CARTOGRAPHIE DU CHÂTAIGNIER EN ALSACE PAR IMAGERIE SATELLITE MULTI-DATE.

Of the many tree species that grow in Alsace forest, chestnut trees are considered as promising and adapted to the challenge of global warning. This species has been the focus of a joint French-German Interreg IV study. This three-year study's objective was to develop conservation strategies and to valorize the sweet chestnut. Therefore, it has focused on conservation, on wood and fruit use, and on sweet chestnut preservation as they are faced a canker disease that threatens the forest stands. Within this project, a method has been developed for the precise and up-to-date mapping of chestnut stands throughout Alsace. To distinguish chestnut from other species, the method is based on a targeted selection of satellite images acquired at different seasons and field plot data geo-locating chestnut trees. Thus, SPOT 5 and ALOS AVNIR-2 multi temporal images covering the chestnut tree vegetative phases were used. The study is based on the multi-temporal spectral characteristic analysis of the main deciduous species using field samples. In this way, the spectral signature analysis identified images acquired in early spring and in summer as differentiating chestnut trees. They correspond to the particular characteristics of this species which are its late bud break compared to other species and its abundant flowering. The results of this mapping covering the whole of the Alsace region were validated during field campaigns. This partial validation has shown an accuracy of detection concerning mature chestnut stands of 85%. [ABSTRACT FROM AUTHOR]