DIRECT REGENERATION IS NOT THE ONLY RESPONSE OF MEDITERRANEAN FORESTS TO LARGE FIRES

It is widely accepted that the postfire recovery in Mediterranean plant communities is carried out by direct regeneration, i.e., the fast recovery of a plant community with the same species pool that it had immediately prior to disturbance. However, there is evidence that not all plant species in the Mediterranean basin survive fire in all situations, suggesting that the direct regeneration process might not apply to all situations. We analyze whether the main combinations of forest tree species (up to 16) of the western Mediterranean basin exhibit a postfire direct regeneration process. Based on data from field surveys, we have developed a stochastic model to predict the medium-term forest dynamics. In general, Quercus species (resprouters) and the pines Pinus halepensis and P. pinaster (seeders that produce abundant seedlings) showed direct regeneration patterns. In contrast, forests of P. nigra, P. sylvestris, and P. pinea (seeders that produce few seedlings) changed to other situations after fire. This outcome was validated by additional data from plots with known fire history. These results did not support completely the direct regeneration model, since only half of the combinations of tree species analyzed exhibited a >50% probability of recovering the original prefire situation after fire. This partial failure of direct regeneration evidences the need for reconsidering restoration and conservation plans for Mediterranean ecosystems after fire.