Self-referencing Taper Curves for Loblolly Pine

We compare the traditional fitting of relative diameter over relative height with methods based on self-referencing functions and stochastic parameter estimation using data collected by the Virginia Polytechnic Institute and State University Growth and Yield Cooperative. Two sets of self-referencing equations assume known diameter at 4.5 feet inside (dib) and outside (dob) bark; and one set assumes known only dob at 4.5 feet. A fourth degree polynomial in one minus relative height describes taper. The proposed methods improved the error sum of squares by up to 47 percent over the traditional method.