Quantifying mortality of tropical rain forest trees using high-spatial-resolution satellite data

Assessment of forest responses to climate change is severely hampered by the limited information on tree death on short temporal and broad spatial scales, particularly in tropical forests. We used 1-m resolution panchromatic IKONOS and 0.7-m resolution QuickBird satellite data, acquired in 2000 and 2002, respectively, to evaluate tree death rates at the La Selva Biological Station in old-growth Tropical Wet Forest in Costa Rica, Central America. Using a calibration factor derived from ground inspection of tree deaths predicted from the images, we calculated a landscape-scale annual exponential death rate of 2.8%. This corresponds closely to data for all canopy-level trees in 18 forest inventory plots, each of 0.5 ha, for a mostly-overlapping 2-year period (2.8% per year). This study shows that high-spatial-resolution satellite data can now be used to measure old-growth tropical rain forest tree death rates, suggesting many new avenues for tropical forest ecology and global change research.