The Alaska four-phase forest inventory sampling design using remote sensing and ground sampling

A four-phase sampling method using Landsat, high-altitude color infrared photography, low-altitude color infrared photography, and ground samples was tested in interior and coastal Alaska from 1982 through 1986. Ratio and regression estimators were applied using variables at the remote sensing phases as covariates related to variables of interest measured on the ground. The four-phase sampling strategy yielded more efficient estimators in coastal Alaska's more heavily timbered area than in interior Alaska's highly heterogeneous vegetation complexes. Advantages and disadvantages associated with each of the phases of the study are presented, as well as a general evaluation of the entire system