COMPATIBLE ESTIMATION OF COMPONENTS OF FOREST GROWTH FROM REMEASURED POINT SAMPLES WITH RESTRICTED GENERALIZED LEAST-SQUARES

Certain of the estimators which have been proposed for estimation of c omponents of forest growth from remeasured horizontal point samples ar e not restricted to ensure that the initial volume estimate plus the g rowth estimate is equal to the final volume estimate. By viewing the i nitial volume, the final volume, and the components of growth as param eters in a linear model within the framework of restricted generalized least squares, estimates can be obtained which satisfy logical restri ctions relating to forest growth. The model should be fitted to data o btained from a relatively large sample of points. Estimates of growth components are obtained on each point in the usual way. However, rathe r than simply averaging these estimates over all points, restricted ge neralized least squares can be used to estimate growth components in t he linear model described above. Since the estimation technique can ha ndle missing or extra points at the two measurement times, the techniq ue can be applied to data obtained by sampling with partial replacemen t.