The effectiveness of sheltering planted Fagus crenata, for preventing miscutting and feeding damage by beasts and insects, and for promoting plant growth was examined. The rate of damage by miscutting amounted to 65% in the non-sheltered plot, but only 11% in the sheltered plot. Thus sheltering was confirmed to be effective for preventing miscutting. The rate of damage by hares amounted to 66% in the non-sheltered plot, but was 0% in the sheltered plot. The upward growth of the planted tree was promoted by sheltering for two years after planting. Boring damage by moths and longicorns was mainly generated in the sheltered plot. It is assumed that the damage by moths and longicorns was concentrated to the vigorously growing trees, which escaped miscutting by sheltering. The cost of reforestation was increased when the tree-sheltering method was used. Depending on the planting number, the cost after planting can be reduced because the enterprise period can be shortened, in spite of the expense of installing the shelter, since the sheltering would promote plant growth and reduce the frequency of miscutting.

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Fungi associated with Swida controversa leaves infested by zonate leaf blight were investigated in relation to symptom development, detachment due to defoliation, and decomposition. Their antagonistic effects on the pathogenic fungus were then studied in dual cultures on a nutrient agar medium. Pathogenic fungus was exclusively isolated from zonate parts of infested live leaves. Both endophytic fungi that were frequent on uninfected parts and pathogenic fungus were isolated from rim parts of symptom. Detection frequency of endophytic fungi was lower in leaf disks from which pathogenic fungus were detected than in those that were not detected, suggesting that endophytic fungi were excluded from leaves as symptom development. In detached leaves, pathogenic fungus was exclusively isolated from zonate parts, and both endophytic fungi and pathogenic fungus from rim parts. On the other hand, saprophytic fungi increased and original endophytic fungi decreased in uninfected parts. These suggest that the colonization of symptom by saprophytic fungi was limited on detached leaves. Pathogenic fungus was not isolated from decomposing leaves but saprophytic fungi were frequent on both zonate and uninfected parts. Eighteen strains in 9 species isolated from leaves showed overgrowth, contact inhibition, or inhibition at distance against four strains of pathogenic fungus in dual culture tests. The antagonistic effects depended on the combination of species or strain of test fungi and strain of pathogenic fungus.

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We discuss the prediction of debris flow characteristics and estimation of sediment runoff control using erosion control facilities such as check dams and channel works in an actual mountain torrent based on the results of field survey and numerical analysis. In the Ohzedani River, a tributary of the Sendai River, a very active sediment runoff took place in September 1961 due to the second Muroto typhoon. A one-dimensional numerical simulation is conducted in order to investigate variations in debris flow characteristics along a river reach with erosion control facilities. According to the analytical results, debris flow discharge increases several orders of magnitude compared to water, and that the sediment transport rate varies with river-bed slope and river width. Flow discharge decreases suddenly at the cross section with check dams due to the variation of sediment transport. Flow path is fixed with channel works and it makes a great contribution for the protection against debris flow flooding. The computational condition of river-bed erosion has much effect on these numerical results.

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The workload and work efficiency on thinning operation by the use of large (L) and small (S) chainsaws in pine plantation in Java Island, Indonesia were examined in March-April, 2005. The workload of three operators was calculated by employing particular relations of heart rate-%VdotO_2max estimated through step test. Besides observation on actual work, a model test: holding L and S chainsaws at F (far off) and C (close) to the body was carried out. The study showed that L demanded significantly greater workload than S. In relating with holding postures, the workload demanded for F and C was significantly different on L, but there was no significant difference on S. A z-statistic analysis on felling, bucking and delimbing showed that the workload demand on L was greater than S due to chainsaw's weight differences. Analysis on vibration and noise (factors associated with chainsaws) confirmed that L generated greater impact to the workload than S. Working performance of L was superior to S. However, L produced lower work productivity than S. As a result, the use of S would provide better protection on safety and health of operators. Improvement on work elements, especially on watching, maintenance and clearing, combined with performing better cutting technique and adequate resting were considered as important attempts to attain optimum work efficiency on the use of S.

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I applied the theoretical volume equation (TVE) to 181 Japanese cedar (Cryptomeria japonica D. Don) sample trees collected from three regions, i.e., Yoshino (Nara Prefecture), Nishikawa (Saitama Prefecture) and Obi (Miyazaki Prefecture). The average relative error and standard error of stem volume estimated by TVE were, respectively, 0.923% and 0.015m^3 for Yoshino, 3.191% and 0.006 m^3 for Nishikawa, and 15.908% and 0.143m^3 for Obi. By contrast, the average relative error and standard error of stem volume estimated by EVE were, respectively, -3.820% and 0.042m^3 for Yoshino, 0.536% and 0.006m^3 for Nishikawa, and 4.327% and 0.030m^3 for Obi. It could not be judged which volume equation, TVE or EVE, had smaller average relative error and standard error. Since the EVE had been widely used in estimating stem volume, the result suggested that the TVE could be practically applied to Japanese cedar. In conclusion, the result of the present study would support the universality and goodness of fit of the TVE.

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We observed the foraging behavior of birds feeding on a common pioneer tree species, Zanthoxylum ailanthoides, in countryside forest on a warm-temperate zone of Shikoku in order to study the feature of seed dispersal. Two bird species, those were Japanese White-eye Zosterops japonicus and Daurian Redstart Phoenicurus auroreus, were observed foraging seeds of Za. ailanthoides among 10 frugivorous bird species observed on the site. We concluded that Zo. japonicus was the most effective seed dispersal agent of Za. ailanthoides because of its high frequency of seed foraging. The number of fruit bunches on observed Za. ailanthoides decreased from late November to December, whereas most fruits opened their pericarp in December. Also Zo. japonicus visited frequently to the observed tree to forage seeds in early and middle December.

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