Estimation of the mean in line intercept sampling

Ratio estimation of the parametric mean for a characteristic measured on pl ants sampled by a line intercept method is presented and evaluated via simu lation using different plant dispersion patterns (Poisson, regular cluster, and Poisson cluster), plant width variances, and numbers of lines. The res ults indicate that on average the estimates are close to the parametric mea n under all three dispersion patterns. Given a fixed number of lines, varia bility of the estimates is similar across dispersion patterns with variabil ity under the Poisson pattern slightly smaller than variability under the c luster patterns. No variance estimates were negative under the Poisson patt ern, but some estimates were negative under the cluster patterns for smalle r numbers of lines. Variance estimates become closer to zero similarly for all spatial patterns as the number of lines increases. Ratio estimation of the parametric mean in line intercept sampling works better, from the viewp oint of approximate unbiasedness and variability of estimates, under the Po isson pattern with larger numbers of lines than other combinations of spati al patterns, plant width variances and numbers of lines.