Derivation, fitting, and implication of a compatible stem taper-volume-weight system for intensively managed, fast growing loblolly pine

Abstract

Geometry-oriented methodology yielded a compatible taper-volume-weight system of models whose parameters were estimated using data from intensively managed loblolly pine (Pinus taeda L.) plantations in the lower coastal plain of Georgia. Two segments (separated at a stem ratio of 0.60 of total height) depicted taper, volume, and weight variations of the stems as well. The taper function defines stem taper as a proportion of the diameter at breast height. The segmented volume equation was derived from integration of the taper function along the stem, and it can be readily transformed into a ratio volume equation. Likewise, the segmented weight equation was obtained from integration of the volume function and a wood density function. Data analysis showed that fertilization has significantly reduced taper (inside and outside bark) on the upper segment and augmented stem merchantable volume in this segment. However, unit-weight (green wood and bark, green wood only, and dry wood only) was not significantly different between fertilized and unfertilized trees, implying that annual fertilization did not reduce the specific gravity very much. Finally, our analysis showed no significant impacts of complete vegetation control on taper, volume or weight characteristics.