In recent years, middle and large-sized wild mammals have become inhabited near the urban areas. By clarifying habitat use in the forests around the city, which is the stage before they appear in the city, it is possible to take efficient measures in advance. In the present study, we investigated what environments are used as feeding places by the wild boars in sub--urban forests. Video images were recorded at 30 sensor camera points for one year, and environmental surveys on soil and vegetation were also conducted at each point. The generalized linear model (GLM) was performed with the frequency of the feeding behavior taken as the objective variable and 13 environmental variables such as vegetation and soil characteristics as explanatory variables. As a result, it was confirmed that wild boar tended to forage more often in soft soils from spring to autumn. However, omnivorous wild boar tended to change the feeding places according to the season. At the foothill forest adjacent to the urban areas, the number of wild boars will increase due to the favorable soil environment for them to forage. In sub-urban forests, it is necessary to predict the risk of wild boar invasion in the city in advance based on the soil environment, and to implement measures such as population management, environmental improvement, and installation of fences at an early stage.

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Leaf biomass and stem biomass production were measured for 10 years in hinoki cypress plantations that were exposed to different thinning intensities in three areas at different altitudes in Kochi Prefecture. Leaf biomass was estimated using a simple method based on the pipe model theory. The increase rate of leaf biomass and percentage of stem removal were positively, linearly related and the increase rate was lower in the higher altitude area. There was a linear log/log relationship between leaf biomass and stem biomass production, the regression lines for which had slopes of 1.066 in the high-altitude area and 0.638–0.661 in the two lower altitude areas. The foliage efficiency, i.e., stem biomass production per unit of leaf biomass, was predicted from these relationships. Foliage efficiency increased with an increasing percentage of stem biomass removal in the lower altitude areas but not in the high-altitude area. The increase in stem biomass production in thinned plots could be divided into the effects of changes in leaf biomass and foliage efficiency. Leaf biomass had a larger effect in the moderately thinned plots with only small difference between areas, whereas foliage efficiency varied between areas in strongly thinned plots. These findings suggest that foliage efficiency is a useful index for comparing thinning effects between areas.

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Late embryogenesis abundant (LEA) proteins are known to accumulate in the late stage of seed development and in vegetative tissues following environmental stress. They exist not only in plants but also some animals, fungi, and bacteria. LEA proteins have diverse structures and gene expression patterns and are considered to safeguard living cells against disadvantageous changes in environmental conditions. In this study, cDNAs encoding two LEA proteins, PnLEA1 and PnLEA2, were isolated and analyzed to characterize LEA proteins in black poplar (Populus nigra L.). The predicted PnLEA1 and PnLEA2 proteins were structurally different; namely, PnLEA1 was identified as an LEA_1 family protein with one LEA_1 domain, and PnLEA2 was identified as an LEA_2 family protein with two LEA_2 domains. The PnLEA1 and PnLEA2 genes were expressed in the roots and leaves. The expression of PnLEA1 was up-regulated by drought, salinity, and cold stress. The expression of PnLEA2 was also increased by drought and salinity stress, though the increment was smaller than PnLEA1. Both PnLEA1 and PnLEA2 conferred early tolerance to high salinity on the Escherichia coli that overexpressed them. These results suggest that PnLEA1 and PnLEA2 are involved in the mechanisms of tolerance to environmental stress in P. nigra.

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To elucidate source areas of leaf-litter that enters river streams, a new model was developed for predicting leaflitter dispersion. This model simulates falling-leaf motion based on physical parameters such as riparian forest wind data, leaf-falling velocity, and tree-crown central height. The new model was applied in two lowland riparian forests to two willow trees. The model estimates fitted in well with the observed willow-leaf dispersion data, except for the vicinity of tree crown. Thus, we considered the new model as more effective than the existing models describing leaf-litter dispersion. Then, the leaf-litter dispersion of two riparian buffer strips was estimated using the new model. It was assumed that each tree belongs to the same species with equal height as other trees and equal distance from the other trees. The strip width had almost no effect on leaf-litter supply for the stream channel because the trees near stream banks had a strong leaf-litter supply into the streams. The riparian forest strips in upwind parts of the streams supplied more litter to the stream channels than the downwind strips. Thus, the upwind strips were considered more important for leaf-litter supply into the streams. Furthermore, the channel form was also considered to influence the leaf-litter supply into the streams. A highly meandering channel located in the same valley as a straight channel probably receives more litter than the latter. However, in a riparian forest with low tree density, the effect of channel form was lesser.

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The applicability of spray pollination for Cryptomeria japonica in the field, as an artificial pollination promotion technique, was examined to effectively utilize a small amount of pollen while improving workability. First, the effect of storage time of the pollen grain-water suspension on pollen activity was evaluated. Pollen grains stored for 12 h in the suspension had a similar germination activity to those evaluated immediately after the suspension was prepared. Then, spray pollination with three levels of pollen concentrations (0.2%, 0.5%, and 1.0%) on multiple mother tree clones with female strobili at different developmental stages (start, half-open, and full-open) was tested. In addition, to evaluate whether mating following spray pollination was successful, the seedlings grown from the collected seeds were subjected to paternity analysis using DNA markers. There was no effect by spray pollination on the levels of cone yield and the 100-seed weight (p > 0.05). Conversely, spray pollination at 1.0% pollen concentration had a significant positive effect on the seed germination rate (p < 0.05). Spray pollination at the two pollen concentrations of 0.5% and 1.0% had a significant positive effect on the ratio of seedlings (mating success rate) for the spray pollen used (p < 0.05 and p < 0.01, respectively). The mating success rate with the 1.0% pollen concentration was higher than that with the 0.5% concentration. Among the three female strobili developmental stages, the mating success rate tended to be higher when spray pollination was performed at the half-open stage. A mating success rate of 0.362 was predicted using a spray pollination with 1.0% at the half-open stage of strobili. In summary, spray pollination was shown to have beneficial effects on mating even in the field.

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Flux observations using the eddy covariance method have been conducted with respect to various types of vegetation throughout the world. The flux data obtained via these observations are used to estimate the net ecosystem production (NEP), gross primary production (GPP), and ecosystem respiration (RE). Various gap-filling methods estimating the NEP and partitioning methods for estimating the GPP and RE have been suggested. To understand the differences between the values obtained using these methods, we compared the data estimated via these methods based on the flux data obtained from the deciduous broadleaf forest at the Sapporo site, which experienced a major typhoon disturbance, and the evergreen needleleaf forest at the Fujiyoshida site. The difference between the values obtained using these methods was large, especially for RE. It is important to estimate NEP, GPP, and RE using various methods to completely understand the uncertainty in the values because the influence of the methods varies at each site. In addition, we estimated daytime RE by four methods using photosynthetic photon flux density (PPFD) and NEP. The estimated daytime REs were different for each method. The differences in daytime RE between these values and RE estimated using nighttime data were dependent on the characteristics of the forest. The difference was small at the Sapporo site, where large amounts of coarse wood debris were present, whereas the daytime RE estimated via the regression function using the PPFD and NEP was considerably less than that estimated by the function using the nighttime air temperature and NEP at the Fujiyoshida site. This suggests that estimating daytime RE is a useful method to evaluate the influence of leaf respiration to RE.

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The dwarf bamboo species have been considered important as indicators of forest vegetation type in Japan. On the other hand, dwarf bamboos inhibit the regeneration of tree species. Understanding the distribution dynamics of dwarf bamboo is a major research issue for forest ecology and forest management. Here, we aimed to examine the following questions: 1) whether the dynamics of dwarf bamboo communities can be predicted by ecological characteristics of culm and rhizome? 2) whether the hybrid-origin Sasaella ramosa compete with its parent species, Sasa nipponica? and 3) Does the dominance of Sasa borealis increases toward the S.borealis-dominated climax beech forest? In this study, we investigated the distribution of dwarf bamboos in Ogawa forest reserve for 30 years (1990-2020). The results of the study in 600 quadrats (2 m × 2 m) on a 10 m grid in the 6-ha Ogawa research site showed that the distribution area of Sasa borealis increased from 4.0% to 9.8%, that of Sasa nipponica from 5.0% to 7.3%, and that of Sasaella ramosa from 44.7% to 47.3% of the site. The annual expansion rate was 117, 47 and 53 m²/year for Sasa borealis, Sasa nipponica and Sasaella ramosa, respectively. The estimated life span of culms was 15, 2 and 7 years, respectively. Thus, the dynamics of these three dwarf bamboo species were closely related to their culm's ecological characteristics. The culm height and other characteristics of Sasaella ramosa and Sasa nipponica are similar. It is suggested that the two species will coexist for long time. Sasa borealis having the highest culm height and the longest culm longevity will dominate and the reserve will change to S.borealis - dominated climax forest. One of the large Sasa borealis communities flowered and died in 2017. Its recovery from seedlings will be a new study issue for future research.

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Cercidiphyllum japonicum has high sprouting ability leading to multi-stem growth form, which may enable successful coppicing after logging. To evaluate multi-stem patterns, we measured stem sizes of C. japonicum trees in a broadleaf forest in central Hokkaido, where selective logging has been conducted, and obtained stem diversity (the inverse Simpson’s index) in terms of their basal area proportions. In a zone (17.8 ha) where all C. japonicum (71 intact and 11 logged) trees were monitored, 33 (40%) trees had multiple stems. In total 123 trees monitored in the zone and sampled along a route (3.4 km), the stem diversity increased in logged trees and in trees reaching forest canopy as their size increased. In 40 logged trees of the 123 trees, we did not detect any factors, including logging conditions (stump size and age), that affected the stem diversity. These findings suggest that logging facilitates sprouting irrespective of environmental conditions, whereas bright-light conditions are responsible for sprouting of intact trees.

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An infestation on fruit-body of Hypsizigus marmoreus by a fungus gnat pest, Lycoriella ingenua (Dufour, 1839) (Diptera: Sciaridae), is reported from Japan for the first time. Sciarid larvae inhabited inside and outside of the sporophore of H. marmoreus. The adults reared from larvae infesting them are identified as L. ingenua based on the morphological features. Additional localities of L. ingenua were recorded from 12 indoor facilities of saw-dust media of Lentinula edodes in six prefectures, Japan. Morphological features distinguishing it from a major fungus gnat pest of agricultural products in Japan, Bradysia impatiens (Johannsen, 1912), are described. Control measures of this pest species proposed in foreign countries are reviewed and biocontrol using nematodes as its natural enemies together with other physical and cultural controls for this pest species are discussed.

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