A QUANTITATIVE ANALYSIS OF PLANT FORM-THE PIPE MODEL THEORY : II. FURTHER EVIDENCE OF THE THEORY AND ITS APPLICATION IN FOREST ECOLOGY

Abstract

To test the applicability of the pipe model theory to actual tree form, the frequency distribution of the thickness of woody organs in a tree was examined in 10 different species. The frequency f(D) of a certain diameter class D proved to have a definite pattern of distribution in the root, branch and trunk respectively, with only a little difference between the species. The obtained f(D)〜D curves showed that a root system could well be approximated by the assemblage of many pipes of unit thickness, a trunk by a few cones piled up one upon another, and a branch system by a geometric model intermediate between the two. The results were well consistent with the pipe model theory of tree form. As an application of the theory in forest ecology, a new method for estimating the amounts of leaves or branches of trees and stands was also proposed, based on the direct proportionality found between those amounts and the cross-sectional area of the trunk at the height just below the lowest living branch.