Stem analysis program for coniferous forest tree species

The objectives of this study were to describe and demonstrate a PC-based stem analysis program applicable to coniferous forest tree species. From annual ring-width xylem sequences obtained from cross-sectional samples located at multiple stem heights, the program computes: radial and longitudinal ring-width sequences, apical growth increments, sectional and cumulative volume production patterns, and stem developmental profiles. Computations are based on the following geometric assumptions: (1) the stump, tip and sections in between are treated as geometric solids of revolution resembling a cylinder, cone, and frustum of a cone, respectively; and (2) for sections in which increments are not continuous throughout, computations are based on a geometric solid of revolution resembling a cone. The program corrects for slant-based sectional length measurements using the Pythagorean theorem and eliminates the need to externally predict height for a given age via a linear interpolation procedure. The utility of the program is demonstrated via a comparison of the longitudinal radial growth patterns of jack pine, Pinus banksiana Lamb., trees that developed under different density management regimes.