Relationships between water, nutrients and productivity in Australian forests: Application to wood production and quality

The application of knowledge of water and nutrient relationships to improve forest management is discussed from an Australian perspective. The objectives of tree planting and forest management have become diverse, and there are outstanding examples of successful application of research results to forestry. Experiments seeking to explain the way water and nutrients influence growth tend to use treatments designed to ensure large differences in growth to increase the opportunities for identifying the mechanisms involved. The application of results from such research to many forestry situations, however, is harder than from research in which there is a closer match between treatments and management practices. The expectations of process-based models as management tools for economic decision-making is yet to be fulfilled. More progress is required in our ability to predict accurately the effects of soil and stand management practices on the production of marketable wood. The extent to which results of research on silvicultural practices are applied in practice is ultimately dependent upon economic return from investment. Water and nutrient relations have a significant influence on production, harvest index and log and wood quality. Recognition and understanding of this influence and the availability of management-oriented growth models incorporating process-based information, will permit better assessment of potential returns from management options.