Compatible cubic-foot stem volume and upper-stem diameter equations for semi-intensive plantation grown loblolly pipe trees in East Texas

The Max-Burkhart taper equation was used to develop compatible taper and volume equations for semi-intensive plantation grown loblolly pine (Pinus taeda L.) trees in East Texas. Semi-intensive plantations in East Texas are characterized by some form of mechanical site preparation, a burn, possibly chemical weed control, improved seedlings if planted after 1985, and, possibly, a midrotation thinning and/or fertilization. The equations in this study were compared with those of Lenhart et al. [Lenhart, J.D., T.L. Hackett, C.J. Laman, T.J. Wiswell, and J.A. Blackard. 1987. Tree content and taper functions for loblolly and slash pine trees planted on non-old field in east Texas. South J. Appl. For. 10(2)109-112.] and Baldwin and Feduccia [Baldwin, V.C. Jr., and D.P. Feduccia. 1991. Compatible tree-volume and upper-stem diameter equations for loblolly and slash pines in the West Gulf Region. South. J. Appl. For. 10(2)109-112.] using independent data. The new equations ranked first (sum of ranks = 9) in terms of percent bias and percent SEE for inside-bark predictions of upper-stem diameters and cubic-foot volumes, while the Lenhart et al. [Lenhart, J.D., T.L. Hackett, C.J. Laman, TJ. Wiswell, and J.A. Blackard. 1987. Tree content and taper functions for loblolly and slash pine trees planted on non-old field in east Texas. South J. Appl. For. 10(2)109-112.] ranked second (sum of ranks = 17) and Baldwin and Feduccia [Baldwin, V.C. Jr., and D.P. Feduccia. 1991. Compatible tree-volume and upper-stem diameter equations for loblolly and slash pines in the West Gulf Region. South. J. Appl. For. 10(2)109-112.] ranked third (sum of ranks = 22). For outside-bark predictions of volumes and diameters, Baldwin and Feduccia [Baldwin, V.C. Jr., and D.P. Feduccia. 1991. Compatible tree-volume and upper-stem diameter equations for loblolly and slash pines in the West Gulf Region. South. J. Appl. For. 10(2)109-112.] ranked first (sum of ranks = 12), while the new equations ranked a close second (sum of ranks = 13) and Lenhart et al. [Lenhart, J.D., T.L. Hackett, C.J. Laman, T.J. Wiswell, and J.A. Blackard. 1987. Tree content and taper functions for loblolly and slash pine trees planted on non-old field in east Texas. South J. Appl. For. 10(2)109-112.] ranked third (sum of ranks = 20). We recommend using the new equations for loblolly pine trees up to a 16-in. dbh and provide examples to illustrate their use.