Remote sensing assessment of forest damage in relation to the 1996 strong typhoon Herb at Lienhuachi Experimental Forest, Taiwan

摘要

Across wide areas of the globe, typhoon disturbance is an important component of landscape-level vegetation dynamics. We used satellite images to evaluate changes in normalized difference vegetation index (NDVI) related to the 1996 typhoon Herb at Lienhuachi Experimental Forest (LHCEF) in central Taiwan. NDVI decreased from 0.89 before typhoon Herb to 0.82 afterwards. NDVI decrease associated with typhoon Herb was only 0.03 (0.93-0.90), at a site in northeastern Taiwan, despite the fact that the typhoon passed directly over northeastern Taiwan. This observation fits the global pattern of comparable storms generating greater damage in less frequently impacted forests than in forests which are impacted more frequently. Topography affected patterns of typhoon damages at LHCEF with the greatest NDVI losses occurring at higher elevations and on west-facing (windward) slopes. Unlike previous studies in North and Central America and in northeastern Taiwan that found greater typhoon/hurricane damages in even-aged conifer stands than in native hardwood forests, NDVI decrease associated with typhoon Herb was greater in the natural hardwood forest (0.08) than the conifer plantation (0.06) at LHCEF. This result suggests that natural forests are not necessarily less vulnerable to typhoon disturbance.