To elucidate the effects of understory vegetation on arthropod diversity after line thinning, we investigated changes in ant community structure after experimental removal of understory vegetation in a line-thinned stand and an adjacent control stand. There was no difference in the number of ant species found in the two stands. The ant community structure of the line-thinned stand was characterized by habitat generalists, whereas that of the control stand was characterized by woodland specialists. Understory removal affected differently the community structure of the two stands. In the line-thinned stand, the effect may be small because the community was characterized by species with high environmental adaptability, whereas in the control stand, the community, which is characterized by species adapted to closed canopy environments, may be more sensitive to disturbances. Although the effect of understory removal on ant community structure was small compared to that of stand thinning, maintaining a diverse understory following canopy closure after intense thinning may increase ant species diversity by allowing habitat generalists and woodland specialists to coexist.

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To estimate impacts by selection cutting on forest ecosystem, we surveyed change of species diversity and detected factors influencing distributions of vascular plants on forest floor in following five years after cutting in a mixed forest in Hokkaido Island, Japan. Dwarf bamboo (Sasa senanensis) grew thickly in the cutting stand. The existence in preceding years was indicated as most important factor for major floor species by GLM that explains existence or frequency of each species by stand cutting, physical disturbance of floor, micro topography, light condition, vegetation cover and existence in preceding years as factors. Light condition and vegetation cover were shown as following important factors, but others did not. While we quantitatively indicated the influence of selection cutting on cover or distribution for some species including dwarf bamboo, the impact on species diversity as number of species or Shannon’s index was not clear. Partiality of environmental change by selection cutting, and perenniality of floor plants could be thought to absorb immediate change of species composition in whole stand.

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To understand the magnitude of changes in evapotranspiration and the main controlling factors of such changes, in association with the long-term natural recovery of forests on denuded hills, we compared the mean annual evapotranspiration during the early 10-year period (initial stage of forest recovery) and late 10-year period (60 years after the early period; transition stage of forest recovery) as measured by the water balance method. The Ananomiya experimental watershed at the Ecohydrology Research Institute (The University of Tokyo Forests) was selected for this study. The 10-year mean annual loss, as calculated by the annual water balance for the late period was 89 mm larger than that measured for the early period. We propose a new method, based on the short term water balance method, to estimate of annual evapotranspiration and have applied this method to evaluate the relationship between annual evapotranspiration and mean annual temperature, annual precipitation, and annual number of days with precipitation. The mean annual evapotranspiration for the late period was 80 mm larger than that measured for the early period. We conclude that the main reason for higher evapotranspiration in the late period may have been the increase in canopy interception as a consequence of forest growth.

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Human resource training for the forestry industry has attracted attention. To consider the future of forestry and forest education in vocational high schools, we analyzed the historical changes in the postwar period based on the Ministry’s official guidelines for school teaching. As a result, forestry and forest education has changed. Education was intended to train technical experts up to the 1970s. Thereafter, employment opportunities declined, and forestry-related courses decreased and diversified. Specialized education turned to training of general workers as members of society, including attending higher-level schools. The contents of education were classified as ongoing contents such as silviculture, additional contents such as forest ecosystem, and decreased contents such as breeding. The number of graduates from forestry related courses decreased, and there are now around 1,000, about 20% of them choose a forest-related career. In future, special education should be aimed at general career training and problem-solving abilities to cope with various situations. The tasks of forestry and forest education are to provide both basic training for general workers and training for technical experts. It is therefore necessary to investigate the contents of education for training forestry experts, educational programs for general career training, and highly specialized teacher training for forestry and forests.

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We assessed the profitability of low-density planting on the reduction of planting cost and felling income. We used multiple stage projection alternative technique (MSPATH) algorithm to search the benefits associated with thinning regime. In addition, we assessed the influence of subsidies on thinning regime. The net present value (NPV) increased with a decrease in initial tree density irrespective of the extent of the subsidy. The primary conclusion of this research is that low-density planting was effective in terms of both income and cost under assumption of this study.

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