After the Fukushima Daiichi Nuclear Power Plant accident in 2011, selecting usable logs for shiitake mushroom (Lentinula edodes) cultivation has become challenging in eastern Japan. In this study, the vertical distribution of ¹³⁷Cs in each tissue-type of konara oak (Quercus serrata) trees from two forests, along with the transfer of ¹³⁷Cs to shiitake mushrooms grown on bed logs obtained from these trees, was investigated to accurately evaluate their usability. The ¹³⁷Cs concentration in the fruiting bodies was more highly correlated with that in sapwood than in the whole wood, including the bark. The K concentration in the sapwood and the transfer factor (concentration ratio) from the sapwood were negatively correlated, indicating an inhibitory effect of K on the ¹³⁷Cs transfer from the sapwood. Furthermore, the analysis of covariance indicated that ¹³⁷Cs concentrations in the sapwood varied with the forest type, individual tree, and sampling height (p＜0.05). However, ¹³⁷Cs concentrations in the fruiting bodies grown on bed logs from the same tree did not vary significantly with sampling height (p＝0.50), due to the corresponding changes in ¹³⁷Cs and K with height. The ¹³⁷Cs concentration could be accurately estimated based on the ¹³⁷Cs contents at the bottom of each tree and the amount and number of fruiting bodies on each log. Therefore, for accurately assessment of forest usability, it was desirable to investigate the ¹³⁷Cs concentrations in the sapwood of multiple trees, and also investigate the K concentrations, with one position per tree (e.g., breast height) being acceptable.

We analyzed the factors that led to the merger of hamlets in the Fudo district of Joetsu City, Niigata Prefecture, in 2020. We realized the importance of the impact of the landslide control work and other public works projects on the area. The purpose of this paper is to clarify the relation of the residents of the Fudo district to landslide control, from three perspectives: (1) designated areas for landslide control, (2) project expenses, and (3) local residents who worked for local construction companies, and to examine the impact of landslide control on the merger of hamlets. The designated areas in the district comprised seven for forestry, and one each for Sabo and agriculture management. The project cost for landslide control increased in the mid-1970s and decreased after the 2000s. The generation whose employment coincided with the district’s industrial shift to civil engineering, hired by local construction companies as heavy machinery operators and engineers engaged in construction and snow removal, led the merger of hamlets. Landslide control also involved the community association managing irrigation canals and asking the local governments for necessary construction, and local residents observing signs of landslides. Landslide control, which involved local residents integrally, has promoted the unification of the district. Future considerations should include comparisons of project cost trends between the district, Niigata Prefecture, and nationwide, residents’ attitudes towards landslide control and disaster risk, the relation between landslides and land use, and comparisons with other areas.

This study examined the perceptions of local government officials regarding the requisite knowledge and skills for forest administration. Data were gathered from a questionnaire survey of participants in a 2023 training course aimed at developing support personnel for municipalities. A total of 111 respondents, including municipal and prefectural officials and other support personnel, participated. The findings indicate that forestry education was not deemed highly important; and even those without forestry education perceived that they had acquired a certain level of expertise through their own experience and research as well as communication with experts. Differences in perceptions of knowledge and skills levels were observed among respondents with three or more years of experience in forestry-related work. Many respondents, including support personnel, felt their knowledge and skills were inadequate overall, with a particular emphasis on the lack of time for knowledge acquisition. The study suggests that enhancing forest administrators’ expertise requires the design and improvement of opportunities and environments for post-employment knowledge acquisition, necessitating revisions in the tasks’ volume and scope within local governments.

Since multi-cavity containers used in open-field cultivation receive direct sunlight on the side surface, the seedlings located near the outer margin have higher root zone temperatures than others. Our investigation focused on the root zone temperature and seedling growths in containers with and without shading on the sides along the four cardinal directions. During the day, without shading from the sides of the container, the root zone temperature of the outer margin seedlings was warmer than that of the central seedlings. Conversely, in containers with sides shielded from sunlight, the root zone temperature did not differ depending on the seedling position. Furthermore, in seedlings near the outer margin of the container whose sides received direct sunlight, the roots were reduced, while height tended to be small. Thus, during the open-field cultivation of containerized seedlings, shading the sides of the container from sunlight is effective in maintaining a suitable temperature for growth.

The flowering levels of the dwarf bamboo Sasa sect. Sasa were surveyed along major roads by Integrated Grid Square of Japan (so-called 2nd mesh, 5 min. along latitude, 7 min. 30 s. along longitude, ca. 10 km square) to determine the area of mass flowering in Hokkaido, northern Japan in 2022 and 2023. The levels were classified into five subjective categories. Out of the 975 meshes on the Hokkaido mainland, 176 and 538 were surveyed in 2022 and 2023, respectively. In 6 and 124 meshes surveyed in these years, respectively, more than half of observed Sasa sect. Sasa plants flowered (levels 3 and 4). In 2023, mass flowering was observed in and around the meshes that exhibited flowering in 2022, and the area was divided into western, central, and northern regions by the area where only a few Sasa plants flowered. The lower-level meshes were distributed around areas where multiple level 4 meshes existed. Various morphology of culms with inflorescences were observed, including those exhibiting intermediate characteristics between sect. Sasa and sect. Macrochlamys. Concerns exist in regard to the effects of the increasing sika deer population on Sasa seedling establishment and regeneration dynamics of trees after the mass mortality events.