c t i n g on t h e s t a y e d stems are c o m p l i c a t e d , as shown i n F i g u r e 1 . The t e n s i o n s on t h e w i r e s , T-^  and T 2 , e x e r t com-p r e s s i o n and the x - d i r e c t e d f o r c e s o v e r t h e stem. I n a d d i -t i o n , t h e stem r e c e i v e d g e o t r o p i c s t i m u l i i f T-j_ ^ T 2 or 8-^  ^ © 2 / t h a t i s , when the stem i s out of i t s normal v e r t i c a l d i r -e c t i o n . These f o r c e s would be c o n s i d e r a b l e when winds a r e l o a d e d , even more so i n h i g h wind. The problems e n c o u n t e r e d d u r i n g t h e i r e x p e r i m e n t s e x p l a i n t h e a c t u a l magnitude and are m a n i f e s t a t i o n s o f t h e s e f o r c e s . Thus, the r e d u c t i o n i n the r a t e o f i n c r e m e n t a l growth o b s e r v e d o v e r t h e s t a y e d stems i s b e l i e v e d t o have been a response t o t h e s e f o r c e s , r a t h e r t h a n 6 7 t h e i r no-wind treatments, perhaps mostly to the compression. The increased rate of growth above the guy may be traced to the wide increment found generally during juvenile wood for-mation, judging from the high positions i n the stems of r e l a -t i v e l y young trees. Steucek and Kellogg (47) employed a rather d i f f e r e n t experimental approach to the study on stem wood development i n r e l a t i o n to mechanical forces. Assuming that the i n t r o -duction of a discontinuity by removing a rectangular (3.8 x 10 cm) core from the stem creates concentrated mechanical stresses at that point when winds are loaded, they examined the d i s t r i b u t i o n of stem growth around the discontinuity. The stems showed a reduced r a d i a l increment i n the plane of and d i r e c t l y above the discontinuity, and no apparent d i f -ferences i n the percentage of latewood, as compared among the stem cross sections taken from varying distances above and below a discontinuity. Perhaps the res u l t s obtained by t h i s experimental approach were a response to the complex mechani-c a l stresses originated by t h e i r experimentation, assuming that the observed changes around the discontinuity zone were the response to mechanical forces. Obviously, the reduction in the area of cross section by removing a stem core induces proportionally increased compression stress on the cross section which was supporting the compression of the tree weight above that point. 8 Many o b s e r v a t i o n s o f r a d i a l l y e c c e n t r i c development i n t h e stem exposed t o winds (20,28,35) suggest t h a t the e c c e n -t r i c i t y i s due t o wind l o a d i n g and may i n t r o d u c e v a r i a t i o n s i n t h e stem wood p r o p e r t i e s . U n f o r t u n a t e l y , l i t t l e i n f o r m a -t i o n i s a v a i l a b l e on t h i s . Bannan a n d . B i n d r a (3) found t h a t growth i n c r e m e n t was w i d e r on t h e l e e w a r d s i d e and the w i d e r i n c r e m e n t was a s s o c i a t e d w i t h s h o r t e r t r a c h e i d s , as compared w i t h o t h e r c a r d i n a l p o i n t s around the stem base. T h e i r d a t a on the windward s i d e showed l o n g e r t r a c h e i d s and narrower i n c r e m e n t s . These v a r i a t i o n s were a s c r i b e d t o t h e p r e v a i l i n g wind. U n l i k e t h e w i n d , t r e e w e i g h t r e c e i v e d l i t t l e a t t e n t i o n from i n v e s t i g a t o r s . M a r t l e y (33) examined t r e e w e i g h t as a p o s s i b l e cause o f growth s t r e s s e s and r e p o r t e d t h a t t h e p r e s -sure g r a d i e n t due t o t h e w e i g h t o f t r e e growth was not s u f -f i c i e n t l y g r e a t t o c o n t r i b u t e t h e o b s e r v e d s t r e s s e s . H i s t h e o r e t i c a l c a l c u l a t i o n s o f t h e p r e s s u r e w h i c h might d e v e l o p from t r e e w e i g h t on t h e b a s a l c r o s s s e c t i o n o f an average 3 0 - y e a r - o l d D o u g l a s - f i r t r e e showed 16.5 kg/cm 2 (235 green l b / i n 2 ) . The t r e e w e i g h t h y p o t h e s i s on growth s t r e s s e s was opposed by Boyd (5) on t h e grounds t h a t t h e e s t i m a t e d v a l u e and c h a r a c t e r o f t h e s t r e s s e s due t o t r e e w e i g h t i s i n a d e -quate t o e x p l a i n t h e measured, h i g h s t a t e o f growth s t r e s s e s i n t h e t r e e s . He conceded, however, t h a t t r e e ' s own w e i g h t has some e f f e c t i n o r i g i n a t i n g growth s t r e s s e s . 9 The e f f e c t of a r t i f i c i a l l y - a p p l i e d longitudinal compres-sion by hanging weights over the stem has been studied mostly with herbaceous plant stems (27,46). The results of these experiments were contradictory. No experimental r e s u l t s are available on stem wood properties of the coniferous trees weighted with load. From the fac t that tree weight i s the earth's gravita-t i o n a l force and also the well-known geotropic responses i n general tree's growth, the e f f e c t of gravity has been inves-tigated as a possible cause of compression wood formation. Observation supporting the theory i s that the compression wood i s always formed on the lower side of i n c l i n e d stems or loops made by bending stems. Details on these experiments were described by Wardrop (52) and w i l l not be re i t e r a t e d here. Conclusively, the e f f e c t s of mechanical forces on stem wood formation and subsequently i t s d i s t r i b u t i o n are much more complicated and greater than i s generally appreciated. The results of experimental studies on them may be confounded by the fact that experimentation for a s p e c i f i c mechanical force induces undesirable, d i f f e r e n t kinds of mechanical forces as well. The pattern of r a d i a l incremental growth under wind loading i s reasonably well established, although detailed wood physical and chemical properties as influenced by wind are s t i l l r e l a t i v e l y unknown. Information on the role of tree weight on wood formation i s lacking. 10 2.2 V a r i a b i l i t y i n Wood Chemical and U l t r a s t r u c t u r a l Prop-e r t i e s Within a Douglas-Fir Stem It i s well documented i n the l i t e r a t u r e that wide v a r i a -tions exist i n chemical composition and ultra s t r u c t u r e of a single stem of coniferous trees i n regard to r a d i a l positions or age and growth zones, as well as normal and abnormal wood. However, information on the variations along heights i n the stem and with cardinal directions on a stem cross section i s r e l a t i v e l y lacking for a clear and certain picture of the patterns, even though a few published works indicate a var-i e t y of trends (21,22,29,38,43,56,58). The l i t e r a t u r e p e r t i -nent to c e l l u l o s e , l i g n i n , c r y s t a l l i n i t y and m i c r o f i b r i l angle of Douglas-fir stem wood i s reviewed with regard to r a d i a l positions and growth zones. Since the v a r i a t i o n trends p r e v a i l i n g i n other coniferous normal and abnormal wood i s generally, but not always, prevalent i n Douglas-fir, some findings on the species are also included. 2.2.1 Growth increment and wood zone l e v e l s Quantitative analyses of cel l u l o s e i n coniferous stem cross sections indicated an increasing pattern i n progressive increments from the p i t h to the cambium. Early i n 1951 the data of Cross & Bevan ce l l u l o s e con-tents obtained for Douglas-fir and Monterey pine showed a tendency for c e l l u l o s e contents to increase r a d i a l l y 11 (51). E xamining t h e v a r i a t i o n i n c e l l u l o s e c o n t e n t e x p e c t e d i n D o u g l a s - f i r , Kennedy and Jaworsky (25) found t h a t most of t h e v a r i a t i o n i n c e l l u l o s e c o n t e n t (from low 57.4 t o h i g h 63.3%) o c c u r r e d d u r i n g the f i r s t 15 y e a r s . T h e i r d a t a on the C r o s s and Bevan c e l l u l o s e showed a s t e a d y i n c r e a s e up t o 81 y e a r s o f growth a f t e r t h e r a p i d i n c r e a s e f o r t h e f i r s t y e a r s o f growth. A s i m i l a r p a t t e r n was r e p o r t e d by E r i c k s o n and Arima (13) who s t u d i e d t h e e f f e c t s o f age and s t i m u l a t e d growth on c h e m i c a l c o m p o s i t i o n o f D o u g l a s - f i r . H o l o c e l l u l o s e y i e l d s i n c r e a s e d r e l a t i v e l y f a s t t o age 18-20 y e a r s and a t a moderate r a t e t h e r e a f t e r , w h i l e a l p h a - c e l l u l o s e con-t e n t s r o s e from t h e p i t h t o age 25 or more. D u r i n g the e a r l y 15 y e a r s , a r a t h e r r a p i d i n c r e a s e i n a l p h a - c e l l u -l o s e c o n t e n t s was apparent i n t h e i r d a t a . Comparative a n a l y s e s o f j u v e n i l e and mature wood suggested t h a t the i n c r e a s e d c e l l u l o s e c o n t e n t i n t h e e a r l y s t a g e o f growth i s m a i n t a i n e d o r s t i l l p r o g r e s s i v e -l y i n c r e a s e d d u r i n g the mature y e a r s o f growth. The d a t a f o r a s i n g l e D o u g l a s - f i r (25) showed c o n s i s t e n t l y h i g h e r y i e l d s o f c e l l u l o s e i n the o u t e r wood t h a n i n the j u v e n i l e wood. Wellwood and Smith (54) a l s o found con-s i d e r a b l y h i g h e r a l p h a - c e l l u l o s e c o n t e n t i n the 41-50th i n c r e m e n t s from t h e p i t h , when compared t o t h e 6-20th i n c r e m e n t s i n D o u g l a s - f i r and hemlock. However, t h e y 12 found l i t t l e d i f f e r e n c e ( s t i l l s l i g h t l y h i g h e r v a l u e s f o r the o u t e r increments) i n h o l o c e l l u l o s e contents between the two increment groups. S i m i l a r p a t t e r n s have been observed i n pines (43,50,60). The v a r i a t i o n be-tween the two wood zones of l o b l o l l y p ine was 3.5% higher i n w a t e r - r e s i s t a n t carbohydrates and 7.5% h i g h e r i n a l p h a - c e l l u l o s e f o r the mature wood. In a D o u g l a s - f i r showing 430 increments, Hale and Clermont (15) found lower a l p h a - c e l l u l o s e y i e l d s from the 27-32nd and 322-400th increment groups, as compared t o those from the increments i n between them. The low a l p h a - c e l l u l o s e y i e l d s of the i n n e r and outermost wood were a t t r i b u t e d t o the wider increment w i t h lower per-centage of latewood, and the t h i n - w a l l e d prosenchyma c e l l s g e n e r a l l y found i n the overmature wood, r e s p e c t i v e -l y . T h e i r data, meanwhile, showed a moderate decrease i n h o l o c e l l u l o s e contents from the i n n e r increments, outward. T h i s d e c l i n i n g h o l o c e l l u l o s e p a t t e r n shows i n -c o m p a t i b i l i t y with the r e s u l t s by Zobel and McElwee (60), who found t h a t the y i e l d s of w a t e r - r e s i s t a n t carbohy-d r a t e s and a l p h a - c e l l u l o s e from l o b l o l l y p i n es were h i g h l y c o r r e l a t e d ( s i g n i f i c a n t a t the 1% l e v e l ) . The r e l a t i o n s h i p has been a l s o noted i n D o u g l a s - f i r t r e e s , even though one of the t r e e s (ages of 70-85 years) gave s l i g h t l y lower w a t e r - r e s i s t a n t carbohydrates and alpha-c e l l u l o s e y i e l d s i n the f i v e outermost increments than 13 i n t h e 16-25th i n c r e m e n t s from th e p i t h ( 2 5 ) . Examina-t i o n s on r e l a t i v e l y o l d e r D o u g l a s - f i r t r e e s i n d i c a t e d t h a t a d e c r e a s e i n c e l l u l o s e c o n t e n t was e v i d e n t i n about 300-400 y e a r s o f growth due t o o v e r m a t u r i t y (15,42). I n g e n e r a l , l i g n i n p a t t e r n f o r t h e v a r i a t i o n w i t h r a d i a l p o s i t i o n s on a stem c r o s s s e c t i o n i s o p p o s i t e t o t h o s e of h o l o c e l l u l o s e and a l p h a - c e l l u l o s e . E r i c k s o n and Arima (13) found i n 3 0 - y e a r - o l d D o u g l a s - f i r t r e e s t h a t t h e h i g h e s t l i g n i n c o n t e n t near th e p i t h g r a d u a l l y de-c l i n e d w i t h age u n t i l v e r y l i t t l e changes a f t e r 23-25 y e a r s . A g r a d u a l l y d e c r e a s i n g tendency i n l i g n i n con-t e n t s was a l s o p r e v a i l i n g i n o l d e r D o u g l a s - f i r , e x c e p t the r e s i d u a l i n c r e a s e due t o o v e r m a t u r i t y . 2.2.2 I n c r e m e n t a l growth zone (earlywood and latewood) l e v e l Marked d i f f e r e n c e s i n c h e m i c a l c o m p o s i t i o n and u l t r a s t r u c t u r e between e a r l y w o o d and l a t e w o o d have been shown i n t h e s t u d i e s on growth zones. I n g e n e r a l , l a t e -wood has h i g h e r c e l l u l o s e c o n t e n t and degree o f c r y s t a l -l i n i t y , l e s s l i g n i n p e r c e n t a g e and s m a l l e r ( s t e e p e r ) m i c r o f i b r i l a n g l e , as compared t o c o r r e s p o n d i n g e a r l y -wood. D o u g l a s - f i r e a r l y w o o d l i g n i n v a l u e s were 3-4% h i g h e r t h a n t h o s e f o r comparable latewood (15,40,59). The d i f f e r e n c e was much g r e a t e r w i t h a l p h a - c e l l u l o s e (15) 14 and m i c r o f i b r i l a n g l e (10). These d i f f e r e n c e s between e a r l y w o o d and latewood have been r e p o r t e d s i m i l a r l y f o r o t h e r s p e c i e s (29,32,40,59). R a d i a l p a t t e r n s f o r i n d i v i d u a l growth zones were examined by S a s t r y and Wellwood (42) w h i l e s t u d y i n g t r a c h e i d w e i g h t - l e n g t h r e l a t i o n s h i p s i n D o u g l a s - f i r . T h e i r r e s u l t s o b t a i n e d f o r s i n g l e t r a c h e i d w e i g h t s ( h o l o -and a l p h a - c e l l u l o s e f r a c t i o n s o b t a i n e d a f t e r d e l i g n i f i -c a t i o n w i t h p e r a c e t i c a c i d ) showed an i n c r e a s i n g t r e n d f o r b o t h e a r l y w o o d and l a t e w o o d t o about 150 y e a r s and t h e n a moderate d e c r e a s i n g toward t h e bark. An i n -c r e a s i n g p a t t e r n f o r C r o s s & Bevan c e l l u l o s e was n o t e d i n t h e e a r l y w o o d o f Monterey p i n e (51). L a r s o n (29) made a s t u d y on the v a r i a t i o n s i n l i g n i n and c o n s t i t u -ent c a r b o h y d r a t e s o f r e d p i n e e a r l y w o o d and latewood w i t h age. He o b s e r v e d i n b o t h growth zones t h a t g l u c o s e and mannose c o n t e n t s f o l l o w e d a p r o g r e s s i v e l y i n c r e a s i n g t e n dency, whereas th e y i e l d s o f g a l a c t o s e , x y l o s e , a r a -b i n o s e and l i g n i n were d e c r e a s i n g w i t h age. C r y s t a l l i n i t y p a t t e r n f o r i n d i v i d u a l growth zones o f D o u g l a s - f i r was examined by Wellwood, e t a l . ( 5 3 ) . They found t h e same p a t t e r n s f o r b o t h e a r l y w o o d and l a t e -wood, i n w h i c h c r y s t a l l i n i t y v a l u e s i n c r e a s e d r a p i d l y from the p i t h t o 20 y e a r s and t h e n g r a d u a l l y t i l l 400 y e a r s . The s t e a d y i n c r e a s e even i n overmature wood i s 15 r a t h e r d i f f e r e n t f r o m what i s e x p e c t e d f r o m t h e o b s e r v e d d e c r e a s e i n a l p h a - c e l l u l o s e c o n t e n t o f o v e r m a t u r e wood (15,42) and t h e s i g n i f i c a n t c o r r e l a t i o n ( a t t h e 5% l e v e l ) between c r y s t a l l i n i t y and t h e amount o f a l p h a - c e l l u l o s e i n t r a c h e i d s ( 5 3 ) . I n a s l i g h t l y d i f f e r e n t p a t t e r n f o u n d i n w e s t e r n hemlock (31) and Norway s p r u c e ( 3 4 ) , c r y s t a l -l i n i t y o f b o t h e a r l y w o o d and l a t e w o o d i n c r e a s e d r a p i d l y f o r t h e f i r s t few y e a r s , t h e n g r a d u a l l y l e v e l l e d o f f and f i n a l l y became more o r l e s s c o n s t a n t . C o n t r a r y t o t h e r e p o r t s i n d i c a t i n g i n c r e a s i n g p a t t e r n , P r e s t o n , e t a l . (39) f o u n d t h a t c r y s t a l l i n i t y i n M o n t e r e y p i n e d e c r e a s e d f r o m t h e 5 t h t o t h e 1 5 t h i n c r e m e n t s . Measurements o f l a t e w o o d m i c r o f i b r i l a n g l e s i n D o u g l a s - f i r showed a d e c r e a s i n g t r e n d i n t h e p r o g r e s s i v e i n c r e m e n t s f r o m t h e p i t h o u t w a r d ( 1 3 , 5 1 ) . The h i g h i n i -t i a l v a l u e s o v e r 30 d e g r e e s d e c l i n e d r a p i d l y t o a b o u t 10 d e g r e e s i n 15 y e a r s , and t h e a n g l e was s t i l l d e c l i n i n g t h e r e a f t e r b u t a t a s l o w e r r a t e . S i m i l a r p a t t e r n s were o b s e r v e d i n l o b l o l l y p i n e (38) and s l a s h p i n e ( 1 8 ) , and so were f o r b o t h e a r l y w o o d and l a t e w o o d o f M o n t e r e y p i n e (51) and Norway s p r u c e ( 3 4 ) , w i t h an e x c e p t i o n i n t h e l a t t e r w h i c h showed more o r l e s s c o n s t a n t v a l u e s a f t e r a r a p i d d e c r e a s e i n t h e f i r s t 15 y e a r s . However, l i t t l e v a r i a t i o n s i n b o t h g r o w t h z o n e s were a l s o r e p o r t e d among t h e i n n e r ( l - 1 0 t h ) , m i d d l e ( l l - 2 0 t h ) and o u t e r (21-30th) i n c r e m e n t g r o u p s sampled f r o m f i f t y l o b l o l l y p i n e s ( 3 2 ) . 16 2.2.3 Abn o r m a l wood The p r e s e n c e o f c o m p r e s s i o n wood i s w e l l - k n o w n t o i n t r o d u c e c o n s i d e r a b l e v a r i a t i o n s i n c h e m i c a l and u l t r a -s t r u c t u r a l p r o p e r t i e s o f c o n i f e r o u s wood. C o m p r e s s i o n wood has b e e n c h a r a c t e r i z e d , as compared t o n o r m a l o r ' o p p o s i t e wood, c h e m i c a l l y (8,9) by t h e p r e s e n c e o f a b n o r m a l l y h i g h e r l i g n i n and l o w e r c e l l u l o s e c o n t e n t s , and u l t r a s t r u c t u r a l l y (31,34) by i r r e g u l a r l y l o w e r d e g r e e o f c r y s t a l l i n i t y and g r e a t e r m i c r o f i b r i l a n g l e . O p p o s i t e wood has been compared w i t h c o m p a r a b l e c o m p r e s s i o n wood and r e c o g n i z e d t o d i f f e r f r o m n o r m a l o r s i d e wood. The o p p o s i t e wood o f p i n e s was r e p o r t e d t o have h i g h e r c e l l u l o s e and l o w e r l i g n i n c o n t e n t s t h a n n o r -mal s i d e wood ( 9 , 3 0 ) . I n t h e meantime, o t h e r s t u d i e s (29,49) c l a i m e d t h a t o p p o s i t e wood had t h e same c a r b o -h y d r a t e and l i g n i n c o n t e n t s as had c o m p a r a b l e s i d e wood. 2.2.4 Summary and t h e t r e e u s e d f o r t h e s t u d y T h e r e i s c o n s i d e r a b l e e v i d e n c e s u g g e s t i n g t h a t c h e m i c a l and u l t r a s t r u c t u r a l wood p r o p e r t i e s o f a stem wood e x h i b i t wide r a n g e o f v a r i a t i o n s i n r e g a r d t o g r o w t h zone l e v e l a s w e l l as g r o s s wood l e v e l . The v a r i a b i l i t y i n wood p r o p e r t i e s s h o u l d be w e l l a p p r e c i a t e d and d e f i n e d i n t h e s t u d i e s on t r e e g r o w t h and wood u t i l i z a t i o n . 17 Generally, the patterns for the r a i a l variations i n wood chemical composition and ultrastructure are the same, whether examined with gross increments or i n d i -vidual growth zones. Increasing patterns are for c e l l u -lose content and c r y s t a l l i n i t y , and l i g n i n content and m i c r o f i b r i l angle decrease. Most of the v a r i a t i o n occurs i n the juvenile wood (the f i r s t 15 years), show-ing some degrees of e r r a t i c changes and fluctuations. The v a r i a t i o n i n mature wood i s moderate or l i t t l e , u n t i l eventually opposite trends to those i n juvenile wood are observed, due to overmaturity. These v a r i a t i o n patterns are more apparent with alpha-cellulose and i n d i -vidual growth zones. Under a normal growth condition, l i t t l e d i f f e r -ences i n holocellulose and l i g n i n contents and micro-f i b r i l angle would be expected during the experimental period of seven years i n the moderately mature Douglas-f i r when compared with respective earlywood and l a t e -wood from the two incremental groups of before and after loading. A s l i g h t increase i n alpha-cellulose content and c r y s t a l l i n i t y , however, might be anticipated. Un-doubtedly, the variations including unusual r a d i a l growth and compression wood formation which might be expected i n response to the treatment for the study, are not consi-dered i n the above conclusions. 18 3.0 MATERIALS AND METHODS 3.1 Experimental Tree and Loading Douglas-fir trees i n a second-growth stand at the south-ern part of the University of B r i t i s h Columbia Research Forest, Maple Ridge, B.C. were selected for a study by Adamovich and Walters (1). In 19 65 they applied compressive (loading-down) and t e n s i l e (pulling-up) loads to two trees, respectively, to study the e f f e c t of tree weight on some wood properties, and have described t h e i r experiments i n d e t a i l . Compressive loads were applied by hanging lead weights to the point i n the stem where the lowest l i v i n g branch whorl i n the crown was located. One of the two trees grown under compression loading was examined i n t h i s study. In March, 1966 the tree was 20.1 m (67 ft) i n height, 30 cm (12.0 in) i n DBH, and had 26 growth increments at the height of 0.3 m above ground. The tree stem below the loading point (9.3 m above ground) has been placed under weight equivalent to 362 kg (800 lb) for 7 years. The load was based on an estimated green weight of the crown (1). I t should be noted that the experiment was not designed to test the mechanistic theory of stem-form develop-ment and actual stresses and str a i n s i n the stem were not measured. 19 3.2 Wood Sample Preparations for Chemical Analysis In 1971 the tree was f e l l e d and 8 cm long disks were obtained from i t s stem, st a r t i n g at 0.3 m above the ground with an i n t e r v a l of 1 m distance. Only three disks taken from the heights of stem base (0.3 m), 1 m below (8.3 m) and above (10.3 m) the loading point were examined. From each disk a wood block (6 cm wide) with the growth increments 1960-71 was sectioned from the south and north cardinal d i r e c t i o n s . The outermost 7 increments for the 1965-71 period were designated as af t e r loading, and the 5 increments formed during 1960-64, before loading, respective-l y , and s p l i t into 2 groups (see Table 1). Earlywood and latewood were separated for every increment within each increment group and then collected. The wood p r i o r to 1959 was excluded from the preparations. Thus, a t o t a l of 2 4 samples (3 heights x 2 directions x 2 r a d i a l positions x 2 growth zones = 24) were prepared and ground i n a Wiley m i l l and screened. The fractions from -40 mesh to +80 mesh were used for chemical analyses. The wood meal samples were extracted with ethyl ether, absolute ethanol and f i n a l l y , hot water and conditioned to equilibrium moisture content, sealed i n p l a s t i c bags and stored i n a constant temperature and humidity room. The 20 TABLE 1: WOOD SAMPLE POSITIONS IN THE STEM Height of disk (m) Cardinal Direction (South & North) Radial Position from P i t h Number-in Growth Increment Series (1960 - 1971) Distance (cm) (1960-1965-1971) 0.3 S 20th - 31st 12.1-15.0-17.8 N 21st - 32nd 13.4-16.8-20.6 8.3 S 12th - 23rd 6.8- 9.9-12.1 N 12th - 23rd 7.1-10.4-12.2 10.3 S 9th - 20th 5.4- 8.9-12.4 N 9th - 20th 5.1- 8.1-10.6 21 equilibrium moisture content was checked from time to time throughout the course of analyses and showed r e l a t i v e l y constant values (8.1% for earlywood, 8.3% for latewood). 3.3 Procedures 3.3.1 Holocellulose and alpha-cellulose In a recent review of the l i t e r a t u r e on i s o l a t i o n of the t o t a l wood carbohydrates (26), the Wood Science Procedure AM/H-l/62-r66 (57) based e s s e n t i a l l y on the c h l o r i t e holocellulose method of Wise, et a l . (55) was recommended for the study because of the r e l a t i v e l y mild action of c h l o r i t e on wood carbohydrates and the alleged quantitative r e p r o d u c i b i l i t y . Some advantageous features i n the procedure are: i) uniform mixing and temperature by using a submerged, rotating mixing head, i i ) several determinations can be carr i e d out at the same time, i i i ) elimination of the continuous and laborious several sequential additions of c h l o r i t i n g solution with cert a i n i n t e r v a l s by using a single c h l o r i t e treatment i n a closed system. A s l i g h t l y modified method from the procedure was used and i s given below: 22 0.500 g of wood meal (prepared as described above), 7 ml of acetate buffer solution (60 ml acetic acid and 1.2 g sodium hydroxide per l i t e r ) and 3.0 ml of 20% sodium c h l o r i t e solution are placed i n a polyethylene tube (20 ml capacity) and the tube i s t i g h t l y capped. A mixture of c h l o r i t i n g and buffer solution i n the same pro-portion should give an i n i t i a l pH 3.2-3.8. Six tubes prepared thus are fixed to a mixing head. The mixing head i s submerged i n a water bath (50 ± 2°C), being held i n an i n c l i n e d position and rotated slowly. After c h l o r i t i n g for 2 0 hr, the tubes are transferred to an ice water bath (5°C). Contents i n the tubes are washed i n Pyrex f i l t e r i n g crucibles (tared sintered glass, coarse porosity, 30 ml capacity) by using 200 ml acetic acid under gentle suction and 20 ml of acetone (gravity-drain) and the washing i s con-cluded by applying suction for 3 min. The chlor-i t e holocellulose i n the crucibles i s conditioned i n a constant temperature and humidity room for at least 24 hr. Two of the four holocelluloses prepared for each sample (see Appendix) are oven-dried at 102 ± 2°C (no more than 4 hr) to deter-mine the equilibrium moisture content upon which the calculations of holocellulose and alpha-23 c e l l u l o s e y i e l d s are based. No corrections for residual l i g n i n i n the chlor-i t e holocellulose were made, although the inventor of the c h l o r i t e procedure i n s i s t e d on the need for the cor-rection. There are reports of c h l o r i t e - r e s i s t a n t l i g n i n (17), modified l i g n i n during c h l o r i t i n g (4,7) and d i f f i -c u l t i e s i n removing the l i g n i n i n intimate association with carbohydrates (2). These reports indicated doubts on the r e l i a b i l i t y of an accurate determination of r e s i -dual l i g n i n content i n the c h l o r i t e holocellulose. On the other hand, i t has been recognized that the loss of carbohydrates due to the degradation and depolymerization by oxidative action of a c i d i f i e d c h l o r i t e i s quite pos-s i b l e . Perhaps the correction i s not worth-while i n a study of t h i s magnitude. Rather, a rapid, simple and reproducible procedure was demanded. Moreover, the l i g -nin procedure adopted for the study i s not suitable for residual l i g n i n corrections because wood l i g n i n treated with c h l o r i t e gives no maxima at 2 80 nm i n the UV-spec-t r a (23,41) . Since the selected holocellulose method was ex-pected to give a reasonable r e p r o d u c i b i l i t y , a p r e l i m i -nary examination of the method was made to determine experimental precision obtainable with the method. The r e s u l t showed that 4 observations for each sample would 24 be r e q u i r e d f o r t h e d e s i r e d p r e c i s i o n (tQ.o5' S x = °«588, the e s t i m a t e t o be w i t h i n 0.8% o f t h e p o p u l a t i o n mean) (App e n d i x ) . F o r a l p h a - c e l l u l o s e d e t e r m i n a t i o n o f t h e remain-i n g two c h l o r i t e h o l o c e l l u l o s e (never o v e n - d r i e d ) , the m o d i f i e d p r o c e d u r e by E r i c k s o n (12) from TAPPI S t a n d a r d T 203 m-58 (48) was f o l l o w e d , e x c e p t u s i n g b e a k e r s (50 ml c a p a c i t y ) i n s t e a d o f h i s ' s p e c i a l l y d e s i g n e d w a t e r b a t h ' f o r h o l d i n g c r u c i b l e s . 3.3.2 . L i g n i n E a r l i e r , Johnson, e t auL. (23) d e s c r i b e d an a c e t y l bromide method f o r t h e q u a n t i t a t i v e d e t e r m i n a t i o n o f wood l i g n i n . The t e c h n i q u e has been re-examined and s l i g h t l y m o d i f i e d by Wu and W i l s o n ( 5 9 ) . The m o d i f i e d p r o c e d u r e was f o l l o w e d i n d i s s o l v i n g t h e e x t r a c t e d wood meal w i t h a c e t y l bromide i n a c e t i c a c i d and measuring the absorbance o f t h e r e s u l t i n g s o l u t i o n a t 2 82 nm on a Beckman DU s p e c t r o p h o t o m e t e r . The l i g n i n c o n t e n t was de t e r m i n e d from t h e measured absorbance on a s t a n d a r d ( K l a s o n l i g n i n o f P a c i f i c s i l v e r f i r ) c a l i b r a t i o n c urve p r e p a r e d by them. A p r e l i m i n a r y e x a m i n a t i o n o f the t e c h n i q u e showed t h a t two o b s e r v a t i o n s f o r each sample would be r e q u i r e d f o r e s t i m a t i n g t h e mean l i g n i n v a l u e s a t t h e d e s i r e d p r e c i s i o n ( t Q Q 5, S-..:= 0.374, D = 0.8%) 25 (Appendix). 3.3.3 C r y s t a l l i n i t y of the c h l o r i t e holocellulose The c h l o r i t e holocellulose obtained for holo-c e l l u l o s e determinations of the samples was conditioned to a constant moisture content and used for determining the c r y s t a l l i n i t y . Rectangular (1.3 x 3.2 cm) p e l l e t s were prepared by compressing 0.30 g of the holocellulose and 1 drop of glue (a solution of 10 ml Duco cement i n 10 0 ml amyl acetate) i n a ' s p e c i a l l y designated die' under a pressure of 106 kg/cm2 (1500 l b / i n 2 ) for 1 min. The p e l l e t s were conditioned i n a constant temperature and humidity room. The average thickness was 1.38 mm (range, 1.23-1.75) and 1.26 mm (range, 1.06-1.46) for earlywood and latewood, respectively. After placing a p e l l e t i n an aluminum specimen holder, the specimen was scanned over the range 20 = 6 to 30° i n a P h i l l i p s X-ray diffractometer equipped with a Cu X-ray ( n i c k e l - f i l t e r e d ) . The diffractometer was operated at 36 kV and 14 mA and the scanning speed was 1° per min with a rate of cps = 4 x 10 2 and time constant of 4 sec for the counter. Detailed descrip-ti o n of the scanning procedure was given elsewhere (11). For evaluating the produced X-ray diagrams, the c r y s t a l -l i n i t y index proposed by Segal, et a l . (45) was computed. 26 3.3.4 M i c r o f i b r i l a n g l e An X-ray t e c h n i q u e f o r e s t i m a t i n g c e l l u l o s e m i c r o f i b r i l a n g l e was d e s c r i b e d r e c e n t l y by E l - O s t a , e t a l . (10) and t h i s was adopted f o r t h e s t u d y . S i x wood b l o c k s o b t a i n e d as d e s c r i b e d f o r c h e m i c a l a n a l y s e s (3 h e i g h t s x 2 c a r d i n a l d i r e c t i o n s ) were f r e e z e - d r i e d . Specimen h a v i n g d i m e n s i o n s o f 1.5 mm f o r ear l y w o o d and 1.0 mm f o r l a t e w o o d , r a d i a l l y , 1.0 cm t a n g e n t i a l l y and l o n g i t u d i n a l l y , were machined on a micro-saw from each growth i n c r e m e n t . The specimens were s t o r e d i n t e f l o n v i a l s p r i o r t o X-ray r a d i a t i o n . The specimens were mounted on a P h i l l i p s 1009 X-ray d i f f r a c t o m e t e r equipped w i t h a P h i l l i p s 1078 t e x -t u r e goniometer and scanned a c c o r d i n g t o t h e p r o c e d u r e . The i n t e n s i t y p a t t e r n s o f X-ray d i f f r a c t i o n were a n a l -y z e d by a computer program ( 1 4 ) . U n l i k e t h e X-ray t e c h -n i q u e based on measurement o f the d i f f r a c t i o n i n t e n s i t y p a t t e r n on t h e p a r a t r o p i c ( 0 0 2 ) , (101) and (101) p l a n e s , t h i s method d i r e c t l y g i v e s t h e average o r i e n t a t i o n o f c e l l u l o s e c r y s t a l l i t e s i n wood by measuring d i f f r a c t i o n s from t h e d i a t r o p i c (040) p l a n e . A computer program i s used f o r r e s o l v i n g t h e (040) d i f f r a c t i o n i n t e n s i t y p a t -t e r n and c a l c u l a t i n g the mean o r i e n t a t i o n a n g l e . 27 4.0 OBSERVATIONS AND DISCUSSION 4.1 Growth Increment Before Loading Individual growth increment c h a r a c t e r i s t i c s from the p i t h throughout the tree's l i f e were measured by the s t a f f at the Western Forest Products Laboratory, Department of the Environment, Vancouver, on an X-ray densitometry system using a computerized tree growth increment scanning densitometer. The technique has been described elsewhere (16,36,37). Data on growth increment width and density, out of the measurements, are presented i n Figures 2 and 3 to show t h e i r variations i n the stem. The figures reveal that systematic v a r i a t i o n patterns for increment width and density i n a stem can be attained when the increment c h a r a c t e r i s t i c s are plotted by the calendar year of formation. In general, however, the density of earlywood remains constantly low with the years. The distinctiveness of 0.3 m height i s made evident i n the great f l u c t u a t i o n of i t s increment width and the smallest difference i n density between earlywood and latewood. The height has the highest density for earlywood and lowest for latewood. With regards to height and cardinal d i r e c t i o n , there are no consistent v a r i a t i o n patterns although some variations are apparent. 28 Figure 2. Variation i n growth increment width at d i f f e r e n t stem heights before loading, with reference to cardinal d i r e c t i o n s . Calendar year F i g u r e 3. V a r i a t i o n i n i n c r e m e n t a l g r o w t h zone d e n s i t y a t d i f f e r e n t stem h e i g h t s b e f o r e l o a d i n g , w i t h r e f e r e n c e t o c a r d i n a l d i r e c t i o n s . » » • ! • • • • | . i . . I . . . . I . . . • 19^5 1950 1955 I960 C a l e n d a r y e a r 30 Thus, during the early stage of growth the tree formed increments having r e l a t i v e l y low density, while increasing r a d i a l increment up to a maximum i n the tree's l i f e t i m e . This young growth was terminated i n 1954 as the age became r e l a t i v e l y mature. The juvenile wood formation during about 15 years was followed by 3 years of t r a n s i t i o n to mature growth. In the t r a n s i t i o n period, substantial changes took place. Increment width became much narrower and latewood den-s i t y increased substantially. Beyond t h i s point, namely i n the mature growth, the variations were very l i t t l e i n both increment width and density. Meanwhile, earlywood increment has maintained i t s i n i t i a l l y low density to the year 196 4. These growth patterns observed i n the moderately mature Douglas-fir are i n agreement with those reported i n the l i t -erature, i n which l i t t l e or moderate changes i n wood proper-t i e s during mature wood formation were indicated. 4.2 Wood Formation After Loading The influence of a r t i f i c i a l compression loading on wood formation was evaluated by comparing wood c h a r a c t e r i s t i c s of the 1960-64 increment group (before loading) with those of the succeeding 1965-71 increments (after loading). Simul-taneously, differences i n the wood formed below and above the plane of load were also examined. 31 The l o a d would have f o r c e d t h e stem p o r t i o n below t h e p o i n t o f l o a d i n t o m a i n l y f u r t h e r l o n g i t u d i n a l c o m p r e s s i o n , i n a d d i t i o n t o t h e t r e e ' s own w e i g h t . The compre s s i o n s t r e s s due t o t h e l o a d p l u s t r e e ' s own w e i g h t was t r a n s m i t t e d t o e v e r y c r o s s s e c t i o n t h r o u g h o u t t h e l e n g t h o f t h e l o a d e d stem p o r t i o n . These assumptions may be j u s t i f i e d by the f a c t t h a t the l o a d i n g was a p p l i e d i n such a way t o be p a r a l l e l t o t h e stem a x i s and t h e r a t i o o f l e n g t h t o d i a m e t e r f o r t h e l o a d e d stem was s m a l l enough not t o i n t r o d u c e a ben d i n g moment. T h e r e f o r e , t h e i n c r e a s e d c o m p r e s s i o n s t r e s s by t h e l o a d i n g on each c r o s s s e c t i o n would have been g r e a t e r w i t h a s c e n d i n g h e i g h t s up t o t h e g r e a t e s t on t h e p l a n e o f l o a d i n g . 4.2.1 Growth i n c r e m e n t w i d t h and d e n s i t y A r e d u c t i o n o f a p p r o x i m a t e l y 50% i n t h e e a r l y w o o d i n c r e m e n t a t t h e h e i g h t s below t h e l o a d i s o b s e r v e d i n th e two y e a r s f o l l o w i n g l o a d i n g ( F i g . 4 ) . T h i s c o n t r a s t s s h a r p l y w i t h almost no changes i n comparable l a t e w o o d , w h i c h g i v e r i s e t o a c o n s i d e r a b l e i n c r e a s e i n t h e p e r -centage o f latewood. I n t h e same p e r i o d , t h e h e i g h t o f 1 m above t h e l o a d shows s l i g h t l y d e c r e a s e d i n c r e m e n t . Reduced i n c r e m e n t due t o a r t i f i c i a l l y i n c r e a s e d com-p r e s s i o n s t r e s s e s has been i n d i c a t e d i n t h e s t a y e d stems and a l s o the stem p a r t w i t h a d i s c o n t i n u i t y . 32 F i g u r e 4. Growth i n c r e m e n t w i d t h a t d i f f e r e n t stem h e i g h t s b e f o r e and a f t e r l o a d i n g . 5.0 -4.0 5.0 -2.0 1.0 -" 1 1 y 10.3 m EW (earlywood) -rH & c cu e cu rH u c •H Xi •P o u u 5.Or 4.0 -5.0 -2.0 -1.0 -6.Op 5.0 4.0-5.0 2.0 1.0 I Stem d i r e c t i o n s South N o r t h The arrow i n d i c a t e s t h e . f i r s t y e a r o f l o a d i n g . 1961 '65 '65 '67 '69 '71 C a l e n d a r y e a r The v a r i a t i o n s i n wood d e n s i t y s i n c e t h e l o a d i n g i s shown i n F i g u r e 5 . A l t h o u g h the changes are not con-s i s t e n t w i t h r e s p e c t t o stem d i r e c t i o n and y e a r , i n -c r e a s e d d e n s i t y i s n o t i c e a b l e i n t h e l o a d e d stem. I n c o mparison, no a p parent changes are o b s e r v e d a t t h e h e i g h t o f 1 m above t h e l o a d . The growth i n c r e m e n t s formed under suddenly i n -c r e a s e d c o m p r e s s i o n s t r e s s e s a r e c h a r a c t e r i z e d by a n a r r ower i n c r e m e n t and p r o b a b l y an i n c r e a s e d d e n s i t y . The magnitude o f t h e changes i n i n c r e m e n t i s much g r e a t -e r i n e a r l y w o o d t h a n i n latewood. T h i s d i f f e r e n c e may be e x p l a i n e d by t h e i n h e r i t e d d i f f e r e n c e s i n t h e i r r e -s p e c t i v e s t r u c t u r e s . E a r l y w o o d t r a c h e i d s n o r m a l l y t e n d t o have l a r g e r l u m i n a , t h i n n e r w a l l s and c o n s e q u e n t l y l o w e r d e n s i t y , as compared t o t h o s e o f l a t e w o o d . When wood i s formed under a s t r e s s , the f o l l o w i n g s t r a i n i s dependent n o t o n l y on t h e s i z e o f t h e s t r e s s a p p l i e d but a l s o on t h e s t i f f n e s s o f each component. From the s t r u c t u r e s o f growth zones, t h e e a r l y w o o d i s e x p e c t e d t o show g r e a t e r s t r a i n and perhaps e q u a l l y g r e a t e r r e s ponse t o t h e same s t r e s s l e v e l . I t i s , i n f a c t , s u r p r i s i n g t h a t l a t e w o o d shows no r e s p o n s i v e changes i n i t s w i d t h . T h i s s u g g e s t s t h a t t h e s i z e o f l o a d i n g was not g r e a t enough t o a f f e c t t h e w i d t h of l a t e w o o d i n c r e m e n t , a l t h o u g h some changes a r e i n d i c a t e d i n i t s d e n s i t y . I t 34 Figure 5. Incremental growth zone density at d i f f e r e n t stem heights before and afte r loading, with reference to cardinal directions. 0.80 .70 -.60 -.50 .40 .30 m E o \ tn -P •H CO c Q .20 0.80r .70 ,6o\-.50 .40 .30 .20 North 0.3 m above the ground 8.3 m above the grjound 10.3 m above the grpund .yf\-— Latewood >odN-^ N,/ \7 \ J L J I South Latewood The arrow i n d i -cates the f i r s t year of loading, ' — — _ Earlywood Calendar year 35 i s possible, however, that when the magnitude of stress i s great enough, the width of latewood zone w i l l be changed i n much the same way as earlywood. Reduced r a d i a l width i n both earlywood and latewood increments i n the same proportion have been reported i n the stayed l o b l o l l y pine stems (6) and the zone of discontinuity i n a Norway spruce stem (47), where presumably much greater compression stresses were a r t i f i c i a l l y introduced. Even i n earlywood, a recovery from the d r a s t i c changes i s indicated after two years of loading. The recovery i s more evident at the height of 0.3 m than that of 1 m below the load. I t i s quite l i k e l y that growth increments during the recovery period r e f l e c t changes i n stem form and tree weight d i s t r i b u t i o n . In other words, the d i s t r i b u t i o n a l pattern of compression stress i n the stem has changed with time as wood was d i s t r i b u t e d i n response to loading. During the consecutive two years following loading, the reduction i n volume growth was accompanied by comparable decline i n weight growth as well (Table 2). Obviously, t h i s suggests that more, probably p r e f e r e n t i a l l y , wood was d i s t r i b u t e d i n the stem portion above the load, causing a higher wood weight concentration i n the top of the stem. Table 2. Growth increment weight* i n the compressed Douglas-fir stem before and a f t e r loading. Height i n Before After the stem Growth Cardinal (m) Zone Direction 1961 1962 1963 1964 1965 1966 1967 1968 0. 3 EW South North 11. 3 15.9 12.4 16.7 13.6 17.3 10.0 17.3 10.2 14.7 5.5 8.8 7.9 20. 3 9.8 20.1 LW South North 14.6 13.3 8.2 7.6 10. 3 9.7 7.1 5.5 9.1 10.8 6.7 9.5 9.0 11.5 8.3 11. 7 8. 3 EW South North 3.9 4.9 5.0 6.0 5.4 6.1 6.4 7.6 5.4 5.9 4.5 4.6 5.1 5.6 4.9 4.8 LW South North 4.1 6.5 3.7 6.0 4.4 7.2 4.0 5.9 4.1 6.5 3.9 5.7 5.3 5.8 5.8 6.2 9. 3 The point of loading 10. 3 EW South North 4.1 4.6 5.5 4.5 6.3 4.0 6.9 5.4 6.9 4.2 6.7 4.7 7.3 4.7 6.8 4.1 LW South North 4.9 2.8 4.4 2.9 5.0 4.2 5.4 3.7 4.6 3.4 6.7 4.7 6.6 4.0 7.7 4.4 *0ven-dry weight i n grams for 1 cm thick disk *The data presented here were measured by the s t a f f at the Western Forest Products Laboratory. EW - earlywood, LW - latewood 37 Observations on the wood d i s t r i b u t i o n i n response to loading suggest that the stress pattern i s ever-changing and also that stem form i s b a s i c a l l y shaped by the stress pattern. 4.2.2 Chemical composition Results of comparative analyses of the wood form-ed before and af t e r loading are summarized i n Table 3. Analysis of variance and multiple range test for the results are given i n Table 4 f which reveal that growth zone, height, loading, cardinal d i r e c t i o n , and some of t h e i r interactions are s i g n i f i c a n t (over the 95% proba-b i l i t y level) factors i n the v a r i a b i l i t y of chemical composition of the stem. The mean holocellulose, alpha-c e l l u l o s e and l i g n i n y i e l d s from' the stem are 73.4% (range 70.6-76.0; standard deviation, 0.177), 43.9%' (37.7-48.7; 0.344) and 28.2% (24.5-32.6; 0.24), respec-t i v e l y . These values were calculated on the basis of the re s u l t s for in d i v i d u a l growth zones. Summations of holocellulose and l i g n i n y i e l d s , which were determined separately, are an average of 101.6% (range 99-104). This variable r e s u l t i s possi-bly due to some de f i c i e n c i e s of the methods adopted for the present study. P a r t i c u l a r l y the c h l o r i t i n g method tends to y i e l d higher values (26). I t should be, there-T a b l e 3. Chemical c o m p o s i t i o n o f t h e l o a d i n g . compressed Douglas i - f i r stem wood b e f o r e and a f t e r H e i g h t i n the stem (m) Growth Zone C a r d i n a l D i r e c t i o n H o l o c e l l u l o s e A l p h a - c e l l u l o s e L i g n i n B e f o r e A f t e r B e f o r e A f t e r B e f o r e A f t e r 0.3 EW South N o r t h 70.6 71.3 72.5 71.4 41. 4 41. 8 43. 8 42.1 29.7 30.6 27.4 29.1 LW South N o r t h 72.9 72.6 73.9 73.9 47.4 44. 8 48.1 46.5 26.4 29.6 25.3 26.6 8.3 EW South N o r t h 73.3 73.0 73.6 73. 7 41.7 41.2 42.6 42.8 31.0 31.1 28.2 28.8 LW South N o r t h 75.5 75.1 75.7 75.9 47.8 47.3 48.6 48.7 25.5 26.3 24.5 25.9 9.3 The p o i n t o f l o a d i n g 10.3 EW South N o r t h 70.7 72.4 71. 8 73.4 37.7 38.8 38.4 29.3 32.6 31.9 29.7 30. 4 LW South N o r t h 73.9 75.4 72. 8 76.0 45.7 46.6 44.2 47.6 27.2 26.5 27.5 24.4 i ) a l l p e r c e n t a g e y i e l d s a r e based on oven-dry w e i g h t of e x t r a c t e d wood. i i ) each v a l u e i s t h e mean p e r c e n t a g e y i e l d on n = 4 ( h o l o c e l l u l o s e ) or n = 2 ( a l p h a - c e l l u l o s e , l i g n i n ) o b s e r v a t i o n s . i i i ) EW - e a r l y w o o d , LW - la t e w o o d 39 T a b l e 4. A n a l y s i s o f v a r i a n c e and Duncan's m u l t i p l e range t e s t f o r t h e c h e m i c a l c o m p o s i t i o n d a t a , and chemi-c a l c o m p o s i t i o n o f growth zones and h e i g h t s b e f o r e and a f t e r l o a d i n g . A. A n a l y s i s o f v a r i a n c e F v a l u e s Source DF H o l o c e l l u l o s e A l p h a - c e l l u l o s e L i g n i n H e i g h t (H) 2 42.68** 130.14** 16.96** D i r e c t i o n (D) 1 9.49** 0.05 11.38** EW v s . LW (E) 1 138.91** 1628.45** 578.11** B e f o r e v s . A f t e r l o a d i n g (B) 1 12.28** 38.51** 121.56** H x D 2 14.46** 32 .28** 26.36** H x E 2 0.62 37.56** 24.63** H x B 2 1.40 6.15** 0.73 D x E 1 0.49 0.03 0.03 D x B 1 0.23 1.69 0.26 E X B 1 1.09 1.07 10.99** H x D x E 2 0.42 5.59* 9.02** H x D x B 2 1.74 3.74* 1.49 H x E x B 2 1.51 0. 81 3.61* D x E X B 1 3.61 9.12** 11.53** H x D x E x B 2 0.75 2.17 3. 7.3* E r r o r T o t a l DF 72 95 24 47 24 47 * S i g n i f i c a n t a t P = .05 ** S i g n i f i c a n t a t P = .01 Table 4. B. Duncan's multiple range test Chemical Component Height i n the (m) stem Growth Zone Before After Direction 0.3 8.3 10.3 EW LW Loading South North Holocellulose 72.4 74.5 73. 3 72.3 74.5 73.1 73.7 73.1 73.7 Alpha-cellulose 44.4 45.1 42.3 40.9 46. 9 43.5 44.4 43.9 4 3.9 Lignin 28.1 27.7 28.8 30.1 26.3 29.0 27.3 27.9 28.4 i) range for alpha = .05 i i ) any two means d i f f e r s i g n i f i c a n t l y , homogeneous subjects 41 T a b l e 4. C. C h e m i c a l c o m p o s i t i o n o f growth zones and h e i g h t s i n th e stem b e f o r e and a f t e r l o a d i n g . H o l o c e l l u l o s e A l p h a - c e l l u l o s e . L i g n i n B e f o r e A f t e r B e f o r e A f t e r B e f o r e A f t e r Growth zones Ea r l y w o o d Latewood H e i g h t s i n t h e stem (m) 0.3 8.3 9.3 10.3 71.9 72.7 74.2 74.7 71.9 72.9 74.2 74.7 The p o i n t o f 73.1 74.5 40.4 . 41.5 46.5 47.3 43.7 45.1 44.5 45.7 l o a d i n g 42.2 42.4 31.2 28.9 26.9 25.7 29.1 27.1 28.5 26.9 2 9.6 2 8.0 42 f o r e , p o i n t e d o ut t h a t t h e d a t a r e p o r t e d i n t h e s t u d y a r e n ot a b s o l u t e , b u t r a t h e r r e a s o n a b l y r e p r o d u c i b l e . As a r e s u l t , s m a l l d i f f e r e n c e s can not be d e t e c t e d o r showed w i t h any c e r t a i n t y . F u r t h e r m o r e , some d i f f i c u l t i e s l i e i n e v a l u a t i n g t h e e f f e c t o f l o a d i n g on wood c h e m i c a l c o m p o s i t i o n un-l e s s t h e o b s e r v e d v a r i a t i o n s a r e d e f i n i t e l y c o n s i s t e n t and g r e a t . U n f o r t u n a t e l y , the m a n i f e s t response i n t h e two y e a r s i m m e d i a t e l y f o l l o w i n g t r e a t m e n t , as shown i n i n d i v i d u a l growth i n c r e m e n t s , was somewhat d i s c o u n t e d by s a m p l i n g t h e seven c o n s e c u t i v e i n c r e m e n t s formed a f t e r l o a d i n g . N o n e t h e l e s s , t h e r e a r e s t r o n g i n d i c a t i o n s t h a t under i n c r e a s e d c o m p r e s s i o n s t r e s s , h o l o c e l l u l o s e and a l p h a - c e l l u l o s e p e r c e n t a g e s i n c r e a s e , w h i l e t h a t o f l i g n i n d e c l i n e s . A. Ear l y w o o d and Latewood I n b o t h growth zones (growth zone x l o a d i n g ) an i n c r e a s e d c e l l u l o s e and a d e c r e a s e d l i g n i n c o n t e n t are apparent. The magnitude o f the changes i s g r e a t e r i n earl y w o o d (EW) t h a n i n l a t e w o o d (LW), w h i c h i s i n a c c o r -dance w i t h t h e r e s u l t on growth i n c r e m e n t . The two i n c r e m e n t a l growth zones d i f f e r m arkedly i n t h e i r c h e m i c a l c o m p o s i t i o n s , as i n t h e i r a n a t o m i c a l 43 c h a r a c t e r i s t i c s . They p r e s e n t t h e most s i g n i f i c a n t d i f f e r e n c e among t h e v a r i a b l e s examined i n t h e s t u d y and t h e d a t a f o r them agree w i t h t h o s e r e p o r t e d p r e v i o u s l y . On t h e a v e r a g e , th e d i f f e r e n c e i n h o l o c e l l u l o s e y i e l d s i s 2.2% h i g h e r f o r LW. The d i f f e r e n c e i n t h e i r a l p h a -c e l l u l o s e c o n t e n t s i s even h i g h e r , w i t h 6.0%. The h i g h e r c e l l u l o s e c o n t e n t f o r LW i s a s s o c i a t e d w i t h a lower l i g -n i n c o n t e n t . The EW y i e l d s 3.8% h i g h e r l i g n i n . A h i g h -e r l i g n i n c o n t e n t f o r EW i s due p a r t l y t o a g r e a t e r p r o -p o r t i o n o f the m i d d l e l a m e l l a ( r i c h i n l i g n i n ) o f EW sub-s t a n c e per u n i t w e i g h t ( 4 0 ) , but m o s t l y t o the e v i d e n c e t h a t the l i g n i n c o n c e n t r a t i o n i n t h e secondary w a l l i s h i g h e r i n EW t h a n i n LW ( 5 6 ) . I t i s i n t e r e s t i n g t o note t h a t t h e s e d i f f e r e n c e s between growth zones a r e t h e g r e a t e s t a t the h e i g h t o f 10.3 m and the s m a l l e s t a t 0.3 m. T h i s i n d i c a t e s t h a t t h e d i f f e r e n c e i n c h e m i c a l compo-s i t i o n between i n c r e m e n t a l growth zones of D o u g l a s - f i r becomes g r e a t e r w i t h a s c e n d i n g h e i g h t s i n t h e stem, even though t h r e e h e i g h t s a r e not enough t o g e n e r a l i z e t h e tendency f o r t h e e n t i r e stem. The s m a l l e s t d i f f e r -ence found a t 0.3 m i s c o n s i s t e n t w i t h t h e r e s u l t f o r d e n s i t y o f t h e h e i g h t . B. H e i g h t s i n t h e Stem The t e n d e n c i e s o f i n c r e a s i n g i n c e l l u l o s e and 44 decreasing i n l i g n i n are also indicated at a l l the three heights (height x loading), yet greater changes are found i n the stem portion placed under the load. In comparison, the height of 1 m above the load exhibits a l i t t l e increase i n ce l l u l o s e content. Although the v a r i a b i l i t y of chemical composition i n regard to height i n the stem i s not so great as the growth zone, there are some differences among the heights studied. The highest holocellulose value i s found at the height of 8.3 m, while 0.3 m has the lowest value. With regard to alpha-cellulose, the heights of 8.3 and 0.3 m show a higher percentage y i e l d than 10.3 m. Max-imum l i g n i n i s yielded from 10.3 m and minimum from 8.3 m. The differences i n holocellulose, alpha-cellulose, and l i g n i n contents between maximum and minimum values are 2.1, 2.8 and 1.1% respectively. C. Growth Zones at Different Heights The e f f e c t s of loading appear to be unique, when examined with the in d i v i d u a l growth zones along the heights (growth zone x height x loading). Both growth zones of the stem part under the load show much greater variations than anticipated i n the adjacent two increment groups of a normal mature wood. 45 Of a l l the v a r i a t i o n s s i n c e l o a d i n g t h e most noteworthy i s a t 1 m above t h e l o a d . E x c e p t i o n a l l y s u b s t a n t i a l d e c r e a s e s i n h o l o - and a l p h a - c e l l u l o s e y i e l d s and a s l i g h t i n c r e a s e i n l i g n i n c o n t e n t are i n d i -c a t e d i n the LW a f t e r l o a d i n g , s p e c i f i c a l l y on t h e s o u t h s i d e o f t h e h e i g h t . T h i s i s a r a t h e r u n u s u a l s i t u a t i o n i n a stem development, i n w h i c h the o t h e r w i s e normal p a t t e r n s o f i n c r e a s i n g i n c e l l u l o s e and d e c l i n i n g i n l i g n i n c o n t e n t would be e x p e c t e d . The u n u s u a l growth p a t t e r n can be found i n c o m p r e s s i o n o r overmature wood. However, the p o s s i b i l i t i e s a re q u i t e u n l i k e l y , because o f t h e age o f t h e t r e e and t h e o b s e r v e d normal growth increment w i d t h and d e n s i t y . The comparable EW and b o t h growth zones on t h e n o r t h stem p a r t o f t h e h e i g h t show a s i m i l a r change t o t h a t d e s c r i b e d f o r the l o a d e d stem p a r t . P r o b a b l y t h e s e d i f f e r e n c e s i n r e s p o n d i n g t o the l o a d i n r e g a r d s t o growth zones and c a r d i n a l d i r e c t i o n s r e s u l t e d from t h e confounded, complex r e s p o n s e s o f t h e t r e e t o t h e e n v i r o n m e n t , b u t no c l e a r e x p l a n a t i o n o f the r e s u l t s can be g i v e n . D. D i r e c t i o n s i n t h e Stem G e n e r a l l y , i n t h e stem ( d i r e c t i o n x l o a d i n g ) , no s i g n i f i c a n t v a r i a t i o n s are o b s e r v e d s i n c e l o a d i n g . There a r e , however, a v a r i e t y o f v a r i a t i o n s w i t h t h e s o u t h and n o r t h d i r e c t i o n s i n t h e r e s p o n s e s o f i n d i v i d u a l growth 46 zones a t d i f f e r e n t , h e i g h t s , as mentioned i n the p r e c e d -i n g s e c t i o n . The d i f f e r e n c e s i n wood f o r m a t i o n between d i r e c t i o n s have been c l a i m e d t o be due t o wind a c t i o n . 4.2.3 C r y s t a l l i n i t y and m i c r o f i b r i l a n g l e R e s u l t s o f c r y s t a l l i n i t y , e x p r e s s e d by an X-ray c r y s t a l l i n i t y i n d e x , a r e i n c l u d e d i n T a b l e 5. M u l t i p l e range t e s t f o r the r e s u l t s (Table 6) show no s i g n i f i c a n t changes by t h e l o a d i n g , but c l o s e i n s p e c t i o n o f T a b l e 5 d i s c l o s e s d e f i n i t e changes and a l s o an u n u s u a l v a r i a t i o n . I n b oth c a r d i n a l d i r e c t i o n s , an i n c r e a s e d c r y s t a l l i n i t y i s o b s e r v e d i n t h e stem under t h e l o a d , e x c e p t f o r t h e LW a t 0.3 m h e i g h t which shows a reduced c r y s t a l l i n i t y . The r e d u c t i o n i n c r y s t a l l i n i t y a f t e r l o a d i n g i s a l s o found f o r b o t h growth zones a t t h e h e i g h t above t h e l o a d (10.3 m). These o p p o s i t e t r e n d s e x p l a i n the s t a t i s t i -c a l l y i n s i g n i f i c a n t changes. I t i s n o t e d t h a t above the l o a d more pronounced r e d u c t i o n i n c r y s t a l l i n i t y has r e s u l t e d i n LW th a n i n EW. L i n e a r r e g r e s s i o n s o f c e l l u l o s e m i c r o f i b r i l a n g l e on age ( c a l e n d a r y e a r ) a r e p r e s e n t e d i n F i g u r e 6. The e f f e c t o f l o a d i n g on t h e a n g l e i s i n d i c a t e d i n the EW o f the h e i g h t s a t 0.3 m above ground and 1 m above t h e l o a d , but t h e v a r i a t i o n s a r e not c o n s i s t e n t w i t h r e s p e c t t o d i r e c t i o n s o f the h e i g h t s . S l i g h t l y l a r g e r and s m a l l e r 47 T a b l e 5. C r y s t a l l i n i t y o f the compressed D o u g l a s - f i r stem wood b e f o r e and a f t e r l o a d i n g . H e i g h t i n - C r y s t a l l i n i t y i n d e x (%) the stem Growth C a r d i n a l (m) Zone D i r e c t i o n B e f o r e A f t e r 0.3 EW South 61. 3 63.1 N o r t h 60.7 61.6 LW South 64.0 63.2 N o r t h 63.1 62.0 8.3 EW South 64.8 65.2 N o r t h 63.2 64.6 LW South 66.5 68.3 N o r t h 67.3 68.0 9.3 The p o i n t o f l o a d i n g 10. 3 EW South 61.4 60. 7 N o r t h 63.3 63.2 LW South 66. 7 62.9 N o r t h 67.7 66.7 i ) each v a l u e i s . t h e mean p e r c e n t h o l o c e l l u l o s e c r y s t a l -l i n i t y o f two o b s e r v a t i o n s . i i ) EW - e a r l y w o o d , LW - latewood Table 6. Duncan's multiple range test for the c r y s t a l l i n i t y data, and c r y s t a l l i n i t y of growth zones and heights before and aft e r loading. A. Duncan's multiple range te s t Height i n the stem (m) Growth zone Before After Direction 0.3 8.3 10.3 EW LW Loading South North 62.4 66.0 64.1 62 . 8 65.5 64.2 64.1 64.0 64.3 i) range for alpha = .05 i i ) any two means d i f f e r s i g n i f i c a n t l y , homogeneous subjects. 00 49 Table 6 B. C r y s t a l l i n i t y of growth zones and heights i n the stem before and a f t e r loading. C r y s t a l l i n i t y index (%) Before After Growth zones Earlywood 6 2.5 6 3.1 Latewood 65.9 6 5.2 Heights i n the stem (m) 0. 3 62.3 62.5 8.3 65.5 66.5 9.3 The point of loading 10.3 64.8 63.4 50 Figure 6. M i c r o f i b r i l angle of incremental growth zone at d i f f e r e n t stem heights before and afte r loading, with reference to cardinal d i r e c t i o n s . A. North 20 r IT G •H U Xi •H o S-l u •H a 10 r 20 104-CU cu S-l cu « 0 50 r 40 50 20 f-10 10. 3 m -Xr-^ Earlywood 0 Latewood -K- ft-. -o u a 8.3 m X The arrow indicates the f i r s t year of loading. 0.3m * x -i 1 1 1 (. 1 -< 1 ' !-1961 »6j '65 '67 '69 Calendar year '71 . Continued • Continued B. South 20 10.3 m X e x Earlywood 0 Latewood 101- x QJ 20 10 4 4-8.3 m The arrow indicates the f i r s t year of loading. 4 40 r 30 20 i-104-0.3 m » e -1 . t 1 U 1961 '65 '65 '67 Calendar year '69 '71 52 a n g l e s a r e o b s e r v e d on the s o u t h s i d e of 10.3 m and t h e n o r t h s i d e o f 0.3 m h e i g h t , r e s p e c t i v e l y . 4.3 About the Experiment A r t i f i c i a l c o m p r e s s i o n l o a d i n g was employed i n t h i s s t u d y t o e v a l u a t e t h e i n f l u e n c e o f t r e e w e i g h t on wood f o r m a t i o n i n the stem, on t h e assumption t h a t the compression l o a d would be a predominant f a c t o r on t h e growth o f t h e stem. But a l l the v a r i a t i o n s o b s e r v e d i n the wood formed s i n c e t h e l o a d i n g can n o t be d e f i n i t e l y a t t r i b u t e d t o the l o a d i n g , s i n c e many f a c t o r s o t h e r t h a n the t r e a t m e n t may be i n v o l v e d i n t h e f o r -m a t i o n o f wood. The e f f e c t s o f wind and p h y s i c a l wounding, among o t h e r s , are u n a v o i d a b l e m a i n l y because o f the t e c h n i c a l d i f f i c u l t i e s i n c o n t r o l l i n g them. The i n f l u e n c e o f p r e v a i l i n g w ind c o u l d be somewhat l i m i t e d by examining the s o u t h and n o r t h d i r e c -t i o n s o f the stem (3,20), y e t v a r i a t i o n s w i t h d i f f e r e n t d i r e c -t i o n s prove o t h e r w i s e i n the d a t a o f t h e p r e s e n t s t u d y . How-e v e r , n e i t h e r pronounced stem e c c e n t r i c i t y nor co m p r e s s i o n wood was n o t i c e d i n the stem s e c t i o n s examined. No attempt was made t o e x p l o r e t h e development o f t r a u m a t i c r e s i n c a n a l s o r any changes i n normal r e s i n c a n a l s , even though minor wounds were e v i d e n t i n t h e r e g i o n o f l o a d i n g . To l e a r n more about the e f f e c t s o f growth f a c t o r s , i n -c l u d i n g c l i m a t e , o t h e r t h a n t r e a t m e n t on e a r l y w o o d g r o w t h , 53 t h e y e a r l y d i f f e r e n c e s i n t h e w i d t h s o f e a r l y w o o d and l a t e -wood i n t h e young D o u g l a s - f i r stems sampled n e a r the e x p e r i -m e n t a l a r e a o f t h i s s t u d y a r e documented i n T a b l e 7. A mod-e r a t e v a r i a t i o n i n e a r l y w o o d w i d t h p r e v a i l e d f o r t h e p e r i o d 1960-71 i n t h e a r e a , w h i l e u n u s u a l l y i n c r e a s e d v a r i a b i l i t y was e v i d e n t i n t h e l o a d e d stem a f t e r l o a d i n g (see F i g . 4 ) . Even i f t h e s u b s t a n t i a l changes i n growth i n c r e m e n t s f o r the two y e a r s i m m e d i a t e l y f o l l o w i n g l o a d i n g a r e m o s t l y due t o the t r e a t m e n t , t h e changes a f t e r t h e f i r s t two y e a r s may be confounded w i t h the e f f e c t o f i n c r e a s e d t r e e w e i g h t f o r the p e r i o d . W h i l e t h e i n c r e a s e d t r e e w e i g h t i s r e l a t i v e l y s m a l l i n magnitude, t h i s g i v e s r i s e t o a change i n compre s s i o n s t r e s s d i s t r i b u t i o n p a t t e r n i n t h e stem as the r a t e o f i n c r e -m e n t a l growth d e c l i n e s i n t h e l o a d e d stem and t h e stem growth i s c o n c e n t r a t e d above t h e l o a d w i t h t i m e . P a r t o f the o b s e r v e d v a r i a t i o n s i n t h e wood formed a f t e r l o a d i n g has been e v i d e n t l y , a t l e a s t t o a l i m i t e d d e gree, caused by o t h e r f a c t o r s . But i t i s b e l i e v e d t o be h a r d t o d e t e c t t h e i r s p e c i f i c i n f l u e n c e s , c o n s i d e r i n g t h e complex i n t e r a c t i o n s between t h e i r a c t i o n s and t h e e x p e r i m e n t a l l o a d i n g on t h e b i o l o g i c a l system o f wood f o r m a t i o n . I t may be, however, r e a s o n a b l e t o s t a t e t h a t h i g h l y s i g n i f i c a n t d i f -f e r e n c e s o r u n u s u a l growth t r e n d s a r e m o s t l y a t t r i b u t e d t o t r e a t m e n t . 54 Ta b l e 7. Average r a d i a l growth a t b r e a s t h e i g h t f o r t h e 180 young D o u g l a s - f i r t r e e s a t U n i v . o f B.C. Research F o r e s t f o r t h e y e a r s 1960-71*. Year Width .01 Earl y w o o d mm Latewood 1960 377.90 166.30 1961 366.10 171.30 1962 367.40 188.80 1963 394.80 212.50 1964 424.90 169.10 1965 339.20 155.60 1966 338.70 158.60 1967 308.40 137.10 1968 292.70 164.90 1969 240.30 148.60 1970 346.60 177.00 1971 321.10 138.50 * The d a t a p r e s e n t e d here were c o m p i l e d by Dr. J . H a r r y G. Sm i t h , F a c u l t y o f 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 C o l u m b i a , Vancouver, B.C. 5.0 CONCLUSIONS AND PRACTICAL APPLICATION The experiment has shown immediate and d e f i n i t e i n f l u -ence of longitudinal compressive stress on the formation of stem wood. This evidence suggests that the stress due to tree weight i s an important factor i n governing wood forma-t i o n and d i s t r i b u t i o n i n the stem. The extent of influence by tree weight depends on the magnitude of applied stress and resultant s t r a i n l o c a l l y and appears to be much greater than the stress l e v e l might suggest. Defining the s p e c i f i c i n f l u -ence of the weight requires further, refined studies on the physiological and biochemical pathways to the observed v a r i a -tions i n wood c h a r a c t e r i s t i c s . If the findings from the study based on a single tree can be v e r i f i e d i n other trees and other species, they would be of considerable importance to knowledge of the variations of tree growth and wood d i s t r i b u t i o n i n the stem. The longi-tudinal compressive stress pattern obtainable by stem form and green weight d i s t r i b u t i o n pattern i n a stem may be used i n predicting the d i s t r i b u t i o n a l pattern for wood properties of the stem. Such information may explain the c o n f l i c t i n g results i n the e a r l i e r studies on the longitudinal variations i n stem wood c h a r a c t e r i s t i c s . I t may also be a h e l p f u l and sound guide to the s i l v i c u l t u r a l practices a f f e c t i n g the green weight or weight d i s t r i b u t i o n of trees. 56 6.0 LITERATURE CITED 1. Adamovich, L. and J . W a l t e r s . 19 66. Mechanics o f s t a n d -i n g c o n i f e r o u s t r e e s . U n i v . o f B. C. Res. F o r e s t , A nnual R e p o r t f o r p e r i o d A p r i l 1, 1965 t o March 31, 1966. pp. 39-40. 2. A h l g r e n , P. A. and D. A. I . G o r i n g . 1971. Removal o f wood components d u r i n g c h l o r i t e d e l i g n i f i c a t i o n of b l a c k s p r u c e . Can. J . Chem. 4 9 ( 8 ) : 1272-1275. 3. Bannan, M. W. and M. B i n d r a . 1970. The i n f l u e n c e o f wind on r i n g w i d t h and c e l l l e n g t h i n c o n i f e r stems. Can. J . B o t . 48: 255-259. 4. B a r t o n , J . S. 1950. The r e a c t i o n p r o d u c t s o f l i g n i n and sodium c h l o r i t e i n a c i d s o l u t i o n . T a p p i 3 3 ( 1 0 ) : 496-503. 5. Boyd, J . D. 1950. Tree growth s t r e s s e s . I I I . The o r i -g i n o f growth s t r e s s e s . A u s t r a l . J . S c i . Res. S e r . B 3: 294-309. 6. B u r t o n , J . D. and D. M. Smith. 1972'. Guying t o p r e v e n t wind sway i n f l u e n c e s l o b l o l l y p i n e growth and wood p r o -p e r t i e s . U.S.D.A. F o r e s t S e r v i c e , South. F o r e s t E x p ' t S t a . , Res. Paper sO-80, 8 pp. 7. Campbell, W. G. and I . R. C. McDonald. 1952. The chem-i s t r y o f the wood c e l l w a l l . P a r t I . The d e l i g n i f i c a -t i o n o f beech, and sp r u c e woods by sodium c h l o r i t e i n b u f f e r e d aqueous s o l u t i o n . J . Chem. Soc. (1952): 2644-2650. 8. C o t e , W. A., J r . , Simson, B. W. and T. E. T i m e l l . 1966. S t u d i e s on co m p r e s s i o n wood. I I . The c h e m i c a l compo-s i t i o n o f wood and bark from normal and co m p r e s s i o n r e g i o n s o f f i f t e e n s p e c i e s of gymnosperms. Svensk P a p p e r s t i d n . 6 7 ( 1 7 ) : 547-558. 9. D a d s w e l l , H. E., Wardrop, A. B. and A. J . Watson. 1958. The morphology, c h e m i s t r y and p u l p c h a r a c t e r i s t i c s o f r e a c t i o n wood. I n "Fundamentals o f papermaking f i b r e s " , ed. by F. Bolam. Tech. S e c t , o f B r i t i s h Paper & Board Makers' Assoc. London. pp. 187-219. 10. E l - O s t a , M. L. M., K e l l o g g , R. M., F o s h i , R. 0. and R. G. B u t t e r s . 1973. A d i r e c t X-ray t e c h n i q u e f o r measur-i n g m i c r o f i b r i l a n g l e . Wood and F i b e r 5 ( 2 ) : 118-128. 57 11. E l - O s t a , M. L. M. and R. W. Wellwood. 1972. S h o r t -term c r e e p r e l a t e d t o c e l l - w a l l c r y s t a l l i n i t y . Wood and F i b e r 4: 204-211. 12. E r i c k s o n , H. D. 1962. Some a s p e c t s o f method i n d e t e r -m i n i n g c e l l u l o s e i n wood. T a p p i 4 5 ( 9 ) : 710-719. 13. and T. Arima. 1974. D o u g l a s - f i r wood q u a l i t y s t u d i e s . P a r t I I : E f f e c t s o f age and s t i m u -l a t e d growth on f i b r i l a n g l e and c h e m i c a l c o n s t i t u e n t s . Wood S c i . T e c h n o l . 8: 255-265. 14. F o s c h i , R. 0. and M. L. M. E l - O s t a . 1973. A computer program f o r r e s o l v i n g the (040) d i f f r a c t i o n peak and c a l c u l a t i n g t he mean m i c r o f i b r i l a n g l e o f wood. Dep't of t he Environment, Canadian F o r e s t r y S e r v i c e , Western F o r e s t P r o d . Lab. I n f o r m a t i o n Report VP-X-114, 16 pp. 15. H a l e , J . D. and L. P. Clermont. 1963. I n f l u e n c e o f prosenchyma c e l l - w a l l morphology on b a s i c p h y s i c a l and c h e m i c a l c h a r a c t e r i s t i c s o f wood. J . Polymer S c i : P a r t C No. 2: 253-261. 16. Heger, L., P a r k e r , M. L. and R. W. Kennedy. 1974. X-ray d e n s i t o m e t r y : A t e c h n i q u e and an example o f a p p l i c a t i o n . Wood S c i . ' 7 ( 2 ) : 140-148. 17. H e r b s t , J . H. E. 1952. The p r e p a r a t i o n o f c h l o r i t e h o l o c e l l u l o s e . Can. J . Chem. 30: 668-678. 18. H i l l e r , C. H. 1954. V a r i a t i o n s i n f i b r i l a n g l e s i n s l a s h p i n e . U.S.D.A., F o r e s t S e r v i c e , F o r e s t P r o d . Lab. Rept. No. 2 003, 6 pp. 19. J a c o b s , M. R. 1939. A stu d y o f the e f f e c t o f sway on t r e e s . A u s t r a l . Commonwealth F o r e s t r y Bureau B u l l . No. 26, 19 pp. 20. . 1954. The e f f e c t o f wind sway on t h e form and development o f P i n u s r a d i a t a D. Don. A u s t r a l . J . B o t . 2: 35-51. 21. J a n s o n s , N. 1950. L i g n i n c o n t e n t i n v a r i o u s c a r d i n a l d i r e c t i o n s o f s p r u c e a n n u a l i n c r e m e n t s . T r a n s l a t e d by P. E. J u r a z s , 1966, Univ. o f B.C., Fac. o f F o r e s t r y T r a n s l a t i o n No. 39, 34 pp. 22. Jayme, G., Schenck, U. and L. Rothamel. 1949. Ueber g e s e t z m a s s i g e Aenderungen d e r E i g e n s c h a f t e n i n n e r h a l b d e s s e l b e n Stammes von P a p p e l h o l z e r n . Das P a p i e r 3: 1-7. 58 23. Johnson, D. B., Moore, W. E. and L. C. Zank. 1961. The s p e c t r o p h o t o m e t r y d e t e r m i n a t i o n o f l i g n i n i n s m a l l wood samples. T a p p i 4 4 ( 1 1 ) : 793-798. 24. Kennedy, R. W. and L. Adamovich. 196 8. An anomalous t r a c h e i d i n D o u g l a s - f i r e a r l y w o o d . Canada, Dep't o f F o r e s t r y & R u r a l Development, B i - m o n t h l y Res. Notes 24: 22. 25. and J . M. Jaworsky. 1960. V a r i a t i o n s i n c e l l u l o s e c o n t e n t o f D o u g l a s - f i r . T a p p i 4 3 ( 1 ) : 25-27. 26. Kim, C. T. 1973. I s o l a t i o n o f t h e t o t a l wood carbohy-d r a t e . U n p u b l i s h r e p o r t , U n i v . o f B.C. 27. L a r s o n , P. R. 1963. Stem form development o f f o r e s t t r e e s . F o r e s t S c i . Mono. 5, 42 pp. 28. . 196 5. Stem form o f young L a r i x as i n -f l u e n c e d by wind and p r u n i n g . F o r e s t S c i . 11: 412-424. 29. . 1966. Changes i n c h e m i c a l c o m p o s i t i o n of wood c e l l w a l l s a s s o c i a t e d w i t h a g e . . . . i n P i n u s  r e s i n o s a . F o r e s t Prod. J . 1 6 ( 4 ) : 37-45. 30. . 1969. I n c o r p o r a t i o n o f l ^ C . i n the d e v e l -o p i n g w a l l s o f P i n u s r e s i n o s a t r a c h e i d s : c o m p r e s s i o n wood and o p p o s i t e wood. T a p p i 52: 2170-2177. 31. Lee, C. L. 1961. C r y s t a l l i n i t y o f wood c e l l u l o s e f i b e r s s t u d i e d by X-ray methods. F o r e s t P r o d . J . 1 1 ( 2 ) : 108-112. 32. M c M i l l i n , C. W. 1973. F i b r i l a n g l e o f l o b l o l l y p i n e wood as r e l a t e d t o s p e c i f i c g r a v i t y , growth r a t e , and d i s t a n c e from p i t h . Wood S c i . T e c h n o l . 7: 251-255. 33. M a r t l e y , J . F. 1928. T h e o r e t i c a l c a l c u l a t i o n o f t h e p r e s s u r e d i s t r i b u t i o n on t h e b a s a l s e c t i o n o f a t r e e . F o r e s t r y 2: 69-72. 34. Mart o n , R., Rushton, P., Sacco, J . S. and K. Sumiya. 1972. Dimensions and u l t r a s t r u c t u r e i n growing f i b e r s . T a p p i 5 5 ( 1 0 ) : 1499-1504. 35. Moss, A. 1971. An i n v e s t i g a t i o n o f b a s a l sweep o f l o d g e p o l e and shore p i n e s i n G r e a t B r i t a i n . F o r e s t r y 4 4 ( 1 ) : 43-65. 59 36. P a r k e r , M. L. and L. A. J o z s a . 1973. X-ray s c a n n i n g machine f o r t r e e - r i n g w i d t h and d e n s i t y a n a l y s i s . Wood and F i b e r 5 ( 3 ) : 237-248. 37. , Schoorlemmer, J . and L. J . C a r v e r . 1973. A c o m p u t e r i z e d s c a n n i n g d e n s i t o m e t e r f o r a u t o m a t i c r e c o r d i n g o f t r e e - r i n g w i d t h and d e n s i t y d a t a from X-ray n e g a t i v e s . Wood and F i b e r 5 ( 3 ) : 192-197. 38. P i l l o w , M. Y., T e r r e l l , B. Z. and C. H. H i l l e r . 1953. P a t t e r n s o f v a r i a t i o n i n f i b r i l a n g l e s i n l o b l o l l y p i n e . U.S.D.A., F o r e s t S e r v i c e , F o r e s t P r o d . Lab. Rept. No. D1935, 11 pp. 39. P r e s t o n , R. D., Hermans, P. H. and A. W e i d i n g e r . 1950. The c r y s t a l l i n e - n o n - c r y s t a l l i n e r a t i o i n c e l l u l o s e s o f b i o l o g i c a l i n t e r e s t . J . E x p ' t . Botany 1: .344-352. 40. R i t t e r , G. J . and L. C. F l e c k . 1926. C h e m i s t r y of wood IX - Springwood and Summerwood. Ind. Eng. Chem. 1 8 ( 6 ) : 608-609. 41. Sarkanen, K. V. 1963. Wood l i g n i n s . I n "The c h e m i s t r y o f wood", ed. by B. L. Browning, John W i l e y & Sons, I n c . , New Y ork, p. 297. 42. S a s t r y , C. B. R. and R. W. Wellwood. 1971. I n d i v i d u a l t r a c h e i d w e i g h t - l e n g t h r e l a t i o n s h i p s i n Douglas f i r . T a p p i 5 4 ( 1 0 ) : 1686-1690. 43. S c h u t t , P. and H. A u g u s t i n . 1961. D i e V e r t e i l u n g des C e l l u l o s e g e h a l t e s im Stamm Untersuchungen uber e i n e Methode der zfl c h t e r i s c h e n Probenahme an 3 0 j a h r i g e n M u r r a y k i e f e r n . Das P a p i e r 1 5 ( 1 1 ) : 661-665. 44. Schwendener, S. 1874. Das mechanische P r i n z i p im enatomischen Bau der Monokotylen. O r i g i n a l not s e e n , c i t e d from r e f e r e n c e 27. 45. S e g a l , L., C r e e l y , J . J . , M a r t i n , A. E., J r . , and C. M. Conrad. 1959. An e m p i r i c a l method f o r e s t i m a t i n g t h e degree o f c r y s t a l l i n i t y o f n a t i v e c e l l u l o s e u s i n g t h e X-ray d i f f r a c t o m e t e r . T e x t i l e Res. J . 29: 786-794. 46. S i n n o t t , E. W. 1960. P l a n t Morphogenesis. McGraw-H i l l Book Co., New York, pp. 345-351. 47. S t e u c e k , G. L. and R. M. K e l l o g g . 19 72. The i n f l u e n c e o f a stem d i s c o n t i n u i t y on xylem development i n Norway s p r u c e , P i c e a a b i e s . Can. J . F o r e s t Res. 2: 217-222. 60 48. TAPPI S t a n d a r d T203m - 58. Tech. A s s o c . P u l p Paper I n d . , New York. 49. T i m e l l , T. E. 1973. S t u d i e s on o p p o s i t e wood i n c o n i -f e r s . P a r t I . C h e m i c a l c o m p o s i t i o n . Wood S c i . T e c h n o l . 7 ( 1 ) : 1-5. 50. U p r i c h a r d , J . M. 1965. The a l p h a - c e l l u l o s e c o n t e n t o f wood by the c h l o r i t e p r o c e d u r e . A p p i t a 1 9 ( 2 ) : 36-39. 51. Wardrop, A. B. 1951. C e l l w a l l o r g a n i z a t i o n and t h e p r o p e r t i e s o f the xylem I . C e l l w a l l o r g a n i z a t i o n and the v a r i a t i o n o f b r e a k i n g l o a d i n t e n s i o n o f the xylem i n c o n i f e r stems. A u s t r a l . J . S c i . Res. ( S e r i e s B) 4: 391-414. 52. . 196 5. The f o r m a t i o n and f u n c t i o n o f r e a c t i o n wood. I n " C e l l u l a r u l t r a s t r u c t u r e o f woody p l a n t s " , ed. by W. A. C o t e , J r . , S y r a c u s e U n i v e r s i t y P r e s s , S y r a c u s e , N.Y., pp. 371-390. 53. Wellwood, R. W., S a s t r y , C. B. R., M i c k o , M. M. and L. P a s z n e r . 1974. On some p o s s i b l e s p e c i f i c g r a v i t y , h o l o - and a l p h a - c e l l u l o s e , t r a c h e i d w e i g h t / l e n g t h and c e l l u l o s e c r y s t a l l i n i t y r e l a t i o n s h i p s i n a 500-year-o l d D o u g l a s - f i r t r e e . H o l z f o r s c h . 2 8 ( 3 ) : 91-94. 54. and J . G. H. Smith. 1962. V a r i a t i o n i n some i m p o r t a n t q u a l i t i e s o f wood from young Douglas f i r and hemlock t r e e s . U n i v . o f B.C., Fac. o f F o r e s t r y , Res. Papers No. 50, 15 pp. 55. Wise, L. E., Murphy, M. and A. A. D'Addieco. 1946. C h l o r i t e h o l o c e l l u l o s e , i t s f r a c t i o n a t i o n and b e a r i n g on summative wood a n a l y s i s and on s t u d i e s on the hemi-c e l l u l o s e s . Paper Trade J . 1 2 2 ( 2 ) : 35-43. 56. Wood, J . R. and D. A. I . G o r i n g . 1971. The d i s t r i b u -t i o n o f l i g n i n i n stem wood and b r a n c h wood o f Douglas-f i r . P u l p Paper Mag. Can. 7 2 ( 3 ) : T95-T102. 57. Wood S c i e n c e P r o c e d u r e AM/H-l/62-r66. U n i v . o f B.C., Fac. o f F o r e s t r y , Vancouver. 58. W o r s t e r , H. and B. K. Sugiyama. 1962. The c a r b o h y d r a t e c o n t e n t and c o m p o s i t i o n o f some w e s t e r n woods r e l a t e d t o growth f a c t o r s . P u l p Paper Man. Can. 6 3 ( 8 ) : T395-T401. 61 59. Wu, Y-t and J. W. Wilson. 1967. L i g n i f i c a t i o n within coniferous growth zones. Pulp Paper Mag. Can. 68(4): T159-T164. 60. Zobel, B. J. and R. L. McElwee. 1958. Variation of c e l l u l o s e i n l o b l o l l y pine. Tappi 41(4): 167-170. 62 APPENDIX: Sample Size for the Desired Precision i n Selected Holocellulose and Lignin Procedures A. Holocellulose A preliminary determination for a sample of ISEA was made to estimate the mean percent holocellulose content, according to the modified Wood Science Procedure. The re-su l t gave a standard deviation among 6 determinations of 0.5882 . The r e s u l t i s given below: 1) 71.39 2) 72.33 3) 72.59 4) 72.83 5) 72.84 6) 73.02 x = 72.50 S 2 = 0.3460 S = 0.5882 Sample size was estimated by the formula: n D 2 Where t 2 Q 5 = 2.5712 = 6.61 S 2 = 0.3460 D 2 = 0.82 = 0.64 (the estimate to be within 0.8% of the popula-t i o n mean) n = 3.57 63 The sample size (n) must be an i n t e g r a l value and, because 3.57 i s too small, a sample of n = 4 observations would be required for the desired precision. B. Lignin 5 determinations for a sample of ISLA were made to e s t i -mate the mean percent l i g n i n content, by using the modified acetyl bromide method (59). The re s u l t i s : 1) 25.02 2) 25.08 3) 25.30 4) 25.50 5) 25.92 x = 25.30 S 2 = 0.14 The formula: n = t 2 S 2 Where t l n c = 2.7762 = 7.70 S 2 = 0.14 D 2 = 0.82 = 0.64 n = 1.68 Therefore, 2 observations would be required for the desired precision. 

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