ASSESSING MEASURES OF TREE COMPETITION USING FIXED-AREA, VARIABLE RADIUS, AND HORIZONTAL-LINE PLOT SAMPLING

Fixed-area plot sampling, variable-radius plot sampling, and horizonta l-line plot sampling performed similarly in estimating competition fro m adjacent trees if only plots were considered that had an adequate nu mber of sample trees to compute the estimated indices. The percentage of plots for which the indices can be computed tends to be largest for variable-radius plot sampling, then line sampling, and last for fixed -area plot sampling. Variable-radius plot sampling performs about as w ell as fixed-area plot sampling in computing the competition measures used in the distance-dependent tree models evaluated in this analysis.