The wood-density-Cirad GitHub repository includes the R script, data and results associated to the following scientific article: Vieilledent G., F. J. Fischer, J. Chave, D. Guibal, P. Langbour and J. Gérard. New formula and conversion factor to compute tree species basic wood density from a global wood technology database. in preparation. The Cirad (http://www.cirad.fr) is the French agricultural research and international cooperation organization working for the sustainable development of tropical and Mediterranean regions. Since the 1950s, scientists at Cirad have compiled data on wood characteristics for hundreds of tree species around the world. Data have been compiled in a unique global wood technology database. Combining our research results with the data from the wood technology database, we were able to compute the basic wood density for each tree and derive the Cirad wood density database (CWDD). The CWDD is available as a comma-separated values file: Cirad-wood-density-database.csv. It includes basic wood-density data Db (in g/cm3) for 4022 trees collected in 63 countries (mostly tropical) and representing 885 species. Basic wood-density has been computed from the wood-density at 12% moisture D12 (in g/cm3), the volumetric shrinkage coefficient R (in %/%), and the fibre saturation point S (in %) for 3832 trees. When R or S values were not available (for 190 trees), the basic wood-density was estimated from D12 using a conversion factor of 0.828: Db = 0.828 D12.