Compatible stem taper, volume, and weight equations for young longleaf pine plantations in southwest Georgia

Outside and inside bark diameter measurements were recorded from tree disks obtained at 0, 0.5-, 2.0-, 4.5-, 6.0-, 16.6-, and at 4-ft-height intervals above 6 ft to a 2-in. diameter outside bark top diameter on 42 longleof pine trees selected from intensively managed longleaf pine (Pinus palustris Mill.) plantations in Dougherty and Worth Counties in southwest Georgia. Trees were sampled from unthinned, cutover stands in their 11th and 14th growing season, which are currently part of an existing growth and yield study. Sample trees ranged from 2 to 7 in. in diameter and from 18 to 40 ft in total height. Parameters for a segmented polynomial toper and compatible cubic foot volume and weight equation were simultaneously estimated using a seemingly unrelated nonlinear fitting procedure to volumes based on a generalized Newton formula and an overlapping bolt methodology. Average error was approximately 0.25 in., 0.04 ft(3), and 2.5 lb for taper, volume, and weight estimation, respectively.