On the nature of form factors and its application for stand volume estimation (I)

UENO Yojiro

doi:10.11519/jjfs1953.60.3_87

The author investigated the ten form factors (ƒ₁_??_ƒ₁₀) for three stands of Cryptomeria japonica with different densities. These factors are based on each diameter at intervals of one-tenth of the distance from the tree top. As the result, sample means, sample variances and coefficients of variation of form factors are found to decrease gradually from ƒ₁ to ƒ₈ in the all stands, and those of ƒ₈ show the minimum value. Then, their values, except sample means, increase from ƒ₉ to ƒ₁₀. Furthermore, sample variances of ƒ₈ and ƒ₁_??_ƒ₆ among the stands are significantly different, but those of ƒ₇, ƒ₉ and ƒ₁₀ are not significantly different. Sample means of form factors except f₇ are significantly different among the all stands. It was not clear whether the relation between each form factor and tree size is linear. The ƒ₇s are not significantly different among the stands, and the pooled coefficient of variation in all the stands gives the stable value of 6. 3%. Therefore, if it is assumed that ƒ₇ is constant in the general theory of plotless sampling, the stand volume may be estimated by multiplying the sum of heights of trees, whose diameters at the 3/10 distance of tree height from the tree base are checked by Spiegel Relaskope, by a constant in the P.S method.

On the nature of form factors and its application for stand volume estimation (I)

Bibliographic Information

Search this article

Description

Journal

Citations (4)*help

Details 詳細情報について

Export

Report a problem