Fuel loading and flammability in the Mediterranean Basin woody species with different post-fire regenerative strategies

Abstract

12 páginas, 5 figuras, 3 tablas.The flammability and combustibility of plant communities are determined by species features related to growth-form, structure and physiology. In some ecosystems, such as the Mediterranean ones, these characteristics may contribute to the existence of fire-prone species. We measured several parameters associated with the flammability and fuel loading of dominant woody species with different post-fire regenerative strategies ( seeders and non-seeders) in shrublands in the western Mediterranean Basin. Overall, seeder species show lower fuel load but are more prone to burning owing to a higher dead-to-live fuel ratio, live fine-fuel proportion and dead fine-fuel proportion. Moreover, they burst into flame at lower temperatures than non-seeders. In the Mediterranean Basin, most seeder species emerged mainly during the Quaternary, under a highly fluctuating Mediterranean climate and during recurrent fires. We propose that properties related to the combustibility and flammability of seeders may be the result of selective pressures associated with both fire and climate. These results suggest that ecosystems dominated by seeder species are more susceptible to fire risk than those dominated by non-seeder species in the Mediterranean Basin. Therefore, the proportion of these types of species resulting from previous fire or management history is likely to determine the characteristics of future fire events.We thank M. Jané, E. Martí, A. Vilà-Cabrera, J. Garcia, B. Moreira, S. Ribeiro and C. Beseler for helping in the field and in the laboratory work. Also, special thanks are due to J. Piñol for his advice and suggestions, and to J. Peñuelas and G. Alessio for supporting the flammability tests. This study was funded by the Department of Universities, Research and Information Society of the Generalitat de Catalunya, the European social funds, and the Spanish Ministerio de Ciencia y Tecnología (MCYT) projects REN 2003–07198 and CGL2006–01293/BOS. It also contributes to the European research group (GDRE) ‘Mediterranean and mountain ecosystems in a changing world’ funded by the Generalitat de Catalunya and CNRS (Centre National de la Recherche Scientifique). CEAM (Fundación Centro de Estudios Ambientales del Mediterráneo) is supported by the Generalitat Valenciana and Bancaixa.Peer reviewe