Characterisation of Afzelia africana Sm. habitat in the Lama forest reserve of Benin

A study was carried out in the Lama forest reserve of Benin to characterize the habitat of Afzelia africana Sm., an endangered multipurpose tree species (found in African humid, dry forests and woodlands), in order to define a sustainable management strategy for its conservation. An estimation of species density was done on 100 square plots of 1 ha each, while tree height and dbh of all the species were measured on subplots of 50 m x 30 m within the 1 ha plots. The regenerations of A. africana (dbh < 10 cm) were counted in the diagonal quadrats of the principal plots. Presence-absence data of the species was subjected to multidimensional scaling and results showed four vegetation communities including: young fallow, old fallow, typical dense forest and degraded dense forest. Significant differences were noted between the four communities with respect to dendrometric parameters of the species. High values of these parameters were noted for the species in typical dense forest (5.2 stems/ha, 66.7 cm, 17.9 m, 7.9 m(2)/ha and 38.8% for the tree-density, the mean diameter, the mean height, basal area and basal area contribution of the species, respectively) whereas the lowest values were obtained for the old preforest fallow as far as the mean diameter (59.7 cm), the mean height (15.7 m) and the basal area contribution (27.7%) of the species were concerned. In general, the basal area of A. africana in the over vegetation types was less than 3 m(2)/ha. No A. africana tree was found in the young preforest fallow while more than 80% of A. africana trees were found in the typical dense forest community. Stem diameter and height structures of the species in all the four communities showed a left dissymmetric Gaussian shape and were well adjusted to Weibull distribution. (C) 2009 Elsevier B.V. All rights reserved.