Predicting Survival of East Texas Loblolly and Slash Pine Plantations Infected with Fusiform Rust
Abstract Repeated measurements during 1982-1992 of East Texas Pine Plantation Research Project permanent plots in loblolly (Pinus taeda L.) and slash (Pinus elliottii Engelm.) pine plantations throughout East Texas were used to develop equations for predicting the future number of trees per acre. A typical condition of East Texas pine plantations is the incidence of fusiform rust (Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme). A regression procedure for fitting nonlinear systems of equations was used to fit survival models that considered the possibility that trees with no rust galls on the stem could either (1) remain uninfected and alive, (2) become infected yet still alive or (3) die. For infected stems, only two possible outcomes were considered in the model: (1) remain infected and alive or (2) die. Analyses of the differences between predicted and observed values indicated no adverse trends for either of the two species. Apparently the models do represent observed survival patterns. South. J. Appl. For. 20(1):30-35.