Recent growth trends and dynamics in subalpine forest stands in the Susa Valley (Piemont, Italy).

MARIANO S. MORALES; RENZO MOTTA

Universita degli Studi della Tuscia - Viterbo, Italia

Congreso; Alberi e foreste per il nuovo millennio; 2001

Societa Italiana di Selvicoltura ed Ecologia Forestale- SISEF

A study on the forest-lines and tree-lines and on the subalpine forest structures was performed in Susa valley, Monti della Luna, Cesana Tor. se (TO). Three plots characterized by the presence of larch (Larix decidua) and stone pine (Pinus cembra) were located at the tree-line (2000 m2), at the forest-line (2000 m2) and inside the subalpine forest (10000 m2). Age structure analysis revealed that the current subalpine forest stands were established 300 years ago. At the forest-lines the stands are open and some trees are more than five centuries old, whereas at the tree-lines most of the trees (almost exclusively stone pine) are younger than a century old. Growth dynamics were investigated both by observing BAI (Basal Area Increment) in old and dominant trees. The larch is locally strongly affected by the larch budmoth (Zeiraphera diniana). Some hypotheses were made about the possible roles of anthropogenic activity, both direct in the form of grazing and harvesting and indirect in the form of climate change, on the forest structures and dynamics at the upper forest limits in the Susa valley.