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This study deals with the estimation of the ratio of thinning (TERAZAKI's B-class). The materials for this study were obtained from 90 stands of AKAMATSU (Pinus densiflora S. et Z.) grown in Kinki district in Japan.The relations between n/N and D_g/D^^- (n : number of trees per hectare just after thinning; N : number just before thinning; D^^- : mean breast height diameter; D_g : diameter computed from mean breast height area; r : correlation coefficient) are illustrated in Table 1,and the following formulas are obtained from the table, n/N=7.0376-6.1395D_g/D^^-, r=-0.6669 The relations between D_g/D^^- and D^^- are illustrated in Table 2,and no relations are recognizable between D_g/D^^- and D^^- in the materials, since r=-0.0623. The following formula is obtained from the data just before thinning, log N_A=5.0719-1.5415 log D^^-(N_A : average number of trees; D^^- : mean diameter)The relations between N_E/N_A and n/N are illustrated in Table 4,and the following formulas are obtained, n/N=0.9802-0.2533 N_E/N_A; r=-0.4808(N_E : empirical number of trees).From the relations above mentioned the following formula is obtained, n/N=6.2158-0.1570 N_E/N_A-5.2623D_g/D^^-.By this formula we can estimate the ratio of thinning, n/N, from the datas of N_E, D_g, D^^-, just before thinning.
一般社団法人日本森林学会の論文
1961-08-25