Increased wildfire activity over the last years has made fire managers to become more concerned about the effectiveness of current fuel treatment practices to reduce fire risk and severity. Fuel treatments lead to changes in the forest structure and therefore modify certain basic parameters that may influence the fire behaviour. The goal of this work is to quantitatively assess the effectiveness of fuel treatments in reducing risk of wildfires spread in some typically Mediterranean forest. Specifically, it envisages to know the characteristics of the fire that can occur in the slash originated from regenerated aleppo pine stands that were thinned after a wildfire and also to know the evolution of slash combustibility after the treatment. First, an extensive literature review has been done, focused mainly on those works that assessed the effectiveness of fuel treatments in reducing the risk of wildfire. Several studies demonstrated the effectiveness of treatments such as prescribed burning or thinning. However, these studies are not consistent about what treatment and slash management technique are the most effective. A study area has been selected and located within the perimeter of a large forest fire occurred in Bages (Central Catalonia, Spain) in 1994 to study the effectiveness of a type of fuel treatment usually performed in the Mediterranean Basin. The site was previously thinned during different periods and the slash was left in, not managed. In this area, the fuel, environment and topographic characteristics have been determined. With the fuel sampling methods used at the site, a protocol has been produced in order to characterize the regenerated aleppo pine stands, useful to obtain the parameters needed to evaluate fire behaviour. Results have led to a new fuel model for regenerated aleppo pine stands and also fuel models for regenerated aleppo pine stands that have been thinned at different times with the slash remaining unmanaged at the site. An experimental burning program has been implemented reproducing two different regenerated structures (6 and 40 months after treatment). With these experiments it has been proved that ex-situ experimentation is not useful to reproduce actual fire situations because it is impossible to repeat faithfully the overall structure of the ecosystem that affect fire behavior. A series of simulations of potential fires that could occur in the study area have been performed, incorporating the determined inputs (environmental conditions and fuel type) and evaluating different simulation tools (NEXUS i WFDS). Results obtained with the two simulations tools used confirm that both tools are reliable. In general values obtained in fireline intensity and rate of spread with WFDS are larger than with NEXUS. Results from simulations of Bages plots carried with both simulation tools generally show that fire behavior is more severe 1 month and 6 months after the treatment. That is, the wildfire effects after the treatment would be worse than in the untreated control plot and that time does not improve this situation, at least six months after treatment. According to the results and given the characteristics of our country where the risk of fires is very high, the effect of thinning treatments performed in central Catalonia after the 1994 fire brings a great fire vulnerability in treated stands, at least during the first months of treatment.

This study was conducted in burned and harvested areas of Catalonia. It was evaluated the effect of the granivorous in predispersive fruit removal of Smilax aspera and Quercus coccifera and postdispersive seed removal. Nuts removal by rodents was nil in the burned area while for S. aspera only occurred in 2008. The minimum distance to any unburned margin and the distance to the fire perimeter explained patterns of seed removal for rodents and ants, respectively. Seed removal was also lower at unlogged sites vs. logged ones but it was only significative for ants. Rodents removed more seeds under piles of branches because logging while ants did so in areas of bare soil. It should consider the impact of granivorous in the management of burned habitats. / Este estudio fue desarrollado en áreas quemadas y taladas de Cataluña. Se evaluó el efecto de los granívoros en la remoción predispersiva de frutos de Smilax aspera y Quercus coccifera así como la remoción postdispersiva de semillas. La remoción de Quercus por parte de roedores fue nula en el área quemada mientras que para S. aspera solo ocurrió en el 2008. La distancia minima a cualquier margen no quemado y la distancia al perímetro del incendio explicaron los patrones de remoción de semillas para roedores y hormigas, respectivamente. La remoción de semillas también fue menor en las estaciones taladas vs. las no taladas, pero solo de forma significativa para hormigas. Los roedores removieron más semillas bajo amontonamientos de ramas producto de la gestión forestal mientras que las hormigas lo hicieron en áreas de suelo desnudo. Se debería contemplar el efecto de los granívoros en la gestión de los hábitats quemados.