The data base structure is organized around three main tables. DENDRO table contains raw tree ring data (ring width, densitometric variables). SITE table gathers information about the sites location (geographical coordinates, administrative and geographical definitions). POPULATION table concerns ecological information about tree sites: topographic characteristics (topography, slope, elevation, aspect), geological and soil characteristics, vegetation characteristics (forest structure and phytosociological context). Some other tables contain meta-data about core description: CORE table, which gives information about the wood (sapwood, bark...), TREE table, about trees, SPECIES table and CONTRIBUTOR table, this last allowing a well-functioning of the data base policy and future exchanges between users and contributors.