Local impact assessment of climate change on fire season length

Wildland fires represent an important disturbance for ecosystems in the Mediterranean Basin. Evergreen sclerophyll shrubland is an important component of Mediterranean vegetation community and constitutes the surface fuels primarily responsible for the ignition and the spread of wildland fires in Mediterranean area. Several works highlighted the importance of vegetation moisture content in relation to ignition and rate of spread in shrubs. Critical threshold values of fuel moisture for fire occurrence and spread were also proposed. The main aim of this work was to present a methodology for evaluating at local scale possible impacts of future climate change on moisture dynamic and length of fire danger period. Measurements of seasonal pattern of live fuel moisture content (LFMC) of three Mediterranean shrub species were performed in North Western Sardinia (Italy). Seasonal patterns of LFMC were also compared with the Drought Code (DC) of the Canadian Forest Fire Weather Index System. A threshold value of drought index useful to determine the end of the potential fire season due to fuel status was identified. In addition, impacts of future climate change on fire season length were simulated at 4 experimental sites located in Northern Sardinia, Italy. A weather generator linked to climate change scenarios derived from 17 available General Circulation Models (GCMs) was used to produce synthetic weather series, representing future climates, and then the expected changes of the fire season length was determined. Results confirmed that the projected climate scenarios over the Mediterranean area will determine a general increase (up to 1 month) of the fire season length.