A Comparison of Various Estimators for Updating Forest Area Coverage Using AVHRR and Forest Inventory Data
Various methods of adjusting low-cost and possibly biased estimates of percent forest coverage from AVHRR data with a subsample of higher-cost estimates from the USDA Forest Service's Forest Inventory and Analysis plots were investigated. Two ratio and two regression estimators were evaluated. Previous work (Zhu and Teuber, 1991) finding that the estimates from the two different data sources differed the most in highly fragmented land-use areas led to an investigation into improving the estimates through the use of independently derived estimates of population density. It is concluded that reasonable updates of percent forest area could be obtained through both the ratio and regression estimators and that use of population density as a surrogate for land-use fragmentation could help improve the estimators, although more direct methods of measuring land-use fragmentation might provide further improvement.