Forest condition in Tuscany (Central Italy). Field surveys 1987–1991

Abstract

Between 1987 and 1991 four surveys on the condition of forests in Tuscany (Central Italy) were carried out. The results, relating to 2275 trees in 111 sampling plots, show that the overall percentage of damaged trees (defined by the EC regulation 1696/87) increased between 1987-88 (51.4 +/- 5.4 per cent; 54.0 +/- 5.6 per cent) and 1990-91 (67.0 +/- 6.2 per cent; 64.0 +/- 6.1 per cent). The percentage of moderately and severely damaged trees also displayed an upward trend. The most severely affected species appeared to be Pinus pinea (a Mediterranean conifer, 96.7 per cent damaged trees) and Fagus sylvatica (a mountain broadleaf, 87.1 per cent damaged trees). Crown condition appeared to deteriorate with decreases in mean annual rainfall and where stand conditions are poor (thin soil, steep slopes). The findings suggest the possibility of an interaction between several different stress factors, some of which seem to be linked to local and stand conditions (exposure, silviculture, soil fertility), while others seem to be connected with long-term variations, such as changes in environmental parameters like precipitation. The actual role of background and/or local pollution can be neither demonstrated nor excluded on the basis of the present results.