Management and restoration of Italian afforestations under global change

Abstract

As a consequence of past deforestation, degraded areas in Italy have been subjected to afforestation since the beginning of the XXI century. These afforestations have been done mainly with conifers (Pinus nigra, Pinus pinaster, Pinus halepensis, Pinus pinea), and with the aim to 1) protect the soil and to 2) prevent floods. Exotic forest tree species have been used for the afforestation of selected sites of the Apennine. In the case of Douglas fir, it is possible to state that after ninety years the results are very good in terms of both ecological adaptability and high growth-rate.

Nowadays, the lack of silvicultural treatments, the ageing processes, insect and fungi outbreaks have led pine afforestations to a condition of an unsteady biological equilibrium in many sites. Moreover, this condition seems to be due to additional factors related to climate change such as wind storms and dryness. The restoration of these pine afforestations is therefore one of the main aims of the present Italian forest management policy which aims to increase their level of resilience. In particular, the priority of the researchers has been given to the most fragile stands where three possible objectives of restoration measures should be considered:

1. To rehabilitate conifer stands by introducing native broadleaves when these stands are in a very degraded condition, and when the local wood energy chain needs to be started;
2. To conserve the conifer stands in the cases where the cultural, aesthetic and recreational functions, are the prevailing obtainable ecosystem services;
3. To foster the mixed stands, with the conifers of the old cycle and native broadleaves, which could increase resilience to the extreme events.

In regards of Douglas-fir stands, new silvicultural models have been developed which aim to a) conserve these stands and to b) combine a higher growth rate with a much improved mechanical tree stability.