ENVIRONMENTAL IMPACTS OF NATURAL FOREST MANAGEMENT IN THAILAND

บทคัดย่อ

Environmental impacts of natural forest management in Thailand were formulated through available information and discussion in various seminars. The quantitative evidence of this study is rather few. Only descriptive and semi- quantitative impacts were discussed in some current publications. It could be generally concluded that, timber harvesting by any silvicultural system ever used in the natural forest of Thailand produced less environmental impact in terms of soil and water deterioration than that caused by agronomic practices. Less than 0.5 ton/ha of sediment was found in the first year of logging operation under selection cutting in the western region. Converting moist evergreen forest in the south into para-rubber plantation, which is equivalent to reforestation after clearcutting, caused about 7 ton/ha/yr of soil loss. Since the selection cutting which has been applied in various types of forest in Thailand for almost century resulted in mutually destructive both the socio- economic and forest ecological systems, clearcutting system at optimal size ranging from 600-2,000 rais and immediatly reforested by suitable species is recommended for forest management in the future. Based on the past situation, however, it is not a matter of environmental consequences to judge whether the forest can be sustainably managed but the socio- political pressures. which sofar received less attention to seriously resolve by the government. Without people's realization on the essential roles of forest on environment and their quality of life, the ideal sustainable management of natural forests in this country is hardly possible.