|Budget Amount *help
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1986: ¥1,200,000 (Direct Cost: ¥1,200,000)
The study was intended to contrive the system of the stem-form control for for-estry. the system was in consideration of the healthiness and the non-taperness of trees, and the control could be recognized as the general standard on the treatment method for a stand, and for a sindle tree.
The stem-form coefficients, Q_0 and Q_1, form exponent of the stem-section, R_j, and others were selected for the numerical indices of the stem-form. For individual trees in conifer plantation(Sugi, Hinoki and the like), it is possible to control the coefficient, Q_1, within wide range. And the coefficient value is between 40 and 100, in the different development-stages of stand, according to growth conditions of the tree. For the older trees in overstory, over 70 years old, we would like to control the coefficient value, which ranges from 50 to 70 and is downward with age. Speaking about the root-swelling, generally, we are able to understand its development by the chang of form exponent, R_1. R_1 is initially small, decrease gradually, and arrive at a minimum. Thereafter, R_1 is increasing gradually, and is proliferate after change in R_1> 2, Q_0@q_1(tree height is some 7m, and this stage is called a critical point of stem-form development). In the case of mortal tree's status, Q_0 is big value, Q_0> Q_1, and R_1 is small value and almost unchanged. On the four sections divided the stem to about 8m above the ground, we compared their form exponents, R_j , in order. As the results by these analysis, we classified the types of the stem-form into several groups, and the variations of the type for a long time were estimated as follows. Simple stem form->C->G->H->A.