Risk factors affecting bark stripping by deer remains unclear, especially in natural forests where effective controls of damage on forestry and forest ecosystems are difficult. We investigated the distribution of debarked trees and the frequency of habitat utilization by deer in the snow melting season in a natural forest located at Furano, Hokkaido. Analyzing these data, we assessed the effects of tree characteristics and surrounding environments on the risk of bark stripping. The susceptibility of bark stripping was negatively affected by stem diameter, even though its basic level was different among species. Ulmus davidiana, which were extremely susceptible to bark stripping, tended to be more damaged in sites with low-elevation, high-irradiance, convex topography and where surrounded by poorly regenerated stands. Also for other species, risk of bark stripping was increased by convex topography and poor regeneration around the tree. These environmental conditions were similar to those conditions which tended to increase frequency of deer utilization. These results suggest higher risk of bark stripping in stands where frequently visited by deer in snow melting season.

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Allometric relationships are powerful tools for estimating biomasses of forest components. However, these relationships are specific to forest types and tree species. In addition, laborious field work is needed to obtain the necessary data. There is a need for common equations based on some biological laws that can be applied to various types of forest stands. In this study, we used the pipe model theory and the static model of plant form to establish common allometric equations for estimating above-ground and root biomasses of trees in cool-temperate forests of Japan. We sampled 22 species (157 individuals, maximum DBH=61.9 cm) for above-ground biomass and 13 species (33 individuals, DBH=72.3 cm) for root biomass. The relative errors of estimation of the common equations were 12.59 and 17.67% for above-ground and root biomass, respectively, which were less than for the conventional allometric equations (18.62 and 22.25%, respectively). The new allometric equations can potentially be used as powerful and nondestructive tools for estimating biomass in cool temperate forests of Japan.

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In implementing forestry activities such as final felling and thinning, the value of logging residues are a distant consideration to those of commercial timber. However, rising oil prices and concerns for energy security are leading to increasing demand for logging residue as a source of renewable energy. We used a dynamic programming model to conduct computer simulations to examine the benefits of recovering logging residue and the effects of doing so on forest stand management strategies. We assumed an even-aged sugi (Cryptomeria japonica) plantation in Kyushu, Japan. The volume of logging residue to be used for fuel was calculated as either whole tree volume or whole tree volume less the logs utilized for timber. The simulations adopted residue prices from 3.0 to 9.0 JPY/kg. As residue price increased, the strategy for selling thinned trees shifted towards increased allocation of logs from timber to fuel. On the other hand, the optimal rotation age and thinning regime have little change against the price increase. The soil expectation value (SEV) increased with the price of logging residue. At a price of 6 JPY/kg, the SEV increased by 15-63% when logging residue was recovered. This increase in benefit mainly derived from the logging residue generated in clear-cutting; the contribution of thinning to benefit was comparatively small.

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A map of site productivity distribution is helpful for sustainable and effective use of forest resources. Combining two techniques, one for estimating local site productivity and the other for applying the estimation technique to large land areas, allows us to make the map. In this study, we presented a method to map site productivity distribution using a score table as the former and a geographic information system (GIS) as the latter. The method has merits as follows: 1) the mapping process is rational and accessible, 2) score tables have been already developed in many regions, 3) many environmental factors in those tables can be mapped using GIS, and 4) many referenced data for mapping are easily available. Therefore, the presented method is practical because of its applicability to many regions.

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Borings of Platypus quercivorus on Fagaceae trees (13 species) were investigated from 2009 to 2010 in the Kyoto Gyoen National Garden which is located in an urban area in Kyoto Prefecture, Japan. 342 trees were bored by P. quercivorus which was supposed to invade from outside, and 71 trees died among them. The bored trees were widely dispersed in the garden. The boring was confirmed in 12 species, and dead trees were found in 9 species. Correlations cannot be found between the rate of trees being bored and the rate of dead trees among bored trees, whereas the former was high in Lithocarpus glaber and low in L. edulis, while the latter was high in L. edulis and low in L. glaber. The rate of dead trees among bored trees was higher when the density of entry holes was higher in L. edulis, Castanopsis sieboldii and Quercus glauca. L. edulis was most liable to death in the same density levels. It was suggested that protective measures were necessary for bigger diameter trees which die more frequently in many species.

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Clone composition of commercial rooted cuttings and scion stools of Shakain, which is a cutting cultivar of Cryptomeria japonica, was investigated by MuPS (multiplex-PCR of SCAR markers) assay. Three major clones of Shakain which are similar in wood properties were identified as the same MuPS type. Three cutting lots purchased in Kumamoto Prefecture were analyzed, and some MuPS types different from the major clones were identified in two of three lots. The MuPS analysis of the scion stools also revealed frequent clone contamination in three scion sources. Adequate management of clones for scion sources is essential to achieve the required uniformity of lumber quality in Shakain.

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