Ching, K. K.

McKimmy, Milford D.

Oregon State University. Forest Research Laboratory

Undetermined

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s_ 9aeee4of Branch and Bole Woodin Young Douglas FirReport G-8February 1968fl L11t t LA iSKim K. Ching1Forest Research LaboratorySchool of ForestryOREGON STATE UNIVERSITYCorvallisCORRELATING SPECIFIC GRAVITIES OF BRANCHAND BOLE WOOD IN YOUNG DOUGLAS FIRMilford D. McKimmyKim K. ChingWe came to the following conclusions for the samplesanalyzed:A very high degree of correlation does seem to existbetween the specific gravities of branch wood and stemwood near the top of young Douglas fir stems.A sampling technique that selects branch and bole woodfrom more than one location in the stem does not seemto be necessary in the young trees sampled.A random sample of two branches from two differentquadrants appears sufficient to determine average spe-cific gravity of a branch whorl.Ability to predict quality of wood without damaging young trees,from five to twenty years old, would be helpful to forest research andfield personnel. In our study, we attempted to find a relation betweenjuvenile stem wood and branch wood in young Douglas fir that wouldmake possible an evaluation of wood quality without either destroyingthe young stem or requiring a large, old stem. If such an evaluationwere possible, forest managers could more easily decide which trees toremove by thinning and which to save. They could also decide whichtimber stands might be managed more profitably on a pulpwood rotation,and which should be managed on a awtimber rotation. Forest geneti-cists could determine the results of tree-breeding programs when thetrees are still young.This report describes the results of a study to establish a cor-relation between the specific gravity of juvenile stem wood and that ofbranch wood in young Douglas fir saplings, similar to the work reportedfor southern pine by Zobel and Rhodes (9)* We selected specific grav-ity as the characteristic to evaluate because it has been studied widelyby other workers (5,6,7), because it seems to be related to other prop-erties that may influence the quality of wood (1, 3,8), and because it wasconvenient to study with the small specimens available.*Nurnbers in parentheses refer to literature cited.1PROCEDUREWe selected nine Douglas fir 8-14 years old from the school for-est at Oregon State University. The growth rate of these trees variedfrom 4 to 8 growth rings per inch at the basal cut. They were growingon high site III land along a forest road in a Douglas fir stand from 110tol25years old. Atthelaboratory, the basal whorland the branch whorlthird from the top were separated from each tree for analyses of branchwood. Samples of branch wood were taken midway between the bole andthe first secondary branch. Samples of bole wood were taken midwaybetween the whorls that were third and fourth from the top, and betweenthe basal whorl and the ground. Each cross section of the tree stem wasdivided into four quadrants, as diagrammed in Figure 1.Specific gravities of branch and stem wood were determined bythe maximum-moisture-content method described by Smith (4). Un-extracted sample weights were used in this analysis because prelirni -nary studies had demonstrated no significant differences in specificgravity attributable to extractives. Values for specific gravity were ob-tained for wood in all four quadrants of the bole in each section. Valuesfor specific gravity of branch wood were obtained from one branch fromeach quadrant at each whorl, whenever four branches were present.Three of the whorls had only three branches; all others had four ormore. The mean specific gravity of two branches from two quadrantsselected randomly at each whorl also was obtained to test the feasibilityof using two branches from a whorl rather than four, in analyzing cor-relation. In this instance, only two randomly selected quadrants wereused to determine the corresponding mean specific gravity of the bole.RESULTSSpecific gravity of the branches always was higher than specificgravity of the corresponding bole samples. Very high correlation co-efficients (beyond the one percent level of significance) were obtainedfrom linear regression analyses of specific gravity of bole wood withspecific gravity of branch wood for only the fourth internode and thirdbranch whorl by both sampling techniques (Figure Z, correlations 3 and6 in Table 1). The correlation coefficients, in this instance, for pre-dicting specific gravity of the bole by use of two branches randomly se-lected from two quadrants (r = 0.8755), or of four branches or morefrom all four quadrants (r = 0.9515), were both highly significant, soeither sampling procedure appears adequate. When analyses of bole and2branch wood at both heights in the stem were combined (Figure 3, cor-relations 1 and 4 in Table 1), no significant correlation occurred. Sim-ilarly, there was no significant correlation of specific gravity of bolewood with specific gravity of branch wood at the basal bole and basalbranch whorl in either sampling technique (correlations 2 and 5 inTable 1).33rd whorl4?h whorlBasal whorlGroundFigure 1. Schematic diagrams showinglocations on bole and branches fromwhich samples were taken.Table 1. Correlations Made from Linear Regression Analysis of Specific Gravityof Bole Wood with Specific Gravity of Branch Wood in Young Douglas fir.CorrelationsBole wood with branch wood(both whorls combined)Basal bole with basal whorlBole at fourth internode withthird whorlBole wood with branch wood(both whorls combined, randomsample, two branches at eachwhorl)ABasal bole wood with basal branch Y = 0.4927 - 0.0205X 0.0457 0.0021 7 0.0376whorl (random sample, two branchesat each whorl)Bole at fourth internode with Y = -0.7568 + l.9726X 0.8755** 0.7664 7 0.0364third whorl (random sample, twobranches at each whorl)= Correlation coefficient.**Beyond 1% level of significance.Std. errorRegression equations r* r2 d. .1. of estimate= -0.1319 + 0.9461X 0.6201 0.3845 7 0.0482AY = 0.4991 - 0.0276X 0.0287 0.0008 7 0.0330= -1.0640 + 2.4980X 0.9515** 0.9053 7 0.0716AY = 0.0169 + 0.7061X 0.5061 0.2561 7 0.0540Figure Z. Regressions ofbole wood on branch woodat top of tree based onspecific gravity of four ormore branches represen-ting each quadrant and oftwo randomly selectedbranches from two differ -ent quadrants.0I-.>0U-0uj 0.40.Cl,0.52 0.56 060 064 066SPECIFIC GRAVITY, BRANCHES (X)5052 0.56 0.60 0.64 068SPECIFIC GRAVITY, BRANCHES (x)Figure 3. Regressions ofbole wood on branch woodat base and top of stembased on specific gravity offour or more branchesrepresenting each quadrantand of two randomly selec-ted branches from twodifferent quadrants.DISCUSSIONThe contrast in significance of correlation coefficients for spe-cific gravity between bole and branch wood at the two different heightsin the stem is probably attributable to increasing maturity of the stemwood and declining vigor of the lower branches. Although no data arepresented as verification, most likely the declining vigor of olderbranches would tend to cause production of lower specific gravity inbranch wood in contrast to the increasing specific gravity in the olderbole wood. Thus, the relationship between age and specific gravity inthe stem and in branches would differ with increasing age, which wouldcause the lack of correlation found. The various ages of the stems an-alyzed would also tend to cause additional variation in specific gravityin the analysis of basal bole wood and basal branch wood. Furthermore,only a few branch whorls contribute nutrients and growth hormones towood formed in the uppermost part of the stem, while many branchwhorls contribute to wood formed at the base.Even though the present study has indicated that specific gravityof young stem wood can be predicted from the specific gravity of branchwood, a correlation between juvenile wood and mature wood of the stemmay show a different relation, as indicated by a preliminary study inDouglas fir (2). Clearly, more information of this nature is needed fora particular species at a given site to help the forest manager makevalid and reliable decisions that would enable him to grow trees withwood of high specific gravity.6LITERATURE CITEDDadswell, H. E. Tree Growth Characteristics and Their Influenceon Wood Structure and Properties. Seventh Brit. CommonwealthForestry Conference, Australia and New Zealand. 19 pp. 1957.McKimmy, M. D. A Variation and Heritability Study of Wood Spe-cific Gravity in 46-year-old Douglas -fir from Known Seed Sources.Tappi 49(12):542-549. 1966.Paul, B. H. The Application of Silviculture in Controlling the Spe-cific Gravity of Wood. U.S. Dept. of Agr., For. Ser., Tech. Bull.No. 1288. 97 pp. 1963.Smith, Diana M. Maximum Moisture Content Method for Determin-ing Specific Gravity of Small Wood Samples. U.S. Dept. of Agr.,For. Prod. Lab., Rpt. No. 2014. 8pp. 1954.Trendelenburg, R. Das Holz als Rohstoff. J. F. Lehmann, Berlin.435 pp. 1939.Turnbull, 3. M. Some Factors Affecting Wood Density in PineSterns. Union S. Africa, Dept. Forestry, Pubi. No. 82. 22 pp.1947.Wellwood, R. W. The Effect of Several Variables on the SpecificGravity of Second-growth Douglas-fir. Forestry Chronicle 28:34-42. 1952.Van Buitjtenen, 3. P. Anatomical Factors Influencing Wood Spe-cific Gravity of Slash Pines and the Implications for the Develop-ment of a High-quality Pulpwood. Tappi 47(7):401-404. 1964.Zobel, B. 3., and Rhodes, R. R. Specific Gravity Estimations ofMature Loblolly Pine from Juvenile Wood and Seedling Limb Sec-tions. For. Sci. 2:107-112. 1956.7ADVISORY COMMITTEES provide counsel on programs of re-search in Forest Management and Forest Products at Oregon StateUniversity.The Forest Products Research Advisory Committee, composedof men from representative interests, helps guide the research programin forest products. Present members are:CHARLES KREIDER, Chairman Western Wood ProductsNEAL I. PINSON, Alternate Association (WPA)PHILIP BRIEGLEB, Principal Pacific Northwest Forest andJOHN B. GRANTHAM, Alternate Range Experiment StationRALPH CASSELMAN, Principal American PlywoodJOHN M. HESS, Alternate AssociationLARRY E. CHAPMAN, Principal Willarnette Valley Lumbermen'sVAL GARDNER, Alternate AssociationC. R. DUFFIE, Principal Pulp and Paper IndustryDR. HERMAN AMBERG, AlternateGEORGE C. FLANAGAN, Principal Southern Oregon TimberJOHN E. HANSEN, Alternate Industries AssociationJ. R. GATES, Principal West Coast LumberRAY L. TODD, Alternate Inspection BureauDONALD W. PLEIER, Principal Western Wood PreserversCHARLES W. BEST, Alternate InstituteW. J. RUNCKEL, Principal Western Wood ProductsT. K. MAY, Alternate Association (WCLA)FRED SOHN, Principal Western Forest IndustriesS. H. ELLINGSON, Alternate AssociationEVERETT L. ELLIS, Secretary8PROGRAM AND PURPOSEThe program of the Forest Research Laboratory is designed toprovide information that will improve techniques of forest managementand promote full utilization of forest products. Able specialists withwell-equipped laboratories study Oregon's forest resources, supportedby the forest industry and by state and federal funds.Research in this field by wood scientists and technologists, chemists,and engineers includes studies of properties, processing, utilization,and marketing of wood and of timber by-products. Technical principlesderived through this research can be applied to the operation of Oregon'sforest industry.The PROGRAM of research includesidentifying and developing chemicals from wood,improving pulping of wood and wood residues,investigating and improving manufacturing techniques,extending life of wood by treating,developing better methods of seasoning wood forhigher quality and reduced costs,cooperating with forest scientists to determine effectsof growing conditions on wood properties, andevaluating engineering properties of wood and wood-based materials and structures.The PURPOSE of research on forest products is to provide informa-tion that will enable the forest industry to expand markets, createnew jobs, and bring more dollar returns by> developing products from residues and timber now wasted, and> improving treatment and design of present wood products.

Correlating specific gravities of branch and bole wood in young Douglas fir

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Correlating specific gravities of branch and bole wood in young Douglas fir

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