An Integrated Growth and Yield Simulator For Predicting Loblolly Pine Dry Weight Pulp Yields

Abstract

Growth and yield simulators are a valuable tool for forest managers in predicting future stumpage yields and selecting the economically best management strategies and rotation ages. These projections are appropriate for the sellers of stumpage but may not be appropriate for the producers of forest products who also own and manage the raw resource. To identify the most desirable management strategies for landbased mills, the yield model must be capable of making good estimates of final product yields, such as dry weight of pulp, lineal feet of veneer, and size and grade distribution of lumber. The Mississippi State University loblolly pine (Pinus taeda L.) growth and yield simulator has a dry weight pulp yield model fully integrated in the program. Dry weight pulp yields were estimated from stand and tree characteristics using a neural network model for predicting the distribution of wood chip weight by thickness class and a single tree dry weight pulp yield model. These models were embedded in the profile function based tree volume estimator of a cutover site-prepared plantation loblolly pine growth and yield simulator. The resulting model produced estimates of dry weight pulp yields comparable to actual yields. The Windows application growth and yield simulator generates harvested volumes by stumpage class, dry weight pulp yield, and net present values for user selected management regimes and merchandizing standards. It is available at http://www.cfr.msstate.edu/fwrc/software.htm (loblolly). Both stumpage sellers and pulp producers can use the software to place a value on chips from stands according to their expected stumpage and dry weight pulp yields or to select management strategies to maximize yields.