Robinia pseudoacacia in the forested agricultural landscape of the Pisan Hills (Italy)

This research is related to study the cause of diffusion and expansion of Robinia pseudoacacia L. in the Pisan Hills. North Tuscany. Italy. Native woods, mixed with agriculture plots are formed by broadleaf deciduous trees with a prevalence of Quercus cerris L., often with Pinus pinaster Aiton. In this context Robinia pseudoacacia spreads in the auctoctone woods or over the uncultivated plots, forming monospecific phytocenosis and transforming the natural landscape, In this first contribution the surface invaded by R. pseudoacacia is quantified and R. pseudoacacia communities are characterized from the floristic and vegetational point of view. Results show: 1) a strong increase of Robinia diffusion over the last 50 years; 2) an extreme floristic poverty of these communities correleted to age of R. pseudoacacia stands; 3) "mature" R. pseudoacacia communities, if not cutted, can be replaced by native formations.