A Model for Assessing Hardwood Competition Effects on Yields of Loblolly Pine Plantations

A model was developed to predict pine survival, growth and yield for unthinned loblolly pine plantations with varying levels of hardwood competition in the main canopy. Inputs for the model are number of loblolly pine trees per acre planted, site index for loblolly pine, percent of hardwood basal area in the main canopy of the stand, and age(s) at which output is desired. From these inputs the model computes, by 1-inch dbh classes, the number of trees surviving, basal area, and volumes per acre. The model, which was constructed using sample plot data from old-field and cutover-site plantations, was validated with independent data from a hardwood conversion/site preparation study. Overall, there was close agreement between the observed values and the model predictions.