Sector subsampling for basal area ratio estimation: an alternative to big BAF sampling

Abstract

Big basal area factor (big BAF) sampling is a widely used subsampling method to select measure-trees. Several studies have shown big BAF sampling to be an efficient sampling scheme. In this study, we use sector sampling (Smith et al. 2008, For. Sci. 54: 67–76) as an alternative subsample selection method. Based on some simulated mapped stands derived from three balsam fir (Abies balsamea (L.) Mill.) spacing trials in western Newfoundland, we show that sector subsampling is comparable to big BAF sampling in terms of estimated mean basal area ratios and their associated standard errors. Differences between big BAF sampling and sector sampling methods showed less than 1% difference across the three sites. As with big BAF sampling, changes in sample intensity had no significant (p < 0.05) effects on the accuracy of estimating mean biomass to basal area ratios and the resulting estimated mean biomasses per unit area.