Evolution après incendie d'une pinède et d'une steppe dans une vallée intra-alpine (Valais central)
Maumary, Lionel; Vallotton, Laurent; Delarze, Raymond
Subsequently to a survey of the recolonisation of vegetation during the three years following fire in a steppic grassland and a pine forest in central Valais (Delarze & Werner 1985) we reassess the evolution of vegetation ten years later (13 years after fire) and compare the results. Two representative sites have been studied: a pine forest (Odonito-Pinetum) and a dry grassland (Stipo-Poion carniolicae), both on a gentle slope. The grassland has not changed much in composition and is slowly returning to a typical steppic grassland, with better adapted, xerophilous and hemicryptophyte species taking over and eliminating more mesophilous ones and therophytes. In the burnt pinewood, the growth of the pines and pioneer trees is very slow, being stopped in the process of recolonisation by the dominance of dry grassland species, compromising the return of the forest.