A new diameter distributin model for unmanaged slash pine plantations in East Texas

Abstract

A parameter recovery procedure for the Weibull distribution function based on four percentile equations was used to develop a new diameter distribution yield prediction model for unmanaged slash pine (Pinus elliottii Engelm.) plantations in East Texas. This new model was similar in structure to the model of Lee and Coble (Lee, Y.J., and D.W. Coble. 2006. A new diameter distribution model for unmanaged loblolly pine plantations in east Texas. South. J. Appl. For. 30(1):13-20) in their work with East Texas loblolly pine plantations. The new model was compared with the diameter distribution model of Lenhart (Lenhart, J.D. 1988. Diameter distribution yield prediction system for unthinned loblolly and slash pine plantations on non-old-fields in east Texas. South. J. Appl. For. 12(4):239-242. 1988), which was developed for slash pine plantations in East Texas, as well as to two other models developed using iterative techniques suggested and inspired by Cao (Cao, Q. 2004. Predicting parameters of a Weibull function for modeling diameter distribution. For. Sci. 50(5):682-685).The model developed in this study was preferred over Lenhart Renhart 1988) and the other two models in prediction of total frees per acre, basal area per acre, quadratic mean diameter, and cubic-foot volume per acre (wood and bark, excluding stump). An example also is provided to show users how to use this new yield prediction system. We recommend thot the model developed in this study be used to estimate growth and yield of East Texas slash pine plantations. Copyright © 2008 by the Society of American Foresters.