Japanese Journal of Forest Planning

The increasing population and rural poverty have resulted in the expansion of agriculture into reserved forest which has been decreasing from 53.33% of the total country area in 1961 to 26.64% in 1991. Being awared of this prblem, the Government of Thailand initiated a forest village program in 1975 to improve the social and economic conditions of the poor and forest reserves occupants, and to resolve conflicts between their needs and the National Forest Policy. This paper provides the background on the development of forest village program implemented by the Royal Forest Department, and also discuss the previous and present situations of forest village projects. Recommendations are given if the government is to continue this program. In addion, the government policy on land reform program is also reviewed as it has been widely implemented since 1992.

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The curve given by the generalized power equation, which has been successfully applied to describe relationships between tree functional amounts and tree size, maintained its shape when plotted on logarithmic coordinates for a fixed exponent value regardless of two other coefficient values. It was found that the generalized power equation belonged to a specified tribe of curves, recognized as a generalization of the well-known Competition-Density curve. The generalized Competition-Density curve is newly abbreviated in this paper as the Size-Dependence curve. The Size-Dependence curve includes Ogawa's Relative-Growth curve as a special case. Explicit formulae of the eight different Size-Dependence curve types were systematically represented. The eight different Size-Dependence curve types were united together by appropriately inverting on logarithmic coordinates. A graphic method for obtaining the Size-Dependence curve coefficient values was proposed.

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This paper reports on the development of a computer system that predicts growth of plantations using information in a stand table data base. Sugi (Cryptomeria japonica) and hinoki (Chamaecyparis obtusa) plantations in the Tokyo University's Chichibu Forest were used as study areas. The computer system developed predicts the future mean diameter, mean height, stocking, basal area, and stand volume when supplied with species and present age, mean diameter, mean height, stocking, and ratios of number of trees by diameter class for each subcompartment. If a user specifies a year, the system retrieves sugi and hinoki plantations from the data base and predicts their states at the specified year. Any beginning prediction age, prediction period length, and initial stand structure can be chosen. Site quality determined growth equation parameters which can vary with each stand. Thus, each stand's growth is predicted separately as its site quality varies. This system is different from existing growth and yield simulation systems because it was developed for a particular purpose and area. The prediction method was developed to match the purpose and the available data. Nonetheless, the computer system developed is applicable to other areas by modifying some parameters, and by constructing and formatting stand table data bases like that of the Chichibu Forest.

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The Ezomatsu is one of the major species constituting forests in Hokkaido. Many of the forests in which Ezomatsu trees are found are either of mixed or multi-storied stand types with large accumulations of biomass. These forests characterize the natural landscape environment of Hokkaido. The Ezomatsu has a high utility value as a lumber resource. Ezomatsu in pre-war period made up 80 million m^3 for about half of the conifer resources. However, more than 1 million m^3 have been felled annually since the development of Hokkaido's forests, and the recent resource level has decreased greatly to less than 50 million m^3, or only 17% of the conifer resources. This large decrease has resulted from felling without replanting, that is, the careless forest management of the past. To maintain and create forests which are suited to the climate of Hokkaido and to secure lumber resources for the future, it is important to reconsider the way in which we have handled the Ezomatsu and to promote sustainable regeneration of the resource.

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