Use of a generalized sigmoid growth function to predict site index for unmanaged loblolly and slash pine plantations in East TexasThis article is part of a larger document. View the larger document here.
A generalized sigmoid growth function was used in this study to model site index (SI) for unmanaged or lowintensity managed loblolly pine (Pinus taeda, L.) and slash pine (Pinus elliottii, Engelm.) plantations in east Texas. Schnute's growth function was fit to 11,367 and 5,040 height-age observations of loblolly and slash pine, respectively. These data were collected over a 20-year period from unmanaged pine plantations located across the east Texas region as a part of the East Texas Pine Plantation Research Project (ETPPRP). The fit model was used to derive SI equations (25-year index age). The SI equations apply to unmanaged or low-intensity managed loblolly and slash pine plantations in east Texas ranging in age from 5 to 40 years. They can also serve as a baseline for SI estimation of intensely managed pine plantations.