Data were collected on open-grown loblolly pine (Pinustaeda L.), longleaf pine (Pinuspalustris Mill.), and shortleaf pine (Pinusechinata Mill.) and analyzed to provide predictive equations of crown width and maximum potential basal area growth for crown competition and growth and yield models. The measurements were taken on 115 open-grown loblolly pine trees and 76 shortleaf pines in southeastern Arkansas. The longleaf pine data consisted of 81 open-grown trees from southern Alabama, Georgia, and Florida. A circle and an ellipse were tested as geometric models of the vertically projected crown. No significant differences between the tree shapes were found based on analyses of length and azimuth of the largest crown diameter, and the circle was chosen as an appropriate model. This indicated that only the distance between trees, not their orientation to one another, need be included in models of crown competition based on crown contact. Predictive equations of mean crown width based on diameter at breast height were fitted for each species for use in models of crown competition. A Chapman–Richards growth rate function with an intercept term was fit to periodic annual inside-bark basal area growth based on initial inside-bark basal area to provide empirical estimates of maximum basal area growth rates for growth and yield modeling of the given species. Additionally, equations to predict double bark thickness as a function of diameter at breast height were fit for each species to facilitate the use of the equations with outside-bark measurements of diameter.

A site-index function is presented for naturally regenerated stands of longleaf pine (Pinus palustris Mill.) in the East Gulf area. The equation resulted in minimum average differences in consecutive site-index estimates five years apart in 170 stands, when compared to two equations currently in use.

Equations are presented for estimating current volume, projected basal area, and projected volume for stands of loblolly-shortleaf (Pinus taeda L.-Pinus echinata Mill.) pine managed under the selection system. The independent variables are initial stand basal area and elapsed time. The estimates should provide a guide to the cubic-foot volume production that might be expected from stands on average sites (site indices 80-90 ft.), medium basal areas (30 to 70 sq. ft.) and time periods of 10 years or less.

In this study, 588 before-cut and 381 after-cut diameter (dbh) distributions of uneven-aged loblolly-shortleaf pine stands were fitted to two different forms of the exponential probability density function. The left truncated and doubly truncated forms of the exponential were used. The fitted distributions were evaluated using the Kolgomorov-Smirnov one-sample test at the 0.05 significance level. The rejection rates for the singly truncated form were 88 and 89 percent, respectively, for before-cut and after-cut stands. The rejections ran 72 and 77 a percent for the doubly truncated function. Neither function adequately describes the structure of the stands used in the study, but each may have utility in certain regulation applications.