Prediction of nitrification activity using easily measured soil physicochemical factors or readily available geographical factors is a great help for forest management planning. We reviewed previous studies aimed to predict regional variation in nitrification activity. The applicability of multiple regression models depends on the range of nitrification activity, and consequently, the scale of the target area. Although geographical factors, especially nominal ones, were less effective than continuous variables describing soil physicochemical properties, whole watershed-scale variation in nitrification activity was well predicted using only geographical factors. Nominal geographical factors (e.g., soil type, dominant species, and parent material) well represent site environmental conditions that relate to nitrification activity ', however, the resolution of available data concerning the geographical factors is not always sufficient. The use of digital elevation models (DEM) with geostatistical approaches should be promoted to overcome the lack of suitable geographical data resources.

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The species richness of epiphytes in a matured beech forest was studied. In a 1-ha plot established at Shirakawa village, Gifu prefecture, central Japan, the vascular epiphytes were investigated for phorophyte trees larger than 50 cm in trunk diameter at breast height. Species, height above ground level, and their location on trunk, were recorded. For this investigation, we used a 10-m long ladder for ascending phorophyte trees, and observation of epiphytes was done with help of binoculars and a video camera system. Also, species composition of overstory and understory plants was investigated. 43 species of vascular epiphytes, three species of vine with climbing root, four species of overstory trees, and 99 species of understory plants including herbaceous species and ferns, existed. Epiphytes comprise about 10% of all vascular plant species. Number of epiphyte species became more on the phorophyte tree with larger trunk diameter. The epiphytes were few in the range of 2-4m in height because of the subsidence pressure of the snowfall. Among the epiphytes, four species (Polypodium fauriei, Lepisorus thunbergianus, Lepisorus annuifrons and Ribes ambiguum) were most abundant. The specificity of the relationship between epiphytes and their location on trunk of phorophyte was observed. Vertically, P. fauriei and R. ambiguum tended to distribute in low parts on trunks compared to L. thunbergianus and L. annuifrons. The distribution of R. ambiguum specialized to trunk part where large boughs attached. The architecture of tree and the environment play an important role on the richness of vascular species in matured beech forest.The species richness of epiphytes in a matured beech forest was studied. In a 1-ha plot established at Shirakawa village, Gifu prefecture, central Japan, the vascular epiphytes were investigated for phorophyte trees larger than 50 cm in trunk diameter at breast height. Species, height above ground level, and their location on trunk, were recorded. For this investigation, we used a 10-m long ladder for ascending phorophyte trees, and observation of epiphytes was done with help of binoculars and a video camera system. Also, species composition of overstory and understory plants was investigated. 43 species of vascular epiphytes, three species of vine with climbing root, four species of overstory trees, and 99 species of understory plants including herbaceous species and ferns, existed. Epiphytes comprise about 10% of all vascular plant species. Number of epiphyte species became more on the phorophyte tree with larger trunk diameter. The epiphytes were few in the range of 2-4m in height because of the subsidence pressure of the snowfall. Among the epiphytes, four species (Polypodium fauriei, Lepisorus thunbergianus, Lepisorus annuifrons and Ribes ambiguum) were most abundant. The specificity of the relationship between epiphytes and their location on trunk of phorophyte was observed. Vertically, P. fauriei and R. ambiguum tended to distribute in low parts on trunks compared to L. thunbergianus and L. annuifrons. The distribution of R. ambiguum specialized to trunk part where large boughs attached. The architecture of tree and the environment play an important role on the richness of vascular species in matured beech forest.

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We investigated a 7-year dynamics of a sedimentation-dominated riparian forest in a warm-temperate region to examine the variations in disturbances regimes and its effect on diverse stand structure along the longitudinal stream gradient. The disturbance type varied from erosion-dominated to sedimentation-dominated with increasing size of disturbance from the upper to the lower stream. In the upper fan zone (UF-zone) and the middle fan zone (MF-zone) with high stability of soil surface, the survival rate of trees was higher than those in the other zones, indicating that established trees hardly disappear unless intensive disturbances associating with canopy destruction occur. This might be a factor in their high tree density with the wide range of tree size in the UF- and MF-zones. In lower fan zone (LF-zone) where the soil surface is unstable, we observed more recruitment of infrequent deciduous species and the characteristic species which had distributional bias in this zone. Thus, less intensive sedimentation in the stage of seedling establishment would be one of the important factors of the formation and maintenance of the differentiated species composition in the LF-zone.

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Because only a few populations of Picea koyamae and P. maximowiczii (Pinaceae) are found on Honshu Island, Japan, the species are listed as threatened and knowledge of their current distributions and suitable site is essential for their conservation. We tried to estimate the distribution of these two spruces using third order mesh cells (30 seconds latitude, 45 seconds longitude). Ground surveys revealed the presence of P. koyamae in 52 cells and P. maximowiczii in 74 cells, all of which were characterized by cool temperatures, low precipitation and light snow cover compared with those of the average of Central Honshu Island. Using upper and lower limits of average monthly temperature, precipitation and snow depth, 376 and 351 cells were identified as being climatically suitable for P. koyamae and for P. maximowiczii, respectively. As a result of analyzing surface geology, limestone had the highest proportion of cells in which the species were present (47% for P. koyamae', 80% for P. maximowiczii). Based on these results, it was suggested that 33 cells for P. koyamae and 34 cells for P. maximowiczii in limestone area at Northwest part of Mts. Akaishi were identified as cells in which the possibility to survive of each spruce will be the highest in future.

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[in Japanese]

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Crown forests in Sado Island, since 1890 to 1925, consisted of 420 forest lots with 6,750 ha in the area. As a result of the analysis on the forest registers which ware made about 120 years ago, classification methods of forest stands and soil types became clear. The forests were grouped into five classes, such as first class, second class, third class, small forest and felling prohibition forest. Almost of the twelve forest stands belonged to the first class, were pine (Pinus thunbergii) forests, and soils under the stands were classified to "loam group". There were one Cryptomeria stand, one Quercus stand and few mixed stands in the second class forests. The others in the second class were also pine stands and the soils were estimated mainly to "loam group" and "clay group". Lots of forest stand in the third class were coppice forests or poor, sparse forests, so it was not possible to expect the much income from the forests. It seemed to carry out the evaluation according to "a tentative regulation on the survey for national forest" which was established 1876. Soil types were classified into six main groups as "humus soil", "clay", "loam", "sand", "rubble land" and "litho-soil". "Clay" and "loam" were subdivided on their color or dryness. It was estimated that the soil survey was carried out on the basis of a latest knowledge in those days. Therefore, it can be guessed that few engineers who were trained by the central government did initiative of the survey group for the forest registration.

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