The integration of water production values for forest ecosystems into forest management models has become increasingly important in sustainable forest management in recent years because forests play a vital role in the quantity and quality of surface and ground water resources. The main objective of this work was to develop a multiple use forest management planning model, focusing on the economic effects of some forest management policy constraints on timber and water production values for forest ecosystems. Each forest value is functionally linked to stand structure and is quantified economically. Various forest management planning scenarios were developed to be applied in a typical forest that has the potential to yield timber and water benefits. The analysis was performed by formulating a linear programming-based multiple-use forest management planning model. The results show that the total net present value (NPV) of timber and water production profits would be reduced by up to 25.3% when area and timber volume policy constraints are incorporated into an unconstrained forest management planning model. The results also indicate that, if forests are managed to meet some forest management policy constraints, the NPV of timber production is considerably reduced. In addition, the interactions between timber and water are found to be complementary, depending on the assumed relationships between forest ecosystem structure and forest values. In terms of forest management, the issue of water quality and quantity is likely to become even more important in the future, due mainly to increasing demand on water.
Keywords: Forest management, Net present value (NPV), Optimization, Timber production, Water quality and quantity