The transmittance of laser beams for different thinning intensities and the effects of sampling density on the estimation of stand density and tree height in the airborne laser scanner measurement of a Cryptomeria japonica stand were investigated. The transmittance of laser beams in plots of heavy thinning, light thinning and no thinning, which affected the accuracy of DEM (digital elevation model), were 95.8%, 86.5%, and 75.2% respectively. The extraction rates of standing trees from DCM (digital canopy model) in 0.25 meter meshes, which were derived from airborne laser scanner data, were 28.1%, 26.8% and 21.3% in plots of heavy thinning, light thinning and no thinning, respectively. The correlation coefficient between tree height derived from DCM and that derived from the field survey was 0.92. The rate of extraction of standing trees from DCM declined suddenly when the sampling density was below 3-5 points/m^2. The mean difference between tree heights derived from DCM with high sampling density and one with low sampling density was 0.5-0.6 meter and the height was underestimated by the low sampling density beams.

View full abstract

To analyze long-term changes of shallow landslides over a wide area as basic data for soil and water conservation, we used aerial photographs to analyze the distribution, area and number of landslides in 1947,1959,1978 and 1993. The study area was the Nakatsu River basin (3,544.0ha) in the Tanzawa Mountains of Kanagawa Prefecture, Japan. We prepared orthophotographs from these four years, then created database using GIS analyze to them. As a result, the number of landslides was 1,801 (sum area 709.6ha) in 1947,1,544 (571.9ha) in 1959, 369 (70.8ha) in 1978 and 178 (39.2ha) in 1993. The long-term distribution tended to concentrate in the high elevation area. At least 90% of landslide area in the latter three years had already existed in 1947, and there were few new ones. The number of landslides extending over the 46-year period was 126, but the area affected by landslides decreased from 179.4ha in 1947 to 36.3ha in 1993. We shall focus on long-term remaining landslides and analyze geographical factors of areas where the vegetation did not recover in the short term.

View full abstract

Evapotranspiration is a key element in water conservation-related forest public functions. The purpose of this study was to establish an estimation for areal evapotranspiration, using a modified Penman method, remote sensing and GIS data. The study area was the Tsuga dam site basin and the Ushiro river basin in Kochi Prefecture. Results were compared with information estimated by hydrological equations. Our results show that this method could reliably estimate and reproduce actual evapotranspiration over a wide area. Moreover, the possibility of using this application for land use simulation was clarified. This method may also be useful in providing information for the evaluation of public function in forest management.

View full abstract

2004 Partnership is an important factor in constructing participatory forest management in local communities, and the process of building needs to be discussed. As a first step, using a questionnaire approach targeted at ninety forest voluntary organizations, I analyzed (1) social backgrounds, (2) stakeholders' contribution to the partnership (finance, land, labor, forestry information) and (3) leadership in constructing the partnership. To get further information for the process of constructing partnerships, two cases in suburban areas were compared. As results, it is suggested that partnerships consist of three primary stakeholders-local residents (Forest voluntary organizations), forest owners, and local government, but that the actual members of the partnership depend on the social setting and background of the local community. Partnership is seen to be constructed through two basic patterns. One can be called a 'bottom-up' style where local residents take the lead in the construction of the partnership and the decision making system. The other is a 'top-down' type where local government constructs the system first and gives local people the opportunity to participate in forest management. After the analysis of the cases and the questionnaire data, five patterns are found (three bottom-up types and two top-down types). The process of constructing partnership seems to be affected a lot by the leadership that the stakeholders take as well as the social background.

View full abstract

The purpose of this paper was to estimate for site indices in a Japanese Cedar forest with the machine learning system C4.5. Data inputted to the machine learning system consisted of four topographical factors : effective relief, topographical exposure, enabled storage capacity and flow accumulation. The output data set up four patterns. Classes 3, 5 and 7 were calculated based on the maximum-minimum value of the observed tree height, and Class 4 was calculated using site indices. Estimations by the machine learning system were compared with estimated results by both a multiple regression analysis model and a neural network model. As a result, the best classification accuracy and the best estimation accuracy for unseen cases were 87.5% and 66.6%, respectively. The machine learning system was superior to the multiple regression analysis model, though its estimation accuracy was slightly inferior to that of the neural network model. It was possible to construct a model with comparatively few rules ; the number of production rules was ≤7.

View full abstract

In Kawakami-mura which is the center of the Yoshino forestry area, the Yamamori system where local peoples called Yamamori are entrusted with the care of absentee owner's forest in response to consignment from the end of the Edo period has performed forest management in the village. However, inactivation of a wood price and aggravation of the profitability of forest management, and continuation of the Yamamori system is a critical situation in recent years. This research aimed at clarifying the actual condition of Yamamori's qualitative change. Fact-finding on the spot to Yamamori was conducted in 2004 based on the Yamamori list made in 1965. Consequently, it turns out that 54% of Yamamori of 243 totals already went out of Yamamori. Yamamori with a smaller management forest area is in the tendency for discontinuance of business to progress, Yamamori of a management forest area of 100ha or less has a low income dependence to forests, and pursuing a side business and aging are advancing more. In the future, they lose the knowledge and technique about forests and are considered that a possibility of playing only the role which patrols forests is high. The amount of enterprises in a management forest is decreasing, and it became clear that some Yamamori produce logs in forest other than management forests.

View full abstract

The demand for paper and pulp is increasing rapidly, as market economy in China is making expands. As a consequence, a bottleneck in supply chain has resulted featuring an unfavorable supply structure and supply shortage of raw materials which is greatly restricting the development of the Chinese paper industry. In relation to this situation, the Chinese Government announced goals to change the supply structure of raw materials by increasing use of wood fiber and other by-products, and to expand recovery and recycling of waste paper, additionally to aim toward more effective use of non-wood fiber (mostly botanical fiber). The purpose of this paper is to ascertain whether the predicted goals could be achieved. Based on the analyses of data and experts' interviews, following results were obtained: (1)Adjusting supply structure of the Chinese raw materials within a short period will be very difficult to achieve. (2)During the present transitional period, primary wood materials shouldn't be the sole main raw material. Raw materials should include the increased use of waste paper, use of wood material should be raised little by little, and similarly reasonable application of non-wood material should be encouraged. (3)Although foreign capital is already invested in construction of raw material plantation and production bases, a remaining important subject is to better anticipate future tendencies of the Chinese paper industry.

View full abstract

The topic related to cost recovery is becoming major issues in recreation planning of natural areas. The equity issues and overuse problems are moving forces behind such movement. This paper first followed the development of user pays such as entrance fees and user fees, then analyzed the trends of user pays in Japan's natural areas. Concession revenue was expected in the early stage of national park management. However, specific user fees such as parking was found to be realistic later. On the other hand, national forests depended on revenues from land rent, but such revenues were not held on each site. Entrance fees have been introduced at specific recreational sites in national forests though the revenue is limited. In both areas planners/managers failed to recognize the cost recovery as a effective tool to supply improved service for visitor satisfaction. At the same time, dual-agency management of the same areas made introduction of concession difficult.

View full abstract