61 間伐に伴う平均直径及び幹材積の変化に就て : 特に收獲表調製への応用に就て

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1. The following result was obtained from the investigations of 90 stands of AKAMATU (Pinus densiflora S. et Z.) in Kinki district in Japan.2. If D_h represents the mean diameter of head-spar-tree, N_h the number of trees of stand per acre, both just before thinning; D_s the mean diameter of the secondary stand, N_s the number of trees, both just after thinning ; and D_<h・s・> the mean diameter of headspar and secondary stand, N_<h・s・> the number of stand; then the correlations between N_h/N_<h・s・> and D_h/D_<h・s・>, or N_h/N_<h・s・> and V_h/V_<h・s・> are highly accurate, and the relations between those may be expressed by the following formulas;D_s/D_h (N_s/N_h)/(1.16870N_s/N_h-0.16870)…(1) log V_s/V_h=1.6958+0.3042 N_s/N_h…(3) log (log D_h/D_s)=-0.465427+1.25108 log (log N_h/N_s)…(2) log (log V_h/V_s)=-0.386325+0.812034 log(log N_h/N_s)…(4) It is statistically recognized that D_h or V_h has no influence on those relations.3. Average diameter or stem volume of the secondary stand on one age-gradation of the yield table may be calculated by the following method;A. Average diameter of secondstand.a. Let the diffferences between the numbers of trees of one age-gradation and the front age-gradation be the numbers of the secondary stand.b. Calculate N_h/N_<h・s・> first, and then calculate D_<h・s・> by the formula (1) or (2).c. Dividing D_h by D_h/D_<h・s・>, obtain D_h._s.d. Since D_<h・s>×N_<h・s>=D_h×N_h+D_s+N_s, obtain D_s from this expression.B. Stem volume of secondary stand per acre. a. Calcuate N_h/_<h・s・> same as for A, and next calculate V_h/V_<h・s・> by the formula (3) or (4).b. Dividing V_h by V_h/V_<h・i・>, obtain V_<h・s・>c. Since V_<h・s・>=V_h+V_s, obtain V_s from this expression.
一般社団法人日本森林学会の論文
1952-11-25

61 間伐に伴う平均直径及び幹材積の変化に就て : 特に收獲表調製への応用に就て

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