Forest site classification and evaluation: a South African perspective

The current South African forest resource is managed through intensive silviculture of fast-growing exotic species. Increased intensity in managed practices in a forestry environment that is characterised by diversity in growing conditions, will require reliable decision support tools that facilitate informed decision making. This paper highlights the conceptual approach of forest site classification, the development of site evaluation models, and the formulation of management systems and policies. The multi-factor, hierarchical approach to site classification used in South Africa is discussed against an international perspective, and possible future directions are highlighted. A review is provided on the outcome of site-growth studies undertaken in South Africa, and the importance of development towards process-based models is indicated. The highly variable, site-specific response found with fertiliser trials is outlined, and the importance of site-classification systems in formulating nutrient management policies is also highlighted. The status of growth and yield modelling in South Africa is briefly discussed, including the crucial role of site-classification systems in developing site-specific growth models. The development of a policy regarding sustainable forest management is a priority, and the importance of spatial site information in this venture is discussed. The integration of the three different concepts; site classification, site evaluation and management systems, into a common platform for decision making, is proposed. Together with geographic information technology, these integrated components can form the, essential elements to a forest management decision support system. (C) 2002 Elsevier Science B.V. All rights reserved.