Journal de gestion de la biodiversité et de foresterie

Vegetation Cover Change in Glacier National Park Detected using 25 Years of Landsat Satellite Image Analysis

Christopher Potter

Landsat satellite imagery at 30-m ground resolution was analyzed for Glacier National Park (GNP) Montana (United States of America) to determine when and where canopy green cover had changed significantly across the National Park area since the mid- 1980s. Image comparisons for the years 1984 and 2010 showed that consistent increases in the normalized difference vegetation index (NDVI) have been observed at several treeline areas, some of which have been monitored for increased tree cover for more than 75 years. Significant correlations between positive NDVI change and elevation were detected between 1500 and 1800 m elevation. Nonetheless, the greatest changes in NDVI over the past three decades in GNP have been caused by wildfires that burned more than 15% of the Park’s forested area over the past 10-15 years. As of 2010, less than 50% recovery of pre-fire canopy green cover was observed in most areas burned at high severity during 2003 and 2006. It is hypothesized that documented snowpack reductions and associated springtime temperature warming may be having detectable impacts on the slowing rate of post-wildfire regeneration rates of forests burned in GNP.