シラカシ択伐林に関する研究(第1報) : 下山佐シラカシ択伐林の実態

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The selection method of "Shirakashi" coppice which has been practised for 40 years by Mr. O. Yamane surpasses other methods in the volume increment and the erosion control.
We have studied the present conditions of that part of his forest in which some improvements were lately made to get better production.
1. The procedures of Yamane's selection coppice method are rather simple; rotation is 21-24 years, cutting cycle 7-8 years, growing stock 130<cm>^3, reserved growing stock 75m^3, selection cutting percentage 12 in number of sprouts.
2. A stand consists of 5 crown layers. The diameter distribution is shown in Table 5.
3. The relation between the total volume (including branch and twig) and D. b. h. of tree is shown by a straight line as expressed in the following equation :
log V=5^^￣.8854+2.71456・log D
And that between the log volume and D.b.h. is shown as follows :
log V=5^^￣.8503+2.69718・log D
4. The relation between the present D. b. h. and that of the same tree 3 or 5 years past is shown by the following straight line:
Y_3 = - 0.63 + 0.84721・X
Y_5 = -0.60 + 0.67418・X
The annual current volume increment per ha. of the stand examined amounts to 21.8 m^3 from the former equation and 20.6 m^3 from another.
These amounts are surprisingly great in the growth of Japanese hardwoods.