The effects of clear-cutting on the decomposition of Camellia japonica leaf litter were investigated in a temperate secondary forest. We focused on the pattern of occurrence of bleached area on leaf litter and the decomposition of acid-unhydrolyzable residue (AUR), which included lignin and was known as a limiting factor of decomposition. Fallen leaves of C.japonica were characterized by the occurrence of bleached portions attributable to colonization of leaf tissues by ligninolytic fungi and decomposition of AUR. The litterbag method was used to follow an 18-month decomposition in a clear-cut (CC) and an adjacent control (CO) plots. Mass remaining of leaf litter was significantly higher and bleached area on the leaf surface was lower in CC plot than in CO plot. AUR content was lower in bleached portion than non-bleached portion. Among explanatory variables in generalized linear model, bleach and accumulated mass loss significantly explained AUR content that was response variable, but plot did not. These results suggested that the clear-cutting affected the rate of extension of ligninolytic fungi responsible for increasing of bleached area but did not affect the activities of fungi to remove AUR from leaf tissues. The reduced mass loss of leaf litter and the suppression of expansion of bleached area in CC plot could be partly due to that the changes in microclimates of the forest floor such as desiccation that would suppress extension of hyphae of ligninolytic fungi.

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Forest damage due to accreted snow occurred in the Unnan region in the eastern part of Shimane prefecture on January 9-10, 2009. In this study, the distribution of the damaged stands and climatic conditions during that period was analyzed. The mean temperature of the area dropped from above 0℃ on the night of January 9 to below 0℃ on the morning of January 10. The precipitation in this area was also simultaneously recorded. Most of 356 damaged stands were located in the area between the mountains and plains. In particular, 52% of the damaged stands were located in Sada-cho, Izumo City. This area is located at a comparatively low altitude, at less than 400 m altitude, and no incidents of serious damage due to accreted snow have been previously reported for this area. Ninety-six percent of the damaged stands belonged to sugi (Cryptomeria japonica D. Don) forests. Most of the damaged stands belonged to age classes 5-7. The climatic conditions, species of the dameged trees, and age class of the damaged trees in the forest damaged during this period were similar to those reported in other region.

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Patterns of occurrence of endophytic fungal taxa were examined for leaves of 73 deciduous tree species in a cool temperate forest in central Japan. A total of 15 fungal genera were encountered on 730 leaves collected in August 2008, with Colletotrichum being the most frequent genus, followed by Geniculosporium, Xylaria, Phomopsis, and Nigrospora. According to the genus composition of endophytic fungal assemblages on leaves, the 73 tree species were generally classified into a continuum with two types at the ends. The first type included tree species with endophytic fungal assemblages dominated by Colletotrichum and associated with Xylariaceous and other genera as relatively minor components. The second type included tree species with endophytic fungal assemblages of Xylariaceae and/or other genera as major components and associated with minor components with, or without, Colletotrichum. Relative frequencies of fungi were not related to the subclass or phylogeny of tree species.

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In 2008, we investigated the bark surface structure and resin duct index (RDI) in cross-section of needles of Japanese black pine (Pinus thunbergii Parl.) trees growing in Okinoshima-cho, Shimane prefecture, Japan, in relation to the hybridity of this species. In most of the sampled trees, called Ai-guro pines, the bark surface had hybrid-like characteristics, between those of the Japanese black pine and the Japanese red pine (P. densiflora Sieb. et Zucc.). However, the RDI values of all the sampled trees corresponded to those of the Japanese black pine. Therefore, on the basis of the RDI values, we considered that pine trees classified as Ai-guro pines in Okinoshima-cho are not hybrids but in fact Japanese black pines.

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