To clarify the responses of undergrowth and surface soil erosion deterrence to line-thinning in a planted Japanese cypress (Chamaecyparis obtusa) stand, we set one scattered-thinning plot (ST) and three types of line-thinning plot, with one cutting row (1CR) and two remaining rows, two cutting rows (2CR) and four remaining rows, and three cutting rows (3CR) and six remaining rows. We also compared the condition of the undergrowth and the forest floor among the plots. The light conditions and vegetation cover increased in the short term after thinning in all plots. In contrast, the relative light scattering intensity decreased in ST, 1CR, and 2CR over several years, but remained high in 3CR at 12 years after thinning. The ratio of vegetation and litter cover was higher in 3CR than in the other plots. The soil erosion susceptibility index, which is an indicator of the relative risk of surface soil erosion, was lower only in 3CR, and tended to be lower with a higher ratio of vegetation and litter cover. We suspect that in 3CR, because of the improvement in light condition caused by the greater row width, restoration of the undergrowth constrained the movement of litter, which decreased surface soil erosion.

Education reforms changed forest science in universities education in Japanese universities during the 1990's, particularly after a terminological shift from “forestry” to “forest” science. To understand the current status and educational contents, two surveys were conducted using 2018 educational curriculums. The first survey conducted among all universities showed that there were no regulations of education content except for establishment of experimental forests. Various curriculums were found in the courses. Forest education science courses were placed in 29 universities; 25 universities placed the courses in departments previously named "forestry", and four in agriculture or environmental science. Courses names showed 60％ of them to be forest-related and 40％ did not, thus students could not easily identify forest science courses unless they fully read the course syllabus. The second survey that narrowed down using Utsunomiya University, Nihon University and Tokyo University of Agriculture, showed that subjects that included forest science were 199 in total, of which 26 to 53％ were compulsory subjects. Comparing the three universities, only half of the subjects had commonality. Other than the general basics, forest science contents were divided into 10 categories (tree physiology, ecology, silviculture and pedogenesis, insects and animals related to control, disaster prevention and hydrology, engineering, management, policy, contents involved in culture, and wood science). The study shows that forest science education has diversified. Further study is needed to define the content of current courses in greater detail.

This paper focuses on Forest Adventure as a new type of forest use, and presents possibilities and challenges for the effective use of forests by analyzing its management style and development process in Japan. Forest Adventure is a business style of adventure park, where visitors with safety equipment can enjoy thrills and views by walking and crossing wire ropes, boards, and ladders at a certain height between standing trees in the forest. It has expanded since the 2000s, and there are currently 31 individual parks in Japan. The required area for the attractions is about 1 ha, and the activity can be deployed if there are standing trees that can support visitors’ weight and movement. Moreover, the profitability of each park is relatively high with tens of thousands of visitors per year. Under the general control of Forest Adventure Co. Ltd., the management of the individual parks is roughly divided into direct management and franchises, and it involves various types of landowners, local governments, and other private companies. The parks are located in public forests owned by local governments and communities, as well as in private forests. There are parks for which landowners become the management entities and other parks that other entities manage by arranging business contracts or leaseholds from landowners, reflecting diverse situations of local societies and forest ownership. On the other hand, in the absence of institutional bases for outdoor security management, Forest Adventure needs to bear the cost of safety responsibility, such as by introducing strict European management standards and building a uniform system of component procurement and maintenance of the attractions.

To quantify the germination rate of Cercidiphyllum japonicum, which inhabits montane zones and Cercidiphyllum magnificum, which inhabits subalpine zones, we conducted germination tests at 10, 15, 20, 25, and 30 °C for 45 days. The germination rate of C. japonicum varied from 12.7％ at 10 °C to 31.7％ at 20 °C, and that of C. magnificum varied from 3.7％ at 15 °C to 22.7％ at 25 °C. The number of germinated C. japonicum seeds was significantly greater at 20, 25, and 30 °C than at 10 °C, and the number of germinated C. magnificum seeds was greater at 20 and 25 °C than at 10 and 15 °C. More C. japonicum seeds germinated at all temperatures relative to C. magnificum, and the mean time to germination was shorter in C. japonicum relative to C. magnificum at 10, 15, and 30 °C. We thus concluded that C. japonicum possesses high germination rates across the range of tested temperatures and that C. magnificum has poorer tolerance to low temperatures during germination and a reduced germination rate. We also observed C. magnificum takes longer to germinate than C. japonicum.

We examined the effectiveness of seed selection based on the specific gravity of water and the duration of moist chilling treatment required to break seed dormancy in Abies mariesii. The proportion of filled seeds significantly increased 74.7-84.7％ after specific gravity-based selection using water compared to the proportion of untreated seeds (28.7％). Therefore, our study indicates that seed selection using specific gravity of water can easily improve the seed filling rate of Abies mariesii. The germination rate between seeds in the moist chilling treatment and non-treatment were compared. The results showed that the germination rate of the former was 75.0-84.7％, which was significantly higher than the latter (18.3％). The duration of the moist chilling treatment showed no statistical difference in the final germination rate, and more than 70％ of the seeds germinated even after 30 days of moist chilling treatment.