Global Forest Biomass Change

The estimation of biome-wide forest cover and forest cover loss by the Global Forest Monitoring Project was based on a probability-based sampling approach employing multi-resolution satellite data. Biome-wide change indicator maps were created using moderate spatial resolution imagery for 2000 to 2005 from the MODerate Resolution Imaging Spectroradiometer sensor (MODIS). These change indicator maps were used to stratify the respective biomes into high, medium and low change likelihood strata. Subsequent samples of 18.5km by 18.5km blocks of high spatial resolution image pairs from the Landsat ETM+ sensor were taken within each stratum and used to determine biome-wide area of forest clearing. The method will be extended to AVHRR 1990s data as well.

The sampling strategy employed the MODIS data in the design to stratify the blocks and also in the analysis via a survey sampling regression estimator of forest clearing. This statistically rigorous sampling strategy provides a biome-level clearing estimate with known uncertainty.

Biome data and results are available for boreal forests, temperate forests, dry tropical and subtropical forests and woodlands, and humid tropical forests. Global data are also available. See individual biome monitoring web pages for relevant scientific publications related to this research. The research was sponsored by the NASA Land-Cover and Land-Use Change Program.