京都大学北海道演習林におけるヤチダモの育林学的研究 : ヤチダモの育林に関する基礎研究 (第I報) : 天然生ヤチダモ老令林の生育状況について

Abstract

Pursing the investigations on yachidamo in the Experimental Forest of the Kyoto University in Hokkaido are follows. A. On the construction of the gregarious stand of the old Yachidamo forest. B. On the difference of the condition of the stand from point of view of the topography, direction and soil conditions. C. On the distribution of age and the presumption of the intruding Yachidamo trees upon the present stand. D. On the process of growth. We tried to explain, "what are the special local properties of Yachidamo tree?" This is the report which summarizes the result of the above investigation. The followings are the results of these investigations, 1. Height-growth (Fig. 5) of Yachidamo is bigger than any other trees which are of sizes from 6 cm to 16 cm ni diameter (breast high.) 2. We found that Yachidamo belongs to the shade-bearer species considering the form of the crown, the stem and its nesissery quantity of light. 3. Considering the age and the degrees of shade-bearing of Yachidamo, we can give the following as the order of the intruder upon this forest, 1st Mizunara, 2nd Harunire, and 3rd Yachidamo. 4. The better growing circumstance of Yachidamo is on the slope of the north-west or south-west side, and at the area of the upper swamp and under the peak. 5. The trees in this forest suffered from active volcanoes (Mt Mashu, Mt Meakan). Most of the present growing Yachidamo (about 80%) are Within from 120 to 160 years old, so we presume that they grew after the great eruption 200~190 years ago (Fig. 8) 6. In comparison with the periodic increment curve of height and diameter in 5 compartments, it seemed that the height growth in youth is more remarkable than the diameter growth.