Two-Stage and Three-Stage Sampling Strategies to Estimate Aggregate Bole Volume in the Forest : National Forest Inventories

1993

S. 201-211

14 Lit. Ang.

Unselbständiges Werk

200103951

Two-stage sampling strategies are presented which consist of horizontal point sampling at stage one followed by a second stage of sampling with replacement conducted separately at each point from a list of accumulated heights. Analogous strategies are also presented when the first stage of sampling consists of fixed-area plots. The third stage consists of either importance sampling or control-variate sampling of individual tree stems, which obviates the need to rely on tree volume/biomass equations to ascertain the stem volume or biomass of selected trees. For all two-stage and three-stage strategies, the design-based bias and variance of alternative probability-weighted estimators are derived.