Altitudinal Gradients and Forest Response:
Climate, Hydrology and Isotope Variability
of a Mediterranean Ecosystem

Abstract:

Located in the western Mediterranean basin, the island of Corsica (France) is expected to be strongly affected by climate change. With its diverse topography and altitudinal gradients from sea level to 2700m asl, it hosts two pine species, i.e. Pinus pinaster in lower areas and P. nigra ssp. laricio in higher regions up to the upper tree line. However, the growth performance of these two dominant forest tree species along different elevation belts is still unknown, so it is not clear how climate change will affect their distribution. The relationships between tree age, elevation, and growth performance were evaluated using growth trajectories derived from tree-ring analysis of pines in different age classes at 13 sites across the island, ranging from sea level to 1600m asl. Results show that the growth performance of both species under the same environmental conditions is very similar. For both species, we found that growth rates change over time, whereby trees younger than 50 years grew faster than older trees. We also found that P. pinaster is becoming common at higher elevation sites, indicating a migration upslope.