Site Factors Affecting Growth of Slash Pine in the Texas Post Oak Belt

A study was conducted in the Post Oak Belt of East Texas to determine which site factors affected height growth of slash pine (Pinus elliottii Engelm. ). Height-age pairs were developed from stem analysis data. Nonlinear regression was implemented to develop a generalized height-age model. After curves were developed, stepwise regression was used to determine impacts of environmental variables on height growth. Environmental factors correlated with height growth included A horizon depth and those related to moisture relations including seasonal precipitation, average daily temperature, and texture of the A horizon. South. J. Appl. For. 21(2):71-74. The Post Oak Belt of East Texas lies to the west of the natural range of southern pines (LBJ School of Public Affairs 1978). Although pine plantations have been established throughout he area, there are few evaluation data available. Thts ts especially true for slash pine (Pinus ellottii Engelm.). Hansen and Bilan (1989) quantified survival and growth of slash pine growing in the Post Oak Belt north of the Navasota Rtver They found the most critical factor in establishing pine plantations to be the initial survival of planted seedlings. After establishment, growth was comparable to those on sites •n the pine-mixed hardwood forests to the east. Site index curves developed by Hacker and Bilan (1991) indicated favorable height growth patterns for slash pine. There are no long-term data available indicating which environmental factors are most critical for successful height growth of slash ptne tn the Post Oak Belt. The objectives of this study were to develop a generalized height growth model for slash pine and to determine the site variables that may affect height growth.