In the fumigation treatment of infested pine logs to eradicate Monochamus alternatus larvae, it is necessary to maintain a steady MITC gas concentration in the coverings during the fumigation period. Factors, such as incomplete coverings would decrease the gas concentrations in the coverings and affect mortalities of the insect larvae in the treated logs. In this study, we set several treatments where the logs were sealed with different covering methods in fall and winter and investigated the temporal changes in inner-covering concentrations during the fumigation and larval mortalities in the treated logs. Spot-pouring treatment of the fumigant, instead of spattering it on the logs, was included in the winter series. The temporal changes in the gas concentrations in the fall series showed a similar trend in the complete wrapping and top covering methods, including those with loose coverings. The concentrations under winter conditions were lower than those under fall conditions and further decreased in treatments with loose coverings in the top covering methods. An exceptionally low concentration was recorded in the spot-pouring treatment of the top covering method with standard covering. Larval mortalities were not affected by the decreases in the concentrations. Nevertheless, we must avoid factors causing the decrease in the MITC gas concentrations, such as loose coverings and/or spot-pouring of the fumigant under low-temperature conditions, to secure a high level of insect mortality.

Two documents written in 1866 describe the parameters of beech trees in the western part of Amagi Mountains, Japan. Assuming that the size composition of beech indicated in these documents is representative of the status of beech forest at that time, I compared this with the status of the present-day beech forests. ‘Medoori’ (the perimeter of trunk at eye height) and ‘Nagasa’ (the trunk length that can be used for timber) of 445 beech trees had been recorded. The former ranged between 38.6 to 115.8 cm, whereas the latter ranged from.8 to 6.4 m. The range of beech diameters recorded is within that of DBH in present-day beech forests. The records also indicate that beech trees ranged in size from medium- to large-diameter trees. On the basis of the diameter distribution, it is clear that large-diameter individuals were predominant in approximately half of the surveyed sites. The height to the first main branch was lower than that of trees in the present-day forests, and is assumed to be attributable to the relatively low density of trees. The predominance of large-diameter trees and the low density of trees are thus considered to be indicative of the continuous logging of trees for charcoal production. Current size structure of beech tree is considered to be a consequence of the continuous growth of saplings after the late Edo period, which is believed to indicate that the past use of trees may have contributed to the establishment of beech seedlings and the growth of saplings.

The period and process of forest recovery in the Satoyama working landscapes were reconstructed using old topographical maps of the northern Keihanna Hills in western Japan. The surveyed areas are thought to have transformed simultaneously from non-forested lands, such as badlands, meadows, and shrub lands, into woodlands in a short period from the end of the 19th century to the beginning of the 20th century. A pioneer tree, Pinus densiflora, may have dominated the newly established woodlands in the beginning, followed by takeover by broad-leaved woodlands in a portion of the pine woodlands in the 1970's. Two factors are thought to be the driving forces of this observed forest recovery from the end of the 19th century to the beginning of the 20th century. The first is the use of forest protection policies such as legal regulation and afforestation promotion projects undertaken by the then government, and the second is the reduced need for grasses and shrubs, which were once used extensively as green manure in the traditional farming systems.

In this study, based on the results of questionnaire surveys conducted in municipalities throughout Japan, we clarified the size and expertise of forest administration staff and examined the possible impact of these factors on forest administration. In recent years, the workload of municipal forest administration has increased at a rate outpacing the staff increase, and most municipalities have indicated feeling understaffed. Municipalities with large forest administration staff often have staff members with expertise, perform a relatively wide range of work types, and frequently visit forests. However, municipalities with higher number of staff indicate feeling more understaffed than municipalities with lesser staff numbers. Conversely, many municipalities that do not feel understaffed have a low amount of forest-related work. Many municipalities, including those with expertise, indicate feeling a lack of knowledge in identifying broadleaf trees and high-risk mountain disaster areas. Some municipalities with low staff numbers do not have the opportunities to focus on the need to identify high-risk mountain disaster areas through their work. The results of this survey indicate that the number of staff and their expertise may affect the scope and level of forest administration work, such as the extent of field inspections and risk assessments.

The effects of moderate low thinning of around 30％ in number ratio on changes in crown length for seven years and DBH growth for four years were investigated in overcrowded mature plantations of Sugi (Cryptomeria japonica D. Don). Mean crown length increased with time in the thinned stands. In the thinned stands, mean height increment was approximately 0.2 m/year, while the rising rate of crown base was nearly 0.0 m/year. Mean DBH increment in the thinned stands was significantly higher than that in the unthinned stand. As for the relationship between initial DBH and DBH increment, the greater the initial DBH, the greater the difference in the increment between the thinned stands and the unthinned stand. There are cases in which the rise of crown base in overcrowded mature stand can be stopped even by moderate low thinning. However, thinning effect on DBH growth would decrease, as the trees which are comparatively suppressed among inter-tree competition.

Damage by wildlife is serious challenge for the Japanese forestry and agriculture alike. Prefectural Forest Environmental Taxes (PreFET) are used for wildlife conservation and management in certain prefectures. We reviewed the status of the tax use and conducted interviews with four prefectural governments. The results revealed 18 out of the 37 prefectures with own PreFET had projects related to wildlife protection and management. The usage ranged from population management, damage management, and habitat management. PreFET budget partially supported policies on wildlife protection and management. Such policies should be pursued by the national government, prefectures, municipalities, and local communities in an integrated manner, and those policies are not necessarily supported by national subsidies. Based on the interviews, we identified that PreFET budgets are complementary to the subsidies provided by the relevant ministry and agencies (i.e., Environment and Forestry). Especially, PreFET budget supported new policies and policies which were not supported by other budgets. For example, hiring instructors for wildlife management and survey for making specified wildlife control plan are implemented by the PreFET budget.

Gnawing by the gray red-backed vole Craseomys rufocanus bedfordiae on planted trees have caused serious damage on forestry in Hokkaido, northern Japan. Rodenticide have been applied to control the damage, based on vole abundance monitored. However, it has not been fully clarified the quantitative relationship between vole abundance, rodenticide application and occurrence of damage. Snow condition could affect the occurrence of damage because the damage usually occur in winter. This study analyzed data of vole abundance and damage on planted trees during 1991-1999 in Hokkaido, Japan, to demonstrate the effect of vole abundance, rodenticide application, tree species, stand age, maximum snow depth and length of snow period using the generalized linear model. Damaged trees increased with vole abundance, and rodenticide reduced damage. Older stands were less vulnerable. Preference of voles for conifers was in the order of Cryptomeria japonica, Picea abies, Larix kaempferi, Abies sachalinensis, L. gmerinii and a hybrid of L. gmelinii and L. kaempferi, and P. glehnii. More damage occurred in a site with deep snow cover with a given vole abundance, suggesting that the criteria for rodenticide application should be varied among regions.