Methods for Modeling Individual Tree Growth and Stand Development in Seeded Loblolly Pine Stands

Methods were developed to model growth and development of seeded loblolly pine (Pinus taeda L.) stands, using individual trees as the basic growth units. Aggregated spatial patterns and individual tree sizes are generated at age 10. Tree diameters and heights are then incremented annually as a function of their size, site quality, competition from neighbors, and stochastic components representing genetic and microsite variability. Individual tree mortality is determined stochastically through Bernouli trials. Subroutines were developed to simulate the effects of hardwood competition and control, thinning, and fertilization. The overall model was programmed in FORTRAN and initial tests were made with published yields. The initial stand generation components were calibrated using a comprehensive set of data from young seeded stands of loblolly pine, but individual tree growth and mortality components relied on previously published relationships developed for plantations. Results indicated that, in order to accurately model stand structure, the growth and mortality relationships must be calibrated for seeded stands. Data collection procedures, calibration methods, and recommendations for further work are discussed.