structure spatiale des arbres des savanes boisées et forêts claires soudaniennes : implication pour les enrichissements forestiers

Spatial distributions and interactions of trees in Sudanian woodlands: implications for forest enrichment. During the last decade, management of woodlands in the Sudanian region of Benin has been based on enrichment with valuable tree-species. Yet, no previous research has been undertaken to support enrichment design with respect to plant eye view, tree growth magnitude or survival capacity under local forest environments. To fill in this gap, Ripley's K function was used to assess the spatial pattern of trees, diameter classes and dominant valuable species in the Sudanian zone. Data were collected in four sites of variable size (150 x 100 m, 150 x 100 m, 100 x 50 m and 150 x 150 m). Mostly, the spatial patterns of the target species revealed small-clumps. Within these small-clumps, intraspecific repulsions were observed on average at a 3 m scale, while interspecific repulsions were noticed at a 4.5 m scale. Only a weak repulsion between diameter size was also remarked, suggesting that proximity to adult trees would not affect the survival of young plants. With regard to observed repulsion scales, we would suggest using a minimum of a 3 m space between trees of the same species and a 4.5 m space between trees of different species, for enrichment plantings in Sudanian woodlands, if based on the target species. However, this suggested spacing may not be optimal with regard to plant growth. Further investigation is needed to address this aspect.