Retention forestry and small-sized clear-cutting are thought to mitigate logging impacts. In the Sakhalin fir plantation stands which were subjected to these logging operations and whole clear-cuttings 1-3 years ago and unharvested― we collected carabid beetles that are thought to respond to changes in forest environment. We trapped beetles using 1-3 fish baited pitfall traps for about 110 days at each stand. Logging operations clearly affected the beetle assemblages because the species compositions of beetles differed between the harvested and the unharvested sites. The species compositions in the dispersed retentions of naturally-regenerated broadleaved trees were between those of unharvested sites and clear-cutting sites, and the total abundance of forest beetle species significantly increased with the amounts of retained trees. The total abundance and species richness of forest species largely differed among the stands in the 0.36-ha unharvested patches of aggregated retentions and these were not different between ca 1 ha and 6-8 ha sized clear-cuts. Thus, we concluded that dispersed retention is a beneficial tree harvesting method that mitigates logging impacts, but also that further studies are needed to evaluate other types of operations. The species richness was slightly fewer than those from another study conducted at the same sites but with different methods (i.e., 20 non-baited pitfall traps for a total of 21 days at each stand one year after logging) but the number of beetles caught per trap per day was same.

This study designed an econometric demand model for Japanese cedar sawlogs and examined longitudinal data from 1960 to 2019. We constructed and estimated a vector error correction model for Japanese cedar sawlog demand and used unit root and cointegration testing to avoid spurious regressions with non-stationary variables. The results indicated that the regression coefficients of long-run parameters had the expected signs, and the price of imported log and the wage for the lumber industry were statistically significant at the 5% significance level. The long-run parameters were inelastic; however, the estimated values demonstrated that sawlog demand was influenced more by the price of imported log and the wage for the lumber industry. The estimation results for short-run parameters such as the speed of the adjustment parameters and lagged variables indicated that there were short-term adjustment processes among the variables related to sawlog demand. At least one of the dummy variables was significant at the 5% significance level for each equation, indicating that the trend of each variable changed in response to economic conditions and other factors.

We conducted a 30-minute lecture about forests in an outdoor experience program for elementary school children, and examined how the content of the lecture affected children's knowledge and behavior. The subjects were 29 elementary school children who participated in the “Uminoko Outdoor Program” organized by the Rikuchu-Kaigan Youth House in Iwate Prefecture. The main part of this program is a marine experience, but it also includes the stream experience activity. We gave a lecture about the topic of trees and forests to children the day before the stream experience. Then, we grasped how the contents of this lecture affected the behavior of the children during the stream experience through behavior observation surveys and interview surveys. We also conducted a questionnaire survey to understand the impact of the lecture on children's knowledge after the program. As a result, we could not confirm the behavior of the children affected by the lecture during the stream experience. However, in questionnaire survey of parents about 50 days later, we confirmed that about half of the children were telling their parents the content of the lecture.

When producing F₁ hybrid larch (Clean Larch), cuttings, there is a supply shortage because the number of shoots for cuttings is low, the rooting rate is unstable, and the rooted cutting production rate is low. However, the number of shoot for cuttings increases under artificially controlled conditions and the rooting rate stabilizes. In this study, we developed a closed nursery as a prototype for commercial production and produced cuttings throughout the year. After rooting, the cuttings were transplanted into containers filled with a slow-release fertilizer medium, acclimatized in a greenhouse, and overwintered in the field during the winter. Consequently, the rooting rate did not differ significantly from month to month even after 1 year of continuous cuttings (deviation analysis), and the annual average rooting rate was 81.1％, indicating a stable rooting rate throughout the year. However, growth after transplanting varied depending on the cutting time (analysis of variance), and the percentage of seedlings obtained was low (23％ to 90％), indicating the need for improving low-temperature acclimation methods and fertilizer application. However, the growth rate of rooted cuttings after transplanting is low depending on the timing of cuttings, so it is necessary to promote growth by improving the fertilizer application method.

Sendan (Melia azedarach), a broad-leaved deciduous species native in Japan, grows fast and can assume straight trunk by bud removal management, and is in recent years regarded as promising silvicultural tree species. The objective of this study is to examine the mass allocated to above- and below-ground organs of M. azedarach and to clarify the characteristics of root distribution. In November 2016, the research was conducted in a 13-year-old plantation in Kumamoto Prefecture, Japan. Six sample trees were harvested and separated into each organ, and root systems were dug out using excavator. Trunk, branch and leaf constituted 81.5, 17.4, and 1.1％ in above-ground total mass, and the root/shoot ratio was 0.25 on average, while the root/shoot ratio was greater in large individuals than in smaller ones. Sinker roots dominated 54 (39-75)％ of all roots in this soil type (andosol), with maximum depth being 1.9 m on average. Length of sinker roots was larger than that of horizontal ones (weighted mean, 1.67, 1.48 m). Fine roots were most abundant at the surface 0-10 cm soil depth, and horizontal distribution of fine roots was considerably even in this stand.