匹見演習林における天然スギの研究(III) : 匹見演習林天然生スギ利用材積表の作成

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In the volume estimation and the evalution of a forest, a tree volume table for log rule may be more helpful and more accurate than the conventional table. We adopt Japanease Agricultual and Forestry Standard for calculation of logs in this study. Construct a tree volume table for log rule, 110 sample trees of natural regenerated "Sugi" were measured in Hikimi College Forest Data of sumple trees are shown in Table 1.
1. Starting from a following Yamamoto-Schumacher equation,
V = 10^a・D^b・H^c
We get a equation for practical use in this district, as folows
V = 0.0000178.D^<1.854497>・H^<1.304321>
where the adjustment coefficient of bias is 0.0038314. By this equation was made a tree volume for log rule, as shown in Table 2.
We find regrresion coefficient b, c and multiple and partial correlation coefficient are very signifficant. By the adoption of this table, the error rate for a tree may be 27 percent.
2. We have prepared a local tree volume table for log rule with the same data as shown in Table 3 by using a following equation,
V = 0.0005143・D^<2.6678346>
the error rate for a tree may be 43% by adopting this table.
3. Utilization percent (ratio of log content for log rule to tree content）correlates with D.b.h. and height of a tree, and we find a following equation ;
P = a.e^<-(b/D)>・e^<-(c/H)>
By applying this equation on all samples, we get
P = 1.50557・e^<-2.5934(1/D)>・^<-7.8647(1/H)>
We find regrresion coefficient and multiple and partial correlation coefficient are very siginficant. The relation between the log contents (v）and tree contents (V）for a tree can be expressed in following equation,
v = 0.893533 V-0.07955