Résumé
Liquidambar styraciflua, or the American sweet-gum tree, is a deciduous species originating in the south-eastem United States and Central America. Its behaviour in plantations is outstanding and its timber is used for multiple purposes. In 1986, under an international provenance trial, the Commonwealth Forestry Institute (CFI) in Oxford distributed Liquidambar styraciflua seeds of thirteen different provenances, mainly harvested in the natural range of distribution of the species extending from the eastern United States to Mexico and Central America. In Madagascar, they were planted by the forestry and fisheries research department (DRFP-FOFIFA) at Mandraka. Data on annual growth were collected for 25 years, but the results, unlike those for Brazil and Mexico, have not yet been published. The aim of our study was to assess adaptation of the species in Mandraka and to investigate intra-species growth variability. Up to 25 years of age, the trees grew steadily to reach, on average, a height of 26 m, a diameter of 38 cm and a basal area of 0.12 m(2) per tree. These average values differ significantly according to provenance. At 25 years of age, heritability in the broad sense is 0.76, 0.60 and 0.63 for height, diameter and basal area respectively, indicating genetic control overgrowth. Under similar ecological conditions and at equivalent age, the growth of L styraciflua is equivalent to that of species of the genus Eucalyptus and better than in Pinus. In comparison with the international CFI trials, the provenance trial for L. styraciflua at the Mandraka site shows better adaptation and a high growth rate for the species.