The Japanese Forestry Society Congress Database

Since April 2002, the revised forest planning system of Japan has come into operation. In this system, forests are classified into three management types, which are timber production, soil and water conservation and environmental conservation. Although, it is a very important and difficult problem to determine the management type for each stand, there is no explicit guide to do this.We proposed, therefore, a proto type method to classify stands into the three management types based on ecological site classification using GIS.We showed an example of this zoning with the ecological site classification in Miyazaki Prefecture. With this example, first, we discussed what criteria and indicators we should use. Second we examined the scaling problem of both resolution and application.We proposed three criteria, which were site productivity, probability of natural disturbance (landslide) and habitat potentiality of a specific species. To evaluate the site productivity, we used a site index model for sugi based on topography. To evaluate the probability of landslide, we used a probability model using topography and climate as independent variables. To evaluate the habitat potentiality, we used the warmth index. Thus, these criteria and indicators were based on only the ecological site factors; such as topology, climate and geology, but land cover information.We applied this zoning to whole Miyazaki Prefecture. The management type zones were located with local biases. This result suggested the zoning should be applied with regional scale.

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The accumulated data are analyzed for a plantation of Cryptomeria japonica during ages of 45 - 94 years at Soehatazawa Experimental Forest. At the age of 45 years, nearest distance from a focal tree to an adjacent tree varied around 2 m. These distances have increased with aging, and at present (94 years), they vary around 5 m , ranging from 3 to 7 m. Mean distance is comparable with natural old-growth stands of C. japonica, but vary to much less degree than natural stands. At any age, annual increments of diameters are positively correlated with the diameters at that time; a larger diameter indicates that that tree has grown under favorable environment and undergone better growth. Distance between trees also showed positive effects on diameter increment, especially at older age. Wider variance in inter-trees distance after thinning at later ages should enable to statistically detect distance effects. The mean diameter at the stands experiencing more intensive thinning was larger than the stands with less intensive thinning. However, leading trees at each stands showed similar values of diameters. These results showed that differences in diameter, either resulting from variation in distance due to thinning or from chance-factor, tend to become large with aging. An individual-based model incorporating above findings will contribute to develop silvicultural prescriptions for even-aged plantations of C. japonica.

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We examined the importance of micro-topography in zoning as a reallocating strategy of semi-natural forests in wood production area for conservation of biodiversity. Expected tree density encouraged by reallocating semi-natural forests was calculated for an endangered species, Quercus hondae, which has short-distance seed dispersal and strong dependence on micro-topography, under constraint of seed source and habitat extent. Candidates for rehabilitation sites with high expected tree density were significantly different between the case with and without micro-topographic constraint, indicating the importance of micro-topography. Analysis of species - area relationship demonstrated priority of lower slopes for conservation of infrequent species, though effectiveness for all species with replacement of small area was higher in crest and upper slopes.

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In a situation where opportunities for biodiversity conservation are severely limited, it is not effective to give a priority to species by species in order to achieve an effective outcome from any conservation efforts. It is rather efficient to evaluate a whole community within a certain area, make comparison between areas, and determine which area should attain the higher priority. In the present study existing objective methodologies for biodiversity evaluation are compared and a methodology that integrates evaluations yielded after the objective methodologies as well as expert opinions. Evaluations were based on (a) the size of distribution area and (b) taxonomic uniqueness, as explained below, (1) through (5), and bird census data in Amami Island, Hyogo Prefecture and Tsukuba were used. A value was calculated for each species and summed up to obtain an evaluation of an area or a landscape in order to compare them.(a) Evaluation based on distribution area: (1) each species score was the number of girds over the whole nation divided by the number of grids covered by the species distribution, (2) square root of the value based on (1), (3) species score increases linearly as the distribution area decreases, (4) calculated in the same way with (1) replacing the whole nation with an arbitrarily determined locality. (b) Evaluation based on phylogenic uniqueness: (5) point 3 for a genus species and point 2 divided by the number of species that belong to the same genus are given. (c) Integrated evaluation was calculated by multiplying standardized evaluation based on (1) through (4) by weighted scores of (1) through (5).Despite of a small number of species observed on Amami Island, method (1) gave it the highest evaluation, since there are some endemic species there that obtained a very high score. The result from (2) was identical with (1) in terms of the rank order among the areas compared, while the difference was much smaller. Method (3) did not yield any great difference in scores among the species, so the rank order was nearly identical with the one that was determined by the number of species. Mt. Hyonosen attained the highest rank according to method (4), since there are some species that are unique to the local area in addition to a large number of species observed there. On the other hand, the result from the method (5) was not similar with any of the above methodologies, and agricultural suburban landscape in Tsukuba was ranked the highest. According to the expert opinions, distribution area should have a greater weight than phylogenic uniqueness, rareness than the number of species, and the whole nation than the local region. Similar with the method (1) and (2), Amami Island had the highest evaluation after the method (c). Thus, the results varied among these methodologies, and it is not possible to determine objectively which one should be adopted. The integrated evaluation may overcome the difficulty. Some international organizations have recognized that the Nansei Archipelago that Amami Island belongs to is to have the highest priority in terms of conservation efforts to be placed.

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