SUZUKI Makoto University of Tokyo, Faculty of Agriculture, Assistant, 農学部(林), 助手 (40012091)
山根 明臣 東京大学, 農学部(林), 教授 (30182588)
TANGE Takeshi University of Tokyo, Faculty of Agriculture, Assistant, 農学部, 助手 (20179922)
|Budget Amount *help
¥1,800,000 (Direct Cost : ¥1,800,000)
Fiscal Year 1993 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1992 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1991 : ¥900,000 (Direct Cost : ¥900,000)
The study was conducted in the forest of Tokyo university in the southern part of the Boso peninsula, to study the weed vegetation and its dynamics in forest plantations of Sugi(Cryptomeria japonica D.DON) at various densities.
Species compositions, structure, etc.of weed vegetation changing with years were investigated mainly in a young plantation of Sugi at various densities.
At the same time, growth status of planted trees, and forest structure were examined.
In a young Sugi-stand with 3 treatment plots(tree density plots of 2,500, 3,906, 6,944 trees per hectare respectively), tall-grass type's Susuki(Miscanthus sinensis ANDERSS) belong to Gramineae has become the most dominant species on 2nd-yr to 5th-yr old stands after planting in each plot.
In both plots of the lowest and the middle densities, the coverage percentages of Susuki plants were judged from an annual changes, decreased markedly on and after 5th-yr-old in both plot stands become into 3m, 45% in the mean height and the mean coverage of Sugi planting trees.
On the other hand, Susuki plants in the highest density plot decreased markedly in the stands on and after 3rd-yr-old stand become into 2m, 30% in the mean height and the mean coverage of Sugi planting trees.
Consequently, in this survey area, when densities of Sugi planting trees were 6,944 trees or over trees per hectare, here showed that Susuki plants have a trend of decreasing markedly in earlier, younger year old stand(on and after 3rd-yr-old stand) after Sugi planting.
From results in these vegetation survey, here could to catching an outline of the actual conditions for dynamics of weed vegetation in relations with tree densities in Sugi forest plantations in the southern part of Boso.