To investigate differences between forest vegetation types in changes of the number of plant species according to deer density, we conducted a vegetation survey for 31 stands in Quercus serrata forests and 30 stands in Japanese cedar plantations in Tajima District, Hyogo Prefecture, which has a geographic variation in deer density. Our results indicated that the rate of decrease in number of plant species according to deer density is larger in Japanese cedar plantations than in Quercus serrata forests. These results suggested that the direct and indirect effects of deer grazing on the rate of decrease in number of plant species differ in these two forest types. The difference in the direct effect may be caused by the difference of species composition between the two forest types, Quercus serrata forests with abundant woody species and Japanese cedar plantations with abundant herbaceous species. The difference in the indirect effect may be caused by difference of dominant species in secondary shrub-layer vegetation involving dwarf bamboos between the two forest types. The results suggest that the pattern of changes in number of plant species caused by deer grazing differs between vegetation types, with a difference in species composition in understory vegetation or in dominant species in secondary shrub-layer vegetation.

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To establish management criteria for watershed forests, basic studies on sugi (Cryptomeria japonica) plantation forests were performed at Okinoshima, Shimane Prefecture, Japan. Fourteen forests were surveyed. In nine forests, which had not been thinned in over 10 years (not-thinned forest), the relative yield index (Ry) was >0.8 and stand density was high. In two forests, which had been thinned in the past 10 years (recently thinned forest), Ry was <0.7 and stand density was low; these values were consistent with the yield table for the San-in region (western part of the Japan Sea littoral zone). In two other recently thinned forests, Ry was >0.7 and stand density was high. In the remaining recently thinned forest, Ry was >0.9 and stand density was very high, despite being thinned recently. Stand density was high after thinning because (1) the forest owner had no clear production target, (2) the forest was thinned only to meet criteria for financial support from the government, and (3) stand density was extremely high before thinning. A definition of thinning is to thin trees to achieve a production or management target; however, with no clear target, the thinning of very dense forests is not for maintenance, but simply to cut some of the trees. Criteria for obtaining financial support from the government involves the ratio of cut trees to total trees before thinning; thus, very dense forests can still remain dense, even after thinning. Therefore, criteria for acquiring financial support from the government must be reconsidered.

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In Indonesia, villagers have developed sustainable, biologically diversified land use systems called "home gardens (Pekarangan)" or "mixed gardens (Kebun)." There are many reports, however, that such "traditional" types of farming systems have changed due to recent rapid rural socioeconomic changes, such as the introduction of cash crops. Based on the case study in Lampung, Indonesia, this study examined what these cash crops have affected crop diversity and biomass accumulation in mixed gardens. We analyzed the list of planted species, the characteristics of the vegetation pattern, and the relationship among cash crops, species number and biomass. The study found that the mixed gardens in the study area still maintained a relatively diversified species composition and structure, though cash crops such as coffee and cacao dominated to some extent. The number of species in mixed gardens tends to decrease as the ratio of cacao trees increases, while it has no significant correlations with the ratio of coffee trees. Regarding the relationship between household income and proxy of biomass in the mixed gardens, we could divide the samples into three groups: 1) low income - low biomass group, 2) low income - high biomass group, and 3) high income - middle biomass group. The above results suggest that the expansion of cash crops does not necessarily bring about simple and rapid unification of species in mixed gardens, and the change of mixed gardens follows path-dependent and gradual processes which reflect regional variations, villagers' preferences and livelihood strategies.

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Recently, intensive thinning and line thinning have been carried out frequently on conifer plantations in Japan, causing concern that these thinning methods may lead to an increase of wood insect pests. Thus, the authors investigated on the density of woodwasps which were major woodd-amaging insect pests in intensively-thinned stands and line-thinned stands of Hinoki cypress plantations. We captured woodwasps with kairomone traps at two experimental sites of Hinoki cypress plantations in Kochi Prefecture, southwestern Japan. The density of the Japanese horntail Urocerus japonicus (Hymenoptera: Siricidae) was the highest among the captured three species of woodwasps at both sites. More Japanese horntails were captured in more intensively-thinned plots at the Okuono site one year after the thinning. There was no significant difference in the density of captured Japanese horntails between the selectively-thinned plots and the line-thinned plots at the Okuono site. On the other hand, the density of captured Japanese horntails in the intensively-thinned plots was not significantly different from that in the control plots where no trees were thinned at the Karakawa site. The Japanese horntail increased every year in the control plots at the Karakawa site. These results suggest that intensive thinning led to a high density of the Japanese horntails, but there was no difference in density between the selectively-thinned plots and the line-thinned plots of Hinoki cypress plantation. It was also suggested that the winter thinning decrease the density of Japanese horntails compared with no thinning.

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Renewable natural energy has started to replace conventional forms of energy in recent years. Especially, hilly and mountainous areas have abundant water resources and high potential for hydroelectric power generation. We evaluated the potential of low-head hydropower of less than 100 kw in Niyodogawa town, which is a mountainous region in Kochi prefecture, Japan. The results suggested that low-head hydropower has high potential as a next-generation energy source in mountainous regions.

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