According to the estimated model, the area is characterised by deciduous Sub-Mediterranean species (Quercus pubescens, Quercus cerris) and Eurosiberian species (Fagus sylvatica). Only two Mediterranean evergreen sclerophyllous species have a spatial distribution wide enough to be included in this analysis: Quercus ilex and Quercus suber.
The predicted climate change should expand the Mediterranean region to the detriment of the Temperate ones. This will accelerate the progressive xerophitization of the areas caused by the human activities as demonstrated by paleobotanical studies indicating the increase of pollen of sclerophyllous tree species, mainly Quercus ilex, starting from 1.500 B.C. This change can be ascribed to the prolonged exploitation of forests caused increasing soil erosion, especially in the southern exposures of the Apennine mountains, favouring Quercus ilex, which is more adapted to xeric environments than deciduous species.
The application of the HADCM3 climatic scenario for 2080 showed that a general increase of the average potential altitude could occur. If area and abundance are analysed, four different trends can be identified: species that could be advantaged by the predicted climate change (Table, group 1), species that could suffer a strong reduction of area and abundance (Group 2) and species showing contrasting behaviour in relation to area and abundance (Group 3, 4). The two Mediterranean species (Quercus ilex and Quercus suber) are likely to be favoured by the predicted increased drought, while the species belonging to the two other chorological types show quite differentiated behaviour: Quercus pubescens, Quercus cerris and Ulmus minor should be also favoured by the increased drought. On the opposite, typically mesophilous species such as Fagus sylvatica, Acer obtusatum, Acer pseudoplatanus, Ostrya carpinifolia will be the most threatened species