[List of Publications]

[Annual Report 97 :
Table of Contents]

Tropical forests are decreasing at the rate of 17 million ha per year, due mainly to clearing for agriculture. Moreover, timber harvesting results in more than 5 million ha of tropical forest becoming secondary forest. The decrease and degradation of tropical forests affect not only the production of timber but also global environment. It is, therefore, an urgent matter to rehabilitate these degraded forests. The main question of rehabilitation is how to create appropriate growing conditions for each species from the juvenile to the mature stage. Where short-rotation plantations are being established there will be changes in nutrient storage and cycling processes due to the harvest of large quantities of wood, changes in organic matter quality, fertilisation, erosion, leaching, etc. All of these factors will affect storage and supply of soil nutrients for tree growth and consequently sustainability of the entire plantation system. Opportunities exist to regulate soil organic matter through silvicultural practices. The challenge for researchers is to develop silvicultural systems to ensure plantation productivity does not decline or is improved over successive rotations. They should also aim to improve soil quality and other environmental values. In 1997 continuing financial support from Japan enabled links with partners to be formalised and experimental plots established in tropical Asia and South America.