Spatial pattern of the upper timberline and heath deficiency of Fagus sylvatica L. in the Northern Apennines (Italy)

The spatial pattern of the northern Apennine upper timberline and its correlation with the heath deficiency in Fagus sylvatica (European beech) was studied. The study area covers the northern side of the Northern Apennines including a timberline, at a latitude of about 44° N. The pattern of the timberline was described on a scale of 1: 25 000, using a digitized map derived from phytosociological vegetation maps. As suggested by the literature on heat deficiency in beech the following thermal parameters were considered: annual mean; summer mean (from June to September); mean of the coldest month (January); mean of the warmest month (July); days with more than 10 °C. The values were calculated using fifty years (1951-2002) of data from five weather stations. Linear regressions of values vs elevation were carried out. The altitudinal distribution of parameter values which correspond to the lowest heat requirements of F. sylvatica and their coincidence with the spatial pattern of the timberline showed that the present upper beech timberline (1875 m) confirms only the hypothesis of its coincidence with the mean temperature of the coldest month (January: -2.5 °C). The other data are slightly different from those supplied in the literature.