Comparison of two remote sensing time series analysis methods for monitoring forest decline

National audienceIn Europe, the 2003 summer heat wave damaged forested areas. The purpose of this study is to compare two methods to analyse time series of NDVI images for monitoring forest decline. The first method is based on phenological indicator linked to spring vegetation activity, and on the analysis of its trend. The second method (BFAST) allows extracting the trend by decomposition of NDVI time series into trend, seasonal and remainder components. The two approaches show similar results for trends estimates. The main advantage of BFAST is its capability to detect breakpoints in the linear trend which highlights the impact of the exceptional climatic conditions in 2003 on forest stands development