Analisi strutturale ed evolutiva in acero-frassineti di neoformazione delle Valli di Lanzo (TO)

In the Lanzo Valley (N.W Piedmont, Italy), 8 ash maple secundary stands with trees 5-35 years old have been studied. Seedlings start immediately after the abandonment and stop after 5-10 years. The stand densities are very high in every phases of the forest's growth. The stands are always dominated by one species: ash on former meadows and maple on former fields. Among the other species present as mother trees, beech neither takes part to the invasion of fallow land, nor regenerate even 30 years after the abandonment. Grassland vegetation persists for a very long time: more than 10 years after abandonment grass species are still dominant in the undergrowth. In the same time the development of nitrophilous species has been observed. A tipical forest vegetation is present after 30-35 years from the abandonment. Generally secundary ash-maple stands have a good ecological and structural stability.