Influence du sol sur la végétation arborescente en forêt guyanaise: État des connaissances

Abstract

On the scale of individual trees, the predominantly superficial root system appears to be attributable to the chemical fertility of soils, whereas the extreme variability of their vertical distribution would seem to be due to the type of drainage. Deep roots, in spite of their scarcity, play an important role in extracting water during the dry season. On the scale of the stand, the lateral variations in the soil influence processes such as inter-tree competition and silvigenesis. For well-drained soils, the more restrictive the edaphic conditions, the fewer the large trees in the stand. The latter is dense when the soil is very shallow, less dense in hydromorphous conditions. The soil clearly influences the floristic composition of the stands. But other factors such as silvigenetic phases or the inherent dynamics of each particular population also have a significant effect. Contrasting results have led to new assumptions being formulated, including the idea that the thickness of the weathering profile might have a major impact.