択伐方式によるソラカシ薪炭林の生産機構に関する研究(第2報) : 下山佐第1固定試験地の測定資料による林分構造と林分生長の解析

In 1959, the author setted up a permanent sample plot in just after cut stand at a shirakashi (Cyclobalanopsis myrsinaefolia Oerst.) a selection coppice forest managed by Mr. O. Yamane.
Ever after he continued studmg of this forest, especially of sources of the high productiyity. This paper will report the regenelation by sprouts, the change of forest structure and the growth of stand volume as a study on the growing structure of this forest.
The permanent plot were measured annually for three years of growth period. And the result of third inventory for the plot shown that the forest structure and the growing stocked were recovered neary so far as appearence of before cutting in 1959.
He observed as follows.
1. The size of permanent plot decided upon 0.0332 ha and the measure of trees carried out by the tape(mm unit) at every inventories.
The calculation method of volume at each invevtories adopted following the local volum table (volume per tree by d. b. h. class).
log V = 4.0636＋2.46663・logD
2. After cutting, the forest reproduction performed chiefly by regeneration under sprout method continuousily. In February 1962, the total number of sprouts was 384, the mean of sprouts length was 77 cm and of these 49 were ingrown to the measurementable class.
The distribution of new sprouts length fitted with Type I of Pearson's distnbution curve.
3. Result of calculation of tree number curve per diameter class by Meyer's formula, the stand structure of this plot recovered to before cutting condition for the three years of growth period.
The treatmental method of this coppice forest is expressed neary as following formulas.
before cutting N = 3730・e^<-0.272・D>
after cutting N = 4590・e^<-0.363・D>
4. The relationship of between the initial diameter and final that for the growing period of the same survivor trees is shown by the following a straight line.
D_3 = 0.311 + 1.251046・D.
The current annual increment for three years of this permanent plot calculated amounts to 14.8m per ha (the rate of increase is about 25%) from the inventory data. The continuous net increase and increment percent are wonderful amounts in the growth of coppice forest.
It is the fundamental treat principle of this forest that theutility middle class tree (7-12cm d. b. h. class) is saved about 70% good sprouts of the whole at cutting works. Naturally, large class trees (13 cm or more d. b. h. clasr) and badness of else class is harvested on raw materials of wood - charcoal or fuel woods. The increase of this middle class survivors taked up approximately 62% of the whole growth of the plot (shown schematically in Fig. 11 and Table 15).