A survey was conducted to clarify the runoff mechanism of four small basins based on a Hida metamorphic rock, which are located in the heavy snow mountains in the southwestern part of Toyama Prefecture. A Hida metamorphic rock is characterized by metamorphic rocks containing a large amount of calcareous gneiss. The runoff consists mainly of rainwater and snowmelt water that has passed through the surface soil and groundwater that has passed through the shallow or deep layer of bedrock. The runoff characteristics of each small basin differed depending on the combination of each component of the runoff. In the basin containing spring water from shallow and deep bedrock layers in its upper/middle and lower parts, respectively, the electrical conductivity during the basal runoff increases, except during the snowmelt season, and the spring water from the shallow bedrock decreases faster than that from the deep bedrock. In the basin consisting of water passing through the surface soil and groundwater from deep bedrock, the electrical conductivity during the base runoff was stable at a large value. When compared with other geological basins, a small ratio of direct runoff to precipitation was observed in every basin during the rainfall events, showing a very large maximum water-holding capacity. Therefore, the basin based on the Hida metamorphic rock exhibits rapid vertical permeation of rain and meltwater, which is then stored as bedrock groundwater and runoff.

As the coconut husk peat (CHP), which is broadly used as a base medium for containerized seedlings, is a material from oversea, considering its high CO₂ emission for transportation, it is better to use local materials. We grew Japanese cypress containerized seedlings with local materials, bark compost (BC) and cattle manure compost (CMC), as base media. We then compared its property and growth characteristics with those of CHP, and evaluated the possibility of the alternative to the CHP. The CO₂ emission for transportation of the CHP was 5 times larger than those of local materials. Subsidence of substrate, pH and EC of local materials were significantly larger than those of CHP. Especially for the EC of CMC was 28.1 times larger than that of CHP. Although local materials inferior to CHP in some growth characteristics, height-diameter ratio and T/R ratio of BC were of equivalent with those of CHP. Statistical models between growth characteristics and growing media properties indicated that seedlings whose subsidence of substrate, pH and EC were low showed superior growth. Consequently, BC can be used as the alternative to CHP by maturing for a long time or by mixing acid grained soils, e.g., akadama soil and kanuma soil, to reduce its subsidence of substrate and pH.

In this study, we aimed to elucidate the size of Chinese fir (Cunninghamia lanceolate) seedlings, of which mainstem is fed by the Japanese hare (Lepus brachyurus). We planted 60 seedlings of various heights (82-197 cm) in a stand in Tarumizu City, Kagoshima Prefecture, and observed the feeding of the mainstem for 1 year. We found that of the 15 dead seedlings, only 1 died after the feeding of the mainstem. Among the surviving seedlings, the mainstem of 25 seedlings was fed by hares. The probability of feeding on the mainstem decreased with the increasing size of the seedlings. Regarding the generalized linear model estimation, the probability of feeding on the mainstem was ＜10％ for seedlings with an initial height of ＞140 cm or an initial diameter of ＞15 mm at the height of 60 cm. Therefore, we predict that Chinese fir seedlings are less likely to suffer feeding damage of the mainstem after they grow to be larger than the abovementioned values.

In order to explore the possibility of reducing the weeding period, we investigated the 6-year growth of planted large container-grown cuttings (90 cm in height) from the “specified mother trees” with weeding being stopped from the third year, and compared to it normal-sized bare-root cuttings (50 cm in height) grown with weeding after planting every year. The large cuttings showed better growth even after weeding was stopped. The difference in mean height between the planted trees and competing plants increased gradually even after weeding was stopped. These results suggest that planted large cuttings do not suffer from severe suppression and that the studied stand will be successfully established even when weeding is stopped after the third year. Compared to the normal-sized cuttings, the large cuttings showed a slight decline in tree height growth and an apparent decline in diameter growth at 1 year and 2 years after stopping weeding, respectively, suggesting possible suppression of the lower crown. Competing vegetation showed a gradual change in species composition toward tall tree-dominated types after weeding was stopped. These suggested that additional weeding could be required in order to take advantage of the high-performance cultivars if growth decline becomes apparent.

Statistics regarding wood volume damaged by Japanese oak wilt (JOW) are presented annually in the government's annual report on forests and forestry. Although these statistics are used as basic information to consider countermeasures against damage due to JOW, they are unverified. Therefore, in this study, the statistics for private forests of Toyama Prefecture, where an epidemic of JOW occurred from 2004 to 2011, were verified. The statistics were based on the number of dead crowns counted visually from roads. The total statistics of damaged wood volume from 2002 to 2017, encompassing the period when mortality from JOW occurred, was 0.12 million m³. In contrast, the estimated damaged wood volume calculated from two successive measurements before and after the JOW epidemic in 101 plots of the National Forest Inventory, was 1.78 ± 0.81 million m³ (point estimate ± 95％ confidence intervals). This suggests that the statistics are an underestimation; the main reason for this is probably the existence of parts that cannot be visually observed. The volume loss rates of Quercus crispula and Quercus serrata were estimated as 57 and 9％, respectively; thus, the impact of JOW on forest resources was clarified at a regional scale.

In recent years, Japan has experienced a rise in timber production. Nonetheless, it is imperative to determine the origin of this augmented production. To investigate the possibility of a sustainable timber supply, it is essential to elucidate the characteristics of the logged areas. Therefore, we aimed to clarify the relationship between annual timber production and the spatial distribution of logging, including slope and distance from roads, in privately owned planted forests across the prefectures of Kyushu. We classified forest areas based on their spatial distribution and utilized linear regression to demonstrate the correlation between annual timber production and the ratio of logged area. Our findings revealed a strong inclination to selectively log forests with gentler slopes and shorter distances from roads as the annual timber production increased. The rise in timber production may have been achieved through a greater supply from more profitable forests. These results suggest that increased timber production could result in an uneven distribution of logging locations. Even in areas with sufficient forest resources on the whole, there may be localized resource scarcities in the more profitable forest areas.