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Morphogenesis of stems of Douglas fir (Pseudotsuga menziesii (mirb.) franco) Heger, Ladislav 1965

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The U n i v e r s i t y of B r i t i s h FACULTY OF GRADUATE  Columbia  STUDIES  PROGRAMME OF THE FINAL ORAL EXAMINATION FOR THE  DEGREE OF  DOCTOR:OF PHILOSOPHY  of  LADISLAV HEGER  Ing.(For.)»  Brno,  (Czechoslovakia)', 1949  M.F. Tlie U n i v e r s i t y o f B r i t i s h Columbia, . 1959  MONDAY, MAY 10, 1965 AT 2:00 P.M. IN ROOM 239, FORESTRY & GEOLOGY  BUILDING  COMMITTEE IN CHARGE Chairman: V. J . O k u l i t c h B. G. G r i f f i t h P. G. Haddock S. W. Nash  J . H. G„ Smith R. W. Wellwood D. J . Wort  E x t e r n a l Examiner: J . L. Farrar A b i t i b i Professor o f Forest Biology F a c u l t y of F o r e s t r y U n i v e r s i t y , of Toronto, Toronto, O n t a r i o  THE MORPHOGENESIS OF STEMS OF DOUGLAS FIR (PSEUDOTSUGA MENZIESII. MIRB. FRANCO) ABSTRACT Widths of :22j,734 bands of earlywood and latewood have been measured s y s t e m a t i c a l l y a l o n g t h e average r a d i i a t t h e c e n t r e s of t h e annual h e i g h t increments of 18 Douglas f i r trees. Shapes of t h e annual growth l a y e r s of earlywood and of latewood, r e s p e c t i v e l y , formed d u r i n g an a c c r u e d growth p e r i o d of 589 y e a r s were i n v e s t i g a t e d : ( i ) using r e l a t i v e measures embodied i n diagrammatic computer o u t p u t s ; ( i i ) u s i n g a b s o l u t e measures by s t a t i s t i c a l and g r a p h i c a l t e c h niques; ( i i i ) by computing H o h e n a d l s form f a c t o r (lambda 0.9) f o r each y e a r of growth of; (a) imaginary "earlywood stems" c o n s i s t i n g ' o f l a y e r s of e a r l y wood; (b) imaginary "latewood stems" c o n s i s t i n g of l a y e r s of latewood; (c) a c t u a l stems c o n s i s t i n g of t o t a l annual l a y e r s . !  The form of earlywood l a y e r s d i f f e r e d markedly and c o n s i s t e n t l y from t h a t of latewood l a y e r s . The maximum w i d t h of earlywood l a y e r s -in i n d i v i d u a l t r e e s o c c u r r e d w i t h i n a zone l o c a t e d in. t h e upper p o r t i o n of t h e l i v e crown; i n t h e stand i t was w i t h i n a zone p a r a l l e l w i t h t h e s u r f a c e of t h e crown canopy. Width of earlywood was a t i t s minimum at some.small d i s t a n c e above the stem base. T h i s d i s t a n c e i n c r e a s e d w i t h t r e e age. Latewood l a y e r s were u s u a l l y widest a l o n g t h e b a s a l p o r t i o n of t h e stems. As a . r e s u l t , the form f a c t o r s of "earlywood stems" were c o n s i d e r a b l y h i g h e r than those of "latewood stems". The shapes o f the growth l a y e r s , and hence t h e form of stems c o n s i s t i n g of t h e s e l a y e r s , c o u l d not be r e c o n c i l e d s a t i s f a c t o r i l y w i t h t h e t e n e n t s o f Schwendener-Metzger*s m e c h a n i s t i c , or H a r t i g ' s n u t r i t i o n a l , or J a c c a r d ' s water c o n d u c t i v e , or hormonal t h e o r i e s of stem f o r m a t i o n . Theref o r e , i t was suggested t h a t t h e shapes o f t h e annual l a y e r s of earlywood and latewood may r e f l e c t t h e r e s p e c t i v e s p r i n g and summer m i c r o e n v i r o n m e n t a l energy g r a d i e n t s . Then the. average form of t r e e s from f o r e s t s of t h e temperate l a t i t u d e s w h i c h i s t h a t of a q u a d r a t i c p a r a b o l o i d , may be d e t e r mined by the average m i c r o c l i m a t i c s t r u c t u r e p r e v a i l i n g i n these f o r e s t s d u r i n g t h e growing season. Form of opengrown t r e e s , e c c e n t r i c i t y of stems, r o o t s and branches, and other so f a r u n e x p l a i n e d anomalies i n r a d i a l growth may be clarified similarly.  I n d i r e c t and some p r e l i m i n a r y d i r e c t evidence supporting the proposed c o n c e p t u a l scheme of stem f o r m a t i o n was presentedIn • addition,, i n f l u e n c e of some s e l e c t e d f a c t o r s of macroclimate on the amount of r a d i a l growth expressed i n terms of the average widths of growth l a y e r s was a n a l y s e d . I n d i v i d u a l t r e e s have been used as sampling u n i t s . The trends i n the growth s e r i e s were removed by a n a l y s i s of covariance: average l a y e r w i d t h i n d i c e s were d e r i v e d by c a l c u l a t i n g d e v i a t i o n s from the s t r a i g h t l i n e s f i t t e d by l e a s t squares t o the a d j u s t e d mean l a y e r w i d t h s . . The degree of a u t o c o r r e l a t i o n of b o t h growth and weather s e r i e s was l a r g e l y non s i g n i f i c a n t . C o r r e l a t i o n s between the growth i n d i c e s of earlywood and latewood were n o n s i g n i f i c a n t or low. In the i n d i v i d u a l t r e e s , s i x weather v a r i a b l e s accounted f o r from 10 t o 48 per cent of t h e t o t a l v a r i a b i l i t y observed i n the r a d i a l growth of latewood. Temperatures of the p r e v i o u s summer c o u l d not be r e l a t e d t o the amount of r a d i a l growth of earlywood of the c u r r e n t y e a r . S i n c e the approximate minimum t r u e c o r r e l a t i o n i n the u n i v e r s e was zero the g e n e r a l i n f l u e n c e of m a c r o c l i m a t e was n o n s i g n i f i cant . I t appears t h a t other s t u d i e s have n e g l e c t e d the i n f l u e n c e of p h y s i c a l m i c r o e n v i r o n m e n t a l f a c t o r s on growth. There i s need f o r r e s e a r c h on the means .by which d i s t r i b u t i o n and amount of r a d i a l growth a r e c o n t r o l l e d by the net. flow of energy i n t r e e s .  GRADUATE STUDIES Field  of Study:  Forest Mensuration  Forest Mensuration Silvics Wood Anatomy F o r e s t Management Related  J . H. G. Smith & J . W. Ker P. G. Haddock R„ W„ Kennedy I. C. MacQueen  Studies:  Biometry and F i e l d DesignP l a n t Physiology. Computer Programming  J . Sawyer D. , J . .Wort H. Dempster  PUBLICATION  Smith, J.H.G., Ker, J „ W , Heger, L. (1960). N a t u r a l and C o n v e n t i o n a l Height-Age Curves f o r D o u g l a s - F i r and Some L i m i t s t o T h e i r Refinement, Proc. F i f t h World F o r . Congress, pp. 546-551. 4  MORPHOGENESIS OF STEMS OF DOUGLAS FIR (PSEUDOTSUGA MENZIESII (MIRB.) FRANCO) by LADISLAV HEGER Ing. ( F o r . ) , Brno, ( C z e c h o s l o v a k i a ) , 1949 M.F., U n i v e r s i t y o f B r i t i s h Columbia, 1959  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE  REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n the Department of FORESTRY  We accept t h i s t h e s i s as conforming t o the required  THE  standard.  UNIVERSITY OF BRITISH COLUMBIA April,  1965  In the  r e q u i r e m e n t s f o r an  British  mission  for reference  for extensive  p u r p o s e s may  be  cation  of  written  Department  of  and  by  degree at  the  study.  the  Library  for  Head o f my  agree for  that  of •  per-  scholarly  Department  shall  of  make i t f r e e l y  or  t h a t ; c o p y i n g or  f i n a n c i a l gain  Columbia,  fulfilment  University  shall  this thesis  permission*.  The U n i v e r s i t y of B r i t i s h V a n c o u v e r 8, Canada  the  I further  I t i s understood  this thesis  w i t h o u t my  that  copying of  granted  representatives.  this thesis i n partial  advanced  Columbia, I agree  available  his  presenting  not  be  by publi-  allowed  i ABSTRACT Chairman;  P r o f e s s o r J . H. G.  Smith  Widths o f 22,734 bands of earlywood and latewood were measured s y s t e m a t i c a l l y a l o n g the average r a d i i at the c e n t e r s of the annual height increments of 18 Douglas f i r trees. of  Shapes of the annual growth l a y e r s of earlywood and  latewood, r e s p e c t i v e l y , formed d u r i n g an accrued growth  p e r i o d of 589 y e a r s were i n v e s t i g a t e d ; (i)  u s i n g r e l a t i v e measures embodied i n diagramatic computer outputs;  (ii)  u s i n g a b s o l u t e measures by s t a t i s t i c a l  and  graphical techniques; (iii)  by computing 0.9) a)  Hohenadl's  form f a c t o r  (lambda  f o r each y e a r ' s growth o f ; imaginary "earlywood stems" c o n s i s t i n g o f l a y e r s of earlywood;  b)  imaginary "latewood stems" c o n s i s t i n g o f l a y e r s o f latewood;  c)  a c t u a l stems c o n s i s t i n g of t o t a l annual layers.  The form o f earlywood l a y e r s d i f f e r e d markedly c o n s i s t e n t l y from t h a t of latewood l a y e r s . of  The maximum width  earlywood l a y e r s i n i n d i v i d u a l t r e e s o c c u r r e d w i t h i n a zone  l o c a t e d i n the upper p o r t i o n o f the l i v e  crown; i n the stand i t  was w i t h i n a zone p a r a l l e l w i t h the s u r f a c e of crown Width of earlywood was the  and  stem base.  canopy.  at i t s minimum at some d i s t a n c e above  T h i s d i s t a n c e i n c r e a s e d w i t h t r e e age.  Latewood  l a y e r s were u s u a l l y widest a l o n g the b a s a l p o r t i o n o f the stem.  ii  As a r e s u l t , the form f a c t o r s o f "earlywood stems" were c o n s i d e r a b l y h i g h e r than those o f "latewood -  stems".  fbe shapes o f the growth l a y e r s , and hence the.form  of stems c o n s i s t i n g of these l a y e r s , could not be  reconciled  s a t i s f a c t o r i l y w i t h the t e n e t s o f Schwendener - Metzger's m e c h a n i s t i c , o r H a r t i g s n u t r i t i o n a l , o r J a c c a r d ' s water f  c o n d u c t i v e , o r hormonal t h e o r i e s o f stem f o r m a t i o n . T h e r e f o r e , a new  scheme was proposed u s i n g the f o l l o w i n g concepts, (1)  H e a t i n g o f stems by s o l a r energy c o n s t i t u t e s a p u r e l y p h y s i c a l p r o c e s s ; the r a t e o f energy t r a n s f e r between a t r e e and i t s environment determines the temperature o f i t s cambial tissues.  (2.)  Because t r e e s are not homoiothermous organisms, at a g i v e n time v a r i o u s p a r t s of the cambial c y l i n d e r may  possess d i f f e r e n t  even i n an i s o t h e r m a l (3)  A pronounced  temperatures  environment.  s t r a t i f i c a t i o n o f the  environment  due t o g r a d i e n t s i n a i r temperature or i n l e n g t h o f time of p o s i t i v e net f l u x of energy has been observed i n f o r e s t s throughout the world. (4)  R a d i a l growth may  proceed a t v a r y i n g r a t e s f o r  unequal p e r i o d s of time w i t h i n the d i f f e r e n t p a r t s of the cambial c y l i n d e r , depending  largely  on the l e v e l s o f s u b c o r t i c a l temperatures. (5)  Consequently, the shapes of the annual l a y e r s  of earlywood and latewood may r e f l e c t the respective energy (6)  s p r i n g and summer environmental  gradients.  Then the average form o f t r e e s from f o r e s t s of the temperate quadratic  l a t i t u d e s , which i s t h a t o f a  paraboloid,  microclimatic f o r e s t s during  may r e f l e c t the average  s t r u c t u r e p r e v a i l i n g i n these the growing  season.  Form o f open-grown t r e e s , e c c e n t r i c i t y o f stems, r o o t s and branches, and o t h e r so f a r u n e x p l a i n e d anomalies i n r a d i a l growth may be c l a r i f i e d  similarly.  I n d i r e c t and some p r e l i m i n a r y  d i r e c t evidence  s u p p o r t i n g the proposed c o n c e p t u a l scheme o f stem f o r m a t i o n was presented.  In a d d i t i o n , i n f l u e n c e o f some s e l e c t e d f a c t o r s o f  macroclimate on the amount o f r a d i a l growth expressed i n terms of the average widths o f growth l a y e r s was a n a l y s e d . t r e e s have been used as sampling u n i t s . growth  Individual  The t r e n d s i n the  s e r i e s were removed by a n a l y s i s o f c o v a r i a n c e : average  l a y e r width i n d i c e s were d e r i v e d by c a l c u l a t i n g d e v i a t i o n s the  s t r a i g h t l i n e s f i t t e d by l e a s t squares t o the a d j u s t e d mean  l a y e r widths. weather the  from  s e r i e s was l a r g e l y n o n s i g n i f i c a n t .  growth  or low.  The degree o f a u t o c o r r e l a t i o n o f both growth and C o r r e l a t i o n s between  i n d i c e s o f earlywood and latewood were n o n s i g n i f i c a n t  In the i n d i v i d u a l t r e e s , s i x weather  variables  accounted f o r from 10 t o 48 per cent of the t o t a l observed i n the r a d i a l growth  o f latewood.  variability  Temperatures  of the  p r e v i o u s summer could not be r e l a t e d t o the amount o f r a d i a l  iv  growth o f earlywood o f the c u r r e n t y e a r .  Since the approx-  imate minimum t r u e c o r r e l a t i o n i n the u n i v e r s e was zero the g e n e r a l i n f l u e n c e o f macroclimate was n o n s i g n i f i c a n t . I t appears t h a t o t h e r s t u d i e s have n e g l e c t e d the i n f l u e n c e on growth of microenvironmental  f a c t o r s and t h a t  there i s need f o r r e s e a r c h on the means by which d i s t r i b u t i o n and amount o f r a d i a l growth are c o n t r o l l e d by the net flow o f energy.  V  ACKNOWLEDGEMENTS Among the many people who assistance  i n preparation  Dr.  Smith, my  J.HoGo  i n i n g committee, Dr. J.W.  Wilson, Mr.  SoWo  most  R.W.  Wellwood, Dr. P.G.  J . Walters and Mrs.  M.R«  Haddock,  Mr.  Grounds; Dr«  Dr.  Lambden, a l l of the  Wort, Department of Botany;  DoJo  Department of M e t a l l u r g y ;  stages a r e :  chairman of. the exam-  Nash, Department of Mathematics; Mr.  B u i l d i n g s and  constructive  of t h i s t h e s i s at v a r i o u s  c h i e f a d v i s o r and  F a c u l t y of F o r e s t r y ; Dr. Dr.  gave me  E.  Klassen,  A. E r i s a l u , Department of  W.V.  Hancock, Canada Department  of  F o r e s t r y ; Dr. K. Westphal, Bedford I n s t i t u t e of Oceanography; Dr.  J o C . Pennel, C o r n e l l U n i v e r s i t y ; Mr.  D i e t z , U n i v e r s i t y of A l b e r t a .  E.D.  B e r r y ; Mr.  I am much indebted  K.  t o a l l of  them. S p e c i a l acknowledgement i s due  t o the  s t a f f of the  Computing Center of the U n i v e r s i t y of B r i t i s h Columbia, i n p a r t i c u l a r t o Dr. Mr.  E. F r o e s e .  J.RoH.  Dempster, Mr.  R.J.  Henderson  and  T h e i r u n f a i l i n g help made t h i s t h e s i s p o s s i b l e .  I thank them a l l * The  U n i v e r s i t y of B r i t i s h Columbia awarded me  Dusen's F e l l o w s h i p  i n F o r e s t r y , Queen E l i z a b e t h S c h o l a r s h i p  U n i v e r s i t y Forest Fellowship,  I r e c e i v e d a d d i t i o n a l support  from Canada Department of F o r e s t r y and Research C o u n c i l of Canada* their  assistance.  Van  from the  National  I thank a l l these a g e n c i e s f o r  and  vi  TABLE OF CONTENTS Page ABSTRACT  *  i  ACKNOWLEDGEMENTS  v  TABLE OF CONTENTS  • • O O * 9 C O « O » * O O * * « 0 O O * O O O 0 O O « * 9 * « * * a «  L I S T OF TABLES L I S T OF FIGURES  VX viii  •o  o o o o * o * « o o * * * » * o o o « o o o < i « * o « * o « o < » * o « * t t  I X  INTRODUCTION..  1  GENERAL MENSURATIONAL CONSIDERATIONS  5  STEM FORM THEORIES - 1  15  STEM FORM THEORIES - 2  ,  20  DISTRIBUTION OF RADIAL GROWTH - PAST WORK  49  MATERIALS AND METHODS  5g  RESULTS PART  PART  • . • . . • • o . ? . . . o . « . « o . o . . . s . . . . . e . e o « « « . . o o . . « . . «  (A):  (B):  £>3  DISTRIBUTION OF RADIAL GROWTH ALONG STEMS OF DOUGLAS F I R  63  Stem Form F a c t o r s  74  IDENTIFICATION  OF THE CAUSAL  FACTORS  DETERMINING  THE FORM OF FOREST TREES  Subcortical  T e m p e r a t u r e s i n D o u g l a s F i r ....  1 ** Bcix*lc T h i c k r i s s s 2 - Moisture  • o » o o o o » « * o » » » « * « » © « » o » » «  Content  3 — I n s o l a t e d Stems  110  112 112  o f Bark . . o « . . o . . o . . . o « . . . . . . . . .  4 - Stems o f F o r e s t - G r o w n T r e e s  77  ............  112 113  5 - Temperature D i f f e r e n t i a l  113  6 - Crown Shade  114  7 - A i r Temperature G r a d i e n t s  114  8 - Heat P r o p a g a t i o n t h r o u g h B a r k  114  Vll  Page  PART ( C ) :  ©o©oo©o©oooeooo©©©©e©o©o©*©oe©oo  ConclllSlOnS  (B)  DlSCUSSlOn  (B) o e o o o © c o f i o o o o « e © o o e e © « « « o o o « o o e e  CORRELATION AND REGRESSION ANALYSIS BETWEEN THE AMOUNT OF RADIAL GROWTH OF DOUGLAS FIR AND SOME SELECTED WEATHER FACTORS  126  I n t r o d u c t i On  12&  o©aooooo«ooo©oo«©ocoQooeo©©o«©o©oo  Msthods snd. R s s u l t s C one In s i on s  (C)  DlSCUSSlOn  (C)  CONCLUDING REMARKS LITERATURE CITED APPENDIX0  117  oo©o©oo©©o©©©©o©o©o©©©©©©©©©  ©o©«o©ooo©o©o«*©o©o©©©©oo©o©o«©© o o o « o o o o « © o o c e « o o o « « e © o « o o « e o o ©  o o o © o 0 o o o © o o o o 0 o o o « o o o o o o o o o « o o o e o o o e » o o  o o o o o o o o o o « © e o © © © o o © © o o o « o o © o © o « © o © © © © « © © ©  DIAGRAMS 1 TO S3  © 0 © © © © * © © 0 © © © © © © © © © © © © © © © © © « 0 © ©  129 139 I/4.I  1/^2 I/4-/4-  177  viii  LIST OF TABLES Table I IT  III IV V  Page Basic  The averages of the c r i t i c a l widths o f earlywood and latewood l a y e r s , and t h e i r average l o n g i t u d i n a l p o s i t i o n i n the stem  VII VIII IX  The averages of r a t i o s o f the c r i t i c a l widths of earlywood and latewood l a y e r s ...........  70  The c o e f f i c i e n t s o f v a r i a t i o n o f the  XII  XIII  ""diniSn S i On *""X*clt 1 O S  *0«4«ooo0o0i>oooc>0O0OO6«*e*  Simple c o r r e l a t i o n c o e f f i c i e n t s between c r i t i c a l dimensions o f annual l a y e r s o f earlywood and latewood ... .<,..........  *71  72  Summary o f covariance and a u t o c o r r e l a t i o n a n a l y s e s of earlywood l a y e r s  130  Summary o f c o v a r i a n c e and a u t o c o r r e l a t i o n a n a l y s e s of latewood l a y e r s .  131  Von Neumann's r a t i o s (K) o f the weather tO  19^2  s e r i e s from  o«9«o*«*oeooo«e«o««o«oo«ooo«eo«9«ao«*«  Summary o f the simple c o r r e l a t i o n a n a l y s i s : the average width o f earlywood l a y e r s c o r r e l a t e d w i t h the average width o f latewood l a y e r s w i t h i n the S3.H16  XI  67 68  l^lO  X  ..  C o e f f i c i e n t s of v a r i a t i o n o f the c r i t i c a l dimensions o f growth l a y e r s ............ ...........  C 1*11 X C 3,1  VI  59  m e n s u r a t i o n a l data o f the sample t r e e s  y©3.1*  • • • o o a * o « 0 9 « > O 0 O * « o e o e o o o e o o « o c e o o o o o o o o o « «  3-33  Summary o f the m u l t i p l e c o r r e l a t i o n a n a l y s i s : mean width of earlywood l a y e r s c o r r e l a t e d w i t h mean monthly a i r temperature and w i t h t o t a l monthly p r e c i p i t a t i o n o f the current y e a r  136  Summary o f the m u l t i p l e c o r r e l a t i o n a n a l y s i s : mean width o f latewood l a y e r s c o r r e l a t e d w i t h mean monthly a i r temperature and w i t h t o t a l monthly p r e c i p i t a t i o n o f t h e current y e a r .........  137  Summary o f the m u l t i p l e c o r r e l a t i o n a n a l y s i s : the average width of earlywood l a y e r s c o r r e l a t e d w i t h the mean monthly a i r temperatures o f the p r e v i o u s S1HT1IT16T*  o e o 0 0 » 0 0 0 0 « o 0 0 O O 9 « » « e 0 « t t 0 0 9 0 0 O 0 0 O 0 O 0 0 0 « 0 0 e o 0 13^  ix  LIST OF FIGURES Following Figure  Page  1  The sampling scheme  2  Band o f earlywood between two bands o f latewood i n a s t r i p t r e a t e d with o i l - c a r b o n suspension .. Widths o f earlywood l a y e r s , t r e e No. 1 ,  3  y©3,r*S  4  19 5 ^ ""-^-9 ^2  ..............<<.......  oo©oo©©*o©o*©©ee©eoo©©©o©©©©©©eo  Widths o f latewood l a y e r s , t r e e No. 1 , years 1958—1962 o . . . o « o . . « o o e » e e o . « . o . .  6 l 6 l  &3  e o . . » . . o »  63  5  Cross s e c t i o n areas o f earlywood l a y e r s , t r e e No. 1 , years 195^~*1962 . . . . . . . . . . . . . . . . . . . .  63  6  Cross s e c t i o n areas o f latewood l a y e r s , t r e e No. 1 , y e a r s 1 9 5 ^ — 1 9 6 2 . . . . . . . . . . . . . . . . . . . .  63  7  The m i d - i n t e r n o d a l growth i n area o f earlywood, "tr*©6  8  10  11  12  13  14  X  «o«ooooo«ooooooooo«e«ooo»«ooooo©©«oo«  63  The m i d - i n t e r n o d a l growth i n area o f latewood, "fc 2?6 @  9  NO «  NO  O  1  O O O O O O O O O O O « O O 0 O © O O O « e © O O O » « O O O « O O O O ©  63  P o s i t i o n o f the maximum r i n g width i n r e l a t i o n t o stem-apex o f earlywood, and o f stem-base, trees 13M, 2 7 M , 3 2 M , 33M  66  P o s i t i o n o f maximum r i n g width o f earlywood, and of the stem-base i n r e l a t i o n t o stem-apex, t r e e s No« 1 , 3? 4> 5 j 6 . . . . a . . . . . . . . . . . . . . . . . .  66  P o s i t i o n o f minimum and maximum r i n g width o f earlywood, and o f the stem-base, i n r e l a t i o n to the stem-apex, t r e e s No. 8 , 9 . . . . . . o  66  P o s i t i o n o f minimum and maximum r i n g w i d t h o f earlywood, and o f t h e stem-base, i n r e l a t i o n t o the stem-apex, t r e e s No. 1 0 , 1 1  66  P o s i t i o n o f minimum and maximum r i n g width o f earlywood, and o f the stem-base, i n r e l a t i o n to the stem-apex, t r e e No. 1 2 •  66  P o s i t i o n o f minimum and maximum r i n g width o f earlywood, and o f the stem-base, i n r e l a t i o n t o the stem-apex, t r e e s No. 1 3 , 1 4 • • • • • •••  66  X  Following Page  Figure 15  Determinants of form, t r e e No. 1  72  '(' 16  Determinants of form, t r e e No. 11  72  17  Schematic diagram of the l o n g i t u d i n a l  sections  of average annual l a y e r s of xylem, t r e e No. 7 18-31  Values o f lambda 0.9,  t r e e s No. 1 t o  72  14,  32  Water content of o u t e r bark as percentage of oven-dry weight, forest-grown Douglas f i r  112  33  Water content of i n n e r bark as percentage of oven-dry weight, f o r e s t - g r o w n Douglas f i r  112  34  R e l a t i o n s h i p between the ambient and s u b c o r t i c a l temperatures at b r e a s t h e i g h t w i t h i n a stand of Douglas f i r , J u l y 28 - September 11, 3-6 p.m. ..  113  35  V e r t i c a l temperature g r a d i e n t s i n a stand of Douglas f i r between 2-4 p.m. on sunny ( S ) , cloudy  (C), and o v e r c a s t  (0) summer days-  114  36  Heat p r o p a g a t i o n through the bark of Douglas f i r  114  37  Width of earlywood, t r e e No. 14  129  38  Width of latewood, t r e e No. 14  129  39-52  Values of average l a y e r width i n d i c e s o f earlywood and latewood, t r e e s No. 8 t o 14,  respectively  ..  129  T h i s t r e e a f f o r d e d anew an example o f something I have observed i n s e v e r a l t r e e s o f good growth, i . e . t h a t although at the b u t t , a c c o r d i n g t o the number o f annual r i n g s , the t r e e s had a g r e a t e r increment than at a h e i g h t  o f 9 f e e t , the s i z e o f  the annual r i n g s was o f t e n g r e a t e r at a height o f 18 than at a height  of 9 f e e t .  to f i n d an e x p l a n a t i o n fortunate  I have been unable  f o r t h i s , but i f I am not  enough t o d i s c o v e r the cause, i t i s my  hope t h a t others, now t h e i r a t t e n t i o n i s c a l l e d t o it,  may be able t o do so. C.D.F. Reventlow  (1748-1827)  /  INTRODUCTION  The the  first  a r b o r e a l forms of p t e r i d o p s i d gymnosperms were  l a r g e p l a n t s which took hold of the l a n d  and  succeeded i n an environment the t r u e f e r n s never mastered. T h i s was  made p o s s i b l e by developing  of t h e i r axes.  The  secondary  thickening  power t o develop u n l i m i t e d wood and  bast  by the a c t i v i t y of a p e r p e t u a l l y young l a y e r of d i v i d i n g i n i t i a l s arranged i n the  cambial c y l i n d e r i s Nature's s o l u t i o n  t o the problem of support of v e g e t a t i v e  and  reproductive  organs of woody p l a n t s . The  cambial l a y e r has  been r e c o g n i z e d  the most s i g n i f i c a n t p r o g r e s s i v e  adaptations  the t r e e h a b i t p o s s i b l e , g r e a t l y advanced the higher p l a n t s .  When evaluated  i n t e r f a s c i c u l a r cambium has Nature's most w a s t e f u l herbs, the r e p r o d u c t i v e  as one  of  which, by making e v o l u t i o n of  i n terms of i t s a c t i v i t y ,  a l s o been considered  the  t o be one  i n v e n t i o n s because, i n c o n t r a s t  of  with  phase i n t r e e s occurs much l a t e r  and  with f a r g r e a t e r expenditure of m a t e r i a l s f o r c o n s t r u c t i o n t h e i r vegetative  organs as compared with the amount of  spend i n the p r o d u c t i o n  of seed.  the  of  materials  V e r t i c a l axes s e v e r a l f e e t i n 1  2  diameter,  o f which only a few outermost inches f u n c t i o n as  conduction pathways and storage organs,  are commonly formed  i n a p l a c e where a hollow column would seem t o be a more e f f i c i e n t way o f s o l v i n g the problem o f conduction, and  storage  support. The b a s i c p a t t e r n o f c e l l u l a r  phloem i s contained i n the cambium.  s t r u c t u r e o f xylem and  Any changes i n s t r u c t u r e  of these t i s s u e s , the number o f c e l l s and a l s o the k i n d and the arrangement o f c e l l s formed d u r i n g the processes o f the secondary t h i c k e n i n g are based on the changes i n the cambial The  tissue.  t o t a l t r e e volume o f wood, i t s q u a l i t y and a l s o i t s techno-  l o g i c a l p r o p e r t i e s are determined  by the number, s i z e , k i n d and  arrangement o f the xylem c e l l s d e p o s i t e d by the cambial and  i t s ramifications.  cylinder  W i t h i n any one c r o s s - s e c t i o n o f the stem  the number and s i z e o f the xylem c e l l s may vary c o n s i d e r a b l y i f measured a l o n g opposing  r a d i i and account  f o r the e c c e n t r i c  p o s i t i o n o f the p i t h and f o r the g e n e r a l l a c k o f c i r c u l a r i t y of the b o l e s .  The number and size- o f the xylem c e l l s vary a l s o  w i t h the d i s t a n c e from the stem apex accounting i n t h i s way f o r the g r a d u a l i n c r e a s e o f the t o t a l  c r o s s - s e c t i o n a l areas and  t h e r e f o r e a l s o f o r the u l t i m a t e l o n g i t u d i n a l shape o f the stem and f o r i t s t a p e r . t r e e during; i t s l i f e distinct  Any o t h e r i n t e r m e d i a t e shape assumed by a can be a s c e r t a i n e d i n t r e e s p o s s e s s i n g  annual r i n g s - b y a d e t a i l e d i n v e s t i g a t i o n o f the annual  l a y e r s o f xylem. The b o l e s o f c o n i f e r o u s t r e e s i n the temperate l a t i t u d e s can be viewed as aggregates  o f l a y e r s o f earlywood  3  and  of latewood formed d u r i n g a number of growing seasons.  diameter at any  p o i n t and at any  of the t h i c k n e s s e s of these  age  layers.  along the bole i s the  Therefore,  constant  the i n v e s t i g a t i o n o f  the dimensions of the annual l a y e r s of xylem i s the f i r s t i n studying the morphogenesis o f the Any  the  of i t s growth  the t h i c k n e s s of the i n d i v i d u a l growth l a y e r s cannot be along the b o l e .  sum  Since i t i s known t h a t  form of the t r e e stem v a r i e s d u r i n g the course  a l l the way  Any  stems of c o n i f e r o u s  step species.  c o n s i s t e n t p a t t e r n with r e s p e c t t o the amount of r a d i a l  growth might h e l p t o i d e n t i f y the f a c t o r s causing the t o produce such a p a t t e r n and, of a g i v e n  t o produce a bole  shape. The  importance of such knowledge i s obvious.  y i e l d of timber taper, and  i n the end,  cambium  sawn from a l o g depends l a r g e l y on the  form of the l o g .  economical one  The size,  C y l i n d r i c a l form would be the most  from the p o i n t of view of a sawmill  For a f o r e s t e r , both too r a p i d l y as w e l l as too  operator.  slowly t a p e r i n g  t r e e s are uneconomical; the g a i n secured by improving  the form  of t r e e s grown i n dense stands might be n u l l i f i e d by the l o s s i n the r a t e of growth. o f widely  On the  c o n t r a r y , an i n c r e a s e i n volume  spaced t r e e s might be o f f s e t by the d e t e r i o r a t i o n o f  both stem form and wood q u a l i t y .  The  economical value of a  stand i s t h e r e f o r e p a r t l y determined by the average form. can be r e g u l a t e d by r e g u l a t i n g the d e n s i t y of the  This  stand.  Growing space has been found t o be r e l a t e d s i g n i f i c a n t l y to the r a t e of growth, to the g r a v i t y of wood.  The  stem form, and t o the  specific  c o r r e c t e v a l u a t i o n of t h i s r e l a t i o n s h i p  4  w i t h i n a p a r t i c u l a r s o i l moisture regime the  can make more probable  l a r g e s t y i e l d s , i n the s h o r t e s t time, o f wood o f d e s i r e d  technological properties.  The i n i t i a l  s p a c i n g and a l l f u r t h e r  measures m o d i f y i n g the stand d e n s i t y seem t o be a b l e t o influence  stem form and q u a l i t y of wood more than the f i x e d  f a c t o r s due t o topography, macro-climate, s o i l and h e r e d i t y . The present study i s concerned with the o r g a n i z a t i o n of the r a d i a l growth o f some young p l a n t a t i o n - g r o w n and some unmanaged forest-grown Douglas f i r (Pseudotsuga m e n z i e s i i (Mirb.) Franco.)  I t i s an attempt t o d e s c r i b e the d i s t r i b u t i o n s  of the annual l a y e r s o f earlywood and o f latewood and t o evaluate them as determinants o f the stem form; t o i d e n t i f y the f a c t o r s r e s p o n s i b l e f o r t h e i r p r o p e r t i e s and, f i n a l l y , them i n a study of the e f f e c t s o f weather on r a d i a l  t o use  growth.  5  GENERAL MENSURATIONAL CONSIDERATIONS  The  term "form" r e f e r s t o the  t r e e -which i s c o n s i d e r e d of a diameter/height index  o f any  criterion  curve  such curve  stem d i a m e t e r w i t h of the  t o be  and  determines the  change i n h e i g h t  stem f o r m b u t  are  taper.  Boles  not  same. confer  do  of the  stems t o w h i c h t h e y In t h i s or trunk,  changeably.  By  forest  any  study  or a  form  are the  boloid; height  by  not  the  specified^  r a t e s of both  form  or  have tapers  or  "slow  true  form  shape o f a stem,  of the  northern  the  breast  form  temperate  height  height,  axis  cylindrical  of the  (Spurr  absolute  Jonson's  1952).  i s meant q u a d r a t i c  by  crown t h e  of  zone.  f o r m c l a s s and  quotient  or  inter-  vertical  designations  paraboloid  total  Boles  absolute  their relative  terms form  different  by  the  taper.  synonymous.  d i a m e t e r i s meant d i a m e t e r a t b r e a s t  i s meant t h e  stem  same f o r m may  terms form q u o t i e n t ,  of S c h i f f e l ' s  power  refer.  i s understood The  modification  the  The  exact  i n f o r m a t i o n r e g a r d i n g the  grown c o n i f e r s o f t h e  quotient  an  s h a f t , o r of a t r e e are used  form f a c t o r .  otherwise  are  t a p e r but  They r e f e r t o t h e  form f a c t o r  i s thus  Terms s u c h a s " r a p i d t a p e r "  taper"  the  having  stem p r o f i l e .  and  a  by r e v o l u t i o n  always of the  "taper"  r a t e s of absolute  always the  bole,  not  shape o f  r a t e o f change o f  i n shape have a l s o d i f f e r e n t  relative  different  generated  d e f i n i n g the  Terms " f o r m " and differing  a solid  longitudinal  height; live  Unless paraby  crown.  6  The  form of a geometric s o l i d has t o be known i f i t s  volume i s t o be a s c e r t a i n e d from measurements of i t s b a s a l diameter and  height.  The  e a r l y m e n s u r a t i o n a l s t u d i e s concerned  w i t h the e v a l u a t i o n o f the volume of f o r e s t t r e e s were conducted w i t h r e c o g n i t i o n o f t h i s f a c t and the form of the t r e e s r e c e i v e d a great  d e a l of a t t e n t i o n .  soon as a v a r i a b l e which was d i f f i c u l t to assess. the exact w i t h the  Form was  h i g h l y unstable  and  classified  a l s o most  Simple mathematical e x p r e s s i o n s  describing  p r o f i l e of the geometric s o l i d s could not be same degree of accuracy t o the  T h i s i s because t r e e stems are each of which may  paraboloid,  and  applied  stems of a l l t r e e s .  composites of a number of  solids,  have a d i f f e r e n t shape only approaching t h a t  o f an i d e a l geometric s o l i d .  conifers.  stems of  Truncated n e i l o i d , frustum o f a  cone are those most f r e q u e n t l y encountered i n  They occupy p o r t i o n s of the  and the r a t e of t h e i r absolute  stem of v a r y i n g  t a p e r may  differ  length  (Newnham  195&S  A l t h e r r I960). Form may  be  considered  a l s o as a product of  several  components, namely: 1.  shape of the main p o r t i o n o f the  stem above the  n e i l o i d a l base which can be n e i l o i d a l ,  c o n i c a l or  paraboloidal; 2.  r a t e of  taper;  3.  amount of upward e x t e n s i o n  4«  bark t h i c k n e s s  (Behre  of butt  1927).  swell,  and  7  The reference  l a s t two  components are important i n t h a t  diameter of most measures of form l i e s w i t h i n a zone  a f f e c t e d by the v a r y i n g amounts of butt  s w e l l , which i s  enveloped by a l a y e r of bark of v a r i a b l e t h i c k n e s s . of butt height  the  s w e l l may  be  Influence  such t h a t the v a r i o u s types of breast  form f a c t o r s cannot be used as v a l i d c r i t e r i a of form.  Form q u o t i e n t s may i n a s i m i l a r way,  be a f f e c t e d by butt  s w e l l and bark  or i n a d i f f e r e n t way,  thickness  depending upon whether  t h e i r upper diameter i s measured w i t h i n the r a p i d l y t a p e r i n g bole w i t h i n the crown or whether i t i s measured w i t h i n slowly t a p e r i n g bole below the crown. variability may  or may  i n form as i n d i c a t e d by  the  Thus, the amount of  standard measures of form  not agree with the a c t u a l amount of v a r i a b i l i t y  present. V a r i a b i l i t y i n form w i t h i n t r e e s of the diameter c l a s s was  found t o be about as great as the  v a r i a t i o n i n form i n the e n t i r e stand ences i n stand d e n s i t y , age,  and  v a r i a t i o n i n volume f o r a given  (Behre 1 9 2 7 ) .  s i t e q u a l i t y may  the  same age,  diameter and h e i g h t ,  same stand, may  total Differ-  cause more  s i z e c l a s s than a d i f f e r e n c e  of a thousand m i l e s i n range (Behre 1927)• of the  average  Individual trees  growing side by side i n  d i f f e r by as much as 20 per cent or more  i n t h e i r cubic content  (Clark 1 9 0 2 ) .  Trees of the same  diameter and height growing on c o n t r a s t i n g s i t e s were found t o d i f f e r i n volume by as much as 30 per cent Glavac 1 9 6 4 ) .  (Emrovic  and  Any d i s t u r b a n c e of the stand d e n s i t y b r i n g s about changes i n the form o f the r e s i d u a l t r e e s and may p r o f o u n d l y the e s t i m a t i o n o f t h e i r volume* western y e l l o w pine  affect  In the case of  (Pinus ponderosa)« t r e e s were found  with  form q u o t i e n t as low as 0 . 4 5 0 and with volumes 30 per cent below the average.  A l s o , t r e e s were found having a form  q u o t i e n t as high as 0o850 and with volume 20 per cent above the average volume (Meyer 1931)» A range of form q u o t i e n t s from 0.550 t o 0.850 was not unusual i n an unmanaged red spruce and white pine f o r e s t (Behre 1932).  Form f a c t o r s of 3248 Scotch pine  s v l v e s t r i s ) stems from managed stands ranged 0.550,  c o e f f i c i e n t of v a r i a t i o n b e i n g 7*5  I960).  (Pinus  from 0 . 3 1 0  per cent  (Grochowsk  A range of form f a c t o r s from O.34O t o O.52O was  i n second  growth Douglas f i r (Smith et, a l . 1 9 6 l ) .  q u o t i e n t s measured on 751  spruce  to  The  found form  stems i n the e a s t e r n United  S t a t e s f l u c t u a t e d between O.462 and 0 . 5 6 7  ( C l a r k 1902).  t r u e form f a c t o r s of Hohenadl, u s i n g a r e f e r e n c e  The  diameter  measured at a h e i g h t equal t o 10 per cent of the t o t a l height (Prodan 1951), were as low as O.38O f o r Scotch pine and  as  high as 0 . 6 2 0 f o r Norway spruce  1958;  ( P i c e a a b i e s ) (Dittmar  A l t h e r r 1953). The i n t e r s p e c i e s v a r i a b i l i t y i n form s m a l l e r than the i n t r a s p e c i e s v a r i a b i l i t y .  seems t o be  However, d i f f e r -  ences i n volume between b l a c k and red spruces of the same diameter  and height amounted t o 12 per cent throughout  range of s i z e c l a s s e s (Spurr 1952).  F o r the same  the  diameter  9  and h e i g h t , and  11  volume of Douglas f i r was,  on the average, 10,  per cent l e s s than t h a t of Norway spruce,  Scotch pine, i n t h a t order  white f i r and  (Hausser and B o l s i n g e r 1956).  under bark form of a l l important B r i t i s h c o n i f e r s was s t a n t i a l l y the  I t was  The  sub-  same f o r the g r e a t e r p a r t of the l e n g t h  t h e i r stems a f t e r the i n f l u e n c e of the b u t t inated.  16  s w e l l was  of elim-  only towards the t i p t h a t marked d i f f e r e n c e s  began to appear (MacDonald 1932,  1933)»  Fast t a p e r combined with l a r g e butt s w e l l  was  observed i n c o n i f e r s on swampy s i t e s ; the t r e e s from upland s i t e s and  from the r i d g e s showed the l e a s t amount of butt  s w e l l and  a l s o tapered  less  (Spurr 1952)o  Highly v a r i a b l e  butt s w e l l amounted t o 5 per cent of the t o t a l volume i n some c o n i f e r s over 16 with any was  inches i n diameter and  could not be c o r r e l a t e d  (Behre 1935)  of the v a r i a b l e s analysed  <• Butt  a s s o c i a t e d with crown development i n white pine;  with long and wide crowns were found t o have g r e a t e r b u t t s w e l l (Gevorkiantz  and  s w e l l i n g a f f e c t e d the measurement of form of 472  i n height, height  root s w e l l i n g was  12  Root Douglas f i r  i n t r e e s over 30  found t o extend as f a r as  i n almost every t r e e , and the amount of s w e l l  with the g i r t h  trees  considerably  Hosley 1929)«  stems i n about 90 per cent of the cases;  (MacDonald 1933 )<>  Butt  swell  feet  breast  increased  s w e l l extended f r e q u e n t l y  f e e t and more above ground i n most c o n i f e r s growing i n  B r i t i s h Columbia (Claughton - W a l l i n and McVicker 1 9 2 0 ) . Determination o f the average form quotient was  a  more important source of e r r o r i n the e s t i m a t i o n o f volume than  10  e i t h e r the allowance f o r b u t t s w e l l or bark t h i c k n e s s , but the l a t t e r was  almost as s i g n i f i c a n t as the former i n the l a r g e r  t r e e s (Behre 1935)»  No a p p r e c i a b l e d i f f e r e n c e s between form  q u o t i e n t s c a l c u l a t e d from measurements o u t s i d e the bark, as compared with underbark form q u o t i e n t s , were found i n white pine  (Gevorkiantz and Hosley 1929)»  l a r g e as 40 per cent may  D i f f e r e n c e s i n volume as  occur i n some A u s t r a l i a n s p e c i e s i f  bark t h i c k n e s s i s d i s r e g a r d e d i n t h e i r form assessment  1956)»  (Gray  Percentage of bark v a r i e d along the bole of B r i t i s h  c o n i f e r s i n a r e g u l a r and c o n s i s t e n t manner; i n the middle of the stem, i t was l e a s t v a r i a b l e and s m a l l e r than e i t h e r at the t i p or at b r e a s t h e i g h t . along the upper f i f t h  The r a p i d i n c r e a s e i n bark percentage  of the bole was  c o n i f e r s i n v e s t i g a t e d (MacDonald  c h a r a c t e r i s t i c of a l l  1933)«  Strobus) t r e e s of e a s t e r n U«S»A-» behaved and Hosley 1 9 2 9 ) »  White pine similarly  (Pinus (Gevorkiantz  Percentage o f bark at breast h e i g h t  decreased with diameter or with g i r t h  1962; MacDonald 1933)p o r was constant  (Grochowski 1961; (Behre 1927).  Korsun Consistent  r e g i o n a l d i f f e r e n c e s i n bark t h i c k n e s s at breast h e i g h t i n t r e e s of the same diameter were found i n pine by Wiedemann ,  (I.932) and Korsun (1962). I t i s e v i d e n t t h a t form of i n d i v i d u a l t r e e s as measured by v a r i o u s methods v a r i e s c o n s i d e r a b l y w i t h i n any one .. specieso  In s p i t e of t h i s , modern methods of volume e s t i m a t i o n  do not r e g a r d measures of form as e f f i c i e n t  statistics.  The  s t o c h a s t i c r e l a t i o n s h i p e x i s t i n g between h e i g h t , diameter and volume of stems i s u s u a l l y determined e m p i r i c a l l y from a l a r g e  11  number of measurements of diameter and h e i g h t *  The  resulting  volume t a b l e s are thus based on a t r e e of an average form; because of t h i s they are not p r e c i s e means of volume e s t i m a t i o n of i n d i v i d u a l t r e e s .  The  average form of most  coniferous  s p e c i e s of the northern temperate zone approaches c l o s e l y t o t h a t of a q u a d r a t i c p a r a b o l o i d .  This fact  can be  deduced from a  s c r u t i n y of the r e s u l t s of volume s t u d i e s conducted i n the As e a r l y as 1883  S t r z e l e c k i suggested t h a t t h e r e  past. was  a d i r e c t p r o p o r t i o n a l i t y between the p a r a b o l o i d a l form f a c t o r and form q u o t i e n t on one  hand, and the form f a c t o r and  quotient of a t r e e bole on the o t h e r .  form  Hence, there was  a  f u n c t i o n a l r e l a t i o n s h i p between the form f a c t o r and between the form q u o t i e n t expressed  of t r e e b o l e s  by the  (Gray 1943)•  equation  form f a c t o r = ( 0 . 7 1 ) form Kunze's formula  published  in  quotient.  1891,  form f a c t o r = form q u o t i e n t i s a d i f f e r e n t f o r m u l a t i o n o f the values of the- constant  Scots pine r e s p e c t i v e l y . were 0.219  Average  e s t a b l i s h e d empir-  f o r Norway spruce  and  Those d e r i v e d i n U.S.A. f o r f i r and (Clark 1902;  constant  Belyea 1925).  The  i s , i n the case of a  0.207.  Reynard (1884)j estimated  same r e l a t i o n s h i p .  and 0.20  and 0.218  t h e o r e t i c a l v a l u e ' o f the paraboloid,  constant,  i n Kunze's equation,  i c a l l y i n Europe, were 0.21  spruce  T h i s r e l a t i o n s h i p was  working with the  concepts of  Strzelecki,  the volume of t r e e stems i n S w i t z e r l a n d by the  V = 0.555 d D H  formula  12  where  V d D H =  =  =  cubic volume, mid-point diameter, b a s a l diameter, t o t a l height.  Reynard's formula ' . . . . I . :  can be w r i t t e n as  ?.-?7l&  ,  I n t h i s form i t g i v e s the volume of the p a r a b o l o i d i n cubic f e e t and  compares f a v o u r a b l y with Spurr's  rule-of-thumb f o r  e s t i m a t i o n o f volume of standing t r e e s  100 4  v  which l a t t e r r u l e was analysis  (Spurr  d e r i v e d by methods o f r e g r e s s i o n  1952).  Similarly,  d e r i v e d from 16 mostly broadleaved  16  o f the volume  equations  s p e c i e s of B r i t i s h  Columbia  averaged V = nine equations  0.22  + 1.3  1957),  (Smith and Ker  f o r c o n i f e r o u s s p e c i e s c o u l d be combined t o  2 V =  0.24 j[Q§ +-©.17  (Smith and Breadpn  In the l o g a r i t h m i c volume equation Schumacher  1964).  of Bruce  and  (1950), log V = a log D 4 b log H + log C  the power of D equals  2.0  and t h a t of H equals 1.0  i n the  t h a t i t i s a p p l i e d t o a bole which has a p a r a b o l i c form. h o l d s i n a l l cases when the form f a c t o r of a p o p u l a t i o n t r e e s i s constant  f o r a l l s i z e c l a s s e s sampled and  independent of diameter and h e i g h t . the powers of D and  The  It of  therefore  respective values  of H based on a n a l y s e s  of 49  ease  different  of  .13  non-form volume t a b l e s i n the e a s t e r n and s o u t h e a s t e r n U.S.A. were 1.94 0.94  and 1.12  f o r p i n e s and spruces combined,  f o r spruces and f i r s combined.  and 1.88  and  In f i v e s e t s o f form c l a s s  volume t a b l e s the slope exponents of D were, without exception, 2.0  (Spurr 1 9 5 2 ) . The value of Hohenadl s t r u e form f a c t o r i s , i n the T  case of a p a r a b o l o i d , 0.555*  Average Hohenadl's form f a c t o r  c a l c u l a t e d f o r v a r i o u s s p e c i e s and numbers of stems were as follows: O.555 f o r 1,330  Norway spruces (Krenn  1944)  0.549 f o r 13,310 Norway spruces (Zimmerle i n A l t h e r r  1953) O.55O f o r 543 European l a r c h e s (Zimmerle i n A l t h e r r  1953) O.55O f o r a " l a r g e number" o f Norway spruces (Schilling  i960).  R e c o g n i t i o n o f the f a c t t h a t , g i v e n a l a r g e mass o f data, the m a j o r i t y o f the c o n i f e r s o f the n o r t h e r n temperate zone has, very approximately, the same form from the top to the bottom i s r e f l e c t e d i n the dictum o f Jonson: The p e r c e n t i l e t a p e r i s the same i n a l l "normal" spruce o f the same form c l a s s n o t w i t h s t a n d i n g the d i f f e r e n c e s i n height and diameter. A l a r g e t r e e i s developed e x a c t l y as a s m a l l t r e e , p r o v i d i n g t h a t both have the same form q u o t i e n t . ( C l a u g h t o n - W a l l i n and McVicker 1 9 2 0 ) . The method o f volume e s t i m a t i o n developed by Jonson new  ( 1 9 2 8 ) , the  concepts o f c o n s t r u c t i n g the t a p e r curve volume t a b l e s  formulated by Baker (1925) and by B e l y e a ( 1 9 3 1 ) , as w e l l as the method of Hohenadl  (Krenn and Prodan 1944)  r e c o g n i t i o n o f the f a c t t h a t form i s ,  are a l l based on the  on the average, independent  14  of diameter and h e i g h t .  The method of Jonson i s f u r t h e r  memorable i n t h a t i t uses the e x t e r n a l c h a r a c t e r i s t i c s of the crown i n the e s t i m a t i o n o f the form of the b o l e .  I t s working  h y p o t h e s i s i s M e t z g e r s "wind pressure t h e o r y " o r " g i r d e r t  t h e o r y " of b o l e  formation.  15  STEM FORM THEORIES - 1 Most s c i e n t i f i c  concepts have t h e i r o r i g i n i n  experiment, o r are supported by experiment t o some e x t e n t . Other kinds of s c i e n t i f i c they may  t h i n k i n g are pure s p e c u l a t i o n s ;  h e l p t o e x p l a i n n a t u r a l phenomena but t h e i r s t a t u s  should always be kept i n mind.  T h e o r i e s are schemes of  w i t h assumptions chosen t o f i t experimental also contain speculative ideas.  scientific  evidence; they  In examining any  scheme i t i s necessary to separate  thought may  conceptual  i t s experimentally v e r i f i e d  concepts from the s p e c u l a t i v e i d e a s which  may  accompany them. The  concepts u n d e r l y i n g the t h e o r i e s of stem form-  a t i o n were t e s t e d e x p e r i m e n t a l l y i n l a r g e t r e e s under f o r e s t c o n d i t i o n s i n only a few the comparatively  isolated instances.  This applies to  recent hormonal theory as w e l l as t o the  n u t r i t i o n a l and mechanistic t h e o r i e s both of which were formulated more than 80 y e a r s ago.  At present, the nature  the above t h e o r i e s , and a l s o of the water conductive i s thus l a r g e l y  speculative.  T h i s statement  of  theory,  i s supported  the r e s u l t s of v a r i o u s r e s e a r c h e s , many of which may  by  have only  an i n d i r e c t b e a r i n g on the morphology of t r e e stems. The  uneven d i s t r i b u t i o n of r a d i a l increment  bole has been a t t r i b u t e d t o the uneven d i s t r i b u t i o n utilization  of e l a b o r a t e d foods w i t h i n the cambial  along the  and cylinder,  not only by e a r l y w r i t e r s but a l s o by some contemporary investigators.  16  The  q u a n t i t y of foods a v a i l a b l e f o r growth at  any  p o i n t w i t h i n the erown bole i s assumed t o stand i n a d i r e c t p r o p o r t i o n to the q u a n t i t y of f o l i a g e above the p o i n t i n question.  In t h i s way  the maximal c o n c e n t r a t i o n o f photo-  synthates i s supposedly  reached  at the base of the l i v e  where maximal r a d i a l growth w i l l o c c u r .  Hardly any  the amount o f r a d i a l growth t a k e s p l a c e a l o n g the p o r t i o n o f the stem.  The  change i n  branchless  b o l e s of open grown c o n i f e r s assume  the c o n i c a l shape of t h e i r crowns.  Suppressed t r e e s produce  only a l i m i t e d q u a n t i t y of foods, consumed i n the course t h e i r b a s i p e t a l t r a n s p o r t , r e s u l t i n g i n depressed  Accumulation  near the r o o t c o l l a r i n the e a r l y s p r i n g , ..and  i n c r e a s e d growth at the base, i s due  t o the d e l a y i n r a d i a l  growth of r o o t s which, i n t u r n , i s caused a t u r e s (Topcuoglu  of  radial  growth or, i n extremis, m i s s i n g r i n g s at the base. of food substances  crown  1941;  Onaka  by low  s o i l temper-  1950a).  I n t e r p r e t a t i o n o f H a r t i g s n u t r i t i o n a l t h e o r y by ?  Paul  (1930),  and by Larson  Topcuoglu and Onaka.  ( I 9 6 3 ) , d i f f e r s from t h a t by  A c c o r d i n g t o Larson, H a r t i g e v a l u a t e d a l l  the growth i n terms of an e q u i l i b r i u m between a s s i m i l a t i o n  and  transpiration.  by  The  i n t e n s i t y of t r a n s p i r a t i o n , c o n s i d e r e d  H a r t i g t o be a f u n c t i o n o f the s i z e of the l i v e  crown, i s the  c h i e f f a c t o r c o n d i t i o n i n g the growth of conductive t i s s u e , i . e . , earlywood. ilation,  and  P r o d u c t i o n o f latewood i s due t o i n c r e a s e d assimi t s f o r m a t i o n begins only a f t e r the  transpirational  17  demands are met*  Any  changes of the s i z e of l i v e crown,  as i t s i n c r e a s e a f t e r t h i n n i n g s , o r i t s r e d u c t i o n by  such  pruning,  i s r e f l e c t e d i n an i n c r e a s e d f o r m a t i o n of earlywood i n the former, case; or i n a decreased of latewood i n the l a t t e r  f o r m a t i o n o f earlywood i n f a v o r  case.  M e c h a n i s t i c "wind pressure t h e o r y " or " g i r d e r theory", conceived by Schwendener i n 1874  and  subsequently  implemented  by Metzger, maintains t h a t wind i s the prime mover shaping b o l e s of t r e e s . bending  the  Force of the wind a g a i n s t the crown s e t s up  s t r e s s e s i n the stem.  These s t r e s s e s are assumed t o be  u n i f o r m l y d i s t r i b u t e d along the b r a n c h l e s s l e n g t h o f the stem and t o a c t as cambial  stimuli.  Amount of r a d i a l growth at  p o i n t a l o n g the b o l e beneath the l i v e the magnitude of s t r e s s developed  any  crown i s p r o p o r t i o n a l t o  at t h a t p o i n t .  Accordingly,  the r e s u l t i n g shape of the stem i s t h a t of a beam of uniform r e s i s t a n c e t o bending.  I t s p r o f i l e i s d e s c r i b e d by a cubic  parabola h a v i n g i t s v e r t e x i n the c e n t e r of g r a v i t y of the crown (Trendelenburg Jaccard conductive  1937;  H i l d e b r a n d t 1954;  (1915> 1930)  concluded,  c a p a c i t y of the r e c e n t annual  Gray 1 9 5 6 ) .  a f t e r determining  r i n g s , t h a t growth i n  c r o s s - s e c t i o n a l area between the r o o t s and the base of the crown was  such as t o permit uniform and  t r a n s p o r t t o the crown.  the  live  continued water  Dead branches remaining  on the stem ,  reduce the c r o s s - s e c t i o n a l area of the most recent r i n g s and, t h e r e f o r e , t h e i r conductive c a p a c i t y c o u l d be maintained  capacity.  Uniform  conductive  o n l y when the c r o s s - s e c t i o n a l area  18  of the most recent was  rings increased  reduced by dead branches.  increase  of r i n g width with  at the  Hence the  same r a t e at which i t commonly  occurring  height.  Every f a c t o r f a v o r i n g the growth of the  crown as a  s i t e of t r a n s p i r a t i o n causes a c o r r e s p o n d i n g i n c r e a s e roots.  Increased growth of r o o t s i s , however, p o s s i b l e  a f t e r they o b t a i n foods from the v i s u a l i z e d as composed of two hydrates .  regions  A t r e e can  annual l a y e r s occurs i n the  only  be  competing f o r carbostem i s under the  The  zone between the two  explained  and  in similar fashion.  changes of form are probably accompanied by of the minimum width of the  the  competing  S t r i k i n g d i f f e r e n c e s i n date o f resumption  r o o t s of a t r e e can be  of  minimum r i n g width of  c e s s a t i o n o f c e l l d i v i s i o n observed i n branches, stems  the h e i g h t  the  crown, whereas growth of the lower p a r t  stem i s dominated by r o o t s .  regions.  crown.  Growth of the upper part of the  i n f l u e n c e o f the the  of  and Gradual  small changes of  annual l a y e r as i t  moves upwards. The  hormonal t h e o r y a t t r i b u t e s the uneven  d i s t r i b u t i o n o f xylem c e l l s along the b o l e t o the of the growth substances which can be detected meristems d u r i n g the  growing season and  concentration,  stimulate  (Soeding 1940,  Onaka 1950  s i d e r e d t o be the  the  i n the  cambial  which, i n s u i t a b l e  p e r i c l i n a l d i v i s i o n s i n cambium b).  The  elongating  c h i e f producers of auxin and  d i s t r i b u t o r s of the  gradients  cambial s t i m u l i .  buds are the  In t h i s way  con-  sole they c o n t r o l  a r c h i t e c t u r e of the whole t r e e , i n c l u d i n g branches and  roots  (Larson 1 9 6 2 ) .  There i s a c o r r e l a t i o n i n time between the  resumption o f the cambial a c t i v i t y and renewal o f bud growth. High a u x i n l e v e l s i n shoots i n s p r i n g cause wide v e s s e l f o r m a t i o n i n angiosperms. of  Mature  l e a v e s produce  small amount  auxin, which may account f o r the continued p r o d u c t i o n o f  latewood a f t e r e x t e n s i o n growth  stopped (Wareing 1 9 5 8 ) .  Auxin i s a c o l l e c t i v e name f o r a complex o f phytohormones such as i n d o l e a c e t i c a c i d , k i n e t i n and g i b b e r e l l i n s which are o f a b s o l u t e n e c e s s i t y f o r some fundamental  reactions  t a k i n g p l a c e i n the d i v i d i n g and growing c e l l s w i t h c e l l u l o s e w a l l s (Maskova  1948, Thimann 1952, Wort i 9 6 0 ) .  Auxin i s  sometimes assumed t o l o o s e n some l i n k a g e s i n the c o l l o i d a l framework o f the c e l l w a l l .  T h i s l e a d s t o a decreased w a l l  pressure and t o s t r e t c h i n g o f the cytoplasm and o f the c e l l w a l l under osmotic uptake o f water.  The next step i s the  f o r m a t i o n o f the new w a l l m a t e r i a l and the growth by intussusception of  (Burstroem 1 9 5 7 ) .  Decrease o r disappearance  auxin i s always a s s o c i a t e d w i t h the c e s s a t i o n o f the  r a d i a l growth even i n cases when r e s e r v e foods abound. Auxin moves downward through protophloem and phloem i n a wave l a s t i n g a few weeks. c l o s e l y by cambial d i v i s i o n  T h i s movement i s f o l l o w e d  (Avery et a l . 1937)*  Due t o  g r a v i t y , a u x i n accumulates on the lower s i d e o f h o r i z o n t a l organs.  Both k i n d s o f r e a c t i o n wood, namely "compression wood"  on the lower side of i n c l i n e d c o n i f e r o u s t r u n k s and " t e n s i o n wood" on the upper s i d e of hardwood stems are due t o uneven c o n c e n t r a t i o n s o r q u a n t i t i e s of auxin (Wareing 1958; and Nasr 1 9 6 l ) .  Wareing  20  STEM FORM THEORIES - 2 The common b a s i s o f the n u t r i t i o n a l ,  conductive,  m e c h a n i s t i c and hormonal t h e o r i e s i s the l i v e crown. to  According  the "wind pressure theory", the i n t e n s i t y o f the wind a t t a c k  i s p r o p o r t i o n a l t o the s i z e o f the l i v e  crown, presumably a t  a l l wind v e l o c i t i e s and f r e q u e n c i e s , and at a l l stand d e n s i t i e s . T h e r e f o r e , the s i z e o f the l i v e stem form. the  The s i z e o f the l i v e  crown i s an i n d i c a t o r o f the crown and the d i s t r i b u t i o n o f  f o l i a g e i n the crown are a l s o important f o r both the con-  d u c t i v e and the n u t r i t i o n a l t h e o r i e s .  Furthermore, i t i s a l s o  believed that The e x t e r n a l f a c t o r s of c l i m a t e and environment e x e r t t h e i r i n f l u e n c e d i r e c t l y on the growth o f crown and only i n d i r e c t l y on the development o f wood ... by a c t i v a t i n g p h y s i o l o g i c a l processes o f t e n q u i t e f a r removed from the a c t u a l s i t e o f wood p r o d u c t i o n (Larson 1963a).• Size o f the crown i s , i n the m a j o r i t y o f cases, l o o s e l y c o r r e l a t e d w i t h v a r i o u s measures of form (Gevorkiantz and Hosley 1929; Jonson 1928; Krenn 1944; Grochowski 1961). A more d e f i n i t e r e l a t i o n s h i p seems t o e x i s t between form and d e n s i t y o f the stand the  (Wright 1927), which i n t u r n determines  depth o f the l i v e  crown i n stands with a c l o s e d canopy  (Brown 1962). The most the  s t r i k i n g changes i n form were observed a f t e r  d e n s i t y of the stand was changed by t h i n n i n g s and c u t t i n g s  (Meyer 1931; Behre 1932; Pearson and F o l l w e i l e r 1927; Yerkes I 9 6 0 ; Myers I 9 6 3 ) .  Such changes are u s u a l l y e x p l a i n e d i n terms  21  o f the m e c h a n i s t i c theory,,i.e» they are  commonly a t t r i b u t e d  a heightened wind a t t a c k (Windirsch 1936,  I963).  I f the  forces  of wind are not  suppressed t r e e s , then the building material  Assmann i 9 6 0 , Myers  important, e.g.,  nearness of crown as the  i s c o n s i d e r e d to be  to  in  the  source  of  s i g n i f i c a n t (Gevorkiantz  and Hosley 1929). Both the  n u t r i t i o n a l and  the  conductive  theories  c o r r e l a t e r a d i a l growth w i t h food p r o d u c t i o n and d i s t r i b u t i o n , as w e l l as with.the water l o s s by (Jaccard  1915,  1928,  stomatal t r a n s p i r a t i o n  Topcuoglu 1941;  Onaka 1950 a ;  A p r o p o r t i o n a l i t y between the  quantity  f o l i a g e , and  d i s t r i b u t i o n of r a d i a l growth  along the  between r a t e and  bole,  of crown and theories  as w e l l as the  quantity  (Fraser  d i s t r i b u t i o n of  p r o p o r t i o n a l i t y between the  of water t r a n s p i r e d ,  et a l . 1964,  Intensity  and  Larson 1963c),  of net  i s assumed by  J a c c a r d 1915,  size  both  1930).  a s s i m i l a t i o n of CO2  and  stomatal t r a n s p i r a t i o n are determined l a r g e l y by  the  rate  of  factors  governing s i z e of the  stomatal a p e r t u r e .  d i r e c t e f f e c t s on the  p h o t o s y n t h e t i c t i s s u e s , temperature i s  believed  t o be a f a c t o r important i n stomatal c o n t r o l  therefore, the  rate  i n c o n t r o l l i n g the  of the  increased  r a t e of the  net  stomatal t r a n s p i r a t i o n and,  of water'conduction and that  Apart from i t s  absorption.  t r a n s p i r a t i o n i s due  temperature, the  Curtis  photosynthesis,  possibly,  the  rate  (1936) maintained  s o l e l y to a r i s e i n l e a f  vapor p r e s s u r e g r a d i e n t  b e i n g a f a c t o r of major importance.  and,  from l e a f t o a i r  Indeed, t r a n s p i r a t i o n  at  22  30°C i s n e a r l y t h r e e times as f a s t as at 20°C (Meyer et alo I960).  T r a n s p i r a t i o n f o l l o w e d very c l o s e l y net r a d i a t i o n  r e c e i v e d by a l e a f as long as t h e r e was s u f f i c i e n t moisture  (Gates 1 9 6 2 ) .  soil  Leaves respond t o t h e i r e x t e r n a l  environment i n accordance  with accepted heat t r a n s f e r t h e o r y .  They tend t o assume the temperature  o f the surrounding a i r .  Leaves are heated by r a d i a n t energy and cooled p r i m a r i l y by conduction o f energy t o the a i r . Leaves i n s u n l i g h t are heated t o a few degrees c e n t i g r a d e above a i r temperature f o r t h i n l e a v e s t o 30°C, o r more, f o r very t h i c k l e a v e s (Loomis 1965; Knoerr and Gay 1 9 6 5 ) .  The o v e r h e a t i n g o f l e a v e s i s  l i n e a r l y r e l a t e d t o the i n t e n s i t y o f r a d i a t i o n .  Temperature  of the exposed t o p s u r f a c e s o f l e a v e s i n wind shadow can be, on the average,  10 times as h i g h as the temperature  l a y e r near the ground (Casperson 1 9 5 7 ) . temperatures  o f the a i r  Leaves may reach  as h i g h as 37°C and be warmer than the a i r by  13 - 20°C ( F r i t z s c h e 1 9 3 2 ) .  Temperature increments  due t o the  p o s i t i o n o f l e a v e s may be more than 7 C and may i n c r e a s e trans' G  p i r a t i o n by up t o 230% (Konis 1 9 5 0 ) .  Exposed l e a v e s may be  12°C warmer than shaded l e a v e s ; a l e a f p e r p e n d i c u l a r t o i n s o l a t i o n may be 3 ° t o 8°C warmer than a l e a f p a r a l l e l t o insolation  (Waggoner and Shaw 1952; W e l l i n g t o n 1 9 5 0 ) .  These  f i g u r e s i n d i c a t e c l e a r l y t h a t d i r e c t p r o p o r t i o n a l i t y between the s i z e of a crown and between the q u a n t i t y o f water l o s t by t h i s crown may not e x i s t i n the f o r e s t .  23  Most o f the l e a v e s d u r i n g  s t i l l weather and a l l  l e a v e s d u r i n g a wind p e r i o d l o s e l a r g e amounts o f water i f the stomates are open so t h a t p h o t o s y n t h e s i s may go on ( C r a f t s .et a l . 1949)•  Increased t r a n s p i r a t i o n , d e s i c c a t i o n o f l e a v e s ,  c l o s u r e of stomates, and r e s u l t i n g c u r t a i l m e n t production  i n the  o f foods, can a l s o be caused by wind (Satoo  1957)•  In t h i s , e f f e c t s o f wind and e f f e c t s o f temperature cannot be separated, j u s t as g r a d i e n t s  o f a i r temperature cannot be  separated from the wind g r a d i e n t s ; each other  (Best in Geiger 1 9 5 0 ) .  they a f f e c t and determine Rapid t r a n s p i r a t i o n caused  by wind i s not harmful as l o n g as the r a t e o f water b a l a n c e s the r a t e o f water l o s s (Satoo 1 9 5 7 ) . rate of absorption  absorption  As a r u l e , the  tends t o l a g behind the r a t e o f t r a n s -  p i r a t i o n so t h a t water d e f i c i t s develop i n p l a n t s growing i n moist s o i l  (Kramer i 9 6 0 ) o r even i n p l a n t s with t h e i r r o o t s i n  water o r n u t r i e n t s o l u t i o n (Kramer 1 9 3 7 ) .  Both s a t u r a t e d and  dry s o i l s reduce the r a t e of apparent p h o t o s y n t h e s i s i n A p e r i o d o f 30 t o 60 hours was necessary f o r water  conifers.  t o pass from the s o i l t o the f o l i a g e i n some (Clark I 9 6 I ) .  seedlings  Absorption  coniferous  l a g seems t o be caused by  the r e s i s t a n c e o f f e r e d by the c e l l membranes o f the r o o t i n g system.  Stem r e s i s t a n c e i s probably a n e g l i g i b l e f a c t o r i n  absorption  i n woody s p e c i e s  (Kramer 1 9 3 8 ) .  In c o n i f e r o u s  s e e d l i n g s t e s t e d without r o o t s , a change i n a b s o r p t i o n f o l l o w e d the change i n t r a n s p i r a t i o n (Satoo 1957)« entered  rate  Water  more r a p i d l y from the s o i l through dead than through  24  l i v i n g r o o t s (Kramer 1933)*  Root pressure was denied any  i n f l u e n c e i n water t r a n s p o r t i n p l a n t s (Braun 1 9 6 l ) , but r a t e s of upward t r a v e l i n root-pruned t r e e s were s i g n i f i c a n t l y lower than those i n normal t r e e s (Greenidge 1 9 5 8 ) e The phenomenon o f time l a g i n water a b s o r p t i o n has an obvious b e a r i n g on the water c o n d u c t i v i t y t h e o r y o f stem formation.,  J a c c a r d ' s concept o f the "stem o f u n i f o r m conductive  c a p a c i t y f o r water" i s i l l o g i c a l i f r e s i s t a n c e t o the passage o f water through the r o o t s r a t h e r than through the stem i s c r i t i c a l in  trees. As i s e v i d e n t , the problem o f water supply i n p l a n t s  r e s o l v e s i n t o r e l a t i o n o f the r a t e o f a b s o r p t i o n t o water l o s s . A c c o r d i n g t o C r a f t s e_t a l . ( 1 9 4 9 ) , clusions of Curtis  and c o n t r a r y t o the con-  (1933)> water vapor i n the atmosphere  p r o f o u n d l y a f f e c t s water movement through p l a n t s .  Diffusion  pressure d e f i c i t o f water vapor i n the atmosphere  i s a factor  of primary importance i n stomatal c o n t r o l .  Indeed, the water  l o s s from l e a v e s was an i n v e r s e l i n e a r f u n c t i o n o f the r e l a t i v e humidity (Thut 1939)«  The c a p a c i t y o f atmosphere t o  h o l d water vapor approximately doubles f o r every r i s e o f 20°F, but the i n f l u e n c e o f temperature at constant r e l a t i v e humidity i s small (Anderson 1936; C r a f t s e t a l . 1949)*  Relative  humidity w i t h i n stand i s governed p r i n c i p a l l y by the water output o f the crown space f o l i a g e  (Geiger 1 9 5 0 ) .  Transpiration,  although estimated t o be as much as the annual e q u i v a l e n t o f 17 - 22 i n c h e s o f r a i n i n an oak f o r e s t i n the e a s t e r n U.S.A«  :  (Meyer et a l . 1960), was  of secondary  importance  i n the  dampening of the f o r e s t atmosphere of an oak f o r e s t USSR; the p h y s i c a l e v a p o r a t i o n from the s o i l was i n t h i s r e s p e c t (Goryshina and  Neshataev  i n the  more  important  i960).  Under l a b o r a t o r y c o n d i t i o n s , the r a t e of e v a p o r a t i o n from a water s u r f a c e i s p r o p o r t i o n a l t o s a t u r a t i o n d e f i c i t  of  the a i r above the s u r f a c e from which i t i s t a k i n g p l a c e (Hammond and G o s l i n 1933)»  However, e v a p o r a t i o n from a water  s u r f a c e d i d not p r o v i d e an index of e v a p o r a t i o n from the ( K i t t r e d g e 1954)° pressure d e f i c i t environmental  soil  In the f o r e s t , the e f f e c t of water vapor i s masked by the i n f l u e n c e of other m i c r o -  factors  ( S e l l e c k and Schuppert  1957; H e i n r i c h  1950).  N e v e r t h e l e s s , the c o r r e l a t i o n between vapor pressure  deficit  and  r a t e of e v a p o r a t i o n i s high and under a s t r o n g  i n f l u e n c e of the mass exchange (Goehre 1 9 5 2 ) . a i r i s hampered by the c l o s e d canopy. p o i n t s of c o n t a c t r e p r e s e n t the  The mixing  of  In the crowns, the  zone of absence of t u r b u l e n t  exchange and have the most s t a b l e c o n d i t i o n s of maximal humidity 1957).  combined w i t h minimal e v a p o r a t i o n Any  opening  of the c l o s e d canopy a c t i v a t e s  the f a c t o r s governing a n a l y s i s , the  e v a p o r a t i o n on which, i n the  increasingly final  stomatal t r a n s p i r a t i o n depends (Niederhof  S t a h e l i n 1942; Haddock 1961)0 the moving a i r cannot conductive  (Pogrebnyak e_t al«  theory.  and  Because o f t h i s , the a c t i o n o f  be d i s r e g a r d e d by e i t h e r n u t r i t i o n a l  or  26  The  d a i l y wind movement i n crowns i n c r e a s e d up to  4 times a f t e r heavy t h i n n i n g s i n white p i n e ; the temperature i n crowns was  a l s o h i g h e r , the  evaporation  i n c r e a s e d by 6 . 2 per cent while the r e l a t i v e  above the ground.  At t h i s e l e v a t i o n the d a i l y wind movement  i n c r e a s e d up t o 3 times and e v a p o r a t i o n was per cent as compared w i t h the unthinned  was of  humidity  Crowns m o d i f i e d the temperature t o 8 inches  decreased..  1935)*  daily  h i g h e r by 24»5  stand  (Adams 1930*  Wind at the p e r i p h e r y of crowns of broadleaved  8 times h i g h e r than i n the c e n t e r of the crown. low v e l o c i t y caused  species  A wind  g r e a t e r d i f f e r e n c e i n the a i r movement  between the c e n t e r and the p e r i p h e r y of the crown than a s t r o n g wind (Hanson 1917)*  Low  wind v e l o c i t i e s were a l s o  most e f f e c t i v e i n i n c r e a s i n g the r a t e of e v a p o r a t i o n i n the forest.  Wind as a component f a c t o r i n an a n a l y s i s of  c o r r e l a t i o n of e v a p o r a t i o n r a t e t o vapor pressure decreased  deficit  the v a r i a n c e i n e v a p o r a t i o n u n r e l a t e d t o vapor  pressure d e f i c i t  by 54 per cent  Apparently,  (Kucera  1954)•  the a c t i o n of wind i n the f o r e s t i s  not simply l i m i t e d t o the inducement of bending  stresses i n  the stems of the swaying t r e e s , hence t o a h y p o t h e t i c a l s t i m u l a t i o n of cambial l a y e r .  The  s t i m u l i caused by p u r e l y mechanical established.  e x i s t e n c e of  cambial  s t r e s s e s has not been  T h e r e f o r e , the n u t r i t i o n a l and the  t h e o r i e s are l i n k e d by a common group of f a c t o r s  conductive governing  the r a t e of the net p r o d u c t i o n o f dry matter and the water  27  balance i n t r e e s . theory  provides  Since  i t i s b e l i e v e d t h a t the  hormonal  a p h y s i o l o g i c a l b a s i s f o r the f a c t s encompassed  i n the n u t r i t i o n a l , water conductive and mechanistic 1 9 6 3 c ) , none of the  (Larson  current  theories  stem form t h e o r i e s can  be  used s e p a r a t e l y t o e x p l a i n the form of t r e e s . The  n u t r i t i o n a l g r a d i e n t s w i t h i n the  or, a l t e r n a t i v e l y , the ageing of the the  p r i n c i p l e of competition  synthate,  cambial c y l i n d e r  cambial l a y e r , as w e l l  as  by the growing c e l l s f o r photo-  were a l l considered  by  some w r i t e r s as being  capable  of e x p l a i n i n g the d i s t r i b u t i o n o f the r a d i a l growth of the conifers.  A stream of organic  migrating  substances, e n v i s i o n e d  along the v e r t i c a l a x i s , s u p p l i e s the  as  competing  produced by p e r c l i n a l d i v i s i o n w i t h the necessary foods. n u t r i t i o n a l s t a t u s of the from one supply  internode  cambium d e t e r i o r a t e d b a s i p e t a l l y ,  The  foods a s s o c i a t e d with the gradual  due  1934;  (Kienholz  Duff and  Nolan 1953,  r a d i a l growth, but the  w i t h i n the  l e v e l which, i n t u r n ,  t o uneven i l l u m i n a t i o n o f the green f o l i a g e  Cambial ageing was the  increasing  d e c l i n e i n width of the xylem  l a y e r p a r a l l e l e d t h a t of the m e t a b o l i t e probably was  The  t o another, owing t o a s t e a d i l y d i m i n i s h i n g  of e l a b o r a t e d  demand f o r them..  cells  1957;  Farrar  1961).  r u l e d out as a f a c t o r c o n t r o l l i n g  concept of the n u t r i t i v e  cambial l a y e r was  b; 1962;  F r a s e r et a l . 1 9 6 4 ) .  gradient  i n the  retained The  (Forward and  existence  of the  cambium or i n the phloem of the  gradients Nolan 1 9 6 l a , nutritive  coniferous  t r e e s , such t h a t i t would c o r r e l a t e w i t h a g r a d i e n t  in radial  28  growth, was  never e s t a b l i s h e d . On the c o n t r a r y , t h e r e seems  t o be a g e n e r a l l a c k of i n f o r m a t i o n i n t h i s r e s p e c t .  In  one  i n s t a n c e s t u d i e d , c o n c e n t r a t i o n of sugar i n the phloem sap c o l l e c t e d at d i f f e r e n t e l e v a t i o n s along the bole of some broadleaved  s p e c i e s d u r i n g a p a r t of one growing  decreased b a s i p e t a l l y . c o l l e c t e d at 1.3  season,  A l s o , the c o n c e n t r a t i o n o f the  sap  m above ground decreased with i n c r e a s i n g  height of t r e e s (Topcuoglu 1941)» shown t h a t n u t r i e n t s may  R a d i o a c t i v e t r a c e r s have  be t r a n s l o c a t e d i n the phloem i n  opposing l o n g i t u d i n a l d i r e c t i o n s s i m u l t a n e o u s l y  (Biddulph  et a l . i n Steward 1 9 5 7 ) . The  presence  of d i r e c t p r o p o r t i o n a l i t y between the  q u a n t i t y of green f o l i a g e and amount of r a d i a l growth achieved i n the stem immediately  beneath the p o i n t o f attachment of  t h i s f o l i a g e , as assumed by n u t r i t i o n a l theory, has not been proven.  U n i l a t e r a l pruning of c o n i f e r s d i d not a f f e c t  the  r i n g width along the stem perimeter, nor d i d i t cause t h e i r stems t o become e c c e n t r i c  (Burns 1920;  Onaka 1 9 5 0 b ) .  Similarly,  asymetric crowns d i d not produce e c c e n t r i c growth i n the b o l e s s u p p o r t i n g them (Lodewick 1 9 3 0 ) .  However, impaired  growth and d i s c o n t i n u o u s r i n g s were observed  radial  on the b r a n c h l e s s  side of the b o l e s of sequoia sprout clumps ( F r i t z and  Averill  1925). The efficiency  q u a n t i t y of f o l i a g e stands apart from i t s  (Schmidt  of l i v e crown may  1953)•  In the same way  as the t o t a l  not be a v a l i d index of the r a t e of the  size total  29  r a d i a l growth (Lodewick 1930%  Wadsworth 1942|  Reukema 1 9 6 l ) ,  the q u a n t i t y of green f o l i a g e born by i n d i v i d u a l whorls of branches may  not have any b e a r i n g on the immediate dimensions  of the xylem l a y e r s .  Within a macroclimatic  i n f l u e n c e of a crown's m i c r o c l i m a t e was  site,  the  shown t o be  critical  f o r the i n t e n s i t y of the gaseous exchange processes and t h e r e f o r e f o r the r a t e of the net p h o t o s y n t h e s i s .  For i n s t a n c e ,  top l e a v e s of a young p o p l a r t r e e i n the northern edge of the stand were more p r o d u c t i v e than the l e a v e s at the base of the crown.  They were a l s o more p r o d u c t i v e than the t o t a l  of a s i m i l a r t r e e l o c a t e d a few of the stand  foliage  yards away on the south edge  ( P o l s t e r and Neuwirth 1 9 5 8 K  Suppressed Norway  spruce t r e e s produced more wood per u n i t of the crown area or per u n i t of f o l i a g e volume than the dominant spruce on the same m a c r o s i t e  (Neuwirth  I963K  The  a s s i m i l a t i o n p a t t e r n s of  young Douglas f i r were s t r o n g l y c o r r e l a t e d with c o n d i t i o n s promoting the s a t u r a t i o n of the l e a f t i s s u e s ; the mid  crowns  were most e f f i c i e n t p h o t o s y n t h e t i c a l l y (Gentle 1959)« M o r p h o l o g i c a l and anatomical d i f f e r e n c e s e x i s t i n g between the l e a v e s i n the sun and crowns of some broadleaved  shaded l e a v e s w i t h i n the  s p e c i e s were g r e a t e r than  d i f f e r e n c e s r e p o r t e d f o r l e a v e s of mesophytic and forms of the same s p e c i e s (Hanson 1 9 1 7 ) »  similar  xerophytic  At the same h e i g h t  i n the crown, the sun l e a v e s were twice as t h i c k as the shade l e a v e s and t h e i r surface area was  1957)0  A g r a d u a l deformation  s m a l l e r ( T a l b e r t and  of needles was  observed  Holch i n crowns  30  of Norway spruce i n b a s i p e t a l d i r e c t i o n .  Three  distinctly  d i f f e r e n t types o f needles c o u l d be r e c o g n i z e d (Schoepfer 196l).  The morphology and anatomy o f sun and shade needles  has a d e f i n i t e b e a r i n g on t h e i r p h o t o s y n t h e t i c e f f i c i e n c y . Shade needles o f white pine and balsam f i r a s s i m i l a t e d  about  150 per cent more CO2 than the sun n e e d l e s at a l l l i g h t intensities.  They a l s o r e s p i r e d l e s s than the sun needles  at a l l temperatures  (Clark 1 9 6 l ) .  The sun l e a v e s o f Ulmus  americana l o s t 12 times as much water as d i d the shade l e a v e s (Hanson 1917)• I t i s g e n e r a l l y known t h a t the shape o f b o l e s and a l s o t h e i r i n n e r s t r u c t u r e change a f t e r t h i n n i n g and a f t e r pruning.  T h i s phenomenon i s e x p l a i n e d by the n u t r i t i o n a l  t h e o r y as f o l l o w s ; Since t h i n n i n g i n c r e a s e s crown s i z e and t r a n s p i r a t i o n , a promotion o f both earlywood and t a p e r would be a n t i c i p a t e d . Pruning, on the other hand, decreases crown s i z e and t r a n s p i r a t i o n , and one would expect a d e c l i n e i n earlywood and t a p e r but resurgence o f latewood f o r m a t i o n (Larson 1 9 6 3 c ) . T h i n n i n g does not always immediately.  i n c r e a s e the s i z e o f the crown  On the c o n t r a r y , branch e l o n g a t i o n and crown  s u r f a c e may decrease i n r e l e a s e d t r e e s  (Reukema 1 9 6 4 ) .  The  r e d i s t r i b u t i o n o f r a d i a l increment along the b o l e t a k e s p l a c e , as a r u l e , immediately d u r i n g the next growing  season  r e l e a s e o r a f t e r crown r e d u c t i o n (Marts 1949, 1951; 1957;  Forward  and Nolan 1 9 6 l a , b; Reukema 1964)«  after  Lehtpere Short-term  changes and the t o t a l r a t e o f e l o n g a t i o n o f r e d pine depended more on the immediate environment  than on the i n h e r e n t g e n e t i c  31  c h a r a c t e r of the t r e e .  Branches d i d not d i f f e r from the main  axes i n t h i s r e s p e c t .  I n f l u e n c e of the environment on growth  of branches i n o l d t r e e s was t r e e age  (Forward  more important  than t h a t of the  and Nolan 1964)0  S i m i l a r l y , pruning does not n e c e s s a r i l y promote growth of latewood.  The  r e d u c t i o n by 75 per cent of l i v e  crowns of open-grown l o n g l e a f pine depressed  the  radial  growth d r a s t i c a l l y but the p r o p o r t i o n o f earlywood w i t h i n the l a y e r formed d u r i n g the season f o l l o w i n g the season of treatment  i n c r e a s e d by about 3 0 per cent at BH The  (Marts 1951)•  v e r d i c t of Buesgen and Muench (1929) on  n u t r i t i o n a l theory was  as f o l l o w s .  A l l ... r e s e a r c h e s d i r e c t e d t o e x p l a i n i n g the d i s t r i b u t i o n o f growth i n i n d i v i d u a l r e g i o n s of the cambium by l o c a l d i f f e r e n c e s i n n u t r i t i o n must be regarded as having m i s c a r r i e d .... A l l observations on the t r e e s as on a l l o t h e r organisms agree t h a t , i n cases of u n d i s t u r b e d development, growth does not take p l a c e where the m a t e r i a l s flow i n , but the m a t e r i a l s flow i n t o the p l a c e where growth i s g o i n g on. The  premises of J a c c a r d s water conductive T  of stem f o r m a t i o n are based on the assumption o f the  theory cohesion-  t e n s i o n theory of water conduction through  stems, i . e . , on a  phenomenon which remains t o be e x p l a i n e d .  In the words of  Meyer et a l . (I960) I t i s e n t i r e l y wrong t o c l a i m t h a t water movement through p l a n t s r e q u i r e s occurrence of t r a n s p i r a t i o n . T r a n s l o c a t i o n o f water t o the extent t h a t i t i s used i n r e s t o r i n g c e l l t u r g o r continues even d u r i n g the p e r i o d s when the t r a n s p i r a t i o n rate i s n e g l i g i b l e .  32  Decapitation hardwoods d i d not extremities  of r i n g porous and  prevent the t r a n s p o r t  of the  stem.  The  d i f f u s e porous  of water t o  the  r e s u l t s were s i m i l a r a f t e r a l l  the water conducting pathways i n the bole were severed r e p e a t e d l y by  a s e r i e s of o v e r l a p p i n g c u t s (Greenidge  T o x i c s o l u t i o n s were t r a n s p o r t e d  1 9 6 2 ) o  heights (Slatyer i960).  Solution  1 9 5 5 >  t o above atmospheric  of P  3 2  moved r a d i a l l y i n xylem towards and believed one  away from the  pith (Kiselev 1962).  t h a t the t r a n s p i r a t i o n a l stream may  or two  o u t e r annual r i n g s  It i s  be l i m i t e d t o  Bigg 1956).  (Chalk and  The  demarcation of the water conducting pathways seems t o g r e a t l y complicated by the s p i r a l growth the and  almost u n i v e r s a l occurrence  1957; The  Kennedy and  and  crown  1957;  Elliot  do not  generally  s i m i l a r r e l a t i o n s h i p s i n the n a t u r a l  U.S.A. were too  poorly  (Wright 1927;  Gevorkiantz and  Hosley 1929)<•  length  l i v e crown was  i n managed stands of the Grochowski I 9 6 I ) .  correlations  seem t o be  i n Canada and  of the  1958).  s i z e of l i v e crown and measures of  form found i n Sweden (Jonson 1 9 2 8 ) The  reduction  Vite  h i g h l e v e l s of s i g n i f i c a n c e of  between measures of the  reproducible.  of  p i t c h of which v a r i e s w i t h height i n t r e e ,  with treatments such as r e l e a s e  (Northcott  be  defined  t o be The  useful  relative  only l o o s e l y c o r r e l a t e d with form  c o n t i n e n t a l Europe (Krenn  Form was  forests  not  1944;  c o r r e l a t e d w i t h crown  i n plantation-grown c o n i f e r s i n England  (MacDonald 1932,  length 1933)*  33  These low accord w i t h the  or n o n s i g n i f i c a n t c o r r e l a t i o n s are not  concepts of the "wind p r e s s u r e "  were found which had  the  same h e i g h t ,  but very d i f f e r e n t crown l e n g t h s . a t t r i b u t e d t o the t o vary  1964)0  diameter and  w i t h i n and  form f a c t o r  This discrepancy  was  between t r e e s of the  same  ( L i t t l e f o r d 1961;  Kommert  homogeneous s i t e  Evidence was  presented t o the  e f f e c t t h a t the  b u t i o n o f s p e c i f i c g r a v i t y i n stems was r e l a t e d t o the  Trees  s t r e n g t h p r o p e r t i e s of wood which are known  considerably  s p e c i e s from one  theory.  in  stem form and  not f o r t u i t o u s but  crown l e n g t h i n a f a s h i o n which  agreed w e l l with the t e n e t s of Metzger's theory In the words of Larson  distri-  (Volkert 194l)«  (1963c).  I t was r e c o g n i z e d not o n l y t h a t stem form and wood d e n s i t y were i n t i m a t e l y r e l a t e d but a l s o that these v a l u e s were i n t u r n s t r o n g l y dependent upon crown s i z e and development. The  i n t e r r e l a t i o n s h i p between taper,  specific gravity  l e n g t h of crown such as shown by V o l k e r t out by the  (1941) was  r e s e a r c h e s of Pechmann (1954) and  of  and  not  borne  Hildebrandt  (1954)o The  s i z e of the  crown i s u s u a l l y not recorded  s t u d i e s concerned w i t h s p e c i f i c g r a v i t y of stem wood.  in The  r e l a t i o n s h i p between s p e c i f i c g r a v i t y and  crown c l a s s , as  w e l l as t h a t between s p e c i f i c g r a v i t y and  r a t e of growth, were  both i n v e s t i g a t e d more f r e q u e n t l y .  the e x i s t e n c e  general may  be  Since  c o r r e l a t i o n between the r a t e of growth and j u s t i f i a b l y assumed (Ker 1 9 5 3 ) , the  s p e c i f i c g r a v i t y and  of a  crown c l a s s  c o r r e l a t i o n s between  r a t e of growth should be  of about the  same  34  order as those which o b t a i n between crown c l a s s and s p e c i f i c gravity.  The l e n g t h of the crown (Kramer I 9 6 2 ) ,  as w e l l as  width of the crown ( L i e b o l d 1 9 6 3 ) , were found t o be w i t h crown c l a s s .  correlated  I f so, then the above r e l a t i o n s h i p s  on the r e l a t i o n o f crown s i z e t o s p e c i f i c g r a v i t y .  bear  A degree of  c o n s i s t e n c y would be expected t o e x i s t among the r e p o r t e d c o r r e l a t i o n s between s p e c i f i c g r a v i t y on one hand, and r a t e of growth or crown c l a s s on the other, i f wood d e n s i t y strongly case.  upon crown s i z e and i t s development.  depended  Such i s not the  The c o r r e l a t i o n between s p e c i f i c g r a v i t y and crown c l a s s  was low i n Douglas f i r (Wellwood and Smith I 9 6 2 ) ,  nonsignificant  i n western hemlock (Wellwood i 9 6 0 ) and i n Douglas f i r (McKimmy  1959).  Dominant Douglas f i r produced h e a v i e r wood than other  crown c l a s s e s Also,  i f r i n g width were h e l d  constant  (Mozina i 9 6 0 ) .  dominant Douglas f i r produced wood o f l e a s t s p e c i f i c  gravity, while differences significant  between crown c l a s s e s were not  (Wellwood 1952).  The r a t i o o f crown l e n g t h t o  t o t a l h e i g h t accounted f o r an a d d i t i o n a l one per cent of the total variation i n specific gravity  (Stage  I963).  The r a t e of growth o f Douglas f i r was not c o r r e l a t e d w i t h percentage of latewood  (Wellwood and Smith I 9 6 2 ) .  No  c o r r e l a t i o n , o r weak c o r r e l a t i o n s , were found between r a t e of growth and s p e c i f i c g r a v i t y  of the same s p e c i e s by H a r r i s and  Orman (1958) and by Mozina ( i 9 6 0 ) , but a s i g n i f i c a n t c o r r e l a t i o n was obtained between s t r e n g t h and r a t e  of growth  ( H a r r i s and Orman 1958).  between  Significant correlations  35  r a t e of growth and by Knigge and  (1958),  s p e c i f i c g r a v i t y were found i n Douglas f i r  European l a r c h by Pearson and  spruce by  (1961),  i n white spruce by K e i t h  (1961);  Schultze-Dewitz  Fielding ( I 9 6 I ) ,  (1954)•  spruce by H i l d e b r a n d t  i n Norway  n o n s i g n i f i c a n t ones i n  s l a s h pine by Z o b e l et a l . ( i 9 6 0 ) ,  l o b l o l l y and  i n Japanese  and  S p e c i f i c g r a v i t y was  i n Norway lower i n  wide-ringed as compared with narrow-ringed Douglas f i r having the  same percentage of latewood Variability  (Desh 1 9 3 2 J  Kennedy I 9 6 I ) .  1950).  i n s p e c i f i c g r a v i t y or i n s t r e n g t h  wood between t r e e s seems t o be trees  (Paul  H a r r i s and  With r e s p e c t  ences between t r e e s on the  greater  than t h a t found w i t h i n  Orman 1 9 5 8 ;  Zobel and  poorest and  same s i t e may  spacing  Schniewind 1 9 6 l ) .  the best  on the  be  same s i t e  t h a t of t r e e s from low  l a r g e r than  i n g a l t i t u d e and (Ericson  regions  to  (Jayne 1 9 5 8 ) ; wood o f mountain-grown lower s p e c i f i c g r a v i t y than  a l t i t u d e s (Paul 1 9 4 6 ;  Europe showed a g r a d i e n t density  differ-  D i f f e r e n c e s between the  S p e c i f i c g r a v i t i e s of Douglas f i r p l a n t e d  Basic  1955;  s i t e s were l e s s than d i f f e r e n c e s due  Douglas f i r or Norway spruce had  1958)o  Rhodes  t o s p e c i f i c g r a v i t y , the  d i f f e r e n c e s between t r e e s from d i f f e r e n t s i t e s or (Goehre 1 9 5 8 ;  of  decreasing  Hildebrandt  across  1954).  continental  from east t o west  of Norway spruce decreased w i t h  (Knigge increas-  l a t i t u d e w i t h i n r i n g s of a constant width  I960). F a c t o r s which cause the  same s p e c i e s , growing on the  cambium of t r e e s of  same s i t e and  the  separated o f t e n  by  36  only a few yards, t o produce w i t h i n an annual xylem l a y e r of approximately the same dimensions s i g n i f i c a n t l y d i f f e r e n t proportions  o f earlywood and latewood were not e x p l a i n e d . (Glock 1955) m i c r o s i t e and  Some i n f l u e n c e o f microclimate  (Kennedy 1 9 6 l ) or h e r e d i t y alone (Wellwood and Smith  heredity  1962) were suspected i n t h i s  respect.  Metzger's d3 r u l e was dismissed  by Gray  because the stems o f t r e e s are, on the average, and not cubic p a r a b o l o i d s .  (1956)  quadratic  Gray (1956) formulated a general  h y p o t h e s i s as f o l l o w s : The mechanical s t r e s s averaged over the whole s e c t i o n underbark i s constant along the l e n g t h o f the main stem and i f t h i s i s c i r c u l a r , the area o f the s e c t i o n i s p r o p o r t i o n a l t o the s t r e s s on i t . As a r u l e , the c r o s s - s e c t i o n a l areas o f t r e e stems are very  seldom c i r c u l a r , and e c c e n t r i c growth, u s u a l l y  connected w i t h n o n c i r c u l a r i t y , i s commonly encountered at any p o i n t along the bole  (Kaburagi 1953)•  I t i s believed  e c c e n t r i c r a d i a l growth i n t r e e s r e p r e s e n t s  an  that  adaptation  brought about by one-sided s t r e s s e s caused by wind o r , i n the case o f l e a n i n g stems, by the f o r c e o f g r a v i t y . p r o c e s s e s supposedly r e i n f o r c e the stem i n a most way and are, i n t h i s r e s p e c t ,  The  adaptive  efficient  comparable w i t h s i m i l a r processes  o c c u r r i n g i n the organs o f animals (Trendelenburg 1 9 3 7 ) • Pronounced e c c e n t r i c growth o f stems was observed even i n s e e d l i n g s explained, attack.  (Burns 1 9 3 7 ) .  T h i s cannot p o s s i b l y be  as i s customary f o r l a r g e t r e e s , by a one-sided wind  D i r e c t i o n o f p r e v a i l i n g winds was found t o be i n  37  alignment with the major a x i s of the stem c r o s s - s e c t i o n by Millet  (1944) and by M u e l l e r (1958).  D i r e c t i o n of p r e v a i l i n g  winds d i d not agree w i t h the o r i e n t a t i o n o f the major a x i s i n Douglas f i r (Walters, -Kozak 1964)° major a x i s was  found t o l i e i n the east-west  Grundner i n C h a t u r v e d i 1926;  was  direction  (Mussat;  Flemes i n Trendelenburg 1939;  Heck  P a t t e r s o n and Colson 1952).  The  i n P a t t e r s o n and Colson 1952; displacement  In most r e p o r t e d cases the  of p i t h towards the southern perimeter of t r e e s  observed and recorded by Leonardo da V i n c i  displacement towards the n o r t h was and Duhamel (Chaturvedi 1926)a  (McMurrich  r e p o r t e d i n 1735  1930),  by Buffon  A l l these r e p o r t s seem t o be  based on measurements taken at one p o s i t i o n w i t h i n the stem. Complete d i s s e c t i o n o f stems r e v e a l e d t h a t the s i t e of maximum r a d i a l growth may  change i t s p o s i t i o n g r a d u a l l y a l o n g the bole  f o l l o w i n g a s p i r a l course  (Misra 1939? 1943)*  A l s o , the  maximum r a d i u s f o r any one y e a r or group of y e a r s was always i n the same v e r t i c a l a x i s Comparatively  little  (Adams 1928).  has been w r i t t e n about  magnitude and d i s t r i b u t i o n o f mechanical by wind i n stems of t r e e s .  not  the  s t r e s s e s brought  T h i s i s understandable  about  since  The s t r e s s e s and s t r a i n s i n (a) l o g of timber are so complex t h a t the problem has not y e t been solved i n a manner t h a t reasonably accords with the known s t r e n g t h of the beam as found by a c t u a l experiment (Claxton F i d l e r i n D'Arcy Thompson 1942). Bending i n the experiments  s t r e s s e s i n stems were e l i m i n a t e d by guying of Jacobs  (1939, 1954)»  t r e e s prevented from swaying was  R a d i a l growth of  d i s t r i b u t e d along t h e i r boles  38  in  a f a s h i o n which was  hypothesis*  The  more or l e s s i n accord w i t h Metzger's  experiment of Jacobs seems t o be  commonly  r e p l i c a t e d , a f t e r a f a s h i o n , i n the t r o p i c a l r a i n f o r e s t where. ... t r e e s are o f t e n bound t o g e t h e r by the woody stems of l i a n e s so t h a t they support one another very e f f e c t i v e l y <> •. a l a r g e t r e e i s o f t e n so s t r o n g l y bound t o i t s neighbors by l i a n e s t h a t even when cut r i g h t through at the base i t w i l l not f a l l (Richards  1952).  Stems of many t r o p i c a l s p e c i e s are known t o possess the buttressing habit.  I t would seem t h a t the  p o s i t i o n o f these s t r u c t u r e s present mechanistic  theory.  But  there  size,  shape  a strong case f o r the  are reasons f o r doubting  whether the advantages of b u t t r e s s i n g are r e a l and buttresses  and  valuable.  are not developed where they are most "needed"; they  are l a r g e s t and most common i n t r e e s i n s h e l t e r e d v a l l e y s arid in  small t r e e s i n s h e l t e r e d undergrowth; they o c c u r l e s s i n  t a l l t r e e s and  l e s s i n t r e e s growing on l o o s e sandy  soils  than i n t r e e s on f i r m c l a y s or i n t r e e s on exposed r i d g e s ; i n the mountains they d i s a p p e a r a l t o g e t h e r . t r e e s may them.  A l s o , the  buttressed  be more o f t e n blown down by wind than those without  Since the b u t t r e s s i n g h a b i t depends on the  p o s i t i o n o f the  systematic  species  ... they must be r e l a t e d t o environmental c o n d i t i o n s ... they are r e s u l t of the a c t i o n of the h a b i t a t f a c t o r s , any u s e f u l n e s s t o the p l a n t they may have b e i n g mainly i n c i d e n t a l (Richards  1952).  In many t r o p i c a l r e g i o n s v i o l e n t winds are l e s s common than i n temperate r e g i o n s .  Nevertheless,  h a b i t i s f a r l e s s common i n e x t r a - t r o p i c a l t r e e s .  the  buttressing  But  i t i s not  39  absent i n them*  The  b u t t r e s s e s bn 46I  Populus i t a l i c a t r e e s i n  S w i t z e r l a n d were most marked when the lower part of the was  i n shade and  i n humid atmosphere.  trunk  T h e i r formation  was  s t i m u l a t e d near s u r f a c e s r e f l e c t i n g heat, sometimes i n a which d i d not c o n t r i b u t e t o the overturning.  stability  way  of the t r e e a g a i n s t  In e f f e c t , i t c o u l d be d e t r i m e n t a l t o i t .  Consequently, b u t t r e s s e s were not c o n s i d e r e d  as f u n c t i o n a l  s t r u c t u r e s but r a t h e r as a c c i d e n t a l by-products of growth (Senn 1 9 2 3 ) . B u t t r e s s i n g has been observed a l s o i n l o b l o l l y l o n g l e a f pine and was of t r e e s t o f i r e  and  c o n s i d e r e d t o be a p r o t e c t i v e r e a c t i o n  (Chapman 1942;  Anderson and B a l t h i s 1944)*  Formation o f the enlarged bases of F r a x i n u s n i g r a i n M i c h i g a n bogs c o u l d not be r e l a t e d t o wind a t t a c k 1925)o  The  (Gates and  Erlanson  c h a r a c t e r of b u t t r e s s e s i n Nyssa depended e n t i r e l y  on the h e i g h t and d u r a t i o n o f f l o o d i n g (Hadley  1926).  enlargement of bases of Taxodium d i s t i c h u m was  c o r r e l a t e d with  s o i l m o i s t u r e regime. of the I9O5). to  In streams and  same height r e g a r d l e s s of the The  ponds the b u t t r e s s e s were s i z e of the t r e e  development of b u t t r e s s e s i n cypress was  the simultaneous presence of water and  prominent cone-shaped, b o t t l e - s h a p e d  a response  and b e l l - s h a p e d  stem;  buttresses  submersion  1934). In the o p i n i o n o f Gray ( 1 9 5 6 ) , M e t z g e r s f  was  (Harper  a i r around the  were produced by v a r y i n g depth and d u r a t i o n o f the (Kurz  The  a r a t h e r a r t i f i c i a l one.  only when a t r e e was  deduction embedded i n  40  a material  sufficiently  of a cubic p a r a b o l o i d pressures.  strong would i t r e q u i r e the  dimensions  t o o f f e r uniform r e s i s t a n c e t o  lateral  As t r e e s are anchored i n weak m a t e r i a l , Metzger's  stem of uniform r e s i s t a n c e was Presumably, the  overdimensioned.  s t a b i l i t y of t r e e s a g a i n s t  t u r n i n g i s as important f o r t h e i r s u r v i v a l as t h a t breaking  or s p l i t t i n g .  form t h e o r i e s pay stem anchorage.  In s p i t e of t h i s , the  little Jaccard  or no  increased production The mechanistic  theory  stem  a t t e n t i o n to the problem of  the  i n the r o o t s .  Forward  case of r e l e a s e d t r e e s ,  o f hormone i n the r o o t  engineering  current  crown as a t r a n s p i r a t i o n a l organ  caused a c o r r e s p o n d i n g i n c r e a s e surmised,in  against  (1915) b e l i e v e d t h a t every f a c t o r  f a v o r i n g the growth o f the  Nolan ( I 9 6 2 )  over-  and  an  apices.  p r i n c i p l e s encompassed by  the  were a p p l i e d t o a study of r o o t systems of  Norway spruce by F r i t z s c h e ( 1 9 3 3 ) *  No  i n f l u e n c e of wind  was  found whatsoever on the development of d e e p - r o o t i n g systems, whereas the formation w i t h the precepts  of shallow-rooting  of Metzger ( F r i t z s c h e 1 9 3 3 ) .  sequoias c o l l a p s e d i n the absence of any 1937),  but  systems conformed Stems of g i a n t  wind a c t i o n  (MacDougal  i n Norway spruce the d e d u c t i o n s of L a i t a k a r i , namely  t h a t the d i r e c t i o n o f the p r e v a i l i n g winds and the  size  and  p o s i t i o n of the r o o t s were c o r r e l a t e d , have been upheld Melzer ( I 9 6 4 ) . t o pine and  by  V e r t i c a l r o o t s were of s l i g h t mechanical  i n A u s t r a l i a and  developed i n response t o s o i l  value  type  s o i l moisture; wind damage or windfirmness were not r e l a t e d  41  t o crown s i z e  (Bryor 1937)•  A r e l a t i v e l y small i n c r e a s e i n  depth of r o o t i n g i n c r e a s e d s i g n i f i c a n t l y the r e s i s t a n c e t o overblow of spruce i n peats over m i n e r a l ( F r a s e r 1962)0  The  s o i l s i n England  o r i e n t a t i o n of the a e r i a l r o o t s i n t r o p i c a l  s p e c i e s agreed with the d i r e c t i o n o f the p r e v a i l i n g wind attack  (Navez 1930)o  A e r i a l r o o t s were a l s o found t o  occur  most f r e q u e n t l y where they were l e a s t needed so f a r as the s t a b i l i t y of t r e e s was  concerned, i . e . , they o c c u r r e d mostly  i n small t r e e s growing i n the (Richards 1952)»  s h e l t e r e d and dense underbrush  Species otherwise  b u t t r e s s e d tended t o  develop a e r i a l r o o t s on a swampy s i t e and  s p e c i e s not u s u a l l y  b u t t r e s s e d developed b u t t r e s s e s under swampy c o n d i t i o n s o A e r i a l , r o o t s were considered  as an extreme form of  response or a d a p t a t i o n to a h i g h water t a b l e , and a moderate form (Beard 1948)o by height  buttresses  Depth of r o o t i n g was  controlled  of water t a b l e i n the case of p a r t l y submerged willow  stems; the f u n c t i o n i n g r o o t s occurred  only i n the  zone r i c h i n  oxygen, i . e . , near the water l e v e l (Zimmerman 1 9 5 0 ) . r o o t i n g of white pine was table.  A high water t a b l e r e s u l t e d i n shallow  Deeper r o o t i n g was 1959)o  r e s t r i c t e d by p r o x i m i t y  Depth of  o f water  root  penetration.  observed w i t h lower water t a b l e s (Husch  High water t a b l e i n h i b i t e d the development of t a p r o o t  of l o n g l e a f pine. inches below the  Roots on an area with a water t a b l e  28  surface were 22 t o 29 inches l o n g compared  with 3 t o 6 f e e t on w e l l - d r a i n e d  soil  (Heyward 1933)»  In  sphagnum bogs the r o o t s spread f a r more than those of the same  42  s p e c i e s growing i n m i n e r a l  soil  Rooting h a b i t o f white spruce was m o d i f i e d inundations roots  profoundly formation  by the p e r i o d i c  which s t i m u l a t e d the p r o d u c t i o n  ( J e f f r e y 1959)•  1931)•  (Rigg and Harrar  o f adventitous  The r o o t system o f b l a c k spruce was  changed when the s u r f a c e o f a swamp was raised? o f adventitous  (Le Barron 1945)*  r o o t s occurred  above the r o o t  Drainage i n c r e a s e d the mechanical  collar  strength  of s o i l , the depth o f r o o t i n g and the r e s i s t a n c e t o overblow ( F r a s e r 1962, F o r e s t r y Commission 1 9 6 4 ) . s o i l s , and i n the m a j o r i t y  On most  mineral  o f s p e c i e s , the s i z e o f the r o o t i n g  system may w e l l be governed by the s o i l moisture regime according t o t h i s r u l e :  the g r e a t e r the a v a i l a b l e moisture,  the  s h o r t e r the r o o t and the g r e a t e r the r a t i o between t o p  and  root  (Haasis 1 9 2 1 ) .  conductive  Hence, p r i n c i p l e s o f mechanical or  t h e o r i e s are not a p p l i c a b l e t o underground organs  of t r e e s under a l l c o n d i t i o n s . A b r i e f survey o f the l i t e r a t u r e w i l l  show t h a t  r e s u l t s o f a number o f s t u d i e s c o n t r a d i c t the b a s i c of the hormonal  credos  theory.  I t was maintained t h a t only the d i f f u s e porous s p e c i e s were e n t i r e l y dependent upon an exogeneous supply o f auxin from extending shoots. Fraxinus  I n r i n g porous s p e c i e s , e.g.,  e x c e l s i o r , another source o f auxin was assumed t o be  a v a i l a b l e i n the i n i t i a l stages o f the secondary growth (Wareing 1 9 5 0 ) .  In contrast with  such f i n d i n g s , new xylem  was found i n stems o f debudded Prunus armeniaca.  Radial  43  growth was  l a r g e s t at the stem base; none o c c u r r e d i n the  branches<>  No abnormal t i s s u e s were d e t e c t e d i n t r e e s without  buds (Dvorak 1 9 6 1 ) .  I t i s w e l l known t h a t bark separates  e a s i l y from the wood w i t h the onset of growth i n the  spring  (Leeuwenhoek i n Commission o f Dutch S c i e n t i s t s 1 9 6 l ;  Bannan  1955)»  Bark s l i p p a g e was  observed on f e l l e d , debranched  r i n g e d stems of spruce and oak and was a t i o n o f growth substances  and  a t t r i b u t e d t o regener-  (Huber 1 9 4 8 ) .  R a d i a l growth at the  base of Monterey pine (Pinus ponderosa) continued f o r s e v e r a l seasons below a l e n g t h of i n a c t i v a t e d cambium (MacDougal 1 9 4 3 ) • The cambial a c t i v i t y of young, v i g o r o u s , open-grown j a c k pine (Pinus Strobus) t r e e s d e f o l i a t e d by i n s e c t s was  suspended f o r  one year t o be resumed again i n the b a s a l r e g i o n only<>  The  presence of a r i n g i n the b a s a l p o r t i o n o f the stem, and i t s absence  immediately above i t ,  c o u l d not be e x p l a i n e d by  n u t r i t i o n a l or hormone- t h e o r y ( 0 N e i l 1963)'• f  Growth of  d e f o l i a t e d l a r c h ceased over some p a r t s of the cambial while the o t h e r p a r t s of i t were s t i l l a c t i v e  were e x t r a c t e d from normal bark of Acer p l a t a n o i d e s o  mantle  (Harper 1913 )<•  Substances a c t i v e i n b i o a s s a y , other than i n d o l a c e t i c  1960)  either  acid, (Row  I t was maintained t h a t cambia of t r e e s contained  growth substances, generated them, and moved them b a s i p e t a l l y , without any s t i m u l u s o r i g i n a t i n g i n the upper reaches of t r e e (Soeding 1937;  Jost 1940).  S i m i l a r c o n c l u s i o n s were drawn  from the s t u d i e s of cambial t i s s u e c u l t u r e s ; i n deciduous s p e c i e s , cambium or adjacent t i s s u e s contained a r e s e r v e of  44  growth substances even d u r i n g the w i n t e r time, i n q u a n t i t i e s p e r m i t t i n g n e a r l y optimum r a t e of growth at a c e r t a i n temperature  ( J a c q u i o t 1949,  1950,  1951,  1952,  1957).  I t was  not  necessary t o add a u x i n t o the c u l t u r e medium i n order t o i n i t i a t e a c t i v i t y of P i c e a and Abies cambial t i s s u e R e s u l t s were the same i r r e s p e c t i v e of whether the  cultures.  tissue  samples were removed from t r e e s i n summer or i n w i n t e r . the l a t t e r case d i v i s i o n might not occur even i f auxin added ( J a c q u i o t 1 9 5 6 ) .  Cambial  t i s s u e of S a l i x  In was  capraea  normally contained enough s t i m u l a n t s necessary f o r i t s d i v i s i o n ; the only i n d i s p e n s a b l e substances from the beginning of i t s i s o l a t i o n was  sugar  (Gautheret 1 9 3 $ ) .  Slow p r o l i f -  e r a t i o n o f cambial t i s s u e of Crataegus monogvna o c c u r r e d i n v i t r o without any a d d i t i o n o f growth substance  (Morel 1 9 4 6 ) .  E v i d e n t l y , the i n i t i a t i o n o f the cambial growth might not depend on the export of hormones from e l o n g a t i n g buds or l e a v e s , or from the dormant buds. R a d i a l growth may growth s t a r t s , and may  thus s t a r t l o n g b e f o r e h e i g h t  not occur i n an o r d e r l y f a s h i o n  f o l l o w i n g the wave of the b a s i p e t a l l y m i g r a t i n g a u x i n . I n i t i a t i o n o f r a d i a l growth was  not o n l y completely d i v o r c e d  from e x t e n s i o n growth i n some evergreen  I n d i a n s p e c i e s , but  it  (Chowdhury and Tandan  also occurred i n acropetal d i r e c t i o n  1950).  R a d i a l growth i n pine s t a r t e d suddenly and u n i f o r m l y  i n the t r u n k and about a week b e f o r e buds showed any e l o n g a t i o n (Wight  1933)*  No c o n s i s t e n t p a t t e r n of cambial i n i t i a t i o n  was  45  observed i n Douglas f i r  (Kennedy 196l)«>  Growth i n L a r i x began  i n the middle of the stem (Knudson 1913)•  New xylem f o r m a t i o n  i n pine began at some d i s t a n c e below the apex and then spread both b a s i p e t a l l y and a e r o p e t a l l y .  As a r e s u l t , growth at the  base began s e v e r a l weeks l a t e r than i n the crown (Brown 1915)• Resumption o f growth i n r o o t s o f Douglas f i r growth i n stem (Goff 1898). c e l l d i v i s i o n began 1 t o 15 1952).  s t a r t e d before  In a number o f c o n i f e r o u s s p e c i e s days before bud break (Ladefoged  In young Douglas f i r ,  s u b s t a n t i a l i n c r e a s e s i n height  began one month a f t e r the s t a r t of comparable i n c r e a s e s i n circumference at BH  (Dimock 1964)0  D i f f e r e n c e s i n growth  i n c e p t i o n a l o n g the b o l e of forest-grown Douglas f i r were of 2 t o 3 weeks, the top s t a r t i n g t o grow b e f o r e the base.  Top  and base o f an open-grown ash s t a r t e d growing at the same time; the south side began t o grow before the n o r t h side d i d . Environmental f a c t o r s of each s i n g l e t r e e were considered important i n t h i s r e s p e c t  (Ghalk 1 9 3 0 a ) .  Cambial a c t i v i t y of  some exposed c o n i f e r s began at the stem base at the same time as it  d i d i n the e x t r e m i t i e s o f the upper branches (Mer 1#92).  In  a p r i c o t s w i t h b u r s t i n g buds, t h e r e was always a more s t r o n g l y developed l a y e r of new xylem at the base of stem than i n the branches (Dvorak 1 9 6 1 ) .  Cambial a c t i v i t y o f lowland spruce  s t a r t e d one week e a r l i e r than apex e l o n g a t i o n ; subalpine spruce s t a r t e d 20 days e a r l i e r by G i e r t y c h  (Mork i 9 6 0 ) .  The f o l l o w i n g c o n c l u s i o n s  (1962) are e s p e c i a l l y v a l u a b l e i n t h a t they are  based on a study o f hormone d i s t r i b u t i o n i n l a r g e r e d pine (Pinus r e s i n o s a ) t r e e s :  46  I t i s not e n t i r e l y c l e a r whether the cambium generates i t s own auxins or depends on t h a t t r a n s ported from the buds, but n e i t h e r p o s s i b i l i t y can be e x c l u d e d . I t i s g e n e r a l l y assumed t h a t i n i t i a t i o n of cambial growth i n the s p r i n g depends on hormone t r a n s p o r t e d from b u r s t i n g buds. There i s l i t t l e evidence i n present data t o suggest t h a t xylem growth i s c o n t r o l l e d by l e v e l s of hormones i n the buds .... The f a i l u r e of c o r r e l a t i o n between content of hormones and p a t t e r n of r a d i a l growth does not ... n e c e s s a r i l y mean t h a t auxin u t i l i z a t i o n by the cambium i s independent of i t s export from the buds, but no p o s i t i v e evidence t h a t even the i n i t i a t i o n of cambial growth i n the s p r i n g depends on such export has been found. Reports concerning l o n g i t u d i n a l p o s i t i o n and date of first  appearance  of the annual increment of latewood are not i n  a b s o l u t e agreement.  Formation o f latewood s t a r t e d f i r s t  ground l e v e l and g r a d u a l l y spread upward (Young 1 9 5 2 ) . was  observed f i r s t  was  s t i l l formed i n the stem  at the Latewood  i n young branches at a time when earlywood (Ladefoged 1 9 5 2 ) .  Changeover from  earlywood t o latewood at the base of l i v e crown lagged about one week behind t h a t at BH.  The d e l a y i n changeover  was  a s s o c i a t e d w i t h d e l a y s i n s o i l moisture d e p l e t i o n (Zahner and Oliver 1962).  T r a n s i t i o n from normal earlywood t o draught-  induced latewood became more g r a d u a l w i t h i n c r e a s i n g h e i g h t i n the  stem of r e d pine (Larson 1 9 6 3 d ) .  first  i n the upper p a r t of the b o l e i n white and p i t c h p i n e s  (Brown 1915)• May,  Latewood f o r m a t i o n began  Formation o f latewood began as e a r l y as i n l a t e  o r as l a t e as i n e a r l y September (Kennedy I 9 6 I ) .  Latewood  appeared at ground l e v e l i n June, at the apex i n September (Young 1 9 5 2 ) .  Pine growing i n s o i l  kept moist at  c a p a c i t y formed earlywood from March t o August Kramer I 9 6 0 ) ,  field  (Zahner i n  47  The  q u a l i t a t i v e d i f f e r e n c e s i n the f o r m a t i o n o f xylem  elements were a l s o e x p l a i n e d i n the l i g h t moisture  l e v e l s w i t h i n the stem:  of the v a r y i n g  a l l d r a s t i c i n c r e a s e s i n the  water content of xylem r e s u l t i n f o r m a t i o n o f earlywood l e s s of the time of v e g e t a t i v e p e r i o d .  regard-  Increases i n the water  content of p l a n t s by the a b s c i s s i o n o f l e a v e s have a s i m i l a r e f f e c t on earlywood  f o r m a t i o n ( L u t t s i n Grudzinskaya  D e c l i n e i n s o i l moisture was  1957)•  c o n s i d e r e d as the  p o s s i b l e cause of the t r a n s i t i o n i n xylem s t r u c t u r e (Kraus Spurr 1 9 6 l ) ; water supply was  static  denied any i n f l u e n c e i n t h i s  (Bannan 1960b; Van B u i j t e n e n 1 9 5 $ ) .  respect  and  D e c l i n e i n hydro-  pressure w i t h i n the t r e e has, a p p a r e n t l y , o v e r r i d e n the  auxin f a c t o r i n determining c e l l s i z e  (Shepherd  I964K  A category of r a d i a l growth, standing apart from r a d i a l growth of t r e e s , c o n s t i t u t e s o - c a l l e d l i v i n g  stumps.  They r e p r e s e n t a growth phenomenon which i s abnormal i n t h a t i t takes p l a c e without the l i v e crown while the net product t h i s growth may  of  at the same time be t h a t of the normal t r e e s ,  namely l a y e r s of xylem d i f f e r e n t i a t e d i n t o heartwood and sapwood (Lanner I 9 6 I ) . l e a v e s or branches,  Covered  living  with l i v i n g bark,  stumps grow i n diameter  h e i g h t s more than 10 f e e t above ground. xylem 12  t o 50 mm  t h i c k was  observed  without even at  Secondary growth of  i n the m o i s t e s t  densest Douglas f i r f o r e s t s (Lamb 1899)°  and  Judging from  the  number of r i n g s formed, Douglas f i r stumps were r e p o r t e d t o l i v e f o r c e n t u r i e s (Munger i n Newins 1 9 1 6 ) .  A woody c y l i n d e r  48  30 t o 60 mm  t h i c k e x h i b i t i n g annual r i n g s "was formed  around  stumps of some Tsuga canadensis and Pinus Strobus (Page 1927)• R a d i a l growth i n stumps i s u s u a l l y e x p l a i n e d by r o o t But, a c c o r d i n g t o P r i e s t l e y a c t i v e f o r 12  y e a r s was  parasitism.  ( 1 9 3 0 ) , a l a r c h stump a l i v e  and  found by Th. H a r t i g i n the c e n t e r of  a beech wood with no o t h e r l a r c h near.  49  THE  DISTRIBUTION OF  RADIAL GROWTH  PAST WORK Most s t u d i e s concerned w i t h r a d i a l growth, expressed predominantly i n terms of t o t a l r i n g width from b a s a l  portion  of stems, belong t o the realm of the t r e e - r i n g r e s e a r c h . believed  It  was  that I t would be immensely h e l p f u l i f the e f f e c t s of known and recent c l i m a t i c changes upon t r e e growth could be e s t a b l i s h e d , thus e n a b l i n g us t o e l i m i n a t e t h i s broad c l i m a t i c e f f e c t from the r i n g p a t t e r n , and so approach n e a r e r to an understanding of the e f f e c t s of l o c a l and h e r e d i t a r y f a c t o r s which are of more p r a c t i c a l importance i n f o r e s t r y . U n t i l the t r e e r i n g r e c o r d can be "broken down" i n t h i s way, the vast amount of i n f o r m a t i o n i t s u r e l y c o n t a i n s i s l i k e l y to remain locked up (Dobbs 1 9 5 1 ) • L i n e a r r i n g width was  a l s o considered  measure of the frequency of cambial d i v i s i o n and i n form o f stems (Topcuoglu 1 9 4 0 ) .  t o be the of the  wood and 196l)  latewood along the  and,  describe  stem (Topcuoglu 1940; form.  Smith and  Since  contemporary b o t a n i s t i s no l o n g e r  the form and  content t o  s t r u c t u r e of p l a n t s , but t r i e s  (Wareing 195&), the  Wilsie  i t i s main-  determine the nature of processes which give r i s e t o observed s t r u c t u r e  relative  a l s o of the l a y e r s of e a r l y -  t h e r e f o r e , to i n f l u e n c e the  t a i n e d t h a t the  change  Amount o f p r e c i p i t a t i o n , as  w e l l as s o i l water d e f i c i t , were found t o i n f l u e n c e the widths of the t o t a l xylem l a y e r s and  correct  to the  o b j e c t i v e s of t r e e - r i n g  s t u d i e s and  of m o r p h o l o g i c a l s t u d i e s i n t r e e s are not  wholly  unrelated.  Furthermore, the f r e q u e n t l y u n s a t i s f a c t o r y outcome  of comparisons between the amount of r a d i a l growth recorded  by  50  t r e e r i n g s at one l e v e l i n the stem on one hand, and of the weather r e c o r d s on the other (Sampson and Glock 1 9 4 2 ) , l e d t o the r e j e c t i o n o f r i n g width, measured at any one  single  l e v e l a l o n g the b o l e , as the v a l i d index of t r e e ' s true growth response  (Burns 1929)«  S i m i l a r l y , increment i n annual c r o s s -  s e c t i o n a l area at BH was not n e c e s s a r i l y the t r u e i n d i c a t o r of the t o t a l annual volume increment  (Schober 1951)  which  latter  q u a n t i t y can be a s c e r t a i n e d o n l y by m u l t i p l e s e c t i o n i n g of the bole o I t was  suggested t h a t "a complete knowledge of  r e l a t i o n s h i p s between t r e e growth and environment obtained by complete d i s s e c t i o n o f stems" atic  could be  (Glock 1941)•  System-  sampling of r a d i a l growth must be conducted i n any  i n t e n s i v e i n q u i r y i n t o the form o f stems.  Hence any  detailed  study of form o f f e r s the i n f o r m a t i o n sought by t r e e - r i n g r e s e a r c h workers i f v a r i a b l e s other than r i n g width measured at one l e v e l are r e q u i r e d .  From the f o l l o w i n g excerpt i t i s  evident t h a t t h i s was the case: .... The q u e s t i o n a r i s e s as t o whether the width o f a growth r i n g i s the most s u i t a b l e measure of t r e e response t o changes i n environmental f a c t o r s . Perhaps volume growth i s a b e t t e r measure A thorough understanding of the d i s t r i b u t i o n o f growth would help t o answer these q u e s t i o n s , and t h i s knowledge would be important i n sampling. Are e x p r e s s i o n s of growth i n the t r e e b o l e r e p r e s e n t a t i v e of t o t a l response? How many samples should be taken ...? Where should the sample be taken i n the t r e e ? .... These c o n s i d e r a t i o n s i n d i c a t e t h a t sampling i s a f o r m i d a b l e t a s k and t h a t a l a r g e number of measurements i s needed f o r accurate estimate of e i t h e r the t h i c k n e s s of the growth l a y e r or the annual volume growth (Hormay i n Sampson and Glock 1 9 4 2 ) .  51  The  sampling  problem unsolved,  always  acknowledged  as  of  difficulties  encountered  the  conclusion  was  a  statistical  reached  valuable  tool  in  methods  capable  tree-ring  of  were  not  solving  research.  some  A  that  S t a t i s t i c s d o n o t t e l l u s t h i n g s we d i d n o t know. At most, i t might j u s t i f y a guess t h a t r a i n f a l l and t r e e growth are not e n t i r e l y u n r e l a t e d ( D o b b s 195l)o Nevertheless, was  the  reiterated  discourse  more  of  recently  Hormay  as  (Sampson  and G l o c k  1942)  follows:  The . . . c o m p l i c a t i o n i s c o m p o s e d o f t h e many problems of u n i f o r m i t y which beset the growth layers themselves. I f volume r e p r e s e n t s the t r u e measure of growth i n a t r e e stem: (1) To what e x t e n t d o e s one r a d i u s r e p r e s e n t a s e c t i o n or a whole tree? (2) To what e x t e n t d o e s one s e c t i o n r e p r e s e n t a t r e e ? (3) To what e x t e n t d o e s one t r e e r e p r e s e n t a g r o u p ? ( G l o c k a n d A g e r t e r I960), The widths  measured  frequently activity  (Douglass by  climate  the  at  activity  conifers  Dinwoodie  the  G.B.  1919,  long  and  was  (Burns  and the  of  the  within  stem  one  been  attributed  Schulman 1964)  earth  cross  1942). of  to  The  the  ring  section, sun  spot  recent  link  and between  in  between  sun  spot  assumptions.  among  range  variability  others,  by M i k o l a  attributed  1929).  latter  variability  (Maddox  short  also  systematic  has  1920;  such  observed,  (1962),  radii  Tucker  surface  production former  the  in nature,  invalidated The  cone  encountered  along  cylical  demolition  of  often  to  were  radial  (1950)  cycles  Significant  variables  in  growth  and  observable  correlations  obtained,  among  in  between others,  52  by Holmsgaard  (1955) and by E i s e t a l .  ones by Daubenmire  (1964);  nonsignifleantz  (i960).  E c c e n t r i c growth was  shown t o c o n s t i t u t e another  source c o n t r i b u t i n g t o the t o t a l v a r i a b i l i t y i n r i n g widths measured at one l e v e l .  The r e l a t i v e v a r i a t i o n was found t o be  approximately equal i n s i z e on a l l  s i d e s of stems (Mikola 1 9 5 0 ) ;  thick  but a l s o so much discordance was found i n the sequences of  and t h i n l a y e r s a l o n g o p p o s i t e r a d i i of the same t r e e t h a t no r e l a t i o n s h i p between xylem f o r m a t i o n and c l i m a t e could be detected  (Daubenmire 1955)*  Maximum r i n g width d i d not always  occur i n the l o n g e s t r a d i u s and v i c e v e r s a (Adams  1928).  Also,  r e l a t i v e v a r i a t i o n s of growth were approximately equal i n the average of two r a d i i and t h e r e was l i t t l e  or no v a r i a t i o n i n  the sequence of h i g h s and lows f o r both r a d i i  (Hansen 1 9 4 1 ) •  Increment cores from 6 t o 8 t r e e s were considered as s u f f i c i e n t t o supply i n f o r m a t i o n about c l i m a t i c a l l y  conditioned  v a r i a b i l i t y w i t h i n the i n d i v i d u a l stand (Holmsgaard 1 9 5 5 ) .  A  p o p u l a t i o n o f 10 r a d i i from 5 t r e e s appeared t o provide an adequate r e c o r d o f growth f l u c t u a t i o n s i n groups of t r e e s which showed c l i m a t i c 1955)*  c o n t r o l o f t h e i r diameter growth (Daubermire  C o e f f i c i e n t s of v a r i a b i l i t y of r i n g width measured at BH  ranged from 30 t o 40 per cent i n evenaged Norway spruce and Douglas f i r  (Marsakova-Nemejcova 1954;  Vins i 9 6 0 ) .  V a r i a b i l i t y of r i n g w i d t h was found t o be h i g h e r at 0.25  m above ground than at 1..30  m (Topcuoglu 1 9 4 0 ) ; r i n g widths  at the t o p o f the bole of some hardwoods gave b e t t e r  correlations  53  w i t h p r e c i p i t a t i o n than those near the base et a l . 1 9 5 7 ) .  ( M i l l e r i n Tryon  A l a c k o f u n i f o r m i t y i n the t h i c k e n i n g o f the  same l a y e r of xylem i n v e s t i g a t e d at 5, 10 and 15 meter l e v e l s was r e p o r t e d by Shreve  (1924).  A study o f 3 t r e e s , d i s s e c t e d a t  5-foot i n t e r v a l s , r e v e a l e d t h a t a s i n g l e core taken a t any p o i n t a l o n g the b o l e gave an accurate r e p r e s e n t a t i o n o f the r e l a t i v e width of the growth l a y e r s  (Marr 1 9 4 3 ) .  The v a r i a b i l i t y  of r i n g widths measured at 6 l e v e l s w i t h i n 8 t r e e s was uniform at a l l h e i g h t s and the r e l a t i v e magnitude o f the v a r i a t i o n was the same (Holmsgaard  1955)•  To c l a r i f y the developmental t r e n d s i n form observed and r e p o r t e d f o r v a r i o u s s p e c i e s (Dittmar 1953; Abetz  I960),  knowledge o f the l o n g i t u d i n a l p o s i t i o n o f maximum r a d i a l increment i s important.  annual  In t h i s r e s p e c t , the r e a s o n i n g o f  Buesgen and Muench (1929)  i s o f some i n t e r e s t :  I f annual i n c r e a s e i n c r o s s - s e c t i o n a l area o f a stem i s the same everywhere throughout i t s l e n g t h the l i n e a r breadth o f the annual r i n g s must i n c r e a s e from below upwards, because the circumference o f the stem, which t o g e t h e r with the breadth o f the r i n g determines the s e c t i o n a l area of the annual increment, d i m i n i s h e s i n an upward d i r e c t i o n . Consequently the annual r i n g s are as a r u l e widest immediately below the l i v i n g crown. I n s i d e the crown they f a l l o f f i n breadth w i t h each branching. "Every stem a n a l y s i s can show t h a t the annual r i n g s are widest d i r e c t l y below the l i v e  crown", maintained H i l d e b r a n d t ( 1 9 5 4 ) ,  but a c c o r d i n g t o Larson  (1963b)  The upward s h i f t o f maximum t r a c h e i d diameter with age and the p o s i t i o n o f t h i s maximum d u r i n g any one year may be r e l a t e d t o the f a c t that maximum r i n g width o c c u r s i n the v i c i n i t y of the branch whorl c o n t r i b u t i n g most t o stem growth.  54  The p o s i t i o n o f the branch whorl c o n t r i b u t i n g most t o the t o t a l c r o s s - s e c t i o n a l area was I t was  s t u d i e d by Labyak and Schumacher (1954)«  found t h a t The average c o n t r i b u t i o n o f the s i n g l e branch depends on i t s l o c a t i o n and the number of i t s b r a n c h l e t s . A branch i n the top l / l O o f the t r e e c o n t r i b u t e s most t o main-stem growth j u s t below i t s base; the p r o d u c t i o n o f lower branches i s evenly d i s t r i b u t e d a l o n g the stem.  Growth i n diameter at any g i v e n p l a c e a l o n g the lower p a r t of the b o l e was a f u n c t i o n o f the s i z e o f crown above t h a t  place  and was  r e l a t e d t o the d i s t a n c e from the crown (Young and Kramer  1952).  Trees were thought t o be most a c t i v e as r e g a r d s wood  f o r m a t i o n i n the neighborhood of the l i v i n g crown; the diameter growth of the lower p a r t o f the stem t a k e s p l a c e only t o provide a minimum degree of r e i n f o r c e m e n t (Van Soest 1959)* In exposed t r e e s , the annual r i n g s i n c r e a s e d i n 1  t h i c k n e s s from the base o f the crown downward; i n suppressed t r e e s , annual r i n g s narrowed  from the base o f the crown downward  and then i n c r e a s e d again near the base of the t r u n k .  The  zone  of i n c r e a s e d diameter growth below the crown moved upward as t r e e s i n c r e a s e d i n h e i g h t , thus t e n d i n g t o m a i n t a i n c y l i n d r i c a l r a t h e r than c o n i c a l form o f t r u n k s (Kramer and Kozlowski  i960).  In very o l d t r e e s i n c l o s e d stands the diameter at about  forty  f e e t was  sometimes l a r g e r than a diameter at about twenty  above the ground. 9/16  An unexpected s w e l l i n g was  o f the t o t a l h e i g h t (Schenck I 9 O 5 ) .  the annual r i n g s b e f o r e the r e l e a s e was  feet  o f t e n found at  The t h i c k e s t p a r t of i n the upper p a r t of the  55  t r u n k i n s i d e the crown ( S i r e n 1 9 5 2 ) .  The maximal v a l u e s of r i n g  width as w e l l as of r i n g area d i d not occur w i t h any degree c o n s i s t e n c y i n the immediate v i c i n i t y of the base of the crown (Berry 1964)«  of  live  T o t a l annual growth l a y e r i n ponderosa  was widest above or at the middle of the l i v e crown (Myers  pine 1963).  The maximum r i n g width i n forest-grown young Pinus d e n s i f l o r a was  i n the crown and near the r o o t s , w i t h a minimal r i n g width  between the two maxima.  The p o s i t i o n of minimal r i n g width  changed from year t o year, g e n e r a l l y t e n d i n g t o r i s e w i t h i n c r e a s e i n l e n g t h of the b r a n c h l e s s p o r t i o n o f the stem (Onaka 1 9 5 0 a ) . The r i n g area i n c r e a s e d downwards at each  branch  l e v e l , h a r d l y changed i n the b r a n c h l e s s p o r t i o n of the b o l e although sometimes i t decreased, and showed an abrupt e n l a r g e ment near the root c o l l a r . i n the crown appeared maximum r i n g width.  The maximal p o i n t of the r i n g area  at a p o i n t l i t t l e  lower than t h a t of  The minimal p o i n t i n the b r a n c h l e s s  p o r t i o n tended t o be much h i g h e r than t h a t of the minimum r i n g width  (Onaka 1 9 5 0 a ) .  C r o s s - s e c t i o n a l area increment was  evenly  d i s t r i b u t e d between b u t t - f l a r e and base of l i v e crown, but s e v e r a l l o c a l enlargements  were observed i n the outer r i n g s i n  the b a s a l t h i r d of the stem (Abetz i 9 6 0 ) . g r e a t e s t j u s t below the l i v e basi-petally.  Decrease  The r i n g area  was  crown and decreased both a e r o - and  i n area from the base of crown t o the  base of stem was more marked i n earlywood than i n latewood (Chalk 1 9 3 0 ) .  56  The width o f latewood i n v a r i a b l y i n c r e a s e d i n descent w h i l e t h a t of earlywood earlywood  decreased.  T h i s meant t h a t width o f  at a lower p o s i t i o n i n the b o l e c o u l d never exceed the  width i t assumed at a h i g h e r p o s i t i o n 196l).  ( T u r n b u l l 1937;  Green  S i m i l a r l y , the s p e c i f i c g r a v i t y or the percentage of  latewood were found t o i n c r e a s e downwards i n most r e p o r t e d cases (Young 1952; 1954;  S i r e n 1952;  Wellwood i 9 6 0 ) ,  (Wellwood 1952;  H a r r i s and Orman 195&;  but a r e v e r s e s i t u a t i o n was  Smith and W i l s i e  Hidlebrandt  a l s o noted  I96I).  Complete stem a n a l y s i s by m i d - i n t e r n o d a l s e c t i o n i n g was  conducted on a c e l l u l a r l e v e l i n P i n u s Strobus by Adams  (1928).  The maximum r i n g width p r o g r e s s e d upwards w i t h each  succeeding y e a r .  The time of the appearance  of maximum r i n g  width and the raUe of a c r o p e t a l advance were c o n d i t i o n e d by spacing.  S i m i l a r c o n c l u s i o n s , based on s i m i l a r methods, were  drawn by M i s r a (1943)«  Complete stem a n a l y s e s were repeated  subsequently by Duff and Nolan Low  (1953,  1 9 5 7 ) ; Mott et a l . ( 1 9 5 7 ) ;  ( 1 9 5 9 ) ; Mason ( i 9 6 0 ) ; Green ( 1 9 6 1 ) ; Forward  b ) ; Smith and W i l s i e Fraser et a l . (1964)0  and Nolan  (I96la,  ( 1 9 6 1 ) ; Walters and Soos ( 1 9 6 2 ) , and by The r e s u l t s o f these works suggest the  f o l l o w i n g p o s i t i v e c o n c l u s i o n which i s important f o r the present study,  the width o f t o t a l annual l a y e r s of xylem i n the stems  of c o n i f e r o u s s p e c i e s i s d i s t r i b u t e d i n a s i m i l a r f a s h i o n r e g a r d l e s s of the s p e c i e s or of the g e o g r a p h i c a l area, but i t i s s u b j e c t t o m o d i f i c a t i o n s due t o crown c l a s s and t o changes i n stand  density.  The considerable l a c k o f agreement between the r e s u l t of works reviewed i n t h i s chapter t e s t i f i e s t h a t the p o s i t i o n of maximum r i n g width i n the stem i s not s u f f i c i e n t l y known o r , a l t e r n a t i v e l y , t h a t t h i s p o s i t i o n , l i k e that of r i n g width i t s e l f , v a r i e s considerably from t r e e t o t r e e .  Since the  maximum r i n g width, or b e t t e r the r a t i o between maximum r i n g width at the top of the stem and r i n g width at the base of the stem w i t h i n any one year, are the obvious determinants of the form of the annual xylem l a y e r s , and t h e r e f o r e of the stem form the present i n v e s t i g a t i o n regarding such data seems w e l l justified.  58  MATERIALS AND METHODS The 18 Douglas f i r t r e e s i n v e s t i g a t e d i n the present study can be c l a s s i f i e d i n two groups! one c o n s i s t i n g o f 11 plantation-grown t r e e s about 25 y e a r s o l d and another o f 7 t r e e s from unmanaged second-growth stands about .50 years o l d . The b a s i c mensurational data p e r t a i n i n g t o both groups are i n Tab. I . A l l the t r e e s , with the e x c e p t i o n o f t r e e number 2 which was an open-grown t r e e , were forest-grown t r e e s from the U n i v e r s i t y o f B r i t i s h Columbia  Campus F o r e s t .  The one-acre p l a n t a t i o n which s u p p l i e d t r e e s 13 M, 27 M, 32 M, 33 M and t r e e s number 1,  3 , 4 , 5 , 6 and 7, i s  l o c a t e d about 300 f e e t above and h a l f a m i l e away from the waters of the G u l f of Georgia at 49°15'N and 123°15 W.  I t was  r  e s t a b l i s h e d i n 1937 on a r e c t a n g u l a r moderately  s l o p i n g t o the south-west,  r e s i d u a l Douglas  beneath  example o f these r e s i d u a l t r e e s .  some young  Specimen No. 1 i s an  Since 1958 the p l a n t a t i o n has  on s e v e r a l o c c a s i o n s by the c u t t i n g o f border  t r e e s , by c l e a r i n g o f the f o r e s t e d l a n d around subsequent  land  f i r , western r e d cedar (Thu.ia p l i c a t a ) and  western hemlock (Tsuga h e t e r o p h y l l a ) .  been d i s t u r b e d  parcel of cleared  i t and by the  windthrow. Trees number 8 t o 14 grew approximately 3 m i l e s away  from the p l a n t a t i o n i n n a t u r a l l y e s t a b l i s h e d stands,  rather  heterogeneous  structure,  as regards t h e i r composition, d e n s i t y ,  depth of s o i l , and s o i l moisture regime. Douglas  In these stands the  f i r t r e e s formed, as a r u l e , the upper s t o r y and grew  TABLE I BASIC MENSURATIONAL  DATA OF THE SAMPLE TREES  FINAL FORM FACTOR FINAL VOLUME Age a t Height Stump above D.B.H. Stump L i v e (LAMBDA 0.9)X ( i . b . ) Height Crown T o t a l Earlywood Latewood Tree Height No. , » ( c u . f t . ) T o t a l Earlywood Latewc (cu.ft. )(cu.ft.) (in.) ( f t . ) (ft.) (yearsj  20 20 20 20 24 22 24 23 23 23 33 46 48 48 48 49 48 50  13M  27M 32M 33M  1  2  3 4 5  6 7 8  9  10 11 12  13 14  x  51.2 51*7 51.8 52.8 60.1 48.I 56.5 57.5 57.9 63.O 74-4 108.2  116.0 116.6  114.2 123.8 111.2 122.2  • 5.7  6.3  5.9 5.4  8.9  8.2 7.4 6.9  6.8  10.6 12.7 15.4 18.6 15.7 17.721.0  20.6  20.9  1.5  3.5  0.8 1.9 1.7 1.8 3.2 5.6 4.7  6.3  3.1 4.0  2.6 2.6  70 64 53 48 47 85 52 52 47 57 63 57 43 53 53 52 40 45  3.5 4.1 4.1 3.5 10.8  6.5 7.3 6.0  6.5  15.1  24.I  6O.4 80.7 65.I  91.0 105.7 87.8 96.4  2.3 2.4  2.6  2.2 7.1 4.2 4.9 3.7 4.1 10.0 15.5  31.9  48.3 37.8 61.6 71.4 61.0 60.6  •1.2 1.7 1.5 1.3 3.7  2.3 2.4 2.3 2.4  4.9 8.6  28.5 32.4 27.3 29.4 34.3 26.8 35.8  F o r m f a c t o r s o f t r e e s 13M t o 33M are based on 10 e q u i d i s t a n t  .449 .470 .478 .495 .508 .454 .537 .493 .509 .509 .456 .512 .488 .484 ^.548 .485 .463 .490  .491 .520 .523 .558 .556 .483 .607 .551 .529 .529 .524 .511 .525 .529 .583 .511 .483 .487  .385 .410 .418 .408 .433 .407 .432 .416 .472  .469 .376 .513 .442 .434 .486 .437 .423 .496  sections.  vn  60  50 t o 100 western  yards apart i n a s s o c i a t i o n with western  red cedar  and  hemlock i n the u n d e r s t o r y , and with undergrowth of red  a l d e r (Alnus rubra) on i m p e r f e c t l y d r a i n e d The  sites.  s o i l of t h i s area belongs t o the N i c h o l s o n  S e r i e s which i s c o n s i d e r e d t o be a c i d , brown f o r e s t  Soil  soil,  mainly  sandy loam with stones, a w e l l - d r a i n e d t o p o o r l y - d r a i n e d , mixed glacial t i l l  and outwash u n d e r l a i n by l e n s e s or benches of  marine c l a y or by sandy hardpan. the hardpan r e s t r i c t the depth s u f f e r s from windthrow. in  The  compacted g l a c i a l t i l l  of r o o t i n g and the whole area  In f a c t , a l l the l a r g e t r e e s i n c l u d e d  t h i s study, as w e l l as the t r e e s number 2,  were uprooted  and  i n the f a l l  of 1962  the uprooted l a r g e stems.  observed  I t was  4,  5, and  7  by Typhoon F r i e d a , which  t r a v e l l e d at speeds i n excess of 100 M.P»H<» t a b l e i n the n a t u r a l f o r e s t was  3,  The h e i g h t of water  i n p i t s dug  beneath  found above the top of the  m i n e r a l s o i l d u r i n g the w i n t e r months and d u r i n g e a r l y s p r i n g ; d u r i n g the summer i t r e t r e a t e d g r a d u a l l y t o lower depths. l e v e l ground i t was  found 3«5 f e e t below the s o i l  the b e g i n n i n g . o f June.  On  s u r f a c e by  In l o c a l d e p r e s s i o n s and r a v i n e s the  water t a b l e d i d not r e t r e a t below 1.5  f e e t even d u r i n g the  summer. The  c l i m a t e of the area can be c l a s s i f i e d as a  m o d i f i e d maritime approximately  one.  30 i n c h e s .  The t o t a l annual p r e c i p i t a t i o n i s The maximum r a i n f a l l occurs d u r i n g  the w i n t e r months, the minimum i n June and J u l y . temperatures  range from an average  minimum of 31°F  The a i r i n January  t o an average maximum of 12 F i n J u l y , the extremes being and  92°Fo  The  average f r o s t - f r e e p e r i o d i s 213  Dept. of Transport The center  I.  r a d i a l growth o f the 18  of each annual height  A sketch  of the  disc.  inches t h i c k was  An average r a d i u s was  s h o r t e s t diameter and mm  wide and  was  cut from the d i s c i n such a way  and  t h a t the  c e n t e r l i n e of the  on the  The  In  this  L e v e l number  one  leader.  removed at each  c a l c u l a t e d from 4 r a d i i measured  Then a s t r i p of wood 12  of the average r a d i u s .  1.  in  stem are known as  c e n t r a l c r o s s s e c t i o n of the  and  the  above ground as given  c r o s s s e c t i o n s of the  A d i s c about 1.5  along the l o n g e s t  sampled at  increment s y s t e m a t i c a l l y from stem-  T h e i r numbering i s always b a s i p e t a l c  c o i n c i d e s w i t h the  level.  stems was  sampling scheme i s i n Figo  study the m i d - i n t e r n o d a l levels.  days (Canada,  1962).  apex t o some v a r i a b l e small d i s t a n c e Tab.  zero  p l o t t e d i n t o the about 0.8  mm  thick  t h a t i t i n c l u d e d the p i t h  s t r i p c o i n c i d e d w i t h the  line  f o l l o w i n g q u a n t i t i e s were measured  s t r i p s t r e a t e d w i t h an o i l - c a r b o n suspension ( F i g .  2):  r a d i u s of p i t h , width of the primary wood, width of earlywood and  of latewood bands w i t h i n each annual r i n g , where d i s c e r n i b l e  The  primary wood as w e l l as the bands i n which no latewood band  could be d i s t i n g u i s h e d under 5X m a g n i f i c a t i o n as bands c o n s i s t i n g of earlywood o n l y . i n transmitted  l i g h t t o 0.001  o f f t o the nearest  0.005 inch.  The  were c l a s s i f i e d  bands were measured  i n c h w i t h a c a l i p e r and The  rounded  measurements obtained  t h i s method were, i n case of t r e e 32 M,  compared with  the  by  I  Figure I - The sampling scheme-  Fig. Band of earlywood  2  between two bands o f latewood  in. a s t r i p t r e a t e d with o i l - c a r b o n (approx. 2 0 X )  suspension.  62  c o r r e s p o n d i n g measurements obtained  f o r the same t r e e by Green  (1961) who used Mork's d e f i n i t i o n o f the latewood-earlywood boundary.  D i f f e r e n c e s between the two groups o f measurements  were not s i g n i f i c a n t when t e s t e d by a n a l y s i s o f v a r i a n c e . consistency  The  o f the measurements as w e l l as the magnitude of the  e r r o r s due t o b i a s i n l o c a t i n g the earlywood-latewood  boundary  and of the e r r o r s due t o expansion o f the s t r i p were t e s t e d d u r i n g the course o f work by comparing two o r more s e t s of readings  taken on the same s t r i p s e l e c t e d by chance.  average d i f f e r e n c e s between r e a d i n g s t o about 8 per cent cent  The  were random and amounted  i n the case of latewood and t o about 5 per  i n the case of earlywood.  The maximum d i f f e r e n c e i n  measurement of latewood was as h i g h as 20 per cent  and t h a t i n  earlywood about 13 per cent, both o c c u r r i n g , on the average, one time i n 40 measurements.  63  RESULTS PART (A) DISTRIBUTION OF THE ANNUAL RADIAL GROWTH ALONG THE STEM OF DOUGLAS FIR The o v e r a l l amount of r a d i a l growth achieved d u r i n g f i v e growing  seasons along the bole of t r e e No. 1 i s shown i n  F i g . 3 and 1+ i n terms o f r i n g width and i n terms o f r i n g area i n F i g . 5 and 6 .  From these graphs i t i s e v i d e n t t h a t the  annual increments o f earlywood,  i n width as w e l l as i n area,  were not d i s t r i b u t e d a l o n g the bole o f t h i s t r e e , d u r i n g t h i s p e r i o d , i n the same way as the corresponding annual of latewood.  increments  The same c o n c l u s i o n can be a r r i v e d at i f t h e  cumulative r i n g areas o f earlywood and of latewood  respectively  are p l o t t e d over h e i g h t a t which they were sampled; the p l o t , shown i n F i g . 1 and 8 , w i l l y i e l d two imaginary stems, an "earlywood  stem" and a "latewood  stem", d i s t i n c t l y d i f f e r i n g i n  shape. More complete  i n f o r m a t i o n concerning the d i s t r i b u t i o n  of r a d i a l growth can be found i n the diagrams appendix  o f t h i s work ( D i a g . 1 t o 8 3 ) •  i n c l u d e d i n the  In these diagrams the  t r i a n g u l a r m a t r i x - o f o n e - d i g i t numbers p o r t r a y s the r i g h t  half  of an imaginary u p r i g h t c o n i c a l stem by i t s o u t l i n e , and t h e r e l a t i v e r a t e s of r a d i a l growth w i t h i n t h i s stem by i t s c o n t e n t s . Only the s u c c e s s i v e a r r a y s o f numbers p a r a l l e l w i t h the hypotenuse o f the t r i a n g l e are meaningful; they show the r e l a t i v e  Figure 4-  2  3  4  Widths of latewood layers.tree No-1,years 1958—1962-  5  10  15  NUMBER OF INTERNODE FROM A P E X  20  24  C U M U L A T I V E RING A R E A OF E A R L Y W O O D {SQ- INO  0  5  10  15  20  C U M U L A T I V E RING A R E A OP L A T E W O O D (SQ- IN-)  25  64  r i n g widths, o r r i n g areas, o r percentages of l a t e wood by area, as the case may the  be, w i t h i n the annual l a y e r s from the apex of  stem t o i t s base or v i c e v e r s a *  Only the v a r i a b i l i t y of  r a d i a l increment w i t h i n the i n d i v i d u a l l a y e r s i s observed, the variability  i n r a d i a l increment between l a y e r s b e i n g e l i m i n a t e d .  The number of h o r i z o n t a l a r r a y s corresponds t o the number of l e v e l s sampled. of  T h e r e f o r e , the l a y e r d e p o s i t e d i n the l a s t year  a t r e e ' s growth i s r e p r e s e n t e d i n the m a t r i x by the l o n g e s t  a r r a y o f numbers which range i n every l a y e r , the f i r s t excepted, from zero t o n i n e . the  Zero d e s i g n a t e s the p o s i t i o n o f  minimum annual r a d i a l increment, the c i p h e r 9 stands i n  place o f maximum annual r a d i a l increment. are  one  The remaining f i g u r e s  the r e l a t i v e measures of the magnitude of r a d i a l growth  w i t h i n t h i s range and i n d i c e s of i t s r e l a t i v e p o s i t i o n w i t h i n the  annual l a y e r .  growth,  The annual l a y e r formed i n the f i r s t  i n d i c a t e d i n the headings of the diagrams,  i n the m a t r i x by a s i n g l e z e r o .  The  year of  i s represented  s i t e s o f the maximal r a d i a l  growth or the s i t e s of maximal percentages of latewood are b l o c k e d out or c r o s s e d by l i n e s of v a r y i n g t h i c k n e s s .  The  double c i r c l e around a number i n the a r r a y , r e p r e s e n t i n g the annual l a y e r d e p o s i t e d i n the l a s t y e a r of growth, the  approximate  p o i n t s out  p o s i t i o n o f the base of l i v e crown which  was  d e f i n e d i n t h i s study as the lowest complete whorl o f green branches. which was  The  s i n g l y e n c i r c l e d f i g u r e i s l o c a t e d i n the l e v e l  c l o s e s t t o the BH p o s i t i o n on the stem.  65  The (1)  i n f o r m a t i o n conveyed  by the diagrams  i s as f o l l o w s ?  The minimum v a l u e s o f a l l the v a r i o u s measures of  r a d i a l growth p o r t r a y e d occur a t the stem-apex and along t h e pith. (2)  The maximum r i n g width o f earlywood  o c c u r s , i n most  i n s t a n c e s , at a short d i s t a n c e below t h e apex i n any one y e a r . I t i s , t h e r e f o r e , found w i t h i n t h e l i v e  crown, but i n t r e e No. 4  i t was below the most r e c e n t base o f l i v e (3)  The zone o f maximum increment  crown.  of earlywood  i s well  d e f i n e d and u s u a l l y very narrow, but i t may be wide as i n the case o f t r e e No. 13« (4)  The width o f earlywood  decreases r a p i d l y i n b a s i p e t a l  direction. (5)  The maximum r i n g width o f earlywood was not at the  base o f open grown t r e e No. 2, but h i g h e r up the stem. (6)  The maximum r i n g width o f latewood o c c u r s w i t h i n the  stem at p o s i t i o n s which are u s u a l l y below those o f maximal r i n g width of earlywood  and w i t h i n a zone which was more o r l e s s  w e l l d e f i n e d only i n t r e e s No. 32M, 5j> 8, 10 and 14•  In the  remaining t r e e s t h e p o s i t i o n o f maximum r i n g width o f latewood f l u c t u a t e d w i d e l y along the lower p o r t i o n o f t h e stem. (7)  I n cases where r i n g width o f latewood  decreases  b a s i p e t a l l y the r a t e of decrease i s small* (8)  The zone o f t h e maximal r i n g area o f earlywood i s  always h i g h e r than the zone o f maximal r i n g area o f latewood. I t s upper border was above the base o f l i v e crown i n t r e e s No. 1,  66  3,  4,  5*  remaining (9)  ll*  12;  i t was b e l o w t h e b a s e  The zone  at t h e v e r y base  o f t h e maximal r i n g a r e a o f latewood i s of live  crown; i n most  instances t h i s i s  o f t h e stem.  C o n s e q u e n t l y , t h e maximum p e r c e n t a g e  area occurs always The  i n t h e l o w e r p o r t i o n o f t h e stem.  t o stem-apex i n t h e i n d i v i d u a l  o f stems i s shown i n F i g . 9 t o 14*  of these graphs wood i n t r e e s  o f l a t e w o o d by  a b s o l u t e p o s i t i o n o f maximum r i n g w i d t h o f e a r l y -  wood w i t h r e s p e c t groups  crown i n t h e  trees.  always below t h e base  (10)  of live  i s the plot  i n which  An a d d i t i o n a l  feature  o f t h e minimum r i n g w i d t h o f e a r l y -  i t was f o u n d t o o c c u r c o n s i s t e n t l y  a number o f y e a r s .  A l l these graphs a r e based  averages  f o r a l l growth  calculated  stems o r i n  over  on m o v i n g  l a y e r s w i t h i n any one t r e e  by a v e r a g i n g 3 measurements o f r i n g w i d t h o f earlywood o r latewood,  respectively, The  of earlywood, as t h e i r  mean v a l u e s o f t h e maximum a n d minimum r i n g a n d t h e maximum r i n g w i d t h o f l a t e w o o d ,  coefficients  standard errors  of variation  i n t h e stem  the  shape  and  cumulatively,  i n Tab. I I .  a r e i n Tab. I I I .  as w e l l  Their  Since the v e r t i c a l  and a l s o t h e m a g n i t u d e o f t h e maximum a n d  minimum t h i c k n e s s e s o f t h e x y l e m  critical  width  a b s o l u t e mean h e i g h t s i n t h e stem, a r e g a t h e r e d  together with t h e i r  position  at a time.  of the individual t h e shape  layers  growth  of both types  determine  l a y e r s and t h e r e f o r e ,  jointly  o f t h e stem, t h e r a t i o s b e t w e e n t h e  d i m e n s i o n s o f t h e l a y e r s were c a l c u l a t e d  f o r each  stem  Figure I i • Position of minimum ond maximum ring width of earlywood,and of the stem-base,  1917  20  25  30  35  40 YFAR  45  50  55  CO  Figure 12-  1917  20  Position of m i n i m u m and m a x i m u m r i n g width of e a r l y wood, a n d of the stem - b a s e ,  2C  30  35  40  YEAR  45  50  55  60  YEAR  YEAR  TABLE I I THE AVERAGES OF THE CRITICAL WIDTHS OF EARLYWOOD AND OF LATEWOOD AND THEIR AVERAGE LONGITUDINAL POSITION IN THE STEM TREE OR GROUP OF TREES  Emax (in.) SE M  h(Emax) top (ft.) M. SE  Emin  h(Ernin) bse (ft.) M'' SE  (in.) M SE  :  Ebse (in.) SE M  Lmax (in.) M SE  h(Lmax) top (ft.) M SE  LAYERS, h(Lmax) bse (ft.) M SE  H  Lbse (in.) SE M  (in.) M SE  N  13M,)  27M, ) 3 2 M ,  )  33M  ) 0 . l 6 l O.Oi  9 . 2 O.35 0 . 0 7 5 0 . 0 0 5  0 . 6 0 . 1 9 O.O78 O.OO5 0 . 0 7 0  1,3, ) 4,5, ) 6 )0.192 0 . 0  .0.2 0.37 0 . 0 9 1 0.005  1.4  0 . 3 7 0.095 0.005 0.079 0.003 2 9 . 1 1.6  7  0 . 2 0 1 0 . 0 '.3.6 1 . 2 9 0 . 1 0 8 0.009  5.2  0 . 9 7 O . I 3 6 0 . 0 1 0 O.O85 0 . 0 0 6 3 3 . 0 3 * 4 4 1 1 . 2 2 . 2 2 O.O65 0 . 0 0 4 2 8 . 4 1 . 8 1 27  8  0 . 1 6 2 0 . 0 .3.9 1.40 0 . 0 8 0 0 . 0 0 6  5 . 0 1 . 0 8 O.O87 0 . 0 0 6 O.O97 0 . 0 0 3 4 0 . 7 4 . 2 1 3 0 . 8 4 - 3 5 0 . 0 7 3 0 . 0 0 3 2 8 . 9 1 . 8 1 39  9  0 . 1 8 5 0 . 0 |0.2 1.05 0.097 0 . 0 0 4 1 0 . 8  1 . 1 6 0 . 1 1 0 0 . 0 0 5 O.O96 0 . 0 0 3 3 7 * 8 3 . 1 4 3 6 . 0 4 . 9 1 O.O84 0 . 0 0 3 2 9 * 6 1 . 5 5 39  10  0 . 1 6 2 0 . 0 '.5.5 1.87 O.O83  1 . 1 5 0 . 0 8 7 0 . 0 0 6 0 . 0 8 7 0 . 0 0 3 3 6 . 9 3 * 5 4 3 5 . 3 4 . 9 8 O . O 7 3 0 . 0 0 3 2 8 . 8 1 . 5 9 44  11  0.211 0.0  12  0 . 2 1 4 0 . 0 !3*9 2.05 0.128  13  0 . 1 9 7 0 . 0 '.5.1 1.95 0.133 0.007  14  0 . 2 0 9 OoO  (Emax) (Emin) (Lmax) (Ebse) (Lbse)  Maxim Minim Maxim Width n  M  s  m  0.006  .4.1 1.11 0 . 1 0 8 0.004 0.009  5.2  4.9 0 . 3 0 0.114 0.004 9.3  O.O83  0.003  2 2 . 4 1.6  1 1 . 4 1 » 7 6 0,058"  3 2 . 8 1 , 6 8 58  1 0 . 6 1 . 3 7 0 . 0 7 1 0 . 0 0 3 3 0 . 6 0 . 9 7 90  0 . 0 0 3 42c6 4 . I 8 2 6 . 6 5 . 2 6 0.075  2 . 0 0 0 . 1 4 1 0 . 0 0 9 O . O 8 4 0 . 0 0 3 5 3 . 2 5«03  C.OO3  0 . 0 0 3 2 9 * 0 1 . 5 2 42  2 2 . 4 5 * 0 8 O . O 7 8 0 . 0 0 4 3 0 . 7 1*56 43  6 . 6 1 . 2 3 0 . 1 4 5 0 . 0 0 7 0 . 0 7 4 0 . 0 0 2 5 8 * 6 4 * 7 1 1 2 . 8 3 * 3 0 O.O67 0 . 0 0 3 2 8 . 4 1 . 6 1 41  .1.3 0.76 0.115 0.007 1 0 . 3 1 . 3 9 0 . 1 2 9 0 . 0 0 8 0 . 1 0 0 0 . 0 0 3 3 4 * 4 . 1 * 9 0  40*6 5 . 4 7 , 0 . 0 8 3  0 . 0 0 4 2 9 * 9 1 - 5 1 45  d i s t a n c e t o (Emax) from stem-apex* h(Emax) t o p " " (Lmax) «» " " h(Lmax) t o p " " (Lmax) " stem-base ; » " latewood « h(Lmax) bse h(Emin) bse - " " (Emin) " " " earlywood l a y e r a t stem-base H . latewood l a y e r " " " annual h e i g h t increment SE standard e r r o r , N - number o f annual l a y e r s d d t h of earlywood  ! tt  tt  tt  layer tt  0  TABLE I I I COEFFICIENTS OF VARIATION OF THE CRITICAL DIMENSIONS OF GROWTH LAYERS TREE OR GROUP OF TREES NO.  13M, 27M,  Emax*  h (Emax) top  Emin  Ebse  Lmax  COEFFICIENT OF VARIATION  32M, 33M  16.0  29-3  1,3,4,5,6  24.6  7  24.2 31.2 18.3  34-5 49-3 63.1 64.3  27-7  80.0  51.2  17.2 23.8 23.1 23.6  51.1 56.3 49-8 45.0  21.6 45.9 35.5 43.4  8 9 10 11 12 13 14  h (Emin) bse  46.6 54.6 41.7 47.6 25.7  255.1 246.6 96.7 133.9 67.2 14.5 105.3 141.0 120.4 90.9  D e f i n i t i o n s o f (Emax), e t c . as i n Tab. I I Non-normal d i s t r i b u t i o n s .  45.1 52.0 39.2 42.5 26.1 48.2 20.6 43 «4 29.2 43.2  27.3  30.7 33.7 19.2 16.5 21.8 21.5 21.3 20.7 18.3  h (Lmax) top  h (Lmax) bse  Lbse  H  N  40.2 38.7 35.7 28.8 24.3 31.3 28.7  23.7 30.1 33.1 39.1  58 90 27 39 39 44 42 43 41 45  (PER CENT)  53.3 52.8 54.2 64.5 51.8  63.7 63.7 62.0 51.5 37.0  117.3 121.9 102.5 88.2 85.3 93.7 12.8 I48.7 I64.8 9O.4  32.7  36.7 34-0 36.O 33-2 25.8 36.2 36.1 33-9  69  and y e a r .  The p r o g r e s s i o n o f the v a l u e s o f these r a t i o s as  e x e m p l i f i e d by t r e e s No. 1 and No. 11 appears i n F i g . 15 and 16, t o g e t h e r w i t h p l o t s o f the p o s i t i o n s o f maximum r i n g width of  earlywood expressed as percentages o f the t o t a l t r e e h e i g h t .  The averages o f the r a t i o s between the c r i t i c a l the of  dimensions o f  growth l a y e r s , t h e i r standard e r r o r s and t h e i r v a r i a t i o n are i n Tab. IV and V.  coefficients  The v a r i o u s shapes which may  be assumed by l a y e r s o f earlywood and latewood are sketched i n Fig.  17 f o r t r e e No. 7«.- In t h i s diagram shape ABDE i s the  g e n e r a l shape o f earlywood l a y e r s without minimal r i n g width; shape ABODE i s t h a t o f l a y e r s e x h i b i t i n g minimum r i n g w i d t h . Shapes MNQR and MOQR are two average shapes which occur whenever growth o f latewood i s l a r g e r a t some d i s t a n c e above the base than i t i s at the base.  The simple c o r r e l a t i o n c o e f f i c i e n t s .  between the v a r i o u s combinations o f c r i t i c a l dimensions o f earlywood and latewood are i n Tab. V I . The above enumerated b a s i s o f the f o l l o w i n g (1)  graphs and t a b l e s serve as the  conclusions.  The earlywood maxima appeared i n the stems a f t e r an  i n i t i a l p e r i o d o f growth l a s t i n g from 5 t o 10 y e a r s a t d i s t a n c e s ranging from 4 t o 11 f e e t below the stem-apex. the  In most t r e e s  maximum growth o f earlywood occurred w i t h i n a narrow  zone  l o c a t e d a t a n e a r l y constant average d i s t a n c e from the apex i n one t r e e and r a n g i n g between 9 t o 25 f e e t i n 18 t r e e s In  studied.  t r e e No. 12 t h i s d i s t a n c e i n c r e a s e d s t e a d i l y w i t h i n c r e a s i n g  age.  A sudden downward s h i f t  o f the zone o f maximal r a d i a l  TABLE IV THE AVERAGES OF RATIOS OF THE CRITICAL WIDTHS OF EARLYWOOD AND OF LATEWOOD LAYERS TREE OR GROUP OF TREES NO.  Emax Emin M  Emin Ebse SE  M  SE  Lmax Lbse M  Emax Lmax SE  Emax Lbse  Ebse Lbse M  Emax (EbseMLbse) SE  M  SE  H Emax M  N SE  M  SE  M  SE  2.52  0.13  3.33  0.21  1 . 6 6 0.18  1.30 0 . 0 6  204.7  5.8  58  I . 4 6 0.10  1.26 0 . 0 4  I 6 4 . 6 5.5  90  2.26  0.20  1.09 0 . 0 9  139.5  6.2  27  13M,27M 32M,33M  2.68 0 . 1 9  0.97 0 . 0 1  1.33 0.06  1,3,4, 5,6  2.59  0.13  0.96 0 . 0 1  1.17  0.03  2.60 0 . 0 9  3.00 0.12  7  2.18 0 . 2 2  0.83 0 . 0 4  1.34 0 . 0 7  2 . 6 1 0.17  3.43  8  2.22  0.10  0.91 0 . 0 2  1.40 0 . 0 6  1.72 0.10  2.31 0 . 1 2  I . 2 4 0.08  1.04 0 . 0 4  1 7 6 . 1 6.4  39  9  1.99 0 . 0 7  0.89 0 . 0 2  1.21  0.06  1.95 0.05  2.34  0.11  I.36 0.06  1.00  158.3  6.8  39  0.06  1.16  1.08 0.05  x  0.26  0.04  10  2.32  0.18  0.94 0 . 0 1  1.24 0.03  1.86 0.05  2.26  11  2.01  0.06  0.95 0 . 0 1  1.15  2.62  3.00 0.12  1.62 0.08  1.14  12  1.86 0 . 0 7  0.91 0 . 0 2  1.14 0 . 0 4  2 . 6 1 0.10  2.92  0.13  1.89 0 . 1 2  1.02 0 . 0 3  143.4  4 . 8 2 43  13  1.57 0 . 0 5  0.90 0 . 0 2  1.11  2.73  0.11  3.05  0.14  2.23 0 . 1 1  0.94 0.02  142.2  4.86 41  14  2.03  0.89 0 . 0 2  1.34 0 . 0 6  2.10 0.07  2.72  0.11  I . 5 8 0.08  1.07 0 . 0 4  143.8  5.84 45  0.09  0.04  0.02  D e f i n i t i o n s o f (Emax), (Emin), (Ebse),  0.09  0.05  (Lmax), (Lbse), e t c . , as i n Tab. I I .  0.03  179.3 7.54 44 1 3 7 . 8 6.53  42  TABLE V THE COEFFICIENTS OF VARIATION OF THE CRITICAL-DIMENSION-RATIOS OF GROWTH LAYERS TREE OR GROUP OF TREES  Emax* Emin  Emin Ebse  Lmax Lbse  Emax Lmax  Emax Lbse  Ebse Lbse  H Emax rse'j + (Lbse) Emax  COEFFICIENT OF VARIATION (PER CENT) -3M, 27M, >2M, 33M  55.1  10.1  32.2  39.9  48.7  84.9  32.8  21.6  46 • 4  10.6  22.4  34.6  37.1  62.0  30.6  31.4  7  51.4  24.6  28.3  34.7  39.8  45.4  42.1  22.9  8  27.7  15.0  27.2  36.4  31.0  40.3  23.8  22.7  9  23.5  10.8  29.3  17.4  29.1  28.8  23.O  27.0  -> 3,4»  5,6  10  50.2  9.8  18.4  18.8  18.6  30.7  29.2  27.9  11  19.8  7.2  21.3  21.7  26.0  33.3  17.8  30.7  12  25.9  13.2  24.1  25.6  29.9  43.1  18.6  22.0  13  I808"  12.8  12.8  26.0  29.2  31.4  15.5  21.9  14  29.8  11.5  30.6  21.8  26.7  32.9  26.3  27.2  * D e f i n i t i o n s o f (Emax), (Emin), e t c . as i n Tab. I I .  TABLE VI SIMPLE CORRELATION COEFFICIENTS BETWEEN CRITICAL DIMENSIONS OF ANNUAL LAYERS OF EARLYWOOD AND LATEWOOD* TREE OR GROUP OF TREES  Emax  Emax  Emin  Ebse  1> 3 > 4* 5,6  0.663  0.680  "M"-TREES  0.377  7  Emax CORRELATED WITH Lmax  N  Emax  Lmax  Lbse  Lbse  0.296  0.306  0.841  90  O.378  0.000  0.257  0.771  58  0.662  O.447  0.021  O.O56  0.781  27  8  0.820  O.694  0.050  0.292  0.509  39  9  0.316  0.137  0.498  0.476  0.602  39  10  0.744  0.728  0.772  0.831  0.876  44  11  0.472  0.452  0.253  0.348  0.845  42  12  O.84I  0.844  0.439  0.559  0.516  43  13  0.868  O.83O  0.455  O.38I  O.898  41  14  0.820  0.743  O.486  0.725  0.822  45  ^ A u t o c o r r e l a t i o n s and t r e n d s of the s e r i e s were not i n v e s t i g a t e d .  -0  Figure 15- Determinants of form,tree No-1  Figure 16- Determinants of form,tree No- II-  Figure 17- Schematic diagram of the longitudinal sections of average annual layers of xylem,tree No- 7Scale of heights, I "= 10'  Scale of widths, l " = 0 - l "  73  growth o f earlywood t o a new p o s i t i o n about 30 f e e t f a r t h e r away from the apex was observed i n t r e e s No. 1 0 , 11 and 13•  Maximal  r a d i a l growth continued at t h i s new p o s i t i o n f o r about 20 years i n t r e e No. 13, and f o r about 10 y e a r s i n t r e e s No. 10 and 11, t o r e t u r n suddenly t o the p r e v i o u s p o s i t i o n about 10 f e e t below the apex. (2)  The earlywood minima appeared e a r l y i n t r e e s from the  n a t u r a l f o r e s t at the average d i s t a n c e s r a n g i n g from 5 t o 11 f e e t from the base.  They d i d not appear c o n s i s t e n t l y every year  and t h e i r p o s i t i o n f l u c t u a t e d c o n s i d e r a b l y , t h e g e n e r a l t r e n d over the y e a r s b e i n g an a c r o p e t a l one. (3)  I n p l a n t a t i o n - g r o w n t r e e s d e f i n i t e earlywood minima  were observed o n l y i n t r e e s No. 6 and 7*  In both these t r e e s  they could be d e t e c t e d f o r the f i r s t time i n l a y e r s only about 15 y e a r s o l d . (4)  The v a r i a b i l i t y  i n maximum r i n g width o f earlywood  i s about o n e - h a l f o f t h a t observed i n the minimum r i n g width of earlywood o r t h a t i n t h e maximum r i n g width of latewood. (5)  Maximum r i n g width o f earlywood can be, on the  average, more than twice as l a r g e as minimum r i n g width o f earlywood o r maximum r i n g width of latewood; i t was, on the average, about as l a r g e as the t o t a l r i n g width a t the stem base. (6)  The r a t i o between maximum r i n g width o f earlywood  and t o t a l r i n g width at the base was t h e l e a s t v a r i a b l e one.  74  (7)  In most stems, t h e c o r r e l a t i o n s between the c r i t i c a l  dimensions w i t h i n the i n d i v i d u a l l a y e r s were s i g n i f i c a n t at P  =  OoOl i n both t y p e s o f l a y e r s . (8)  The c o r r e l a t i o n s between maximum r i n g width o f  earlywood and maximum r i n g width of latewood were  non-significant  or s i g n i f i c a n t but low. (9)  The average annual increment i n height can be more  than 200 times t h a t  o f maximum r i n g width o f earlywood. Stem Form  Factors  Three t y p e s o f Hohenadl's t r u e form f a c t o r , lambda 0.9, were c a l c u l a t e d f o r each y e a r o f growth o f t r e e s 1 t o 14, namely: (1)  a s e r i e s of form f a c t o r s measuring t h e form o f the  "earlywood stem",  i . e . o f an imaginary stem c o n s i s t i n g o f  l a y e r s o f earlywood, (2)  a s e r i e s o f form f a c t o r s measuring t h e form o f t h e  "latewood stem",  i . e . o f an imaginary stem c o n s i s t i n g o f l a y e r s  of latewood, (3)  a s e r i e s o f form f a c t o r s measuring the form o f t h e  stem c o n s i s t i n g of the t o t a l annual l a y e r s , i . e . , o f the a c t u a l stem. Three s e r i e s o f t h r e e d i f f e r e n t t y p e s o f form f a c t o r s are p o r t r a y e d , f o r each t r e e important c o n c l u s i o n s  derived  separately,  i n F i g . 18 t o 31«  More  from these graphs are as f o l l o w s :  75  (i)  The form f a c t o r s o f "earlywood stem" are the h i g h e s t  ones, those o f "latewood stem" the lowest ones. of the a c t u a l  The form f a c t o r  stem assumes approximately i n t e r m e d i a t e v a l u e s  between t h e s e .  In a few i n s t a n c e s the v a l u e s o f a l l t h r e e types  of form f a c t o r s were n e a r l y  the same f o r a p e r i o d  from 3 t o 6  years ( t r e e s No. 2 and 8 ) . "Latewood stem" form f a c t o r s were h i g h e r than the remaining two i n the l a s t  seven y e a r s o f growth  of t r e e No. 14* (ii)  Values o f a l l t h r e e types o f form f a c t o r s  increased  with age. (iii)  The f l u c t u a t i o n s i n the stem form were due p r i m a r i l y  t o the s i m i l a r f l u c t u a t i o n s observable i n the form f a c t o r s o f "earlywood (iv)  stem". W i t h i n the same year, the "latewood stem" form f a c t o r  may vary independently o f the "earlywood stem" form f a c t o r .  I94S  1950  I9SS YEAH  I960  600r  F i  f l e 20- Values of A u r  ,tree No- 3  •550  •500 01  xP •450 "Latewood Stem"  •400  •350  1945  J  L  1950  J  1  I  L 1955  I960  YEAR  "Earlywood Stem" .  5 5 0 |  _  Figure 21- Values of X ,tree No-4 og  •500  •450 - ^ L a t e w o o d Stem  01  6  •400r-  •350  •300-  1945  J  L  1950  J  I YEAR  L  1955  J  L  I960  •550r  •350 -  F  '9  u r e  2  7  • Values of X  ,tree No IO-  J  •300.  2 5 0  -  1920  I I I I  I 25  I I I I  1I 30  I I I  1I 35  1  I I  I  40 YEAR  I I I i  I 45  i i I I  I 50  i l  l  I  I 55  i I l  I  1II 60  YEAR  P l a n t s are not homoiiO-thermous organisms and plant  physiologists,  physiologists,  unlike  human and animal  have not been much  concerned  w i t h the e f f e c t s o f e x c e s s i v e heat, though of course p l a n t  cells,  are r e a d i l y k i l l e d  like  animal  or i n a c t i v a t e d  cells, by high  temperatures. P.W.  Life  Richards  (i960)  i n both the f o r e s t and the sea i s d i s t r i b u t e d  in horizontal  layers.  The students o f the sea have  always been keenly aware o f t h i s ,  but the students  of t h e f o r e s t p a i d  t o the problem o f  depth.  less attention  To study the f o r e s t man must c l i m b . Marston  Bates  (1961)  77  PART  (B)  IDENTIFICATION OF THE CAUSAL FACTORS DETERMINING THE FORM OF FOREST TREES The  systematic  p a t t e r n observed i n l o n g i t u d i n a l  d i s t r i b u t i o n o f r a d i a l growth of earlywood and,  i n contrast  t o t h i s , the c o n s i s t e n t l y d i f f e r e n t p a t t e r n of r a d i a l increment of latewood cannot be r e c o n c i l e d s a t i s f a c t o r i l y with any e x i s t i n g t h e o r i e s of bole f o r m a t i o n .  Since  of the  i t i s desired to  i d e n t i f y the c a u s a l r e l a t i o n s h i p s t h a t would make sense of the phenomena encountered, a d i f f e r e n t theory  i s needed.  S t r u c t u r e s such as b u t t r e s s e s and a l r e a d y been a p p r a i s e d .  T h e i r formation  enlarged bases have  i s occasioned  by  i n t e n s i f i e d r a d i a l growth m a n i f e s t i n g i t s e l f by wide annual rings.  The  r a t i o between r i n g width w i t h i n the enlarged  and t h a t w i t h i n the "normal" trunk  base  (Gates and E r l a n s o n 1925)  is  comparable with the average r a t i o s between the maximum and between the b a s a l widths of the l a y e r s of earlywood found i n t h i s work.  Whereas the p o s i t i o n i n stem of the maximal annual  r a d i a l increment of earlywood i s not  s t a t i o n a r y , and  not d e t e c t a b l e from the outward appearance of the  therefore  stem, the  p o s i t i o n o f the i n c r e a s e d r a d i a l growth w i t h i n the enlarged  or  b u t t r e s s e d bases does not change l o n g i t u d i n a l l y with t i m e . Hence the r e a d i l y r e c o g n i z a b l e abnormal phenomenon of the a t r o p h i e d stem bases which has occurring butt f l a r e s . t o be  The  i t s analogy i n the  normally  o r i g i n of the l a t t e r s t r u c t u r e s i s  sought, as shown i n the present  study,  i n the  greater  78  width of latewood l a y e r s which are widest, r a t h e r c o n s i s t e n t l y , w i t h i n the b a s a l p o r t i o n o f the stem. As a l r e a d y s t a t e d , the mechanical value of b u t t r e s s e s as s u p p o r t i n g s t r u c t u r e s was (Richards 1 9 5 2 ) .  questionable i n t r o p i c a l trees  Experience has shown t h a t the m a j o r i t y of  breakages i n stems of spruce and beech occur h i g h above ground 1913,  even i n t r e e s without prominent b u t t s w e l l (Ursprung H i l d e b r a n d t 1954)»  A c o n c l u s i o n was  reached t h a t the r e i n f o r c e -  ment of the b a s a l p o r t i o n o f stems, which tend t o be overdimensioned  even i f u n b u t t r e s s e d , had a f u n c t i o n o t h e r than  t h a t of support (Ursprung 1913)» f a c t o r s of environment,  I t was a l s o s t a t e d t h a t  o t h e r than the mechanical i n f l u e n c e of  wind, r a t h e r than h e r e d i t y have been suspected as those responsi b l e f o r the f o r m a t i o n o f b u t t r e s s e s i n both t r o p i c a l e x t r a t r o p i c a l s p e c i e s ( R i c h a r d s 1952;  Senn 1 9 2 3 ) .  and  Similarly,  f a c t o r s c a u s i n g the f o r m a t i o n of e n l a r g e d bases were i d e n t i f i e d as those b e l o n g i n g t o the environmental complex (Kurz 1934)* I f so, then i t can be assumed w i t h some l o g i c t h a t the l o n g i t u d i n a l p o s i t i o n of maximum r i n g width of both and latewood i n the "normal"  earlywood  stems of f o r e s t grown t r e e s i s due  p r i m a r i l y t o extraneous p h y s i c a l f a c t o r s of the  environment.  T h i s assumption w i l l be adopted as a working h y p o t h e s i s i n e x p l a i n i n g the n o t a b l y c o n s i s t e n t d i f f e r e n c e s i n shape of the annual xylem l a y e r s encountered i n Douglas F a c t o r s of environment  fir.  have been p o i n t e d out by some  authors as d i r e c t agents c a u s i n g noteworthy  qualitative  and  79  q u a n t i t a t i v e changes i n wood s t r u c t u r e .  In f a c t ,  specific  g r a v i t y and the h i s t o l o g i c a l c h a r a c t e r i s t i c s of wood from the a t r o p h i e d bases d i f f e r e d remarkably from those of wood from the upper p o r t i o n of stems of normal outward appearance (Gates and E r l a n s o n 1925;  Penfound 1934;  Paul and Marts 1934)•  It  was  believed that Stems of p l a n t s i n g e n e r a l had become v a r i a b l y m o d i f i e d t o meet the e x i g e n c i e s of c l i m a t e s i n which they l i v e . Roots, on the other hand, due to l e s s e x a c t i n g environment surrounding them, have changed but l i t t l e through ages and represent a r e l a t i v e l y c o n s e r v a t i v e organ i n most p l a n t s (Andrews 1947)* Nevertheless,  xylem of r o o t s exposed t o the  i n f l u e n c e s of the atmosphere a c q u i r e d r a p i d l y the i s t i c s of the normal xylem from stems (Kny in Morrisson  1953;  Morrisson  1953)«  character-  i n Brown 1915;  Wieler  Length of t r a c h e i d s , t h e i r  t h i c k n e s s , as w e l l as percentage of latewood i n Pinus c o n t o r t a from bogs d i f f e r e d s u b s t a n t i a l l y from the  corresponding  a t t r i b u t e s of wood of Pinus c o n t o r t a on l a v a beds (Kienholz Thickness  of earlywood t r a c h e i d s v a r i e d i n the  a c c o r d i n g to the h a b i t a t (Groom 1914)*  1931)•  same s p e c i e s  Average l e n g t h of  t r a c h e i d s i n c r e a s e d by up to 25 per cent i n P i n u s ' s y l v e s t r i s a f t e r t h i n n i n g s (Savina 1 9 5 6 ) ; i t was western hemlock (Wellwood and  reduced a f t e r t h i n n i n g s i n  Smith 1 9 6 2 ) .  Average diameter and  l e n g t h of t r a c h e i d s i n jack pine i n c r e a s e d with an i n c r e a s e i n spacing. and  There was  no c o r r e l a t i o n between l e n g t h of t r a c h e i d s  l e n g t h of internode  i n which they were formed (Adams 1928).  80  The f i r s t  law o f Sanio ( i n the stems and branches the t r a c h e i d s everywhere i n c r e a s e i n s i z e from w i t h i n outward, throughout a number of annual r i n g s , u n t i l they have a t t a i n e d a d e f i n i t e s i z e , which then remains constant ....) ( B a i l e y and Shepard 1915)  c o u l d not be a p p l i e d t o some c o n i f e r s .  F a i r l y regular cycles  i n t r a c h e i d l e n g t h were observed t o occur w i t h age at one i n the stem  ( B a i l e y and Shepard 1 9 1 5 ) °  dimensions of t r a c h e i d s may factors  (Bailey The  I t was  level  suggested t h a t the  r e f l e c t the i n f l u e n c e of c l i m a t i c  1920).  second law of Sanio  (the ... s i z e (of t r a c h e i d s ) i n c r e a s e s from below upward, reaches i t s maximum at a d e f i n i t e h e i g h t and then d i m i n i s h e s toward the summit ....) was  a p p l i c a b l e i n red spruce and S c o t s p i n e . However, a f a c t u n n o t i c e d by Sanio i s t h a t the maximum average t r a c h e i d l e n g t h o c c u r s h i g h e r from the ground i n r i n g s nearer t o the b a r k . T h i s probably bears a r e l a t i o n t o the f a c t t h a t each s u c c e s s i v e increment i s ... f a r t h e r from the ground ( B a i l e y and Shepard 1 9 1 5 ) . Presumably,  t r a c h e i d l e n g t h w i t h i n the same annual  l a y e r e x h i b i t s l o n g i t u d i n a l t r e n d s comparable t r e n d s i n r i n g width..  T h i s assumption  the r e p o r t s o f v a r i o u s authors who  with  i s hard t o r e c o n c i l e w i t h  found t h a t an i n v e r s e  r e l a t i o n s h i p e x i s t s between r i n g width and t r a c h e i d G r e a t e r growth i n diameter was  similar  length.  c o r r e l a t e d with a shorter  t r a c h e i d i n Douglas f i r (Lee and Smith 1 9 1 6 ) .  In the same  s p e c i e s , t r a c h e i d length decreased a l o n g l o n g e r r a d i i o f eccentric trees  (Wellwood  and Smith 1 9 6 2 ) .  The  longest  t r a c h e i d s i n any one r i n g were from the narrowest p a r t and the  s h o r t e s t from the broadest (Chalk 1 9 3 0 b ) . to  p a r t o f a r i n g . i n S i t k a spruce  In white spruce the maximum c e l l l e n g t h appeared  be a s s o c i a t e d with the p a r t i c u l a r r i n g width which marks  the lowest  p o i n t t o which r a d i a l growth may drop without b r i n g i n g  about an i n c r e a s e i n frequency (Bannan 1 9 6 3 ) .  of m u l t i p l i c a t i v e d i v i s i o n s  T h i s i n v e r s e r e l a t i o n s h i p between t r a c h e i d  l e n g t h and r i n g width was found a l s o i n Thu.ia o c c i d e n t a l i s ; among t r e e s o f s i m i l a r diameter mean c e l l l e n g t h i n the p e r i p h e r a l wood was g r e a t e r i n t r e e s with the narrower r i n g s .  A similar  r e l a t i o n s h i p was observed i n Pinus Strobus (Bannan 1960a, 1962)0 No r e l a t i o n s h i p between t r a c h e i d l e n g t h and r i n g width was found i n s l a s h p i n e .  I t was assumed t h a t t r a c h e i d  l e n g t h was under r i g i d g e n e t i c c o n t r o l (Echols 1955)• assumption and f i n d i n g o f the same author (Echols 1955)  This that a  l i n e a r r e l a t i o n s h i p e x i s t s between f i b r i l a r angle and l e n g t h of t r a c h e i d i n latewood o f a l l r i n g s and at a l l l e v e l s , are at v a r i a n c e with the f i n d i n g o f V i t e (195$) who r e p o r t e d t h a t f i b r i l a r angle The  i n c r e a s e d i n suddenly r e l e a s e d P i n u s first  law o f Sanio was confirmed  taeda.  i n western  hemlock; age was found t o have the strongest e f f e c t on t r a c h e i d length  (Wellwood i 9 6 0 ) .  Trees with  s h o r t e r o r l o n g e r than  average t r a c h e i d s r e t a i n e d t h i s f e a t u r e . as a g e n e t i c e f f e c t • .  T h i s was  considered  (Wardrop and Dadswell 1953; Wellwood i 9 6 0 ) .  I t was maintained t h a t Growth i s c o n t r o l l e d p r i m a r i l y by g e n e t i c makeup of the p l a n t s , importance o f environment i s completely dependent upon r i g i d i t y with which g e n e t i c f a c t o r s c o n t r o l the p l a n t . S i l v i c u l t u r a l treatments have been shown t o be i n s u f f i c i e n t t o produce wood f o r s p e c i a l i z e d uses (Zobel and Bruce i n McKimmy 1959)•  82  I t was  a l s o maintained t h a t the e f f e c t of environment  may  completely mask any g e n e t i c v a r i a b i l i t y  (Hoist I960).  r e s u l t s of one of the o l d e s t provenance  experiments  The  speak f o r  the l a t t e r arguments with r e s p e c t t o growth, the behaviour of v a r i o u s provenances  of Norway spruce was  t r e e s of one common o r i g i n  b a s i c a l l y t h a t of  ( F i s h e r 1949)•  Also, i n Fraxinus  e x c e l s i o r , the e x i s t e n c e of d i s t i n c t l y d i f f e r e n t " s o i l r a c e s " , assumed t o e x i s t by Muench, has not been proven Furthermore, demonstrate strains  (Weiser  I964K  study of h y b r i d s e e d l i n g s of corn was unable t o any d i f f e r e n c e s i n water l o s s between v a r i o u s  ( C r a f t et a l . 1 9 4 9 ) .  Environmental f a c t o r s masked  completely the h e r e d i t a r y i n f l u e n c e s i n v a r i o u s s t r a i n s of c o t t o n (Simpson  1 9 4 6 ) . N i n e t y - e i g h t v a r i e t i e s of apple t r e e s ,  segregated i n t o 16 groups a c c o r d i n g t o t h e i r assumed o p t i m a l temperature  requirements, possessed much g r e a t e r c a p a c i t y f o r  a d a p t a t i o n t o v a r i e d summer temperature  than had been assumed.  C l i m a t i c c o n d i t i o n s f a v o u r i n g one group favoured a l l groups r e g a r d l e s s of t h e i r temperature Formation of lammas shoots was environment  optima  (Caldwell 1928).  found t o be governed more by  than by h e r e d i t y (Walters and Soos 1 9 6 1 ) .  A general  l a c k of c o r r e l a t i o n between wood q u a l i t y and e x t e r n a l f e a t u r e s was  noted i n Douglas f i r t r e e s (Wellwood and Smith 1 9 6 2 ) .  No  secure c o n c l u s i o n s c o u l d be drawn from the outward c h a r a c t e r i s t i c s of Norway spruce f o r the purposes of the b r e e d i n g work ( B l o s s f e l d and Haasemann 1 9 6 4 ) .  Ring p o r o s i t y c o u l d be  about  s p e c i e s by environmental  i n normally d i f f u s e porous  (Barner I 9 6 3 ) .  brought stress  $3  The appearance of annual r i n g s i n the J u r a s s i c epoch i n response t o inclement seasonal c o n d i t i o n s . c o r r e l a t e d w i t h the appearance of t a n g e n t i a l p i t t i n g and of t r u e parenchymateous storage elements ... has been the most important f a c t o r i n the e v o l u t i o n a r y development of p l a n t s from the e a r l i e r epochs t o the present ( J e f f r e y 1 9 1 7 ) • Annual r i n g s were c o n s i d e r e d as a s t r u c t u r a l a d a p t a t i o n t o a r i d and s e m i - a r i d environment.  They support g e o l o g i c a l evidence  p o i n t i n g t o w e l l developed dry or monsoonal c l i m a t e s i n temperate l a t i t u d e s d u r i n g the Mesozoic  (Barghoorn i n Shapley 1 9 5 3 ) •  N e v e r t h e l e s s , a f e a t u r e as o l d as t h a t of annual r i n g was not found t o be g e n e t i c a l l y  fixed:  The f a c t t h a t i n a c o n t r o l l e d environment t h e r e was no v a r i a t i o n i n lumen diameter and c e l l w a l l t h i c k n e s s a c r o s s the growth r i n g demonstrates t h a t the normal p a t t e r n of e a r l y - and latewood development i s s u b j e c t t o environmental r a t h e r than g e n e t i c c o n t r o l , a c o n c l u s i o n drawn by F r y and Chalk (1957) from t h e i r examination o f Pinus p a t u l a grown i n Kenya (Richardson i 9 6 0 ) . Both wind and adverse s o i l moisture c o n d i t i o n s brought about anatomical and m o r p h o l o g i c a l changes which were c o n s i d e r e d as a d a p t i v e .  I t was  e s t a b l i s h e d t h a t p l a n t s possess a  "compensating  mechanism", i . e .  a b i l i t y o f a genotype t o r e a c t t o i t s environment producing advantageously m o d i f i e d phenotypes (which) must be of importance i n determining s u r v i v a l i n nature; i t was  f u r t h e r maintained t h a t The v a r i e t y , extent and p h y s i o l o g i c a l s i g n i f i c a n c e of compensating mechanism has yet t o be determined but they may be of g r e a t e r importance i n e c o l o g i c a l s e l e c t i o n and c o m p e t i t i o n than i s r e a l i s e d at present (Venning 1949? Whitehead a n d - L u t i 19631 Whitehead 1 9 6 3 ) .  84  The  rough-barked specimens of B e t u l a verrucosa  were  shown t o form s i g n i f i c a n t l y longer f i b r e s i n r i n g s which were a l s o wider as compared w i t h s i m i l a r t r e e s of the Gardiner 1963).  with smooth bark (Newall and of wood formed on the  side of longer r a d i i  same s p e c i e s  Specific gravity  of some Douglas f i r  and western hemlock stems was  c o n s i s t e n t l y h i g h e r than  g r a v i t y of wood sampled a l o n g  s h o r t e r r a d i i of the  (Wellwood and w i t h i n the phenotype. was  Smith 1 9 6 2 ) .  stem of one  the same  i n stems of Pinus r i g i d a i n v e s t i g a t e d  by Brown ( 1 9 1 2 ) . the d e n s i t y of xylem was  the north  and  observed  T h i s " c u r i o u s f e a t u r e l o n g known t o former workers"  e s p e c i a l l y prevalent  of t r e e s .  same stems  A s i m i l a r phenomenon was  opposing s i d e s of the  specific  T h i s was  due  to a greater proportion  side as compared with the  i n wood formation  was  l e s s on the  south side  of latewood  south s i d e .  on  This d i s p a r i t y  not marked i n young t r e e s .  As t o the cause of t h i s l e s s e n e d d e n s i t y on the south s i d e , no reasonable c o n c l u s i o n was a t t a i n e d i n these i n v e s t i g a t i o n s , nor has i t ever been s a t i s f a c t o r i l y accounted f o r . I t i s without doubt c o r r e l a t e d w i t h i n s o l a t i o n i n some way, but f u r t h e r study i s necessary t o determine t h i s d e f i n i t e l y (Brown 1 9 1 2 ) . In a more recent (1959),  i t was  found t h a t  i n f l u e n c e i n m o d i f y i n g the conifers.  sun and  l e n g t h of t r a c h e i d s i n open grown of the  equator were  south side of t h e i r stems, f i b e r s of t r e e s from  southern hemisphere were s h o r t e r on the north  stems.  Dadswell  shadow can have a pronounced  F i b e r s of t r e e s which grew north  s h o r t e r on the the  i n v e s t i g a t i o n by L i e s e and  side of t h e i r  D i f f e r e n c e s i n l e n g t h of t r a c h e i d s between the  insolated  85  and  shaded side corresponded roughly  t o the d i f f e r e n c e s i n  l e n g t h of earlywood and latewood t y p e s of t r a c h e i d s from w i t h i n one  annual r i n g .  The authors o f f e r e d the f o l l o w i n g  explanation  of t h i s phenomenon, the h e a t i n g o f the bark by the sun s t i m u l a t e s the cambial a c t i v i t y ; t h e r e f o r e w i t h i n an annual r i n g , the t r a c h e i d l e n g t h and the growth i n t e n s i t y stand i n d i r e c t p r o p o r t i o n t o each o t h e r .  The d i f f e r e n t a t i o n o f xylem  elements on the warmer s i d e s o f the stem occurs the  cooler northern  side.  i n an  Therefore,  f a s t e r than on  t r a c h e i d s on the i n s o l a t e d  side have l e s s time f o r t h e i r e x t e n s i o n  growth and, consequently,  they are l o n g e r on the shaded side o f the stem. The  two l a t t e r i n v e s t i g a t i o n s are o f e s p e c i a l i n t e r e s t  to t h i s study f o r two reasons.  F i r s t l y , out o f the whole complex  of environmental f a c t o r s , temperature was s e l e c t e d as the key f a c t o r adjudged t o be able t o i n f l u e n c e both t r a c h e i d l e n g t h and c e l l wall thickness.  Secondly, the temperature  differential  a f f e c t e d wood q u a l i t y w i t h i n the opposing s i d e s of the same stem differently. I t i s w e l l known t h a t a l l the growing t i s s u e s , and sex c e l l s , are very  s e n s i t i v e t o temperature extremes and t o  temperature f l u c t u a t i o n s (Belehradek i n Precht  e_t a l . 1955) •  In h i g h e r organisms, growth means an i n c r e a s e i n s i z e and i s always connected with m u l t i p l i c a t i o n o f the c e l l s . i n f l u e n c e o f temperature has t o be considered the  The  separately f o r  i n c r e a s e i n s i z e and f o r the i n c r e a s e of the numbers of  newly-formed c e l l s  (Christophersen  i n Precht  e t a l . 1955)*  86  The s i z e of the c e l l s i n the secondary xylem i s determined by the s i z e of the cambial i n i t i a l s and by  changes  t h a t take p l a c e i n t h e i r d e r i v a t i v e c e l l s d u r i n g d i f f e r e n t i a t i o n i n t o t r a c h e a r y elements  (Bailey 1920).  Temperature  seems t o  exert some i n f l u e n c e d u r i n g the l a t t e r stage; i n r o o t s c e l l t e n s i l i t y decreased i n d i r e c t response t o i n c r e a s e d (Burstroem 1 9 5 6 ) .  wall  temperature  The r o o t s of peach and apple, s u c c u l e n t and  m e c h a n i c a l l y weak at 65°F or l e s s , were found t o be  typically  woody and of c o n s i d e r a b l e mechanical s t r e n g t h at 75°F ( N i g h t i n g a l e 1935) •  I n t e n s i f i e d l i g n i f i c a t i o n i n p a r t s of a t r e e w i t h a  sunny aspect was  recorded by F i s h e r ( i n M o r r i s s o n 1953)•  d i v i s i o n w i t h i n the cambial l a y e r of F r a x i n u s and Acer f a v o r e d at 60°F, l i g n i f i c a t i o n was above 70°F (Hanson and Branke  Cell  was  a c c e l e r a t e d at temperatures  1926).  Maximum d a i l y  temperatures  o f about 70°F were o p t i m a l f o r diameter growth of ponderosa p i n e . Higher temperatures depressed the r a d i a l growth  (Mace and Wagle  I964). The numbers of xylem c e l l s produced by a cambial l a y e r w i t h i n one season showed the same tendency as annual r i n g width, nor was t h e r e always a c o r r e l a t i o n between the maximal number of c e l l s and maximum r i n g w i d t h .  Ring width depended not  only on a number of c e l l s but a l s o on t h e i r s i z e  (Adams 1928).  Increase i n r i n g width i n t r e e s from a humid h a b i t a t , o r i n r i n g s from w i t h i n the crown, was due i n part t o an i n c r e a s e i n diameter of t r a c h e i d s but more t o the number of t r a c h e i d s down ( K i e n h o l z 1931;  Zahner and O l i v e r 19,62; Shepherd  laid  1964).  87  The  i n c r e a s e i n width of the swollen bases was due t o a g r e a t  i n c r e a s e i n the number of c e l l s o f latewood 1925)o  (Gates and E r l a n s o n  G r e a t e r s i z e o f the b a s a l p o r t i o n o f t r e e s was due  p r i m a r i l y t o g r e a t e r number and o n l y s e c o n d a r i l y t o a l a r g e r s i z e o f the xylem  cells  (Penfound  I t can be concluded t h a t  1934), i t i s l a r g e l y the number o f  c e l l s which determines the width o f the annual l a y e r s of xylem; the r e l a t i v e r i n g width may be, as a l r e a d y mentioned, the d i r e c t complexo  subject t o  i n f l u e n c e on the stem o f f a c t o r s from the environmental Temperature  the enormously  was found t o be important i n t h i s  s t i m u l a t e d one-sided r a d i a l growth  F i c u s repens was a t t r i b u t e d t o i n f l u e n c e s o f E f f e c t s of l i g h t ,  respect;  i n stems o f  atmosphere.  o r temperature, o r humidity were suggested  (Massart i n Ursprung 1913)«  R a d i a l increment on the south s i d e  of stems o f Norway spruce growing 1350 m above sea l e v e l was, on the average, 1.5  times t h a t found on the n o r t h s i d e o f the stems.  T h i s r a t i o was e x a c t l y o p p o s i t e i n t r e e s growing 230 m above sea l e v e l  (Kern i 9 6 0 ) .  G r a f t s o f f r u i t t r e e s h e a l e d f a s t e r on  the southern s i d e than on the n o r t h e r n side of t r e e s i960).  (Braun  Trees on a southern slope i n c r e a s e d i n r a d i u s more  r a p i d l y d u r i n g the e a r l y p a r t of the season.  However, by the  end o f the season t r e e s on the n o r t h e r n slope made the l a r g e s t i n c r e a s e s (Cantlon 1953)* The l e n g t h o f the growth t o the amount o f r a d i a l growth  p e r i o d was d i r e c t l y  related  o f both earlywood and latewood  and  p  consequently, t o t h e percentage o f latewood (Chalk 1927?  Savina 1956; M i k o l a I960; Kennedy 1961).  The l e n g t h o f t h e  p e r i o d o f t h e cambial a c t i v i t y i s determined by the date o f i t s i n c e p t i o n and by the date o f i t s c e s s a t i o n .  Both these  data were found t o be c l o s e l y r e l a t e d t o temperature. V e r n a l ambient temperature was assumed t o be t h e c h i e f f a c t o r r e s p o n s i b l e f o r c o n t r o l l i n g the r a t e o f enzymic r e a c t i o n s a s s o c i a t e d w i t h secondary growth; v e r n a l i n c r e a s e i n ambient temperature, r a t h e r than p h y s i c a l t r a n s p o r t o f a u x i n from d e v e l o p i n g buds, was c o n s i d e r e d t o be r e s p o n s i b l e f o r i n i t i a t i o n o f cambial a c t i v i t y  (Steward 1957)•  High temperature  was the main f a c t o r i n i n i t i a t i n g diameter growth i n t h e s p r i n g (Larsson e t a l . I964K  The c o r r e l a t i o n between r a t e o f cambial  a c t i v i t y and temperature was p o s i t i v e up t o 60°F, but n e g a t i v e f o r temperatures above 60°F (Hanson and Brenke 1926).  Prelim-  i n a r y changes i n t h e cambial t i s s u e o f branches were observed i n March a t average a i r temperature o f 40°F, t h e maximal temperature not exceeding 53°F (Ladefoged 1952).  Formation o f f r o s t  rings  was observed i n a y e a r i n which u n u s u a l l y warm weather i n March was f o l l o w e d by a s p e l l o f c o l d weather A g e r t e r 1963)0  in April  (Glock and  F r o s t r i n g s i n f r u i t t r e e s were found mostly on  the south side o f t h e stem ( T i n g l e y 1936).  B e g i n n i n g and con-  t i n u a t i o n o f cambial a c t i v i t y depended on the a l t i t u d e  I960).  More than a three-month  (Kern  v a r i a t i o n i n the i n c e p t i o n date  of r a d i a l growth was observed i n t u p e l o gum t r e e s . a s c r i b e d t o the e f f e c t s o f temperature  T h i s was  (Eggler 1955)*  89  Prolonged high temperature was assumed t o be the cause of c e s s a t i o n o f r a d i a l growth  a t a time when a l l o t h e r e n v i r o n -  mental f a c t o r s were not l i m i t i n g i n t h i s r e s p e c t 1950; E g g l e r 1955;  Mace and Wagle 1 9 6 4 ) .  S i t e q u a l i t y was not  c o r r e l a t e d with the time of c e s s a t i o n o f growth Kern i 9 6 0 ) , in  (Jacquiot  ( G r i f f i t h I960;  yet the l e s s t h e t r e e grew i n t h i c k n e s s the e a r l i e r (Ladefoged 1952).  summer the wood f o r m a t i o n d e c l i n e d  bases of t r e e s i n a stand, having an increment of 1 mm  In stem or l e s s ,  cambial a c t i v i t y ceased l a t e i n J u l y or e a r l y i n August. open-grown t r e e s w i t h annual r i n g wider than 2 mm c e l l occurred as l a t e as September (Bannan 1955)•  In  division  F r o s t damage i n  c r o t c h e s o f apple t r e e s was due t o the prolonged cambial a c t i v i t y i n t h i s region.  The acuteness of the b r a n c h i n g was  c o r r e l a t e d w i t h the amount of i n j u r y ; the r i n g s were widest i n narrowest c r o t c h e s (Horsfau 1932; P o t t e r 1 9 3 8 ) .  Continued  cambial a c t i v i t y and root growth was observed i n root s t o c k s o v e r w i n t e r i n g i n the greenhouse  (Hoist  1956).  A c c o r d i n g t o Brown ( 1 9 1 5 ) , the r a p i d i t y o f v e r n a l growth i n white pine depended on the amount of r e s e r v e foods, moisture and temperature. optimum. of  air,  The f i r s t  two were always at the  The t o t a l temperature e f f e c t d e r i v e d from temperature from the d i r e c t i n s o l a t i o n and from the temperature of  s o i l water.  The f i r s t  two f a c t o r s were d i s m i s s e d as e n t i r e l y  n e g l i g i b l e or minor i n t h i s respect because l a y e r s of bark.  of the t h i c k  I r r e g u l a r i t i e s i n dimensions o f xylem  tissue  and i n the number of new xylem elements, observed a l l along the stem, were due t o i r r e g u l a r c y c l e s i n cambial a c t i v i t y .  90  The  following generalizations applied with  respect  to time of c e s s a t i o n o f r a d i a l growths growth i n t e n s i t y f a l l s off  first  i n the upper p a r t s of the b o l e , more t a r d i l y below;  c e s s a t i o n of xylem f o r m a t i o n  does not  f o l l o w the  same law  growth p e r s i s t s s l u g g i s h l y i n a l l p a r t s of the b o l e . d i s p a r i t y i n growth along the bole was " c o n d i t i o n s of temperature". operative  first  but  The  assumed t o be due  to  Temperature changes become  where the primary c o r t e x  s t i l l persists;  they are l e s s e f f e c t i v e i n the b a s a l p o r t i o n of stem because of t h i c k l a y e r s of bark. pine was  retarded f i r s t  Therefore,  r a d i a l growth i n white  a l o n g the upper stem but went  v i g o r o u s l y along the lower stem f o r a much l o n g e r Contrary  t o Brown ( 1 9 1 5 ) , Adams (1935)  t h a t i n s o l a t i o n i n the  s p r i n g was  responsible  i n c e p t i o n of cambial a c t i v i t y i n t r e e s . start  on  period. believed  f o r the  Cambial a c t i v i t y  may  sooner i n the upper p a r t of a t r e e because bark i n t h i s  r e g i o n i s t h i n n e r and more exposed t o d i r e c t s u n l i g h t than the t h i c k e r bark i n shade of the lower stem. of xylem l a y e r i n the upward d i r e c t i o n may of the  The  i n c r e a s i n g width  be due  to  proximity  source of foods or i t may be due t o the response of the cambium t o a g r e a t e r heat stimulus e a r l i e r i n the season and t h e r e a f t e r . There are no data t o support the l a t t e r h y p o t h e s i s but the f a c t remains t h a t stands which have been t h i n n e d show g r e a t e r diameter growth i n the iower p a r t of the stem ... the nature of the e f f e c t of the d i f f e r e n c e s i n a i r temperature on the p h y s i o l o g i c a l a c t i v i t y of the v a r i o u s p a r t s of the t r e e can only be assumed s i n c e s u f f i c i e n t data are not a v a i l a b l e t o warrant d e f i n i t e statements (Adams  1935).  91  Deductions of Brown (1915) and supported by f i n d i n g s of H a r t i g  Adams (1935) are  ( i n Brown 1915)  (1913)»  D i s p a r i t y of r a d i a l growth a l o n g the  reported  by Topcuoglu (1940) and  by Mer  and  Knudson  stem was  also  (1892); upper p o r t i o n  of t r u n k s of f o r e s t grown t r e e s grew f a s t e r i n diameter the  s p r i n g months than the b a s a l p o r t i o n .  reversed  d u r i n g the  summer.  the b a s a l p o r t i o n was  Conditions  ( H a r t i g i n Brown 1915).  base of f r u i t dry  the  trees  soil  observed t o s t a r t growing i n diameter  T h i s d i s p a r i t y was  known t o i n c r e a s e  were  In open grown t r e e s on bare  f o u r weeks b e f o r e the bases of t r e e s i n the humus l a y e r .  during  a t t r i b u t e d to  Indeed, f a l l  incidence  c l o s e d stand  temperature  plowing i n orchards i s  of sun-scald  (Mix 1916)°  with  i n j u r y at  Rings formed d u r i n g  summer were e x c e p t i o n a l l y narrow along the  the  a hot  and  lower p o r t i o n  of the b o l e ; they were more n e a r l y normal w i t h i n the  crown  (Schober 1951)o Both the amount of r a d i a l growth, at one a l l a l o n g the b o l e ,  and  the  q u a l i t y o f wood were  r e l a t e d to the bark t h i c k n e s s two  and  level  or  frequently  bark c h a r a c t e r ,  which  latter  v a r i a b l e s were, i n t u r n , c o r r e l a t e d w i t h f a c t o r s of  environment.  S o l a r r a d i a t i o n and  important f a c t o r s i n t h i s  respect.  For example, bark on the t r o p i c a l t r e e s was on the  2.5  a i r humidity were the most  edges of b u t t r e s s e s  times t h i n n e r than the  stem ( F r a n c i s I924).  Bark t h i c k n e s s  of  bark h i g h e r  was  well  up  correlated  with stem diameter i n t r e e s from the temperate zone; no  such  92  c o r r e l a t i o n e x i s t e d i n t r e e s from t r o p i c a l r a i n f o r e s t they showed a l s o l i t t l e the b o l e (La Rue  and  v a r i a t i o n i n bark t h i c k n e s s a l o n g  1932/3 F u l l e r 193$) •  In t r e e s from  temperate  l a t i t u d e s percentage of bark i n c r e a s e d w i t h h e i g h t i n stem and c o u l d be l a r g e r at the upper l e v e l s than i t was  at the ground;  slowly t a p e r i n g stems had l e s s v a r i a t i o n i n bark percentage as compared w i t h r a p i d l y t a p e r i n g stems (La Rue of s y s t e m a t i c a l l y r e l a t e d  1932).  Trees  s p e c i e s growing i n savannas were  t h i c k - b a r k e d ; those from the r a i n f o r e s t were t h i n - b a r k e d ( R i c h a r d s 1952)«  Pine from the c o a s t a l r e g i o n s was  typically  t h i n - b a r k e d ; t h a t from dry r e g i o n s possessed t h i c k l a y e r s of bark  (Wiedemann 1932).  Cypress growing a l o n g f r e s h water had  s i g n i f i c a n t l y t h i n n e r bark than t h a t from p o o l s of stagnant and t h e r e f o r e warmer water  (Mattoon 1915;  In e c c e n t r i c branches of T i l i a ,  Demaree 1932).  bark was twice as t h i c k on  sides  of the l o n g e r r a d i u s than on the s i d e of the s h o r t e r r a d i u s (Krabbe 1882) < > Bark was where the growth was McMurrich  rougher on the south s i d e of t r e e s  a l s o more a c t i v e  (Leonardo da V i n c i i n  1930). Abrading dead bark and s l i t t i n g the c o r t e x l o n g i t u d -  i n a l l y promoted  growth from the cambium; l i g a t u r e s around the  stem decreased the number and s i z e of xylem elements 1887; l803)o  De V r i e s ; Krabbe; P f e f f e r i n Newcombe 1894,  (Sachs  1895; Knight  Prominent widening of annual r i n g s under the f i s s u r e s  o c c u r s commonly i n s p e c i e s w i t h d e e p l y f i s s u r e d bark (Huber i n Ursprung 1906)o  Growth i n t h i c k n e s s o f cambial l a y e r may  be  93  f a v o r e d under c r e v i c e s of Robinia  (Braun 1955)•  cambial l a y e r the more r a p i d l y were the new xylem  The wider the elements  formed i n F r a x i n u s and Acer(Hanson and Brenke 1 9 2 6 ) .  Crevices  were found on the convex side of bent T i l i a t r e e s w h i l e t h e i r concave side was  smooth-barked  (Karzel 1906).  Thickness and/or c h a r a c t e r of bark were r e l a t e d t o the amount, o r t o the d u r a t i o n o f r a d i a l growth, o r t o the wood q u a l i t y i n p o p l a r (Joachim 1 9 5 4 ) ; i n western y e l l o w pine (Dunning 1 9 2 2 ) ; i n southern cypress (Mattoon 1915)j i n redwood  (Luxford  1 9 3 0 ) ; i n Norway spruce ( B l o s s f e l d and Haasemann 1 9 6 4 ) ; i n Scots pine  (Dengler i n Joachim 1 9 5 4 ) ; i n a l p i n e f i r (Kennedy  1954a, b ) ; i n b i r c h I 9 6 3 ) ; i n beech  (Newall and G a r d i n e r I 9 6 3 ) ; i n oak  (Svoboda 1 9 6 4 ) .  c o l o r , bark of the l i v i n g  (Kirst  With r e s p e c t t o t e x t u r e and  stumps sometimes bore l i t t l e  lance t o the bark of normal t r e e s (Lamb 1899; c h a r a c t e r was  and Wilson  resemb-  Page 1 9 2 7 ) .  r e l a t e d t o the degree of bark s l i p p a g e  Bark  (Huber 1 9 4 8 ) .  Aspen from h i g h a l t i t u d e s had a t h i c k e r corky l a y e r than t h a t from lowlands (Shope 1927)•  The r e l a t i v e volume of  cork i n bark of Douglas f i r was h i g h e r than t h a t of any o t h e r North American c o n i f e r s t u d i e d  (Chang 1954)  and ranged from  20 t o 45 per cent i n the oven dry bark (Grondal 1 9 4 2 ) .  The  t h i n l a y e r of cork i n the bark o f t r e e s from the t r o p i c a l f o r e s t was due t o the e f f e c t s of humidity (Whitford Schimper  i n F r a n c i s 1924)*  rain  1906;  E x c e s s i v e moisture suppresses  s u b e r i z a t i o n ; i n s o l a t i o n hastened f o r m a t i o n of deep cork (Esau 1958;  de Zeeuw 1941)*  With r e s p e c t t o the u n i f o r m i t y o f  94  activity,  cork cambium behaved as the v a s c u l a r cambium, i t  could be a c t i v e i n some p a r t s of stem w h i l e s t i l l r e s t i n g i n other p a r t s of the same stem ( G r i l l o s and Smith  1959).  The v a l u e s o f the c o e f f i c i e n t o f d i f f u s i v i t y o f ground cork and o f water are e x a c t l y the same (Carslaw and Jaeger 1 9 5 9 ) ,  but the p r e v e n t i o n o f water l o s s from stems was  c o n s i d e r e d the primary f u n c t i o n o f the corky l a y e r 194l)<>  (de Zeeuw  On the other hand, i t was shown t h a t l a y e r s o f bark are  not impermeable? l i q u i d s c o u l d reach the cambial l a y e r o u t s i d e as w e l l as from i n s i d e .  from  F o r example, a r s e n i c a l  s o l u t i o n s p e n e t r a t e d by l e n t i c e l s and by f i s s u r e s i n the o l d bark  (Swingle and M o r r i s 1 9 1 7 ) °  O i l s o f low v i s c o s i t y p e n e t r a t e d  through the cork i n t o the cambium o f apple twigs (Ginsburg 1931)» R a d i o a c t i v e fluorochrome was t r a n s l o c a t e d from v e s s e l s through the sclerenchyma  r i n g i n t o the bark  (Heinrich 195$).  Radio-  a c t i v e phosphorus moved through bark i n t o wood o f branches; i t was concluded t h a t n u t r i e n t s may be s u p p l i e d t o t r e e s v i a the bark  (Kiselev 1962).  A b s o r p t i o n o f water by the bark and not  by the r o o t s p r o v i d e d the necessary s t i m u l u s f o r l e a f f o r m a t i o n in ocotillo  (Lloyd I9O5).  The  c o n c l u s i o n o f Brown ( 1 9 1 5 ) , namely t h a t r e s e r v e  foods are not l i m i t i n g i n the b e g i n n i n g of cambial seems t o be i n agreement w i t h more r e c e n t f i n d i n g s ;  activity, carbohydrate  r e s e r v e s were adequate a t any p o s i t i o n i n the stem t o support growth i n t h a t l o c a t i o n once i t s t a r t e d  (Wilcox i 9 6 0 ) .  Depletion  o f s t a r c h was c o n s i d e r e d t o be p r o p o r t i o n a l t o the amount o f  95  radial  growth  ditions radial trees  in  cases  presence growth  2,5  a  and H e p t i n g  sapwood  of  Douglas  and  early  spring  was  shown  to  of  spruce  Photosynthesis Bark  chlorophyll contained any  of  per  in the In  is  the  too  more  subcortical  1897). spruce trees and  thick  spring,  tarred  trees  Cambial reached they  80°F  up t o  occur  the  unit  leaves  its  in  in  of  of  bark  chlorophyll  (Pearson  per  bark  than  per  (1915)  of  Brown s  to  permit  the  not  wholly  might  be  temperatures, subcortical  131°F  attained  during the  (Hartig  100  to  winter  f i r  113°F  f a l l  stored  of  of  the  stem  exposed unit  area  In  possible  (Parker  sun of  net  I964K  mature  1953)•  aspen more  and  it  surface  than  1958).  conclusions, up  true.  of  e_t  that  cambial  large  fruit  trees  winter,  reached  71°F.  rose  92°Fc(Selby  side al.  the  1944)•  namely  the  In  south  during  in  total  contained to  in  winter  was  point  Precht  (Eggert  the  (Helms  stems  and  photosynthesis  freezing  d u r i n g the  in  with  (Hepting  photosynthate  warming  on t h e  of  con-  healthy  early  starch  cent  temperatures  temperatures  of  Winter  and Lawrence T  the  of  Douglas  side  connected  spring  1963).  below  north area  early  normal  maximum d u r i n g l a t e  25  accumulation  could  Another bark  for  in  amount  e_t a l .  temperatures  from  also  the  (Chapman  at  photosynthate  d u r i n g the  treeso  was  under  stem b a r k  food  in  The  but  causally and  stored  minimum,  f i r  some  not  Root  I964K  account  Norway even  1933)*  the  Jackson  gain  was  minimum i n  times  annual  defoliation,  starch  (Wight  reached  maximum,  of  of  to of  open  1955)j  summer  in  grown fruit  (Ferkl  Subcortical  layer  i960),  96  temperatures 30 f e e t above ground reached 90°F at a i r temperature 1  of 108 F (Reynolds 1 9 3 9 ) .  Temperature  side of an o l d f i r t r e e was 90°F a t BH a t a i r  south-west  temperature of 75°F (Gerlach eratures  of the' canibium on the  i n Geiger 1950).  Cambial temp-  f l u c t u a t e d as much as the a i r temperatures i n o l d  basswood t r e e s under a 6 mm-layer of bark l a c k i n g corky l a y e r s and T r a b e r 1 9 6 4 ) .  (Kuebler  Temperature  of xylem midway between  p i t h and bark of the shaded side of P i n u s r a d i a t a i n f e s t e d by S i r e x was always h i g h e r than t h a t of a i r i n shadow by 1 t o 5°C; healthy  t r e e s were always c o o l e r by 2 t o 5°C than the a i r .  Temperature  of t r e e s of d i f f e r e n t crown c l a s s e s d i f f e r e d  (Jamieson 1 9 5 7 ) .  Temperature  of dead t r e e s was up t o 18°F  h i g h e r than t h a t of l i v i n g t r e e s  (Rameux i n Mason 1 9 2 5 ) .  S u b c o r t i c a l temperatures i n l o g s f l u c t u a t e d more than the a i r temperatures and v a r i e d d i r e c t l y w i t h i n t e n s i t y of s o l a r radiation  (Graham 1 9 2 5 ) .  They were h i g h l y v a r i a b l e w i t h i n the  same l o g as w e l l as i n l o g s of the same s p e c i e s , and more i n l o g s of d i f f e r e n t species  still  (Graham 1 9 2 2 ) .  The temperature d i f f e r e n t i a l , i n the cambium or under the bark, between i n s o l a t e d and shaded s i d e s of the same trunk was between 35 and 55°F d u r i n g the w i n t e r time Eggert 1944)  and between 15  i n G e i g e r 1950;  (Selby  and 36°F during the summer  1897; (Gerlach  F e r k l and F e r k l 1 9 5 4 ) .  E v i d e n t l y , temperatures which can be t r a n s m i t t e d  to  s u b c o r t i c a l t i s s u e s through the l a y e r s of bark are h i g h enough t o be considered  as c r i t i c a l i n i n c e p t i o n and maintenance  of  97  r a d i a l growth because, i n p l a n t s , the o p t i m a l temperatures of most types o f growth are g e n e r a l l y lower.  T h i s f a c t can be  shown by the i n s p e c t i o n o f the r e s u l t s o f t i s s u e c u l t u r e studies. I t was b e l i e v e d t h a t a growing u n d i f f e r e n t i a t e d mass of c e l l s such as a c a l l u s c u l t u r e o r a c u l t u r e o f e x c i s e d  roots  e x h i b i t i n g a l i m i t e d amount o f d i f f e r e n t i a t i o n should possess fewer i n t e r n a l v a r i a b l e s and should a l s o permit c o n t r o l o f the external v a r i a b l e s at w i l l  (White 1943)»  A rigorous  control  of temperature was shown t o be e s p e c i a l l y important i n t h i s respect;  a maintained i n c r e a s e  caused a 20 per cent i n c r e a s e root t i p s .  i n temperature from 28 t o 30°C i n growth r a t e of e x c i s e d  tomato  A f u r t h e r i n c r e a s e from 30°C t o 31°C caused a 30  per cent decrease i n growth rate  (White 1937a, b ) . The range  between optimum and l e t h a l temperatures i s very narrow.  A  maintained r i s e o f 5°C above optimum w i l l k i l l the c u l t u r e s . C u l t u r e s w i l l endure maintained low temperature without i n j u r y and w i l l resume normal growth at temperatures more n e a r l y optimal (White 1943)»  Temperature  o f t i s s u e s growing i n the  dark was t h a t o f the a i r temperature.  Illuminated  always warmer than a i r due t o i n t e r c e p t e d r a d i a n t transformed i n t o heat (de Capite 1955;  t i s s u e s were energy  Gautheret 1 9 6 1 ) .  The o p t i m a l temperatures of the cambial t i s s u e c u l t u r e of S a l i x capraea was about 60°F (Gautheret 1 9 3 8 ) . Cambial t i s s u e o f v a r i o u s (Jacquiot^, 1950,  1951;  s p e c i e s p r o l i f e r a t e d i n v i t r o a t 77°F  Gautheret 1 9 3 8 ) ; t i s s u e o f Pinus banksiana  98  grew w e l l at 72 °F (Loewenberg and of Sequoia sempervirens was t h a t of H e l i a n t h u s d u r i n g the n i g h t  Skoog 1 9 5 2 ) o  Callus culture  maintained at 70°F ( B a l l 1 9 5 0 ) ,  annuus at 68°F d u r i n g the day and at 79°F  (de Capite 1 9 5 5 ) ; t h a t of sunflower at 76  83°F (Hildebrandt e_t a l . 1945)*  to  E x c i s e d tomato r o o t t i p s grew  w e l l at 86°F, a temperature of 95°F b e i n g l e t h a l : ( W h i t e 1937 E x c i s e d r o o t t i p s of pea, temperature optima at 50°, ( G a l l i g a r 1938)»  sunflower, 68°,  77°  corn and 77°,  and  cotton  a).  had  respectively  Asparagus r o o t i n i t i a l s kept growing at 77°F  (Galston 1948); asparagus e x c i s e d stem t i p s at 79°F (Loo  1945)•  T o t a l increment and a l s o the l a r g e s t number of l a t e r a l s i n i s o l a t e d r o o t s of Pinus s y l v e s t r i s were produced between 63 and 66°F ( S l a n k i s 1949)» r o o t s was i n apple  Maximum growth of apple and  observed at 65°F ( N i g h t i n g a l e 1935)* c u t t i n g s and g r a f t s was  Callus  peach formation  o p t i m a l at 68°F; i t occurred  w i t h i n the range 32 t o 104°F.  Oxygen, even below the a i r  c o n c e n t r a t i o n was  (Shippy  I t was  not l i m i t i n g  1930)o  maintained t h a t  T i s s u e c u l t u r e s of the cambium are d e r i v e d from complexes of l i v i n g c e l l s , which i n c l u d e , i n a d d i t i o n t o cambial i n i t i a l s t i s s u e c e l l s t h a t are known t o be capable of d e d i f f e r e n t i a t i o n and subsequent d i v i s i o n . Furthermore, when p a r t s of the cambium are removed from a t r e e and are grown i n t i s s u e c u l t u r e s , the i n i t i a l s cease t o f u n c t i o n normally and form c a l l u s (Bailey 1952). I t was  a l s o r e p o r t e d t h a t p e r i o d s of growth of the  c a l l u s cambium are not i n v a r i a b l y i d e n t i c a l w i t h those of normal cambium (MacDougal 1943) <»  Nevertheless,  the above survey makes  99  it  c l e a r t h a t the optimal temperatures of cambial t i s s u e  c u l t u r e s are not s u b s t a n t i a l l y d i f f e r e n t from those o f c a l l u s tissue cultures.  The range o f both o f them i s from about 60°F  to 79°F and i s t h e r e f o r e c o n s i d e r a b l y lower than the upper of the s u b c o r t i c a l temperatures found i n t r e e s .  limit  I t i s well  known t h a t The temperature r e l a t i o n s of p h y s i o l o g i c a l p r o c e s s e s do f o l l o w c e r t a i n t y p i c a l curves which seem t o be i d e n t i c a l o r n e a r l y r e l a t e d f o r p r o c e s s e s of the same fundamental nature i n d i f f e r e n t organisms (Krogh i n L e i t c h 1916). T h e r e f o r e , temperatures o p t i m a l f o r growth o f p l a n t t i s s u e i n v i t r o may w e l l be i n d i c a t i v e of temperatures o p t i m a l f o r the r a t e o f the r a d i a l growth i n t r e e s .  Conversely,  temperatures found t o be supra-optimal i n t i s s u e c u l t u r e s may be c r i t i c a l f o r cambial growth i n t r e e s because  the o p t i m a l  temperatures o f t i s s u e c u l t u r e s are h i g h e r than those u s u a l l y observed i n growing i n t a c t p l a n t s (de Capite 1955; Gautheret 1961).  In the absence  o f any i n q u i r y which would evaluate the  i n f l u e n c e of cambial temperature  on the p r o c e s s e s of r a d i a l  growth i n t r e e s the phenomenon o f h e a t i n g o f stems m e r i t s further attention.  R e s u l t s o f r e l a t i v e l y few s t u d i e s seem t o  be a v a i l a b l e i n t h i s r e s p e c t . The more important f a c t o r s governing the l e v e l s o f the s u b c o r t i c a l and xylem temperatures can be l i s t e d as f o l l o w s : (1)  i n t e n s i t y , a l t i t u d e and angle of i n c i d e n c e o f s o l a r radiation;  (2)  t h i c k n e s s , s u r f a c e t e x t u r e , i n n e r s t r u c t u r e and c o l o r o f bark;  100  (3)  amount of shading;  (4)  moisture  (5)  a i r temperature  (6)  p r o x i m i t y of other r a d i a t i n g and a b s o r b i n g s u r f a c e s ;  (7)  the c o o l i n g e f f e c t of the t r a n s p i r a t i o n d e r i v i n g i t s temperature from the s o i l ;  (8)  s i z e of the stem.  (Selby 1897;  content of bark and of xylem;  Graham 1922;  and a i r movement;  Mason 1925;  stream  F e r k l and F e r k l  1954).  During the w i n t e r the maximum h e a t i n g e f f e c t p l a c e on the p a r t of t r u n k o r i e n t e d towards south and between noon and 2 pm.  takes culminates  During the summer bark of t r e e s i s  n e a r l y p a r a l l e l t o the d i r e c t i o n o f the sun r a y s at noon. Maximum underbark  temperatures were found d u r i n g second  half  of J u l y on the s i d e s of stems o r i e n t e d towards west between 3 and 5 nip. not two  During a sunny day,  pm  i n t r e e s i n the open, t h e r e are  s i t e s w i t h i n the cambial c y l i n d e r which would have the  same temperature  ( M i l l e r 1931;  F e r k l and F e r k l 1 9 5 4 ) .  l e a n i n g t o the n o r t h e a s t were most s e v e r e l y i n j u r e d by r a d i a t i o n ; the i n j u r y was southwest  solar  c o n f i n e d almost e n t i r e l y t o the (Mix 1 9 1 6 ) .  s i d e of the t r u n k  a t i o n which was  Trees  equal t o 100  The  e f f e c t of i n s o l -  per cent i n branches p e r p e n d i c u l a r  t o the d i r e c t i o n o f sun's r a y s , decreased t o 30 per cent i f the angle of i n c i d e n c e was  50 degrees  Bark t h i c k n e s s was,  ( F e r k l and F e r k l 1 9 5 4 ) .  by f a r , the most  important  f a c t o r d e t e r m i n i n g the r e l a t i o n of a i r temperature c o r t i c a l temperature.  t o sub-  In t r e e s with a t h i n l a y e r of bark the  101  s u b c o r t i c a l temperature corresponded c l o s e l y t o a i r temperature; shadow o r wind caused immediate  and r a p i d drop i n s u b c o r t i c a l  temperature; r e f l e c t i o n from snow had an o p p o s i t e e f f e c t 1923a.; B e a l 1 9 3 4 ) .  With a surface temperature  (Harvey  o f 135°F i t took  9 minutes t o reach 122°F a t the cambium s h i e l d e d by 0 . 2 - i n c h l a y e r o f bark.  With t h i c k e r bark and h i g h e r e x t e r n a l temper-  ature the cambial temperature continued t o r i s e a f t e r the heat was removed; the c o o l i n g p e r i o d was c o n s i d e r a b l y prolonged (Kayll 1963b).  M o r t a l i t y due t o f r e e z i n g i n western pine b e e t l e  v a r i e d i n v e r s e l y as the t h i c k n e s s o f bark p r o t e c t i n g the brood. T h i s r e l a t i o n s h i p h e l d only f o r bark l a y e r s more than 0 . 5 thick  (Keen and F u r n i s s 1 9 3 7 ) .  Stems of smooth-barked  were warmer than those h a v i n g rough bark ( R u s s e l l  inch  trees  1889).  F i s s u r e s occupied as much as 44 per cent of the circumference of a 15 i n c h p i n e .  When a temperature o f 500°C was a p p l i e d at  the bottom o f a f i s s u r e 0 . 5 i n c h deep a temperature o f about 1000°C was recorded on an adjacent p l a t e  (Kayll 1963b).  Black  bark may be 8°F warmer i n s u n l i g h t than white bark (Harvey  1923b).  In t r u n k s o f f r u i t t r e e s p a i n t e d b l a c k the sun s c a l d i n j u r y was c o n f i n e d e n t i r e l y t o the blackened p a r t o f stem In l a r c h , growth d i d not begin f i r s t  (Mix 1 9 1 6 ) .  i n those r e g i o n s w i t h the  t h i n n e s t bark and best i n s o l a t i o n but i n the middle r e g i o n o f stem because,  supposedly, t h e r e the bark was o f the same c o l o r  as t h a t of the b a s a l r e g i o n s and only h a l f as t h i c k  1913).  (Knudson  102  Exchange of energy between p l a n t and a i r by f r e e or f o r c e d c o n v e c t i o n t r a n s f e r s energy from the p l a n t i f i t i s warmer than the a i r and t r a n s f e r s energy t o the p l a n t i f the a i r i s warmer than the p l a n t .  In the steady s t a t e the  exchange  of energy between p l a n t and a i r w i l l r e s u l t i n the p l a n t having an e q u i l i b r i u m temperature  ( T i b b a l s et a l . 1 9 6 4 ) .  The r a t e of  energy t r a n s f e r between the p l a n t and the environment the temperature of the p l a n t .  determines  V a r i o u s p a r t s of a p l a n t  may  possess d i f f e r e n t temperatures because of v a r y i n g r a t e s o f energy t r a n s f e r (Gates I 9 6 5 ) . in  Temperature  o f p a r t s of stems  shadow are always i n an approximate agreement  ature of a i r i n shadow (Gerlach 1954)•  i n G e i g e r 1950;  with the  temper-  F e r k l and F e r k l  The temperature i n the base of s e e d l i n g s was l a r g e l y  i n f l u e n c e d by the amount and p o s i t i o n of the shade cast by the  c o t y l e d o n s and by the t r u e f o l i a g e (Baker 1929)• C o n f l i c t i n g evidence e x i s t s on the e f f e c t s of moisture content on heat t o l e r a n c e (of cambium). Thermal c o n d u c t i v i t y of wood i n c r e a s e s w i t h i n c r e a s i n g moisture content, and bark may r e a c t i n the same manner .... Conversely, the e f f e c t s of an i n c r e a s e i n thermal c o n d u c t i v i t y may be o f f s e t by an i n c r e a s e i n thermal c a p a c i t y . However, i n importance o f e f f e c t on h i g h temperature heat t o l e r a n c e , moisture content i s probably f o u r t h , f o l l o w i n g bark t h i c k n e s s , temperature of a p p l i e d heat, and i t s d u r a t i o n ( K a y l l 1 9 o 3 a ) . Bark o f some deciduous s p e c i e s c o n t a i n e d 2 t o 7  times as much moisture as bark o f Tsuga canadensis, depending on s p e c i e s and. p o s i t i o n above ground. t r e e was  Bark o f any i n d i v i d u a l  s e v e r a l times as moist near the base as i t was  above s o i l l i n e  ( B i l l i n g s and Drew 1 9 3 8 ) .  The  6 feet  absorptive  103  c a p a c i t y of bark f o r water d i f f e r e d among the s p e c i e s . A c t i o n of wind was  assumed t o be the cause of d i f f e r e n c e s i n moisture  content i n bark o f d i f f e r e n t t r e e s of the same s p e c i e s (Young 1937)«  Water content of bark was  lower i n w i n t e r and at the  end of the summer; i t f l u c t u a t e d more than t h a t of wood (Gibbs 1957)»  Phloem of southern p i n e s contained c o n s i s t e n t l y over  200 per cent of moisture on a dry weight b a s i s , whereas the outer bark showed an average temperatures  of about 10°F  of l e s s than 30 per cent at  (Beal 1933)«  Water content of  s e e d l i n g s grown under uniform c o n d i t i o n s . r a n g e d from 100  to  250 per cent ( K a y l l 1963a) < > Water content of xylem i n young p o p l a r s a p l i n g s was maximal i n June, minimal i n September. From A p r i l t o September moisture content rose from the base to the apex; the g r a d i e n t was season  r e v e r s e d d u r i n g the dormant  (Butin 1957) < > Severance  of l a t e r a l s d i d not a f f e c t  n o t i c e a b l y the moisture content i n stems of Douglas f i r (Chalk and B i g g 1 9 5 6 ) .  R e g i o n a l d i f f e r e n c e s i n moisture  content of sap wood i n Abies balsamea c o u l d not be e x p l a i n e d (Clark and Gibbs  1957).  Temperatures bark were brought  of o v e r w i n t e r i n g cambium under i n s o l a t e d  down t o a i r temperature  breeze i n 2 t o 3 minutes. temperature  The h e i g h t t o which the  cambial  rose depended on v e l o c i t y and d i r e c t i o n o f wind  (Harvey 1 9 2 3 a ) . may  by a 50 feet/minute  A warm wind t r a n s f e r r i n g energy t o a p l a n t  b r i n g about the same p l a n t temperature  f l u x of i n c i d e n t r a d i a t i o n  (Gates 1 9 6 5 ) .  as would a d e f i n i t e  104  Long wave radiation of earth and r e f l e c t e d solar r a d i a t i o n can be more important sources of the energy, f o r a body above ground, than the d i r e c t solar radiation (Precht .gt .al. 1955)•  The energy content of plants i s moderately  coupled to the incident sunlight, but strongly coupled to the infrared thermal radiation from the surrounding surfaces (Gates 1962, 1965). Growth may go on i n date palms even when minimum temperature of a i r i s below freezing, provided the maximum temperature of the day i s well above 50°F.  Differences i n  the i n t e r i o r temperature from the a i r temperature have ranged from 26°F warmer on the coldest morning t o 32°F cooler on the hottest day, but the d a i l y range of i n t e r i o r temperature was r a r e l y above 7 t o S°F.  The s t a b i l i z i n g of temperature  of the meristematic tissues of the date palm i s believed t o be due to a protective envelope around the phyllophore, and to the ascending sap current with temperature acquired from the s o i l (Mason 1925)«  The cooling effect of t r a n s p i r a t i o n  stream i n trunks of forest trees was found t o die out r a p i d l y above ground l e v e l (Mayr i n Baker 1929)• Trees with a trunk diameter of l e s s than a foot suffered from sun scald more than larger t r e e s .  Rarely, i f  ever, was sun scald observed on large old trees.(Selby 1&97)• In bringing the cambial temperature t o 65°C, 7**inch DBH balsam f i r withstood an external temperature of 300°C longer than a 12-inch DBH beech; 9-inch DBH hemlock was almost twice as  105  r e s i s t a n t t o heat as 15-inch DBH  balsam f i r .  were a t t r i b u t e d t o c h a r a c t e r of bark  These  differences  ( S t i c k e l i n K a y l l 1963b).  Width of the bark l a y e r was important i n heat t r a n s f e r t o cambium.  considered a f a c t o r Bark width i s d i s t -  r i b u t e d along the bole i n a f a s h i o n which i s d i r e c t l y o p p o s i t e to t h a t of t o t a l r i n g width or of r i n g width of earlywood, but which resembles t h a t of r i n g width of latewood.  It follows  that the i n s u l a t i o n of the cambial l a y e r i s l e a s t e f f e c t i v e i n the  upper reaches of the bole i f the i n f l u e n c e of shading and  i n s o l a t i o n are d i s r e g a r d e d . E f f e c t s of temperature thus might be f e l t  f i r s t w i t h i n a p a r t of the cambial c y l i n d e r p r o t e c t e d  by t h i n n e s t l a y e r of bark even i n case t h a t the temperature p r o f i l e w i t h i n the f o r e s t would be i s o t h e r m a l at a l l times, d i s c o u n t i n g the e f f e c t s of i n s o l a t i o n .  E x i s t e n c e of v e r t i c a l  temperature g r a d i e n t s i n the f o r e s t , and a l s o i n the open, d u r i n g the growth  season, or part of i t , d u r i n g the day  and/or  n i g h t , supports the concept of d i s p a r i t y of r a d i a l growth xylem a l o n g the It  of  stems.  i s known t h a t a f o r e s t t r e e extends through a  s e r i e s of temperature regimes from the m i c r o c l i m a t e of a root tip,  where the l a r g e s t temperature d i f f e r e n c e s d u r i n g the  growing  season might not be over 15°F,  temperatures may  t o t h a t of a t w i g where  range from -40 t o 100°F ( F r a s e r 1 9 5 7 ) .  v e r t i c a l g r a d i e n t s i n summer a i r temperature between  The  soil  surface and crown r e g i o n o f an oak stand were as high as 36°F (Goryshina and Neshataev i 9 6 0 ) .  A s i m i l a r gradient i n a  106  n a t u r a l stand o f Norway spruce was Temperature  only  2  t o 4°F (Kautu  1952)»  i n crown space d u r i n g the day was p r o p o r t i o n a t e t o  t h e : d e n s i t y o f the stand which, t o g e t h e r with h e i g h t and area, determined the whole m i c r o c l i m a t i c (Goehre and Luetzke  1956).  s t r u c t u r e of the stand  In t h i s r e s p e c t , even the  d i s t r i b u t i o n o f t r e e s i n the f o r e s t was  spatial  c o n s i d e r e d t o be  important: temperature c o n d i t i o n s i n p l a n t a t i o n s w i t h r e g u l a r spacing might d i f f e r from those w i t h random s p a c i n g t o such a degree as t o a f f e c t the r a t e of growth ( S e l l e c k and Shupert  1957), Three t y p e s of d i u r n a l m i c r o c l i m a t i c  temperature  g r a d i e n t were observed d u r i n g the growing season: under heavy shade the temperature was h i g h e r i n the crown space than at the ground; a complete r e v e r s a l o f t h i s g r a d i e n t was  observed  i n stands w i t h small openings; under medium,shade v e r t i c a l temperature g r a d i e n t s disappeared (Cantlon  1953)• Canopy  tended t o i n c r e a s e temperature at h i g h e r e l e v a t i o n s above ground d u r i n g the summer. 20  The lowest temperatures were at  cm above ground throughout the y e a r ; m i c r o c l i m a t i c  structure  of t h r e e h a b i t a t s was pronouncedly d i f f e r e n t d u r i n g v a r i o u s seasons of the y e a r (Sparkes and Murray  1955)*  The crown space  of an o l d stand was the space of h i g h e s t a i r temperatures and of the most u n s e t t l e d c o n d i t i o n . ground  showed uniform temperature.  The l a y e r 3 m h i g h above the Sinking cold a i r i n a  stand o f low d e n s i t y r e s u l t e d i n a temperature minimum at the forest floor  (Geiger  1950).  Higher maximum and lower minimum  107  a i r temperatures  were found  i n crowns and w i t h i n the  below the crowns i n t h i n n e d stands of pine "Secondary temperature  maximum" was  space  (Adams 1935)•  observed  d u r i n g the  day  at some small d i s t a n c e above the ground; i t s v e r t i c a l  position  v a r i e d and depended on l o c a l c o n d i t i o n s ( V u j e v i c 1909,  Geiger  1950).  Mean monthly temperatures  l a y e r are not independent 13°F  w i t h i n the m i c r o c l i m a t i c  of h e i g h t .  D i f f e r e n c e s as much as  were observed between maximum a i r temperature  5 cm above ground I t was  at 2 m  and  (Baum 1949 > Cantlon 1953)» recognised that meteorological v a r i a b l e s  such as a i r temperature  and a i r humidity c o n f e r only a l i m i t e d  amount of i n f o r m a t i o n r e g a r d i n g the processes which bear the heat and water economy of a f o r e s t  on  stand: they are meteor-  o l o g i c a l elements the knowledge of which may  only lead to a  p a r t i a l comprehension of a phase of m i c r o c l i m a t i c processes t a k i n g place i n p l a n t community. may  In f a c t , the a i r temperature  be very m i s l e a d i n g as an environmental  (Bates I962).  parameter by  Both the m i c r o c l i m a t i c and the  itself  physiological  processes w i t h i n the p l a n t community depend on the  radiation  balance, i . e . on the r a d i a t i o n - r e r a d i a t i o n d i f f e r e n t i a l . r a d i a t i o n balance  i s the v a l i d e x p r e s s i o n o f the energy  The con-  v e r s i o n o c c u r r i n g w i t h i n the v a r i o u s zones of the stand p r o f i l e ; the heat budget, which i n the end determines s t r u c t u r e of a stand, depends upon i t .  the m i c r o c l i m a t i c  Heat budget can be  estimated by e v a l u a t i n g r a d i a t i o n balance and by the r a t e of exchange of heat and  determining  of water vapor going on between  f o r e s t atmosphere and  raoisture  and the space above the canopy.  budget  The  energy  of a f o r e s t are i n s e p a r a b l e : a l l the  v a r i a b l e s e n t e r i n g thero must be measured at the same time at v a r i o u s h e i g h t s w i t h i n the stand and above the stand. The measurement o f r a d i a t i o n balance showed t h a t the r a d i a n t energy r e c e i v e d by a young Norway spruce stand d u r i n g the h e i g h t o f summer amounted t o , on the average, 615  cal/em  2  per day; o f these only 29 were r e - r a d i a t e d d u r i n g the n i g h t . The remainder was  converted i n t o o t h e r forms o f energy which  was u t i l i z e d by the stand.  Up t o 60 per cent of the t o t a l  energy r e c e i v e d was  r e t a i n e d w i t h i n the zone o f t r e e t o p s ,  i . e . w i t h i n the  crown".  sun  rt  T h i s f a c t was  c o n s i d e r e d as  r a t h e r s u r p r i s i n g because the wood volume i n t h i s zone i s much s m a l l e r as compared w i t h the volume of wood w i t h i n the zone of "shade crown" ( i . e . o f the crown beneath the p o i n t o f c o n t a c t o f the n e i g h b o u r i n g crowns) .... T h e r e f o r e , the a c t i v e s u r f a c e i n the l i f e - o f the f o r e s t i s not the crown space but the space o f t r e e t o p s ...» The h e i g h t of the "zone of t r e e t o p s " d e c i d e s about the q u a n t i t y of the energy r e c e i v e d by r a d i a t i o n and about i t s f u r t h e r c o n v e r s i o n .... In the space between the upper l i m i t of shade crown and between t r e e apex every decimeter of the h e i g h t by which a t r e e t o p s i t s neighbour s i g n i f i e s a s u b s t a n t i a l g a i n i n energy. (Baurogartner 1952, 1957). A marked s t r a t i f i c a t i o n i n the environment was  produced  i n stands o f pine by ^the combination o f a Jaeat s i n k at the c o o l ground  s u r f a c e and of a heat source i n the t r e e s  above.  As the sun h e a t s the t r e e s , the l e v e l o f h i g h e s t temperature m i g r a t e s from 50 f e e t downward t o 30 f e e t and lower. For s e v e r a l hours t h i s middle l e v e l i s warmer than the a i r e i t h e r above o r below i t , and heat f l o w s both upward and downward from i t . T h i s heat  109  source, evident i n temperature p r o f i l e s i n the f o r e s t . . o cannot be e x p l a i n e d except as a r e s u l t of a b s o r p t i o n o f sunshine by the f o l i a g e of the trees ( M i l l e r 1956). There i s no doubt t h a t s i m i l a r phenomena should occur i n c o n i f e r o u s f o r e s t s throughout the world (Gates 1 9 6 2 ) . The  " p h y s i c a l g r a d i e n t s " i n " f o l i a g e c l i m a t e " from a  crown's p e r i p h e r y toward a t r e e trunk are, e s p e c i a l l y i n c o n i f e r s , m i n i a t u r e r e p l i c a s o f the more i n t e n s e v e r t i c a l g r a d i e n t s i n the atmosphere from the f o r e s t f l o o r t o the canopy. In both  s i t u a t i o n s the f o l i a g e m o d i f i e s p a t t e r n s o f e v a p o r a t i o n ,  c o n v e c t i o n and r a d i a t i o n , and t h e r e f o r e of temperature  (Wellington  1950). Temperatures w i t h i n wide ranges d i d not a f f e c t s i g n i f i c a n t l y the r a t e of t r a n s l o c a t i o n o f o r g a n i c n u t r i e n t s i n stems of some small p l a n t s ( C u r t i s 1929; C r a f t s 1932; C u r t i s and Herty 1936; Went and H u l l 1 9 4 9 ) .  110  S u b c o r t i c a l Temperatures  i n Douglas F i r  The i n t e r n a l temperatures of stems o f f o r e s t  trees  were s t u d i e d , among o t h e r s , by Hunter, Schoepf, de C a n d o l l e , H a r t i g and W i e l e r i n 1775» 1783, order (Mason 1925;  1832,  1874 and 1889,  L i e s e and Dadswell 1959)•  i n that  There seems t o  be a g e n e r a l s c a r c i t y of works d e a l i n g w i t h t h i s type o f problem a f t e r the b e g i n n i n g of t h i s c e n t u r y .  A p p a r e n t l y no r e s e a r c h  on s u b c o r t i c a l temperatures was ever done i n Douglas  fir.  In o r d e r t o g a i n some knowledge about the l e v e l s of temperatures which can be reached w i t h i n the t i s s u e s of the phloem-xylem  boundary  i n stems of Douglas f i r an i n q u i r y  was  conducted i n t h i s r e s p e c t d u r i n g the growing season o f 1964° Working  i n the unmanaged, n a t u r a l l y e s t a b l i s h e d stands  of the U n i v e r s i t y Campus F o r e s t , an attempt was made t o f i n d : (1)  the average t h i c k n e s s of bark at BH, i t s v a r i a b i l i t y and the degree of i t s c o r r e l a t i o n w i t h DBH i n t r e e s from stands about 50 y e a r s o l d ;  (2)  i n t r e e s from the same stands, and s e p a r a t e l y i n the border t r e e s , the amount and the seasonal f l u c t u a t i o n s of water content of the o u t e r and of the i n n e r bark at BH:  (3)  the l e v e l of s u b c o r t i c a l temperatures a t t a i n a b l e at BH i n the i n s o l a t e d stems;  (4)  the range and the seasonal t r e n d of s u b c o r t i c a l temperatures at BH of t r e e s growing i n the stands of normal d e n s i t y ;  (5)  the temperature d i f f e r e n t i a l at BH between i n s o l a t e d and shaded p a r t of the same stem; temperature d i f f e r e n t i a l at BH between l i v i n g and between dead t r e e s .  (6)  the e f f e c t s of own crown's shade on the temperature at the stem s u r f a c e of young open grown t r e e s ;  Ill  (7)  the v e r t i c a l a i r temperature g r a d i e n t i n a stand of Douglas f i r ;  (8)  the r e l a t i v e importance of bark t h i c k n e s s and of i t s water content on the r a t e of heat propagation through the bark. The temperatures were measured d u r i n g June,  August and the f i r s t h a l f o f September.  July,  The y e a r 1964  was  g e n e r a l l y r a i n y and c o o l w i t h the annual mean temperature than h a l f a degree above the a l l - t i m e low.  The mean temper-  ature f o r every month except January and February was normal.  A l l the summer months were d u l l e r ,  less  below  c o o l e r and w e t t e r  than u s u a l , J u l y being the wettest and d u l l e s t on r e c o r d , as •f w e l l as one o f the c o o l e s t . the a l l - t i m e low.  B r i g h t sunshine was not much above  The maximum a i r temperature, 8 l . 4 ° F ,  recorded on the 11th  o f August  was  (Canada, Dept. o f T r a n s p o r t 1 9 6 4 ) .  Both the s u b c o r t i c a l and the a i r temperatures were measured and r e c o r d e d e l e c t r i c a l l y ; two  single-channel portable  r e c o r d e r s and two k i n d s of t h e r m i s t o r probes were used; the t u b u l a r probe used i n measurement of s u b c o r t i c a l temperatures was 11.5 was 3«7  cm l o n g and 3*95 mm seconds.  i n diameter; i t s time constant  The extended d i s c type of probe was used f o r  measurement of a i r and stem surface temperatures; i t s time constant was 0 . 8 Temperatures  seconds.  Both types were o f s t a i n l e s s  c o u l d be r e c o r d e d c o n t i n u o u s l y at 2-second  i n t e r v a l s w i t h i n the range from 40 t o 115°F o f 1.5°F.  steel.  w i t h an a c c u r a c y  112  1 The  average  bark t h i c k n e s s at BH  t r e e s having an average the c o e f f i c i e n t  - Bark T h i c k n e s s  DBH  of 15-5  inches was  of v a r i a t i o n b e i n g 31  54 per cent of the v a r i a b i l i t y f o r by the concomitant  of I63  Douglas f i r  0.97  per c e n t .  inches,  Only about  i n bark t h i c k n e s s was  variability  in  accounted  DBH.  2 - Moisture Content A l t o g e t h e r , 64 forest-grown t r e e s and were sampled at BH between June 12  of Bark  26 border t r e e s  and August 1 4 .  Average  water content of the outer bark of the f o r e s t grown t r e e s  was  85 per cent, c o e f f i c i e n t of v a r i a t i o n being 30 per cent. Corresponding  v a l u e s f o r border t r e e s were 64 and 40 per cent.  Average water content of the i n n e r bark of the f o r e s t grown t r e e s was  132  per cent, c o e f f i c i e n t  of v a r i a t i o n b e i n g 10  c e n t j the corresponding v a l u e s f o r border t r e e s were 125 10 per cent.  per and  S c a t t e r diagrams, prepared f o r f o r e s t grown t r e e s  only, are g i v e n i n F i g . 32 and  33• 3 - I n s o l a t e d Stems  The h i g h e s t temperatures  at the phloem-xylem boundary  were measured at BH of t r e e s which grew along the border of a stand which was years ago. 9 to 11 DBH  opened by c l e a r c u t t i n g s e v e r a l  They were as h i g h as 102°F on sunny days between  am under 0 . 7  t o 0.8 i n c h e s of bark i n 10 t o 1 4 - i n c h  t r e e s , where the temperature  65 t o 67 F. temperature  southeast  In i n s o l a t e d 17  of the a i r i n shadow  t o 2 0 - i n c h DBH  t r e e s the  was subcortical  rose by 5 t o 6 . 5 ° F i n about 60 t o 75 minutes under  o  O  a> o  0>  o  P E R C E N T A G E OF WATER ( D W )  o  6/12 6/15  6/22  3?  s» * S  7/1 7/3  o x»  *? o o?  S2  W  (0 (fi  <n  a*  7/12  ~  OJ  O  a w  *? J T  7/17  3  a n  o o <  8/1  8/14  <0 6/121—  o o  T "  = O  PERCENTAGE OF WATER ( D W )  5 O  6/lsl—  6/22  7/1  o  7/3  o 3> 7/12  Z  Z  II  II  Ul  o  7/17  8/1  8/141  •  •  ••  •  •  o  113  l a y e r s o f bark 0 . 8 t o 1.2  inches t h i c k , when the a i r temperature  one i n c h above the s u r f a c e o f the exposed side o f the stem was 7'5°»  Temperatures a t the surface o f i n s o l a t e d stems were  commonly i n excess o f 115°F when the surface o f bark i n shade r e g i s t e r e d 60 t o 65°F.  Temperature o f the xylem o f the f i r s t  r i n g , c o u n t i n g from the bark, about 70 f e e t above ground i n a forest-grown t r e e about 100 f e e t high, reached 81° on August  11.  4 - Stems o f Forest-Grown Trees S u b c o r t i c a l and a i r temperatures were measured simultaneously on r a i n l e s s days i n the a f t e r n o o n d u r i n g August and the f i r s t  h a l f o f September a t BH, f o r 82 stems  selected  at random i n a f u l l y stocked stand about 50 y e a r s o l d . The r e l a t i o n s h i p between the ambient and between the s u b c o r t i c a l temperatures i s p o r t r a y e d i n F i g . 34« 5 - Temperature  Differential  The s u b c o r t i c a l temperature:of the i n s o l a t e d  side  of border t r e e s was commonly 11 t o 12°F h i g h e r than the temperature o f the shaded s i d e , the l a t t e r side assuming the temperature o f a i r i n shadow.  The h i g h e s t temperature  d i f f e r e n t i a l was 30°F i n a 14-inch DBH t r e e under 0 . 6 i n c h e s of bark. Temperature o f xylem o f dead i n s o l a t e d t r e e s was 11°  t o 1 2 ° h i g h e r than t h a t o f l i v i n g i n s o l a t e d t r e e s o f a  s i m i l a r diameter.  114 6 - Crown Shade Temperature  of a i r i n shadow at the bark s u r f a c e of  stems o f open grown t r e e s was as much as 25°F lower than the air  temperature at the i n s o l a t e d t i p of branches 4 t o 6 f e e t  l o n g whenever the l a t t e r temperature reached about 90°* 7 - A i r Temperature G r a d i e n t s The v e r t i c a l a i r temperature g r a d i e n t s were measured i n a f u l l y - s t o c k e d stand of Douglas f i r , about 90 f e e t h i g h , between the e l e v a t i o n s of 2 and 80 f e e t above ground*  The  measurements were taken on 6 sunny and 6 cloudy a f t e r n o o n s d u r i n g August and the f i r s t i n F i g * 35° 11*  h a l f of September; they are p l o t t e d  The l a r g e s t d i f f e r e n c e observed was 15°F  The average temperature d i f f e r e n t i a l was  days or on days with o v e r c a s t sky; i t was  on August  6*5°F on cloudy  8*7°F on sunny days*  8 - Heat P r o p a g a t i o n through Bark The p r o p a g a t i o n o f heat from the surface of bark through i t s i n t e r i o r t o phloem-xylem  boundary was  studied i n  b l o c k s of wood w i t h bark cut out from Douglas f i r stems at d i f f e r e n t e l e v a t i o n s above the ground.  The b l o c k s were about  5 i n c h e s wide, 9 inches l o n g and 2 t o 3 inches t h i c k .  As a  source of heat an i n f r a r e d lamp was used; the heat at the surface of bark was  100°F i n every case t e s t e d .  Moisture  content of bark was determined at the end of each r u n .  Some  r e s u l t s of t h i s phase of the work are shown i n F i g . 3 6 ; temperature under the bark 0 . 4 first  cm t h i c k rose by about 20° i n  15 minutes of the t r i a l when the water content of bark  _™  I  55  60  ,  I  I  1  1  1  65  70  75  80  85  AMBIENT TEMPERATURE (°F)  115  was 13 per cents temperature rose by 15° under the bark o f the same t h i c k n e s s a t a water content o f 105 p e r cent; the tempera t u r e s under the "wet" bark d i d not a t t a i n the l e v e l s reached under the " d r y " bark. Temperature under 2»2 cm o f bark rose by about 10° a f t e r one hour o f h e a t i n g ; temperature under 1.7 cm o f bark rose by about 13° d u r i n g the same time, the moisture content b e i n g 60 per cent i n both c a s e s . Temperature  under 1.45 cm o f bark r o s e by about 16°  i n one hour, a t a moisture content o f 38 per c e n t .  116  CONCLUSIONS (B) (1)  No pronounced  seasonal t r e n d was  evident i n the water  content of the o u t e r as w e l l as of the i n n e r bark of both forest-grown t r e e s and border t r e e s .  Border t r e e s had, on the  average, a lower water content of the o u t e r bark.  Hence, sun  and wind exert some d r y i n g e f f e c t i n t h i s r e s p e c t .  The  water content of i n n e r bark of both groups of t r e e s was  average about  the same; i t was much h i g h e r than the water content o f the outer bark and f a r l e s s (2)  variable.  In l a r g e t r e e s , having t h i c k l a y e r s of bark,  insolation  brought about s u b c o r t i c a l temperatures which were h i g h enough t o be c o n s i d e r e d as supra-optimal f o r r a d i a l growth,  i f i tis  assumed t h a t the o p t i m a l cambial temperatures are between 65 t o 75°F. (3)  Temperature  of a i r i n shadow determined the  c o r t i c a l temperatures of the shaded side of i n s o l a t e d (4)  The r e l a t i o n s h i p between ambient  about 2° at the ambient  ambient  temperatures; the d i f f e r e n c e  temperature of 55° and 7° at the  temperature of 70°F.  (5) pronounced  The v e r t i c a l temperature g r a d i e n t s were most on sunny a f t e r n o o n s .  Temperatures  i n the crown  space were always h i g h e r than those i n the stem (6)  well  S u b c o r t i c a l temperatures were  always lower than the ambient was  trees.  and between sub-  c o r t i c a l temperatures at BH of f o r e s t - g r o w n t r e e s was d e f i n e d and c u r v i l i n e a r .  sub-  space.  The h e a t - c o n d u c t i n g p r o p e r t i e s of bark depended more  on i t s t h i c k n e s s than on i t s water c o n t e n t .  117  DISCUSSION (B) The importance of temperature as a f a c t o r profoundly the f u n c t i o n i n g o f l i v i n g  influencing  systems i s w e l l r e c o g n i z e d .  The range of temperature at which c e r t a i n p h y s i o l o g i c a l p r o c e s s e s may  occur at a l l i s r e l a t i v e l y narrow.  Slight  temperature  changes a f f e c t markedly the speed even of p r o c e s s e s h a v i n g more extended ranges.  Little  i s known about the e f f e c t s of temp-  e r a t u r e on the a c t i v i t y o f the cambial l a y e r i n t r e e s i n g e n e r a l . V i r t u a l l y n o t h i n g i s known about the ranges o f cambial tempe r a t u r e s as r e g a r d s i n c e p t i o n , r a t e and c e s s a t i o n o f the r a d i a l growth of earlywood or latewood i n Douglas f i r . N e v e r t h e l e s s , it  i s agreed t h a t the g e n e r a l shape of the  growth-temperature  curve does apply t o v a r i o u s k i n d s of growth of d i v e r s e organisms. I t f o l l o w s t h a t the behaviour w i t h r e s p e c t t o temperature of cambial t i s s u e c u l t i v a t e d at maintained temperatures i n v i t r o may  be i n d i c a t i v e of the r e s p e c t i v e behaviour o f the cambial  l a y e r i n the growing t r e e s , i f the r a t e of temperature change i s not s i g n i f i c a n t as compared w i t h the degree of temperature itself. Knowledge of the r e l a t i o n s h i p between growth maintained temperature may for  and  c o n s t i t u t e only an incomplete b a s i s  i n t e r p r e t a t i o n o f growth under c o n d i t i o n s o f n a t u r a l  environment, i . e . , among o t h e r t h i n g s , under temperature c o n d i t i o n s which are i n a s t a t e of continuous f l u x . of  Heating  stems was found t o c o n s t i t u t e a p u r e l y p h y s i c a l p r o c e s s  u n a f f e c t e d by the l i f e p r o c e s s e s of t h e M i v i n g stem t i s s u e s .  118  S u b c o r t i c a l temperatures under t h i n l a y e r s of bark f l u c t u a t e d almost as much as d i d the a i r temperatures. On the other hand, s u b c o r t i c a l temperature of stems i n shadow was was  a f u n c t i o n o f the a i r temperature i n shadow and  s t a b l e f o r l o n g e r p e r i o d s of t i m e .  Furthermore,  sub-  c o r t i c a l temperatures i n i n s o l a t e d b a s a l p a r t s of stems,  under  r e l a t i v e l y t h i c k l a y e r s of bark, reached l e v e l s which may  be  s a f e l y c o n s i d e r e d as supra-optimal f o r any type o f growth. i s probable t h a t  s u b c o r t i c a l temperatures caused by  It  insolation  under t h i n l a y e r s of bark a l o n g the upper p o r t i o n o f b o l e s are even h i g h e r .  Consequently, the growth p r o c e s s e s w i t h i n some  p a r t s of the cambial c y l i n d e r may t o a c e r t a i n degree, o r they may  slow down, p u r e l y  locally,  stop completely f o r some time,  depending on the degree and d u r a t i o n o f temperature reached by the cambial t i s s u e s , i r r e s p e c t i v e o f the r a t e of temperature change.  Hence the phenomenon o f d i s p a r i t y o f r a d i a l  growth  a l o n g the b o l e as regards i t s p o s i t i o n , r a t e , and date of cessation. The phenomenon o f d i s p a r i t y i n time and  position  w i t h i n the cambial c y l i n d e r of the i n c e p t i o n o f r a d i a l may  be e x p l a i n e d s i m i l a r l y : ambient  growth  temperatures and/or d i r e c t  i n s o l a t i o n o f the stem, and not o t h e r appurtenances of growth, such as carbohydrates, water and hormone, were, r e p o r t e d l y , the f a c t o r s l i m i t i n g i n the s t a r t of the v e r n a l r a d i a l Cambium may  growth.  not b e g i n t o f u n c t i o n u n i f o r m l y a l l along the b o l e  at the same time, but some p a r t s of i t may  be a c t i v e at a time  119  when o t h e r p a r t s are s t i l l dormant.  I t f o l l o w s t h a t the t o t a l  p e r i o d of the s e a s o n a l cambial a c t i v i t y anywhere w i t h i n the cambial c y l i n d e r may  vary.  Consequently, the amounts of annual  r a d i a l increment produced at d i f f e r e n t p o i n t s a l o n g the d u r i n g a c e r t a i n l e n g t h o f time may  stem  a l s o vary i f the r a t e of  growth at the p o i n t s i n q u e s t i o n d u r i n g t h i s time p e r i o d i s about the same. I t i s not known t o what degree the t o t a l l e n g t h of time d u r i n g which a p a r t i c u l a r p o r t i o n o f the cambial c y l i n d e r i s a c t i v e agrees w i t h the l e n g t h o f time o f o p t i m a l r a t e of growth.  N e v e r t h e l e s s , the annual r a d i a l increment of both  earlywood and latewood, u s u a l l y expressed i n terms of r i n g width at b r e a s t h e i g h t , was  found, by a number o f workers, t o  be p o s i t i v e l y c o r r e l a t e d w i t h the l e n g t h o f the growing It  seems reasonable t o expect t h a t t h i s d i r e c t  season.  proportionality  between width of r a d i a l increment and l e n g t h of time of growth found at one l e v e l i n a stem h o l d s a l s o f o r a l l o t h e r l e v e l s of the same stem.  I f so, then the v a r i a b l e widths of both  earlywood and latewood l a y e r s at any one l e v e l i n a stem are a f u n c t i o n o f a time p e r i o d d u r i n g which the r a d i a l growth was i n p r o g r e s s at these l e v e l s , n o t w i t h s t a n d i n g the e v e n t u a l d i f f e r ences i n r a t e o f  growth.  As a l r e a d y mentioned, of s e a s o n a l cambial a c t i v i t y was by the l e v e l s of the ambient  the l e n g t h of the t o t a l found t o be governed,  period primarily,  temperature and t h e r e f o r e ,  supposedly, by the l e v e l s o f the cambial temperature.  I f so,  120  then the shape of the i n d i v i d u a l l a y e r s , and t h e r e f o r e the  shape  of t r e e steins, i s determined, p r i m a r i l y , by the seasonal v e r t i c a l temperature g r a d i e n t s of the l a t e r a l m e r i s t e m a t i c tissues.  The a v a i l a b l e e x p e r i m e n t a l evidence suggests t h a t  cambial temperature g r a d i e n t s i n stems of t r e e s d e r i v e from v e r t i c a l temperature g r a d i e n t s of a i r around the stem and from the amount and d i s t r i b u t i o n a l o n g the stem of d i r e c t  insolation,  depending on the p o s i t i o n o f the sun above the h o r i z o n and on the a v a i l a b l e growing space.  In t h i s r e s p e c t , the thermal  p r o p e r t i e s , as w e l l as t h i c k n e s s of bark p r o t e c t i n g the cambial l a y e r exert a powerful m o d i f y i n g i n f l u e n c e .  Nothing i s known  concerning the s i g n i f i c a n c e o f f r e e and of bound stem water the f u n c t i o n i n g o f cambium.  on  T h e r e f o r e i t i s assumed t h a t  seasonal temperature g r a d i e n t s w i t h i n the cambial c y l i n d e r are r e f l e c t e d i n the d i s t r i b u t i o n o f annual r a d i a l increment a l o n g the b o l e . In t h i s study, the l a y e r s of earlywood were, without e x c e p t i o n , widest at some short d i s t a n c e below the stem apex once the p e r i o d o f open growth was  over.  They narrowed  very  g r a d u a l l y downwards t o stem base and a b r u p t l y t o stem apex. In c o n t r a s t t o t h i s , most of the latewood l a y e r s were widest at the base; i f not t h e r e then at a p o s i t i o n which was,  i n the  vast m a j o r i t y o f cases, below t h a t of maximum growth of earlywood.  Narrowing of the earlywood and latewood l a y e r s  o c c u r r e d w i t h i n the zone of t r e e t o p s , i . e . , w i t h i n a stratum r e c e i v i n g the l a r g e s t amount of s o l a r r a d i a t i o n throughout the  121  year.  Cambium a l o n g the t o p p o r t i o n o f the b o l e s i s p r o t e c t e d  by a t h i n l a y e r of bark, and f a r removed from any h y p o t h e t i c a l c o o l i n g e f f e c t s of the t r a n s p i r a t i o n stream; the mass of xylem c o n t a i n e d w i t h i n the t o p s o f stems i s small and may  be  t o d i r e c t i n s o l a t i o n at any hour d u r i n g sunny days.  subject  Consequently,  cambial temperatures a l o n g the upper p o r t i o n o f b o l e s may  be  supraoptimal f o r growth of earlywood and of latewood as w e l l , at l e a s t d u r i n g the warm weather. In most of the i n d i v i d u a l t r e e s the maximum width of earlywood was  observed, once i t s t a r t e d a p p e a r i n g above the  base, at some short d i s t a n c e below the apex.  stem  This distance  v a r i e d w i t h y e a r and t r e e , but, i n a group o f t r e e s , the maximum growth of earlywood always o c c u r r e d w i t h i n a r e l a t i v e l y and w e l l - d e f i n e d zone.  T h i s zone was  narrow  l o c a t e d immediately below  the zone of t r e e t o p s and was more o r l e s s p a r a l l e l w i t h the g e n e r a l canopy l e v e l .  There were few e x c e p t i o n s t o t h i s  Warming o f masses o f c o o l f o r e s t atmosphere  rule.  occurs  from the top o n l y d u r i n g the e a r l y s p r i n g when the ground i s still  c o o l - a p r o c e s s not u n l i k e t h a t of warming o f masses  of sea water.  In the f o r e s t , the upper and the lower boundaries  of the zone o f maximum growth of earlywood c o i n c i d e , probably, with the upper and lower l i m i t s of an a i r l a y e r which may and m a i n t a i n , because of i t s p o s i t i o n , a c e r t a i n l e v e l e a r l y i n the s p r i n g . may  Temperatures  reach  temperature  of t h i s l a y e r of a i r  be o p t i m a l f o r the s t a r t i n g and c o n t i n u a t i o n o f cambial  a c t i v i t y a l o n g the p o r t i o n s of stems p a s s i n g through t h i s a i r  122  l a y e r at a time when the lower masses of a i r are s t i l l too c o o l to e x e r t a s i m i l a r e f f e c t a l o n g the lower p o r t i o n s of  stems.  The l o n g p e r i o d of cambial a c t i v i t y a f f o r d e d by the temperatures p r e v a i l i n g d u r i n g the day w i t h i n the top l a y e r of a i r may e x p l a i n the p o s i t i o n o f maximum r i n g width of earlywood i n the Douglas f i r stems s t u d i e d . Gradual decrease i n width of earlywood l a y e r s the stem base may  be e x p l a i n e d by c o r r e s p o n d i n g l y g r a d u a l h e a t i n g  of the lower l a y e r s of a i r with the advancing season. cambial a c t i v i t y may stem. may  towards  Consequently,  s t a r t p r o g r e s s i v e l y l a t e r a l o n g the lower  Earlywood l a y e r s t a p e r i n g o f f i n t h i c k n e s s b a s i p e t a l l y  be formed d u r i n g the c o r r e s p o n d i n g l y s h o r t e r p e r i o d s of  growth i f the d i f f e r e n c e s i n time of t r a n s i t i o n from earlywood f o r m a t i o n to latewood f o r m a t i o n are not s i g n i f i c a n t i n t h i s respect. The phenomenon of earlywood-latewood not been s a t i s f a c t o r i l y c l a r i f i e d .  has  I t i s known t o occur  commonly d u r i n g the warmer p a r t of the growing Temperature  transition  c o n d i t i o n s w i t h i n the f o r e s t and,  season. presumably,  w i t h i n the cambial c y l i n d e r , p r e v a i l i n g d u r i n g the time of latewood f o r m a t i o n may earlywood f o r m a t i o n .  d i f f e r from those p r e v a i l i n g d u r i n g The d i f f e r e n t  c h a r a c t e r o f cambial  temperature g r a d i e n t s e x i s t i n g d u r i n g the summer i s , perhaps, r e f l e c t e d i n the shape of latewood l a y e r s .  These were widest,  i n most of the t r e e s s t u d i e d , along the stem base, i . e 6 ,  under  r e l a t i v e l y t h i c k l a y e r s of bark which are, i n forest-grown t r e e s ,  123  seldom exposed t o prolonged d i r e c t i n s o l a t i o n ; the mass o f xylem c o n t a i n e d w i t h i n t h i s stem r e g i o n i s l a r g e r than e l s e where i n the stem, while c o o l i n g e f f e c t s o f the t r a n s p i r a t i o n stream, i f any, a r e most pronounced  here.  Consequently,  cambial a c t i v i t y may be o p t i m a l o r n e a r l y o p t i m a l a l o n g the stem bases even d u r i n g hot summer p e r i o d s at a time when growth i s i n h i b i t e d along more e l e v a t e d , and t h e r e f o r e warmer, p o r t i o n s o f stems. The range i n the l o n g i t u d i n a l p o s i t i o n o f the maximum width of latewood which was, as compared w i t h t h a t o f earlywood, much wider, i s a t t r i b u t a b l e , c o n c e i v a b l y , t o the g e n e r a l l a c k o f s t a b i l i t y i n summer temperature regime w i t h i n f o r e s t s o f irregular spatial  organisation.  The phenomenon o f "minimum r i n g width o f earlywood" found i n t h i s and i n other s t u d i e s , may be a s c r i b e d , perhaps, t o the d e p r e s s i n g e f f e c t s on cambial a c t i v i t y o f the "secondary temperature maximum".  T h i s p e c u l i a r f e a t u r e o f t h e temperature  g r a d i e n t s , a l r e a d y mentioned,  was observed i n the open.  It i s  not known whether a "secondary temperature maximum" occurs i n the f o r e s t , but "subnormal  diameters", due t o l o c a l l y depressed  r a d i a l growth, have been r e p o r t e d f o r a number o f forest-grown s p e c i e s , i n c l u d i n g Douglas  fir.  Sudden and a l s o g r a d u a l long-time changes i n l o n g i t u d i n a l p o s i t i o n o f the maximum, as w e l l as of the minimum, r i n g width o f earlywood were observed i n t r e e s from the n a t u r a l forest.  These changes a r e , p r o b a b l y , caused by c o r r e s p o n d i n g l y  124  g r a d u a l or abrupt changes i n growing i n m i c r o c l i m a t e of i n d i v i d u a l t r e e s .  space and,  consequently,  D e n s i t y of a n a t u r a l  f o r e s t decreases slowly w i t h age, w h i l e abrupt changes are caused u s u a l l y by n a t u r a l c a l a m i t i e s . stands may  D e n s i t y of managed  a l s o be changed by s i l v i c u l t u r a l t r e a t m e n t s .  An  e x p l a n a t i o n o f the o r i g i n of the f r e q u e n t l y d r a s t i c and always immediate changes i n stem form a f t e r t h i n n i n g and p r u n i n g i s t o be sought  i n the changed m i c r o c l i m a t i c s t r u c t u r e of the  t r e a t e d stand which i s r e f l e c t e d i n the cambial  temperature  g r a d i e n t s of the i n d i v i d u a l t r e e s composing the stand. The of  shape of stems of open-grown t r e e s ,  stems, r o o t s and branches  growth may  eccentricity  and o t h e r anomalies  in radial  be e x p l a i n e d with the h e l p of s i m i l a r  concepts.  O f t e n expected o r hoped-for c o r r e l a t i o n s the  between  temperature and ... growth d i d not show up and,  i n f a c t , i n many cases i t would have been i f they had ....  I t i s not s u f f i c i e n t t o measure  j u s t the a i r temperature essential  surprising  ....  I t i s absolutely  t o e v a l u a t e the f l o w o f energy when  c o n s i d e r i n g the i n t e r a c t i o n environment.  o f organisms w i t h t h e i r  The response o f the organism may have  very l i t t l e t o do w i t h the a i r temperature. D.M. Gates (1962)  126  PART (C) CORRELATION AND  REGRESSION ANALYSIS  BETWEEN THE AMOUNT OF RADIAL GROWTH OF DOUGLAS FIR AND  SOME SELECTED WEATHER FACTORS Introduction  Systematic sampling of the two types of r a d i a l growth seems t o p r o v i d e more r e l i a b l e i n f o r m a t i o n c o n c e r n i n g the amount of  r a d i a l growth achieved by the i n d i v i d u a l t r e e than  similar  i n f o r m a t i o n based on sampling of the t o t a l r i n g width at one levelo of  The t o t a l r i n g width, or a l t e r n a t i v e l y the percentage  latewood, might not be s a t i s f a c t o r y v a r i a b l e s f o r use i n  s t a t i s t i c a l a n a l y s i s where the two  components of the t o t a l  ring  width, namely the width of earlywood and the width of latewood are  not c o r r e l a t e d .  Only a few  of r a d i a l growth s e p a r a t e l y . the  s t u d i e s c o n s i d e r the two types  I n f o r m a t i o n about the nature of  r e l a t i o n s h i p between earlywood and latewood l a y e r s or  widths w i t h i n the same annual l a y e r o r r i n g i s even  scarcer.  S i g n i f i c a n t c o r r e l a t i o n s between earlywood and latewood were obtained i n Sweden (Eklund 1957)•  In l a r c h from h i g h  a l t i t u d e s the f l u c t u a t i o n s i n r i n g width of latewood the  f l u c t u a t i o n s i n t o t a l r i n g width  widths  followed  (Jazewitseh 1 9 6 1 ) .  Ring  width of latewood d i d not agree w e l l with the t o t a l r i n g width i n Douglas f i r (Knigge 1 9 5 8 ) .  The v a r i a b i l i t y  i n earlywood  r e s p o n s i b l e f o r almost a l l v a r i a t i o n i n t o t a l r i n g width i n C o r s i c a n pine (Low 1959)  and i n Douglas f i r (Berry  I964).  was  127  The annual increment of latewood o r the p r o p o r t i o n o f latewood was  shown t o be p o s i t i v e l y c o r r e l a t e d w i t h the amount  of a v a i l a b l e s o i l moisture and/or the amount o f p r e c i p i t a t i o n (Paul and Marts, 1931; Chalk 1951; Mammen 1952; Savina 1956; Green 1 9 6 l ; Smith and W i l s i e 1 9 6 1 ; was  Hall I962).  A i r temperature  found t o i n f l u e n c e n e g a t i v e l y the f o r m a t i o n o f both latewood  and earlywood i n Douglas f i r (Chalk 1930; Green I96I; H a l l 1 9 6 2 ) . Temperature  was  p o s i t i v e l y c o r r e l a t e d w i t h the widths of both  earlywood and latewood i n Norway spruce (Eklund 1 9 5 7 ) * R e s u l t s o f these and o t h e r s i m i l a r r e p o r t s are based, as a r u l e , on sampling of r a d i a l growth at one p o s i t i o n i n the stem, u s u a l l y at BH.  Using t h i s method, o n l y 3 t o 12 per cent  of the t o t a l v a r i a b i l i t y i n annual r a d i a l growth were a t t r i b u t a b l e t o f l u c t u a t i o n s i n weather (Schumacher and Day 1939)« Since the b i o l o g i c a l u n i t of r a d i a l growth i s the l a y e r of xylem l a i d down on every p a r t of the stem  ( F a r r a r 1 9 6 1 ) , i t was  decided. (1)  t o use the average width and the average  cross-  s e c t i o n a l area, r e s p e c t i v e l y , o f the xylem l a y e r s i n a l l the analyses; (2)  t o f i n d the degree of c o r r e l a t i o n between the  two  components of the t o t a l annual l a y e r s and, i n case t h a t they are not r e l a t e d , t r e a t them s e p a r a t e l y i n a l l subsequent analyses; (3)  t o f i n d what f r a c t i o n o f the t o t a l v a r i a b i l i t y i n  r a d i a l growth can be accounted f o r i n m u l t i p l e  regression  128  a n a l y s i s by a few  s e l e c t e d weather f a c t o r s of the c u r r e n t  of the p r e v i o u s year, (4)  and  respectively;  t o f i n d the degree of simple  c o r r e l a t i o n between the  amount of r a d i a l growth and between the v a r i o u s f a c t o r s of macroclimate  used i n m u l t i p l e r e g r e s s i o n a n a l y s i s .  Current annual p r e c i p i t a t i o n and temperature are shown by most authors t o be the most important in  s t u d i e s of r a d i a l growth i n t r e e s .  independent  variables  C o r r e l a t i o n s between t o t a l  annual r a d i a l growth and p r e c i p i t a t i o n were p o s i t i v e  (Hansen  1941; M i l l e t 1944; Koch 1958"; Kern I960; G r i f f i t h i960) or, i n t r e e s from h i g h a l t i t u d e s , n e g a t i v e  (Koch  1958"; Kern  i960)  or,  i n h i g h l a t i t u d e s , n o n s i g n i f i c a n t (Eklund 1 9 5 7 ) • C o r r e l a t i o n s between temperature and r a d i a l growth of xylem were n e g a t i v e  ( D i l l e r 1935;  G r i f f i t h i 9 6 0 ; Kern  I960;  1952;  Eklund 1957;  C o i l e 1936;  Hansen  Rudakov 196l) or p o s i t i v e  Koch 1958;  1941; (Ladefoged  Mikola I 9 6 0 ; Jazewitsch  196l).  A l l these p o s i t i v e c o r r e l a t i o n s were obtained f o r t r e e s from h i g h l a t i t u d e s or from h i g h  altitudes.  The measurements on t o t a l r i n g widths w i t h i n one s e c t i o n were found t o be a u t o c o r r e l a t e d i n England and  i n Sweden (Eklund 1957)«  In the l a t t e r case t h e i r  icance increased considerably with l a t i t u d e . s e r i a l c o r r e l a t i o n s were found E i s et a l . ( 1 9 6 4 ) •  (Chalk  cross1927)  signif-  Nonsignificant  i n c o a s t a l Douglas f i r by  129  Methods and R e s u l t s (1)  The s e c u l a r t r e n d s e x h i b i t e d by the s e r i e s of the  average widths o f earlywood and latewood l a y e r s e x e m p l i f i e d by t r e e No, 14 i n F i g . 37 and 3$, analysis of covariance.  respectively,  were removed by  The s e r i a l number o f the r i n g from  p i t h w i t h i n each annual l a y e r was a b a s i s f o r t h e r e g r e s s i o n adjustment of data, thereby removing the e f f e c t of the g r a d i e n t i n r i n g width w i t h i n the l a y e r .  The r e g r e s s i o n equations  employed were o f the f o l l o w i n g form: l n y = a(lnx) f  (A) where and (B)  bx t c  y = r i n g width o f earlywood x = s e r i a l number of t h e r i n g from p i t h ,  l n y = a + b (lnx) where  y - r i n g width of latewood, x having the same meaning as above. The  summaries o f the c o v a r i a n c e a n a l y s e s are i n Tab.  V I I and V I I I . (2)  A s t r a i g h t l i n e was f i t t e d t o the i n d i v i d u a l  series  of the a d j u s t e d mean r i n g width of earlywood and. latewood, r e s p e c t i v e l y , by the method o f l e a s t (3)  squares.  D e v i a t i o n s from t h i s l i n e were m u l t i p l i e d by the  square r o o t o f the number of o b s e r v a t i o n s of r i n g widths w i t h i n the i n d i v i d u a l l a y e r . shown i n F i g . 39 t o 52.  The r e s u l t i n g r i n g i n d i c e s are  01  I  1917  I I  20  I  I  I 25  I  I  I  I  30  I I I  I  I  35  I  I I  I 40  YEAR  I I  I I  1 45  I  I I I  50  I  I I I  I  55  1  I  I  I I  60  I  I  I I  I  I  I  I  YEAR  Figure 39- Average layer width index of earlywood,tree No-8  -H2r-  F i  9  u r  e 40-  Average loyer width Index of latewood, tree No- 8  Figure 41- Average layer width index of earlywood,tree No-9-  YEAR  I  I I 1920  I  I  I  I  I 25  I  I I  I  I 30  I  I  I  I  I 35  I  I  I  I  I 40  YEAR  I  I  I  I  I 45  I  I  I  I  11 50  I  I  I  I 55  I  l l l I 60  I  I  + .20r-  Figure 43- Average layer width index of earlywood,tree No 10  YEAR  + 121-  figure  4 4 - Average layer width index of latewood,tree No-10  + 08  30  I  35  I  I  I  I  I  40  YEAR  I  i  I  I  I 45  I  I 50  55  60  Figure 4 6 '  Average layer width index of latewood, tree No- 1I-  YEAR  YEAR  + •20.  Figure 49-  Average layer width index of earlywood,tree No- 13-  + 10  S oh z  -IOr  •201/  ±-L± i i i i 1920  I 25  30  I, I I  1 i i i i I i i i i Ii  35  40  YEAR  45  M 50  | I 55  I  I  I  1 J_J  60  +-20r-  4.|2  r  + 08 h  Figure 51- Average layer width index of early wood, tree No-14  Figure 52- Average layer width Index of latewood, tree No-14  TABLE V I I SUMMARY OF COVARIANCE AND AUTOCORRELATION ANALYSES OF EARLYWOOD LAYERS  Tree No.  Years o f Growth  D.F. Error Year  R  2  px  K**  24.71  1.592  1920-1962  1030  42  • 392  .9  1918-1962  1123  44  .468  9.68  1.552  10  1918-1962  1123  44  .509  21.92  1.611  11  1918-1962  1123  44  .517  4.53  1.463  12  1917-1962  1171  45  .586  19.16  1.622  13  1918-1962  1123  44  .682  24.70  1.708  14  1916-1962  1220  46  .484  12.96  1.837  8  * A l l significant at P = 0.001 ** A l l n o n s i g n i f i c a n t  at P = 0 . 0 5  K = von Neumann's r a t i o  TABLE  VIII  SUMMARY O F COVARIANCE AND A U T O C O R R E L A T I O N A N A L Y S E S O F LATEWOOD L A Y E R S  Tree No.  Years of Growth  D.F. Error Year  r  2  p3€  3€3€  K  8  1920-1962  1030  42  .505  4.68  1.424  9  1918-1962  1124  44  .587  7.78  1.755  10  1918-1962  1124  44  .447  9.61  1.917  11  1918-1962  1124  44  .569  5.87  1.594  12  1917-1962  1172  45  .526  8.53  I.84O  13  1918-1962  1124  44  .591  10.83  1.757  14  1916-1962  1221  46  .476  7.97  1.819  *  P = 0.001  All  significant  All  n o n s i g n i f i c a n t at  K  = von  at  P = 0.05  Neumann's r a t i o  132  (4)  The  degree of a u t o c o r r e l a t i o n  growth s e r i e s was Fox Tab.  1959)* VII  The  and  (5)  calculated  radial  Neumann's r a t i o  (Ezekiel,  v a l u e s of these r a t i o s are  average c r o s s - s e c t i o n a l  of earlywood and  (6)  the  in  VIII.  The  steps 1 t o  e v a l u a t e d by von  within  areas of the  latewood were t r e a t e d  i n the  way  annual  layers  outlined  in  4» A s t r a i g h t l i n e was  f i t t e d by  least  squares t o  each  monthly s e r i e s of observations on average a i r temperature  as  recorded at the Vancouver C i t y weather s t a t i o n between 1910 1962  and  the  deviations  and  from these i n d i v i d u a l l i n e s were  calculated. (7) that  Of n e c e s s i t y ,  large  and  d e s p i t e the  precipitation variations  d i s t a n c e s i n the  area of  of r e c o r d s of two  (Canada, Dept. of T r a n s p o r t 1 9 6 2 ) ,  of the  e x i s t i n g over the  study make any  weather s t a t i o n s  recognition  combining or  impractical  or  satisfactory  fact  short correlating  impossible  regressions  were developed f o r t o t a l monthly p r e c i p i t a t i o n s e r i e s measured between 1938  and  1962  at Vancouver C i t y on the  those measured at Vancouver A i r p o r t regression  period  then pooled w i t h the  1938  1910  the  and These  Vancouver C i t y  t o 1938.  t o 1962  hand  other hand.  equations were used i n c o r r e c t i n g  p r e c i p i t a t i o n s e r i e s f o r the s e r i e s was  on the  one  The  corrected  s e r i e s recorded  at Vancouver A i r p o r t . (8)  Straight  i t a t i o n s e r i e s by l i n e s were  l i n e s were f i t t e d t o pooled monthly l e a s t squares and  calculated.  the  deviations  precip-  from these  133  (9)  The  s e r i e s was (10)  a u t o c o r r e l a t i o n w i t h i n the i n d i v i d u a l weather  then evaluated  (Table  Degrees of c o r r e l a t i o n between the average widths of  earlywood and  latewood l a y e r s was  annual l a y e r s f o r t r e e s No. are shown i n Tab. (11)  IX).  investigated within individual  8 to 14«  R e s u l t s of t h i s a n a l y s i s  X.  R e l a t i o n s h i p s between r a d i a l growth and weather of  the  c u r r e n t y e a r were s t u d i e d by means of m u l t i p l e c o r r e l a t i o n  and  regression analyses  latewood. Tab.  The  XI and (12)  summaries of the  c o r r e l a t i o n analyses,are  and  in  XII.  Information  o f the p r e v i o u s Tab.  conducted s e p a r a t e l y f o r earlywood  about the i n f l u e n c e of the weather f a c t o r s  summer on f o r m a t i o n  o f earlywood i s contained  in  XIII. (13)  The  s e r i e s developed f o r average c r o s s - s e c t i o n a l area  of the xylem l a y e r s of earlywood and  latewood, r e s p e c t i v e l y ,  were found t o be a u t o c o r r e l a t e d and t h e i r a n a l y s i s discontinued  at step No.  4«  was  TABLE IX VON NEUMANN'S RATIOS ( K ) OF THE WEATHER SERIES FROM 1910 x  MONTH  TO  JULY  1962  MARCH  APRIL  MAY  JUNE  AUGUST  1.555  1.711  1.867  I.644  1.618  1.807  1.937  1.772  1.948  I.848  2.101  2.039  Aver. Monthly A i r  Temperature Total  Monthly  Precipitation  The s i g n i f i c a n t v a l u e s of K a t P = 0.05 are l e s s than I.5856 or l a r g e r than 2.4914.  TABLE X SUMMARY OF THE SIMPLE CORRELATION ANALYSIS'. THE AVERAGE WIDTH OF EARLYWOOD LAYERS CORRELATED WITH THE AVERAGE WIDTH OF LATEWOOD LAYERS WITHIN THE SAME YEAR Tree No.  N  r  r  8  43  -  0.034 *  9  45  -  0.154  10  45  0.329*  11  45  0.l66  12  46  0.384**  .1475  13  45  0.316* '  .0999  14  47  0.157  N  S o  N e S a  .1082  N o S o  N o S  *  TABLE XI SUMMARY OF THE MULTIPLE CORRELATION ANALYSIS: MEAN WIDTH OF EARLYWOOD LAYERS CORRELATED WITH MEAN MONTHLY AIR TEMPERATURE AND WITH TOTAL MONTHLY PRECIPITATION OF THE CURRENT YEAR SIMPLE CORRELATION COEFFICIENTS TEMPERATURE NO.  MARCH  APRIL  MAY  PRECIPITATION JUNE  MARCH  APRIL  MAY  JUNE  8  43  -0.039  0.115  -0.125  -O.O84  -0.014  -O.O43  0.045  0.104  0.101  9  45  0.094  0.061  0.037  -0.041  -O.I85  0.289  0.031  0.006  0.150  10  45  -0.016  0.081  -O.O95  -0.123  -0.173  -0.033  -0.058  0.062  0.107  11  45  0.308  O.329  O.I38  0.259  -O.O83  0.011  0.132  -0.105  0.154  12  45  0.128  0.225  -0.053  0.108  -0.188  O.O65  0.166  -0.106  0.140  13  45  0.246  0.339  O.I64  0.284  O.O46  0.135  0.206  -0.066  0.197  14  45  -0.042  0.100  -0.188  0.031  -0.107  0.244  0.104  -O.O97  0.223  ON  TABLE XII SUMMARY OF THE MULTIPLE CORRELATION ANALYSIS. MEAN WIDTH OF LATEWOOD LAYERS CORRELATED WITH MEAN MONTHLY AIR TEMPERATURE AND WITH TOTAL MONTHLY PRECIPITATION OF THE CURRENT YEAR  TREE NO.  SIMPLE CORRELATION COEFFICIENTS TEMPERATURE PRECIPITATION N  R2  JUNE  JULY  AUG.  JUNE  JULY  AUG.  8  43  -0.073  -0.355  -0.094  0.09$  O.48O  -0.148  0.267  9  45  -0.259  -0.045  0.023  0.235  0.209  0.211  0.255  .10  45  0.080  -0.144  0.202  0.170  0.294  -0.087  0.214  11  45  -0.017  -0.17$  -0.017  0.300  0.458  0.273  0.3$3  12  45  0.164  0.032  -0.147  0.035  -0.028  0.173  0.106  13  45  -0.159  -0.275  -O.O47  0.450  0.337  0.228  0.409  14  45  0.060  -0.127  0.136  O.446  O.462  0.110  O.48I  -0  TABLE XIII SUMMARY OF THE MULTIPLE CORRELATION ANALYSIS: THE AVERAGE WIDTH OF EARLYWOOD LAYERS CORRELATED WITH THE MEAN MONTHLY AIR TEMPERATURES OF THE PREVIOUS SUMMER SIMPLE CORREL. COEFF. MEAN MONTHLY AIR TEMP. AUG. JULY JUNE  2  TREE NO.  N  8  43  -0.182  -0.218  0.087  0.1253  9  43  -0.146  -0.118  -O.OI4  0.0287  10  43  -0.027  -0.030  0.209  0.0750  11  43  O.I65  0.028  0.285  0.1277  12  43  0.098  0.124  0.240  O.O585  13  43  0.277  0.233  0.320  0.1358  14  43  0.015  0.047  0.087  0.0099  R  139  CONCLUSIONS (C) The c o n c l u s i o n s  based on the r e s u l t s o f the f o r e g o i n g  procedures and a n a l y s e s are as f o l l o w s : (1)  The c o r r e l a t i o n s between the average widths o f  earlywood and latewood l a y e r s were n o n s i g n i f i c a n t ,  o r when  s i g n i f i c a n t , low. (2)  Only a n o n s i g n i f i c a n t  degree of a u t o c o r r e l a t i o n  was  found w i t h i n the s e r i e s o f mean widths of both earlywood and latewood l a y e r s . (3)  Low s e r i a l c o r r e l a t i o n was d e t e c t e d only  monthly temperature (4) included  i n the  s e r i e s f o r March.  In the i n d i v i d u a l t r e e s , e i g h t v a r i a b l e s o f c l i m a t e i n the m u l t i p l e  regression  a n a l y s i s accounted f o r  from 10 t o 22 p e r cent o f the t o t a l v a r i a b i l i t y observed i n r a d i a l growth o f earlywood.  The simple c o r r e l a t i o n c o e f f i c i e n t s  between weather f a c t o r s and r a d i a l growth o f earlywood were mostly n o n s i g n i f i c a n t  and not c o n s i s t e n t  The approximate minimum t r u e  with respect  to sign.  c o r r e l a t i o n i n t h e u n i v e r s e was  zero. (5) multiple  I n the i n d i v i d u a l t r e e s , regression  s i x weather v a r i a b l e s i n the  a n a l y s i s accounted f o r from 10 t o 48 p e r cent  of t h e t o t a l v a r i a b i l i t y observed i n the r a d i a l growth o f l a t e wood.  The simple c o r r e l a t i o n c o e f f i c i e n t s between the l a t t e r  v a r i a b l e and between monthly p r e c i p i t a t i o n were c o n s i s t e n t l y p o s i t i v e only i n the case o f June p r e c i p i t a t i o n .  The e f f e c t o f  140  temperature on f o r m a t i o n o f latewood was mostly n e g a t i v e .  The  approximate minimum t r u e c o r r e l a t i o n i n the u n i v e r s e was z e r o . (6)  In the i n d i v i d u a l t r e e s , temperature o f the p r e v i o u s  summer accounted f o r from 1 t o 13 p e r cent of t h e t o t a l v a r i a b i l i t y i n growth o f earlywood.  Most o f the simple  c o r r e l a t i o n c o e f f i c i e n t s d e r i v e d i n t h i s a n a l y s i s were nonsignificant.  The approximate minimum t r u e  i n the u n i v e r s e was zero.  correlation  141  DISCUSSION (C) The o v e r a l l l e v e l o f s i g n i f i c a n c e of c o r r e l a t i o n s between the v a r i a b l e s of macroclimate and amount o f r a d i a l growth of the i n d i v i d u a l stems was  low even when the average  widths of growth l a y e r s were used i n s t e a d of simple r i n g widths. The h i g h e s t p o s i t i v e simple c o r r e l a t i o n c o e f f i c i e n t s were those obtained between growth of latewood and r a i n f a l l of the c u r r e n t summer months f o r t r e e s growing i n small d e p r e s s i o n s and c o l l e c t i n g water by l a t e r a l  seepage  ( t r e e s No. 1 1 ,  high water t a b l e d u r i n g the s p r i n g months was  ravines  13, 14)•  The  probably respons-  i b l e f o r the observed l a c k o f c o r r e l a t i o n between macroclimate and growth o f earlywood.  Phenomena such as w i n t e r and  fall  p h o t o s y n t h e s i s , as w e l l as the absence of c o r r e l a t i o n between the r a t e of c u r r e n t p h o t o s y n t h e s i s and amount o f c u r r e n t growth  (Helms I 9 6 4 ) .  radial  seem t o have a d e f i n i t e b e a r i n g on the  problem o f the type d i s c u s s e d .  In any^case, p r e c i p i t a t i o n seems  t o be, a l o n g w i t h the a i r temperature, a l i m i t i n g f a c t o r i n growth of Douglas f i r even i n the humid c o a s t a l zone of B r i t i s h Columbia.  In t h i s r e s p e c t , the r e s u l t s of the present study  based on a few t r e e s sampled of growth  i n t e n s i v e l y , agree w i t h the r e s u l t s  s t u d i e s based on a l a r g e number of t r e e s  extensively  ( E i s 1 9 6 2 , G r i f f i t h I960),  sampled  142  CONCLUDING REMARKS The  concept of d i s p a r i t y i n time, r a t e , and  along the b o l e of the r a d i a l increment  position  i s used i n t h i s study t o  e x p l a i n the shape of i n d i v i d u a l growth l a y e r s and, t h e r e f o r e , of stem form i n Douglas f i r .  I t i s suggested t h a t  microenvironment  of i n d i v i d u a l t r e e s determines the form of t h e i r b o l e s and that the m i c r o c l i m a t i c s t r u c t u r e of a f o r e s t  stand determines  the  average form of stems i n t h i s stand. T h i s and a l s o o t h e r s t u d i e s have shown t h a t the average form of forest-grown t r e e s from the n o r t h e r n  temperate  z o n e . i s e x a c t l y , or very n e a r l y , t h a t of a q u a d r a t i c p a r a b o l o i d . I t f o l l o w s then t h a t the average  shapes of annual l a y e r s i n  stems of forest-grown s p e c i e s from the n o r t h e r n temperate are, approximately, those d e s c r i b e d i n t h i s study.  zone  I t can be  s a f e l y assumed t h a t m i c r o c l i m a t i c s t r u c t u r e w i t h i n the  conif-  erous f o r e s t s i s of about the same nature throughout the w o r l d . Hence the e x p l a n a t i o n s w i t h r e s p e c t t o m o r p h o l o g i c a l phenomena observed i n stems of Douglas f i r may to t h i s  not be r e s t r i c t e d  solely  species. Since t h e r e was  little  d i r e c t f a c t u a l evidence which  would support the c o n c e p t u a l scheme of stem f o r m a t i o n e v o l v e d i n t h i s study, i n d i r e c t evidence was  sought i n l i t e r a t u r e .  F i n d i n g s of other workers have been used as a b a s i s of a l l important assumptions.  The most important of them i s t h a t  concerning the c h a r a c t e r of the- s e a s o n a l cambial  temperature  143  g r a d i e n t s i n the growing t r e e s . tested.  T h i s assumption can be readily-  Such a t e s t might prove t o be much s i m p l e r than those  necessary f o r t e s t i n g of n u t r i t i v e or hormone stem form t h e o r i e s . The present e x p l a n a t i o n s c o n c e r n i n g the shape o f annual growth l a y e r s are t h e o r e t i c a l i n that t h e i r experimental basis i s slender. and, above a l l ,  However, they are not wholly s p e c u l a t i v e  they are not t e l e o l o g i c a l .  In t h i s r e s p e c t the  scheme proposed i n t h i s study has a d e f i n i t e advantage  over the  m e c h a n i s t i c and water conductive t h e o r i e s because: Science r e j e c t s purpose as a s a t i s f a c t o r y e x p l a n a t i o n of n a t u r a l phenomena. The a c t i v i t i e s of l i v i n g organisms ... are now c o n s i d e r e d t o be r e s u l t s of the o p e r a t i o n o f the same fundamental laws which d e s c r i b e the p r o p e r t i e s o f matter and the t r a n s f o r m a t i o n s of energy which are known t o apply t o n o n l i v i n g systems. To e x p l a i n p l a n t behaviour i n terms of purpose i s t o make an assumption which cannot be t e s t e d experi m e n t a l l y and so l i e s beyond the reach of the s c i e n t i f i c method. Assumptions which cannot be v e r i f i e d do not c o n t r i b u t e t o the d e p e n d a b i l i t y o f knowledge .... Any assumptions which by t h e i r very nature cannot be t e s t e d f o r accuracy are o b s t a c l e s t o p r o g r e s s r a t h e r than c o n t r i b u t i o n s t o knowledge (Meyer et a l . i 9 6 0 ) .  144  LITERATURE CITED Abetz, P., i 9 6 0 . Ueber der Wachstumsablauf J a p a n i s c h e r Laerchen und F i c h t e n auf gleichem S t a n d o r t . A l l g . F o r t s u. Jagdzeitung 131, pp. 265-280. Adams, W.R., J r . , 1928. S t u d i e s i n t o l e r a n c e o f New England f o r e s t t r e e s V I I I . E f f e c t o f spacing i n a j a c k pine p l a n t a t i o n . Vermont A g r . >• Exp. S t a . B u i . 282, 51 PP« Adams, W.R., 1930.' S t u d i e s i n t o l e r a n c e of New England t r e e s . Vermont Agr . . Exp. S t a . 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Rep. 11, 32 p p .  1  APPENDIX  DIAGRAMS  1 T O 83  O  r-i O  O .  o <r ; o lA  r-l fM O ;—I fNJ [\l I—I  t iM H rf( H  jr; b -o  •O -t  <f  >t (\l  ^ ^ *  cn m (<"i rr> ,n m m sf i~-  •;)•>  o :  <  i  "1  id • O O H H r H H H r \ J H r \ J H i n o < — a  o LU • z u • — sx cx v- :  OOOOO—•'-•'-'^-(^Oi-trM o  o  o  o  o  o  o  o  o  o  o  o  o  o  .-v:  <  ON  o <-.  ^  o e> ii,  0 1  6 5 5 5 6 5 7 6 ^ \ 7 / 6 7 7 7 7 6 7 •* 2 2 2 i  "  2  7 7  7V>  7  5 2 2 0 0 2 3 0  y / g^v  7 a a 3\, 9\,fa b b 6 7  r r ^ T T T X  0 1 1 1 i  q (K? ?VSg  DIAG.6 RING WIDTH OF EAKLYWOOJ TREE N 0 . 2 7 M '" YEARS 193»-1^5<j  DIAG.7  DI A G - 6 KING AREA OF EAkLYWOOl) T,<EE N0.27M " YEARS 1939-195(3  DI A G • 1 0 r-LRCENTAGc  RING WIDTH OF LATEWOOu TREE N G . 2 7 M EARS 1939-1956 V  T K E E YEARS  Ur  uATEWOOO  N0.27M  1939-1958  _ 9 9N£ 5Ng 9 9 9 9 9 9  DIAG.9 RING AREA OF LATEWOOD IKtE N0.2/M YEARS 1 9 3 9 - 1 9 5 6  9 9  2 2  DI AG.  11  RING  WIDTH  TREE  N0.32M  YEARS  OF  EAKLYWV/JL)  1939-1958  DI A G . 1 4 RING AREA OF LATEWOOD 1 v E N0.32M YEA;>S 1939-1958 c  DI AG. 12 •-. IiMG WIDTH OF LATEWOOD T'<EE N0.32M Y'ARS 1939-1958  orAG. i s " " PERCENTAGE OF LATEWOOD [SEE -N0.32M Y E A h"; S 1939-1958  DI AG.13  "  RING  AREA  T:%FF  N0.32M  YEARS  OF  EAKLYWOOD  1939-1958  U 0 0 O O P 0 0 0 0 4 4 0 0 4  0 2 ONg 0 ^  7 b \ g \ 6 6 6 4 3 4 OSJNA 2 9N6 7 4 3 3 5 4 1 1 0 2 3 9 9 l \ 7 3 3 3 3 2 0 1 1 2 4 2 2 2 3 1 0 0 0 1N9 8 \ 4 4 2 3 4 2 0  5^  DIAG.16 RING WIDTH  2 3 0 3 0  0. 6 7 5 6  6  2 0 0 3 1 1 2 3 1 1  UrSG"."T7 OF  EARLYWOOD  TREE N 0 . 3 3 M YEARS 1939-1958  0 0 0 0 0 0 0 0 0 0 0 6 4 3 0 0 4 4 v9Nft 5 7 0 0 4 4 0 4 3 3 0\5Sft 3 0 0 6 4 0 3 4 4 0 2 5 5 0 0 6 ^ ^ 0 5 5 6  Q-Sg 9 0N9N5.  DIAG.19 R I N G A R E A O F LATEWOOD TREE_N0.33M _ YEARS 1939-1958  "D TAG", I S " " • " R I N G AREA OF EARLYWOOD TREE N 0 . 3 3 M YEARS 1 9 3 9 - 1 9 5 8 " ""  R I N G W I D T H OF L A T E W O O D TREE N 0 . 3 3 M y E A R S " ! 9 3 9 - 1 9 5'8~  4 3 5 6 3 3 4 4 6 ^ 6  3 4 5 5 5 5 5 5 6 2 4 3 5 3 5 4 5 4 4 3 5 5 4 4 5 4 5 5 4  9N4N9 5Ng 9  9 8  4 4  4 6 5 6 6 5 7 6  9" 8 9  9  DIAG.20 P E R C E N T A G E OF L A T E W O O D TREE N0.33M YEARS 1939-1958  6  6  6  0 6 3 6  o o  o(&)  1 1 1 2  DIA6.21 RING WIDTH Of EARLYWOOD IK-i NO.l YEARS 1 9 3 9 - 1 9 6 2  DlAG.24 RING AREA OF LATEWOOD TREE N O . l YEARS 1 9 3 9 - 1 9 6 2  1  d\3S6 7 3 5" 0 0 0 7 6 6  0 !?vX'?SiNv7 t  DIAG.22 RING WIDTH OF LATEWOOD. TREE" N O . l" YEARS 1939-1962  DlAG.25 PERCENTAGE OF LATEWOOD  T R e r w o . : " ~ ~ VEARS  1939-1962  UI A G . 2 3 RiNG AREA OF EARLYWOOD I REE NO.1 TEARS 1 9 3 9 - 1 * 6 2  ^  0 0 0 0 0 0 0 0 0  0 0 0 0 0  6  6  7X9 6  16  6  0 0 0 0 2 2 0 0  0 0 5 4 4 1 2  0 2 4 4 f 5 5 2 4 3 2 5 3 4 5 3^N6  0 7 7 4 7 7~o\3\6 6 6 5 6 6 6 6 6 0  0 3 /S$S^  5  6X9  9X3 !  2 5 2 6 4 7 6 4 6 7 7 b 6  7 4  6  7  5  4  5  5  6  7  5  OVg  6  9  $  9 ^  4  4  ^jNg  7  0X9X6  7  5  1  3  6Xg\7  3 2 3 4 4 4 6 5 6 5 ^  1  6  01 A G . 2 6 _ ^ RING WIDTH OF EARLYWOOD TREE N O . 2 YEARS 1 9 4 3 - 1 9 6 2  0 0 0 0_0_ 0 0 0 0 0 0  0_ 0 0 0 0 1 0 1 0 3 b o o ~T~1 2 2 0 0 0 0 0 0 0 0 1 0 0 1 0_ 0 ~0 0 1 0 0 1 0 0 0  3 0 1 1 1 6 4 1 1 1 1 1 1 2 1 2 3 4 1 2 2 2 4 4 4 5 2__2 4 3 4 3 5 6 1 " l 2~ 3 4 3 "4 3 6 4 1 2 1 2 2 5 4 4 4 5 5 2 2 2 1 3 2 4 5 4 4 6 7  0 2 0 4X9 8 \ 4 \ 9 0X9 9X7X9  6  4  6  6  6  4  0  0  2 2 2 2 2 4 3 3 3 3  1 2  2 3 3 3 3 4 3 4 4 4 4 4 4 4 4 4 3 4 5 5 4 5 4 4 5 4 4 6 5 5 4 3 4 5 5 3 4  3  6 5 6 6 5 6 . 6 7 6'\fr\,  J^SVjJ  0 5 7X? 9 9 8 0X9 9 9 * ^  6  PI A G . 2 8 RING AREA OF EARLYWOOD TREE NO.2 YEARS 1 9 4 3 - 1 9 6 2  D1AG.27 RING WIDTH Or LATEWOOD TREE NO.2 YEARS 1 9 4 3 - 1 9 6 2  0 0 0 0 0 0  oooo 0 0 0 0 0 0  0 7 5 0 0 5  7 6 6 2 3 5  4 4_ 5 b 2 4 3 3 6 4 5 4 3^^^. 4 3 5 3 5 6 6  C ^ N A 4 5 6 6^jb*7 6 6  0 0 5 6 6 5 7 7 7 6 6 0 0 4 4 4 4 7 7 6X8X6 O^^b 4 5 4 6 5X.8 8 \ 6 0 0 6 7 6 6 4^^4 5 7  8X2  DIAG.29 RING AREA OF LATEWOOD TREE NO.2 YEARS 1 9 4 3 - 1 9 6 2  0  0 0 1 11 0 1 1 1 1 2 1 2 1 2 1 2 1 2 1 2 1 2  0 1 1 rSg~9N6 _3 3 6  0 4 3 2 6 7 5 2 3 3 7 . £5N6 5 7 ^ ^ 6 5 (gj) 6  0 0 0 0 0 0 0 0 0 0 1 0 0  5  6  5  7  0 2 1 2 2 6 4 5 6 5 7 6 6 6 6 7 0 3 5 3 3 4 7 6 6 6 6 7 6 6 7_ 0 1 4 7 7 3 4 6 5 7 6 5 7 6 0 1 ZX9X7 7 2 4 4 6  6 7 7 6 5 6  6x7  0 0 0 0 0 0 0 0 0 0 0 0 0 0  DIAG.30 PERCENTAGE OF LATEWOOD TREE NO.2 YEARS 1 9 4 3 - 1 9 6 2  7 7 T~ 6 6 5 7 7 7 7  6 5 7 6 SNK,5 7 6 3 6 4 5 6 4 6 5 4 4" 3 4 5 4 4 4 5 3 3 ~3 5 4 3 2 3 2 2 2 1 2 i 1 42 1  4  _ 4(j(p 6 54 4 5 4 4 3 3 5 2 3 5 2 3 5 2 2 2 3 3 5 3 3 3 2 1 22 2 3 3 2 1 1 1 12 23 3 2 1 2 0 1 11 11 3 0 0 1 0 0 0 2 0 1 1 2 0 0 1 0 0 1 0 0 0 0  3 2 4 3 3 2~7 0 2 1 1  01 A G . 3 1 RING WIDTH OF EARLYWOOD ~TRE~E NTDTT YEARS 1 9 3 9 - 1 9 6 2  9 .  DIAG.32 RING WIDTH OF LATEWOOD "TREE N O . 3 YEARS 1939-1962  0 0 0 _0_0_0 0 0 0 0 0 0 0 1 0 0 0 1 1 O T TT T T T T 0 0 1 1 1 1 1 2 0 0 2 1 2 1 2 2 2 0" 1 2 3 2 3 3 T T 5 0 1 1 2 3 2 2 3 3 3 4 0 1 2 4 4 5 3^V4 4 3 3 0 l ~2~2"4~3" 7 " 5 T T 0 0 2 3 3 4 4 7 5 2 6 5 \ 7 0 0 0 1 4 4 6 6 7 4 4 6 4 7 4 0 1 2 3 4 6 5 6 5~7 5 \ 6 \ 7 6 6 4 0 1 1 5 5 2 5X^^ 7 7 6 5 5 0 0 2 2 3 5 5 6 6 7 7 6 5 4 6 5 5 4 0 1 1 4 4 5 5 ii frsg"" E T J T S 7 0 2 3 3 3 4 6 5 5 ^ S 6 7 6 6 6 5VJ 9 \ 7 6 0 1 4 3 5 5 4 7 5 6 7 6 7 7^gS6\9\7 6 6 5 8 9 9 9 8 8 \ 6 5 9"^7^TN6 % X V " 7 T ~ 6 ~ 4  0 0 0 0 0 0 0 0 13 0 0 0 7 4 0 2 3 3 3 3 0 0 4 3 4 3 4 0 3 3 4 3 3 2 0 2 6 3 3 2 3 0 3 3 5 3 4 4 4 4 4 0 4 2 4 4 3 2 3 3 3 5 0 6 5 5 4 5 4 7 5 4 5 0 5 5 3 4 3 6 4 3 4 3 5J 0 3 4 4 4 4 4 6 6 2 6 5 0 3 1 2 3 4 4 4 5 4 3 6 4 7 0 5 6 4 5 4 5 4 5 6 6 6 7 7 6\£v 5 7 6 ?S2\ 0 4 4 6 5 2 5 6 3 4 6 4 0 4 5 4 4 5 4 5 5 5 6 6 6 4 7 5 6 7_ Q^£l\5 6 6 5 4 4 4 6 6 6 7 7 6 6 6_ 5 4 6 6 5 5 5 6 6 7 6^7 5 0 4 7 5 7 6 6^N6 5 7 7 6^  DIAG.34 RING AREA OF LATEWOOD TREE N O . 3 YEARS 1 9 3 9 - 1 9 6 2  D1AG.35 PERCENTAGE OF LATEWOOD TKEE. N O . 3 YEARS 1 9 3 9 - 1 9 6 2  -  t^N5  T~rS£  DIAG.33 RING AREA OF EARLYWOOD TREE NO.3 YEARS 1939-1962  0 0 0 0 0 0 0 0 0  0 0 0 0 0 0 0 0 0 0 0 4 4 0 4 0 0 0 3 3 2 5 0 0 2 2 2 3 4 3 0 2 3 2 3 5 4 4 3  cfo  oooo  0 2 3 T~5~T~T~5-5~b 0 4 5 4 4 5 1 3 3 3 4 0_1 6 4 5 5 5 2 2 3 5 S 3 3 4 5 5 3 5 5^Sft 4  3 4 4" 5 5(g)) 5 6  0 0 0 "0 0 0  1 0 1 0 12 12 2 2 0 2 2 4 3 0 2 3 3 4 0 1 2 3 3 1 1 3 3 5 1 2 4 5 6 1 2 4 6 6 1 2 3 5 0 2 2 4 5 1 1 4 5 6 2 3_3_6_' 5 2 "5 5 2~7" 3 4 7 7 6 1 5 £\^SJ  3 3 3 5 4 4 6 7 5 5 6 7^Nj 7  0 2 4 6 7 7 7 7 6 0 2 6 4\9 9 6 ~ 0 5 6 7^ 9  6^  DIA6.36 RING WIDTH OF EARLYWOOD TREE N O . 4 YEARS" 1 9 4 0 - 1 9 6 2  0 0 O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  0 O P P 0 0" 0 0 1 1 0 0 0 0 1 0 0 1 1 1 2 0 0 0 1 1 1 1 0 0 0 1 1 1 1 1 0 1 1 F T 1 1 2 2 "" 1 1 1 1 2 1 1 1 2 2 0 1 1 2 2 2 1 1 2 3 2 1 1 2 2 3 2 2 1 2 2 2 2 1 1 1 2 2 3 3 3 2 3 3 3 1 2 2 2 3 3 4 6 4 3 4 4 1 1 2 2 3 ~4~~3~ 5 4 4 1 3 3 4 3 4 5 4 6 6 1 2 4 3 4 4 6 6 4 7 2 3 2 4 5 6 4 "5"  o  3 5\g\t  D i AG.3 7 RING WIDTH OF LATEWOOD TREE NO.4 YEARS" : 9 4 0 - l ? 6 ? "  0 2 ^ \ t g^Nfr 7 7 7 6 e v  -  ^  7 4 \4  DI A G . 3 9 RING AREA OF LATEWOOD TREE N O . 4 ' YEARS "T9"W-r96"2  DI A G . 4 0 PERCENTAGE OF LATEWOOD TREE NO.4 YEARS 1940-19"62  15 I A G . 36 RING AREA OF EARLYWOOD TREE NO.4 YEARS 1940-19752  0 0 0 0 0 0  ?N8 9X5 6 2 5 7 6 7 5' 9 9 9NT 4  "2 5 5 3 4 4 6 4 3 5 4 1 3 3  6 5 2 4 3 3  0 0 5 3 1  0 4 5 5 4 5 3 7 7 7  5 5 4 5 4 3 2 .2 5.1  4 2 4 0 5  3 5 3 2 3 1 2 4 4 4 2 2 1 4 4 0~"4^Nff 5 T T T T 3 0 "1 2 3 1 2 1  "DTAG741 RING WIDTH OF EARLYWOOD TREE NO.5 YEATR3~l?4T>-="r3T2^ '  7 5 5 3 7 7 7 3 5 6 7 5 6  DI A G . 4 2 RING WIDTH OF LATEWOOD TREE NO.5 YEARS 1^40-1962 :  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  0 0 0 0 0 1 0 1 1 1 0 1 1 2 3 0 13 2 3 0 1 2 4 2 0 12 15 0 1" 2~7 2 0 1 2 2 6 1 2 2 3 3 1T l 1 2 2 3 3 1 3 4 5 4  4 2 4 3 2 3 T~52 6 3 5 5  5 % 3 5 i _  4 4 4 3 5 5 6 7 45 5 4 3 5 5 5  ^ 4 2 7 5 6 5 6 4 5 7 1 7 7 6 7 6 7 3 5 5 7 5 5 6 4 6 5^5\? \ 7 5^3\6 7 6 5 ^ X 5 7 7 5  DlAG.45 PERCENTAGE OF LATEWOOD TREE NO.5 YEARS 1 9 4 0 - 1 9 6 2  DI A G . 4 4 RING AREA OF LATEWOOD TREE NO.5 YEARS 1940-T97o2  2 2 "5" 4 2 6 3 2 3" 2 46 3 6 4 3  2 '6 4 5 7~4 3 4  "DIAG.43 RING AREA OF EARLYWOOD TREE NO.5 T EAR'S I940-iy6"2 -  2 4 4 2 3 1  3 1 2 4 2~r 3 4 2 1 3 3 3 1 4 2 2 4 2 1 5 0 1 0 3 4 1 0 4 4 0 1 1 1 3 1 0 0 2 2 1 2 1 z~r~r 1 0 3 2 1 0 0 2 3  DIAG.46 RING WIDTH OF EARLYWOOD TREE N O . 6 YEARS m"0-l'9B2 "  01 A G . 4 9 RING AREA Or LATEWOOD TREE N O . 6 YEARS" 1 9 4 0 - 1 9 6 2  DIAG.47 RING W l i T n Or LATEWOOu TREE NO.6 YEARS 1940-1962  DI A G . 5 0 PERCENTAGE OF LATEWOOD TREE NO.6 YEARS" T9"40"-l9'&"2  "DIAG.48 RiNG AREA OF EARLYWOOD TREE NO.6 YEARS 1 9 4 0 - 1 9 6 2  0N9 >v5  DIAG.51 RING WIDTH OF EARLYWOOD TREE NO.7 YEAR"5~T^T0-1962  5 6 7 7  w.  4- 7NJX5  3 3 6 5 7 7 6 5 5^RSwf 6^BVf "2 4 5 5 6 5 5 6 3 5 6\£  DlAG.52 " RING WIDTH OF LATEWOOD TREE NO.7 YEARS19'30-1*6 2 ""  >£>|  - .  r ~ - v O (NI C O r  vO*xn in  -3" v O  co  CM  c o : co  A  \D m ' c o  co  co-d- o  i <r m i c o  ro  | < M < J - CO CO  in  m  m  ro  CO  J -  CO  CO  CM  CM CO  CO  CM  CM  i—I  CM  CNJ  <J<J-  (\J  (M  >—I ! • — I C M  i—l  H J H  o  O  O  o  o  o  o i o  o  7  CM  vO  CO  CM  r~  <J-  CO  CM  r-  m  (M  vO  m  n  vO  <r r -  r-  r- r~ r-  <J"  in  r-  <f  in  <r in  :<f  <->  <r m <r CO  CO  < T ! < f C CO O C OC O CO  CM CM  CO m  <r  <»-  O  i—I r - H  O  |r—( C M  CCMM C M  CO  CM CM  CM  co  CM  CO  o  O O  r—I  Ii—( i—i  i r— -l l i — 1 r - l  •—I r H  CM  CM  CM  CM  0|0 O d o i  J  co -d-  CM • O i—I r H |r—I O  <*•  >£> <r  CM  CM ICO H  m  vO  I i—I j r H  vO  m m  <t i n [CO  in r- in  I o j o  O O I O O OO o o  o  j o  o  Oo  o  o  o  o o o o  i-H  O O  o  O  O Oo O j O O O O O O  0  0  0  ooo o_o o o 0" do 0 0  0 0 0 0 0 1 0 0 0 0 1 1 1 0 0 0 1 1 O i l 0 0 0 0 1 0 1 1 1 0 0 0 0 0 1 1 1 2 2 0" 0' 0 0 1 2 1 T 1 " 1 2 0 0 0 0 1 1 1 1 1 1 3 2 0 0 1 1 1 1 1 2 2 2 2 2^_3 0~0 0 1 1 1 2 3 4 7 5 4 3 3 0 0 0 1 1 2 2 2 2 1 2 2 2 2 3 0 0 1 1 2_ 2 2 2 3 3_ 5 5 2 2 3 3 0 6 0 1 "1 " " l 2 3 " 4 " 4 4" 6 2 3 3 4 4 0 0 0 1 1 2 2 3 3 5 4 3 7 7X5x7 5 6 0 0 0 1 1 2 2 4 4 3 3 3 4_7 7 4 3 4 3 0 0 1 1 1 1 2 3 3 3 2 4 "2 6\&X3 3 T T C T 0 1 1 2 1 2 3 2 3 4 4 3 4 3 6 7X8X3 4 5 4 0 1 2 2 5 2 2 3 4 4 4 5 3 5 5 5 6 7 5 3 3 4 0 0 2 3 1 4 2 4 3 4 "5 4 7 4 6 5 5X8 9 9X6 5 6" 0 0 1 2 4 2 4 2XlN4 4 6 5 6 5 5 5 5 5 6 5 6 4 5 0 0 0 2 2 4 2 4 2 6 4 4 6 5 7 6 6 6 6 6 6 4 6 6 5 0 1 1 2 3 4 5 3 6 3 4 4 4 5 7 6 4 5 5 6- 7 7 5 4 4 5 0 1 1 2 3 4 5 7 2 5 3 3 3 4 6 6 7 6 7\8 9 X 7 ffiNj 6 7 0 0 1 2 1 3 5 7 2 4 3 4 7 6 7 6 5 ^ 8 X 4 4XflX6 5 0 2 1 2 4 4 4 5 5 X 8 X 4 7 X 9 9 9 9 X ? V ^ 6 X 9 9 " 8 ^ " ~ 6 '6VNj~"5 0 0 4 2 4 4 6 3\ji 9 ^ V t 7 5 X 9 X 7 6 ^ X f l X ^ V X ^ 7 \ f f X 7 5 5 7 9  0 4 3 4 2 3 4 5 5 5 5 X \ 3 5 3 6 4 6 6 5 6 4 6 6 i X B 9 8 9XjNs>X 0 0  ^V8 (Tv9  9 * 9 S . 6 X c N 5 x 8 9 9 X 7 X 9 X 4 ^ X 9 X ^ 9 X 6 7 6 5^X9\6 5 7 X 9 X 6 4 6 6 ' 5 X g 9X^X8 9 9 9 9 X 7 7 X 9 X 3 X 5 X 3 5 4 5 7 6 5 5 6 5 5 X 9 X 6 X 8 8 9"  DIAG.54 RING A R E A O F L A T E W O O D TREE N O » 7 YEARS 193 0 - 1 9 T 2  <tfaj r o ir-T--.. '-n r o v£><T ico ro  m  j^o  iO. ro  co ;ro r\j  co -cyrjoyin ro  i^.(Nip3/flo  cofayro  ao o."2  L O <J-  rO|<j-oo <|-/^j'\J tTi :<|- r— r o p  corfrajcsj  rsj roI-o| <)-.<)• ;vO  ro  •o  CNI  CO  r\j  <f - <t  /oJ <)• O^O  io  ro  if\  r  :r\j  <f  ro  ro  <f  r o (Ni r o  <f  ir\  <j- : r o <f  <f  (\iJO-l  r o jro m  r o j r o in  <f  Lrv<r r o IvO  ro  UJ  <j"  <f>^)  t  <r»^> ;co  ro  <f  m  <t  r o :ro (Nj <(• i <)-<)-  f\l (NJ  O  1  <  (NI  c*  LL.  |-H  I  o  rsj  ro  <  "CNJ  ro  iro r o  CNI  I-I r o i-d- •£> r o |<f r o r o !ro --i i n ;r\i r\j CNJ I I i ! •.O O O JO O O : 0 r\j <}• <ro r o \ 0 iCN) (Nj <—i j r o (NI r o , I i ' o o o o o o o io o o 'o o o !o o o ' o o o O  I—  ;  LO  UJ LU  CC  < cc  UJ  <  —.  CC  LU  a  LU  a  r- >-  i_ f—i  O  x o  Q  1  s» —J *  »—<  tr-  •  LD <T. LU <3 «—• 1—1 •Y ' J j >' <— >  C J O O O — ' O O O O O O  O ic >•  -1 a: <t UJ  rsj  u.  1  UJ CO  t  <  ^. —i • 0O .—1 7^  >L! CC < z UJ <t t—< t—< UJ Q y r- >  o  O  - ^ —* rsj ^ —< - -—1  1  i—i r s i  o  o  o a  o  o  o  o  .—1  o  o  o o  o o  o o  o  o  o  o  o  o  o  o  o  o  o  J—^  o O  •—i  o  -™  O  O  O —i  o  o  o  O  O  O  O  O  —<  o  o  o  o  o  a  o  o  o  f\i  r\j  i\j  ."sj  (^i  i-Ti  d O D .s :  JJ  t— <l _l  M  O <T —j 1  LL  a  LU IO  •  <  cc a  •o  <  LO  o UJ TC UJ  *—• a  <  LU  >  -  -<  o  -  o  c t> o  o o  o o  —« F—1  o  —«  o  —«  o  o o o  o  o o o o o  o  o  o  o  o o  o o o  o  o o o  o o •o o  o o  —<  •J-  ro rsj  -  •s-  ro  ro  r\l  rsj ( M r o  oj  ro  OI  r\l  ro  OJ  ro  ro  r\J r\j  r l  OJ  rsj  ^  (NJ  * rsj  ro  -< o o o  OJ  rr\  • — I rsj r -  r\l  fM  oj  <—( r\J r \ l r o  ->,—tpH »—<  o o o  >r  ro  r\l  1—1  o  o o  -o ro  -o  ro  ro  OJ  OI  OJ  >r  -> <N  ^  ro  <• ro  •si  rsj r o  i—i —4  OJ  OJ  rO  O  —< - <  O J rs]  •—t H  O  o o  ro  OJ  o o  o  o o o o o o  o o  o O  o  -r  ro  (\J  o o o o  .-NJ  OJ  rO  -«  o rH  o  o o  ro  - - -- -o  -o  oj  -r -r  (M  r—1 o j  —4  ro  *r\  O)  - oj  r\j  O J —<  <M  Oi  r\j  ro  m  sT  <r  .—t -or  OJ  o  o o  o  o o  O  i  o o  o O o  < j—i o  o  o  o  o  o jo  O  O  O  O  —i O O  O  rsi  —•  O  j—i  'jo  jrH j o  O  O  r\l O  o  o  O  o  CT-  O  o  0  1  1 l ' 3  4  6 73  C  0  5 > ^ 5  C  ~2 3  3  DIAG.60 RING WIDTH OF EARLYWCUD TREE NO.9  0 0 0 C 0 0 0 c c 0 0  0 0 0 0 0 0 0 0 0 0 0 0 0 o 0 0  0 0 0 0 3 0 0 5 0 6 0 0 o 0 0  0 00 0 0 4 6 0 3 3 4 3 5 4 66 3 4 5 34 6 64 6 55 o\ 0 0 0 0  DIflG.61 RING WIDTH CF LA I tKliliU TREE N 0 . 9 _ YEAR S 1915-1362  0 0 0 00 1 0 0 11 0 0 11 0 00 1 1 0 00 0 1 1 0 00 1 1 1 0 00 1 1 1 0 00 0 2 2 C I1 1 0 0 0 1 1 11 1 12 2 3 2 3 0011122222323 00111122222334 001111222222334 0001111222233434 00112122334433545  DI AG.62  RING AREA UF EARLYWOGO TREE NO.9 YEARS 1915-1962  3  o  a  .2  rsi •3. _l LL  H  a  in  «  LU •CO  ac o  '-i O  •—'  s•o<. o o  z.  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LO LO '.O  -J-  JD «O -O  iO ro CSJ IM - Ni - - •*Sl .-0 - - - - - rh - i-rsi |--• - -rv -h - rsj  rsj r H  O o  o O a  <SJ rsj  LO  ,  ^  LO LO r-/  -T  NT -1-  LO  -r •M -r r o ro rsj • sT o r s j rv l-o r~4 OJ LO ;ro r o 1  --  •—I r-l  r-l j r o  o  1 |rsj ;0  o o  o  r-4  —^ —1 —4  O  •—I  o o  o  <r >r <r  >T  rsj r o rsj  ro  rsj r v  O  o  I!  3  3 a .s  ><  >o  CJ  :y —^  LL  a  —4 —H  UJ •vD  *  a  c-4  <  •O  L5  < ~Z U J t  Q  1  O  s  or  c£  <  >-  ^ m^ rr,  <  f  \  IM  M  CSI CM r —i  —4  <  M r  f  if,  „4  \  j <  —i - 4 M  C M s  rr, rr,  J  rr, rr, (  v  j (  r\i C  N  I M i (— M 4I M  —4  »^ —'  —I - 4  f \ | c-4 .—( —4 —4 I M  ( N i  c-4 —I  o  O O O  O O O O  c-4  -4  O  O  —I - i  o o o o  O O O  O o o o o o  o o  o o o o  o  o o  o o  o o o o  o  o  o o o o  M M  rr, j  r  s  j  o o o  o  o  < rt UJ •  r- or o t  < Z  O O UJ  < ziu or  CM CNI CM  ( M CM CM fSJ  f\J  rtrt H  H  H  CNJ CNJ  CM CM CM  r\j r\j r\j  • 4rtCNJ rr\  CM CM  rt -4 -4rt-4 C^i  rsi  ^4 ^ ^4  O *-4 O  4rt— 4Qrt f-t ^ ^ ^* ^ r-4 i-^ O cH OO rt — o o o o o — o o O rt O O rt O C*) ~4 <-* ~4 —* o o o O O O O O O o o o o o o O O O rt o o o o o o o o o o o o o o o o o oo o o o o o o o o o o o o o o o o o o o o o oo o o o o o  0 I AG . 5 8  RING WIDTH OF EARLYWOOD TREE N O . 1 1 YEARS 191-3-1962"  6  5 4 b 4 b 'J 4 6 6 6 4 6 6 5 4 6 4 4 <i 4 4 4 3 3 4 2 3 3 4 2 i. 3 4 3 4 3 4 2 3 3 I 4 4 2 2 3 5  3  6 \ b 4 "3 b b A 6  4 5 b 4 2 3 4 3 3 3  1  2  3  5 6 3 6 4 5  3 6 4 4 4 3 5 b 3 f) 4 b b 5 4 5 5 4 4 6 4 4 3 4 4 4 4 4 3 4 2 4 3 3 2 4 1 2 4 4 3 3 3 4  2 5  3  <t 4  4 6 3 3 7. b u 4 5 5 4 5 3 6 3 3 3 4 '+ 3 1 3 2  3 6 5 3  f) 6 3 5 6 3 4 4 j 5 4 4 4 4 4 3 4 4 2 4 3 4 2 b 4 4 i 4 ? b •)  4 b b ^'  4 4 b 4 3  i  H b  2 i>  0  o o o o o o o  <o o o o  1 11 11 2 0 G 0 0 1 1 CC 1 I 2 CC 1 1 12 C 0 1 12 2 12 2 2 12 2 2 0 1 1 1 2 11 12 2 2 12 2 2 2 2 2 3 C1 1 2 2 2 G 0 1 1 12 T r T 2 CU C 0 12 2 2 C 0 2 2 2 3 0 0 12 12 0 0 2 3 3 3 C 0 2 3 3 3 0 0 2 3 34 3 3 3 1I 3 3 4 1 3 3 •f A 5 2 4 5 2 3 4 5 2 2 3 4 4 2 5 4 5 3 3 4 4 4 2 5 6 6 4 4 6 6 6 3 5 6 6 2 5 "5 6 2 2 4 4 5 4 r> b 5 6 5 5 5 5 6\ 5 6 4 5 6 4 4 5" 6 46 3  6  01 A G . 7 0 RING TREE YEARS  Ai<bA NO.11  OF  rARLYVUJGD  1915-1-J62'  -J .;j  »— <i _j  rt  u.  1 a rt <r rtrt UJ » CT a rt  •  UJ a ;  <J3  <;  or  »—  <  LU >•  r M r t r t r v j ^ - f l u o i j - J - r o , " " ^ -  o O  O  ^  O r t O O O O r t O r t o o  rtOrt^rtfl|ror\jf\jrnrn  o  O O r t r t r t f \ i ! f \ J r t r S j r \ ) ^ J N  O  o O  o O  o O  o O  o O  o O  O  o O  o C  o J  o O  o o u o c j . v j o o ' a o c j o o o  J ,  i  '  oaoortO|Ortrt(Nj_irvj-_. u  j  a  o  a  o  o  o  b  o  u  o  o  /  .  o o o  a  x f\J  r^  r•  O M  -I  •  •  i 7.  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