We developed a quantitative model for lumber, plywood, and paper (including pulp for paper production) consumption to predict the demand for wood in Japan to 2050. Parameters were estimated using a least squares fit. The primary variables were population, GDP, construction, and technology data during 1960–2010. The characteristics of the model were as follows: (1) lumber demand was described by construction, GDP, and population data; (2) plywood demand was described by construction and GDP data; (3) paper demand was described mainly by population and GDP data, and the rate of recycled paper use. The demand predicted by the model for a moderate-case scenario for 2011–2050 revealed the following: (1) due to the long-term decline in population, wood demand, especially for lumber, will decline by 2050; (2) the model results regarding the demand for lumber and paper differed significantly from the values in the National Forestry Agency Basic Plan; (3) the demand for paper as a proportion of the total wood demand will increase, and policy programs for hardwood will therefore gain importance in analyzing self-sufficiency with respect to wood in Japan.

The density of woodwasps in bucked and non-bucked stems was investigated for Sugi cedar (Cryptomeria japonica). The trees were thinned in March and April, 2006 and their stems were either left full length (non-bucked), or bucked to 2 m, and were left until December 2006 so that they could be oviposited by woodwasps. The stems, 6 m from the butt end, were then placed in a netted room. The moisture content of the sapwood, and the number of emerged adult woodwasps and oviposition holes were investigated. As a result, three species of adult woodwasps was emerged. The number of adult Urocerus japonicus that emerged from bucked stems was lower than the number that emerged from full-length stems. Furthermore, the sapwood moisture content of the bucked stems in December 2006 was higher than that of the full-length stems. Additionally, there were significantly fewer oviposition holes in stems felled in April, which had high moisture content, than in stems that were felled in March.

Among the various methods of forest restoration in Japan, restoration of mid-successional, secondary forests, which have high biodiversity, could contribute to maintaining biological diversity in human-disturbed landscapes. In many restoration projects, the neighboring natural secondary forest is often chosen as the target vegetation. However, there is no established methodology for secondary forest restoration in Japan. Here, we compared tree species composition and stand structure between a restored site (10 years after planting) and the neighboring secondary forest designated as the target vegetation. We found that restoration contributed to increasing tree cover, but the vertical structure of the stand was poorly developed. Moreover, the species composition of the neighboring secondary forest had changed markedly in ten years, mainly due to pine-wilt disease. As a result, compositional similarity between the restored and target plots had not increased in 10 years, while structural similarity was lower than 10 years ago. We conclude that, although current forest restoration methods contribute to increasing vegetation cover, single plantings of native species may be insufficient to restore the natural community structure, especially because vegetation of the target forest is constantly changing. Subsequent adaptive management is needed to direct succession of restoration sites toward natural forest composition and structure.