Development of Growth Models for Pinus radiata in New Zealand-Experience with Management and Process Models

Pinus radiata is intensively managed in New Zealand for both the domestic wood market and the expanding export trade. With a tightening of the timber-supply situation in relation to industry demand, there is a need for precise yield regulation and analyses of the economics of silviculture. Concerns regarding the accuracy of growth and yield models have led to the development of stand-growth models that reflect individual growth regions, and seven such models have been developed, covering the main plantation areas of the country. The resultant models for improved resource management, which embrace both process and management regimes, are profiled. While the management-growth models have been developed based on data from more than 10,000 permanent plots, the process models have so far not been of much use to forest managers. Efforts continue into integrating the process models with existing knowledge about tree physiological growth processes.