This paper is to investigate the standing crops and microfungal flora in soil in Phyllostachys reticulate forests in both the Yesan area (A) and the Kwangsan area (B).
The stand density of the bamboo revealed 17,250 shoots per ha in area A, and in area B 14,780 shoots which were 16.1 less in number than area A.
In respect to the environmental factors between the two areas, the mean temperature during the growth period was 1.5∼2℃ higher in area B than in area A, soil temperature also was 1∼2℃ higher in area B, and the total quantities of nitrogen, phosphoric acid and organic compounds contained in the soil of area B were also slightly higher than those of area A.
In area B the quantities of dried leaf matter, humus, and vegetation in the bamboo forest were also larger than in area A. In addition, five more species of microfungi which play a role in the decomposition of the various organic materials in the bamboo forests were identified in area B: Mortierella elongata. Mucor circinelloides, Aspergillus japonicus, Penicillium waksrnani and Trichoderma lignorum.
The atmospheric temperature in the inner portions of the bamboo forests was lower than the outside temperature, but the humidity was higher. The rates of relative illuminance were measured in area A at 4.19%, and in area B at 2.7%. These values revealed that the photosynthetic activity in the lower part of the bamboo was lost but it was considered that lower illuminance increased the microfungal activities in the vicinity of the surface soil. Since the productive structure of the bamboo showed that the maximum amount of photosynthesis was located in the upper portion of the bamboo in area B, it was considered to be an effective structure in maintaining the high productivity of the bamboo.
The allometric relation between D²H and dry weight of stems(Ws), branches(Wb) and leaves(Wl) of the bamboo in area A were appoximated by log Ws=0.5262 log D²H+1.9516; log Wb=0.6288 log D²H+1.5723; log Wl=0.5181 log D²H+1.8732,
and those of the bamboo in area B were approximated by lug Ws=0.5133 log D²H+1.5610; log Wb=0.1630 log D²H+2.3175; log Wl=0.4509 log D²H+2.0041.
From the above, the standing crops in area A were measured thus : Ws was 1.128.83㎏; Wb 689.05㎏; Wl, 926.69㎏ and Wt, 2,744.57㎏ per 10a. In area B, Ws was 1,206.66㎏; Wb, 679.92㎏ Wl, 1.112.51㎏ and Wt, 2.999㎏ per 10a. Significant differences from the result of t-test were for D²H Ws, Wl and Wt between areas A and B. But no significant difference was found for Wb.
In order to record as completely as possible the microfungal flora of the areas, every possible means was tried, and 158 strains of fungi were isolated, and of these, the microfungi of 55 species were identified. The dominant species were Trichoderma viridc, Penicillium jantnincllurn, P. commune. Aspergillus oryzae, A. niger, A. gigantus, A. fumigatus, Mortierella ramaniana, var. angulispora, Mucor hiemalis and Zygorhyncicus moelleri.
According to the above results, it was revealed that optimum soil, the increases of soil materials, more species of soil microfungi, and the atmospheric temperature during the growth period have made the bamboo flourish and bring more species and larger quantities of vegetation in the bamboo forests. The correlation between the standing crops and environmental factors in the bamboo forest is considered to be a complicated relationship of all the factors, but the stand density is thought to be the most important factor involved.
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