In recent decades, forests worldwide have experienced dramatic and often unexpected drought-related tree mortality events. California recently suffered its most extreme drought on record, resulting in the deaths of tens of millions of trees. Beyond the immediate impact on forests, such mortality events substantially increase the risk of catastrophic fires, which have the potential to change entire landscapes overnight. Faced with forecasts of similar droughts in the future, assessments of forest vulnerability may help resource managers effectively target treatments to reduce the risk of extreme mortality.
U.S. Geological Survey (USGS) scientists combined high-resolution remote sensing imagery obtained during the drought by the Global Airborne Observatory with robust ground-based data to develop models of tree survival probability. These models were used to create a drought vulnerability assessment for a large swath of the mixed conifer forests in Sequoia and Kings Canyon National Parks. The researchers then validated these assessments with an independent dataset. The models were found to be highly accurate for the most abundant species in the forest. Future work may expand the use of these vulnerability tools to the mixed conifer forests of the entire Sierra Nevada. The associated manuscript is available here.
%20We.jpg)
Four-year survival probability for trees in Sequoia and Kings Canyon National Parks. The associated manuscript is available here.
Disclaimer: Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.