Tropical forests are decreasing at the rate of 16.9 million hectares per year due mainly to clearing for agriculture and shifting cultivation. Timber harvesting results for more than 5 million hectares of tropical forest becoming degraded looged-over forests every year without any adequate management. The decrease and degradation of tropical forests caused by anthropological activities affect not only the sustainable production of timber but also global environments. The clarified scientific information on the rehabilitation of degraded tropical forest ecosystems enables managers to devise silvicultural systems which enhance soil properties and forest resources important to sustainable production and minimise deleterious effects associated with harvesting impacts and short rotation of plantation. Rehabilitation is aimed to improve biological diversity, increasing commercial value for timber and non-timber products, increasing forest functions, improve soil fertility. Technically developments are expected for reducing logging impacts, accelerating natural regeneration, species selection, enrichment, sustainable site management, catalytic plantation, site evaluation and classification. Socioeconomic developments are also expected for local community participation and socio-economic acceptability. Following research activities have been considered (1) evaluation of forest harvesting impacts on the forest ecosystems: (i) evaluate logging and yarding methods on disturbance of forest ecosystems, (ii) analyse the demography of regenerated tree population, (iii) model a/de-gradation processes in forest ecosystems, (2) development of methods to rehabilitate logged-over forests and degraded forest lands: (i) treatments accelerating natural regeneration, (ii) development of enrichment planting methods, (3) development of silvicultural techniques on degraded forest lands: (i) development of species-site matching methods, (ii) management options for sustained productivity, (iii) social and economic acceptability of management options. In Indonesia, CIFOR co-operates with Universitas Mulawarman, and looks at (a) evaluation of forest harvesting impacts on the forest ecosystems, and (b) evaluation of forest harvesting and fire impacts on the forest ecosystems and development of methods to rehabilitate logged-over forest and degraded lands. The site is Bukit Soeharto Education Forest, a mixed Dipterocarp forest logged by INHUTANI I in 1976. The forest has been heavily burnt in 1998 after experimental treatment. The approach to rehabilitation has been through the "taungya system" whereby farmers are allowed to grow annual crops among the newly-planted trees. With the Instituto Nacional de Investigacion Agraria (INIA), Peru, the project is trying out re-vegetation of abandoned fallow fields after agricultural use. There is specific interest to select tree species having high economic value that can adapt and grow rapidly in abandoned agricultural land and on infertile soils. Sites are all located in the Ucayali region of the Peruvian Amazon. After the first two years, results are pointing to specific promising species that can be recommended. The project involves small farmers in silvicultural activities and even species choice takes into account their preferences.
. Proceedings of International Seminar on Restoration Research of Degraded Forest Ecosystems, College of Agriculture and Life Sciences, Seoul, Korea, April 13rd-15th 2001
Seoul National University, College of Agriculture and Life Sciences