PREDICTING THE CROWN SHAPE OF LOBLOLLY-PINE TREES

A model to predict the crown shape of loblolly pine (Pinus taeda L.) t rees in stands is presented. Crown shape changes due to growth, compet ition, and age are modeled as functions of changes in individual tree characteristics. An average symmetrical vertical cross-sectional profi le is assumed for practicality, which consists of outer and inner shap e functions. The outer shape is modeled with a second-degree polynomia l constrained to equal zero at the crown tip. Its flexibility allows t he vertical movement of maximum crown radius due to competition. The e ssentially cone-shaped inner defoliated area of a loblolly pine crown is modeled as a straight line. The equation system allows determinatio n of key crown measures such as maximum crown radius and its height, c rown volume, and crown surface area. Fitted equations presented are va lid for unthinned loblolly pine in Louisiana, U.S.A., stands, but the model, methodology, and results should be useful more generally.