Fuel structural traits modulating soil temperatures in different species patches of Mediterranean Basin shrublands

The ability of a fuel to burn is determined by its flammability, a property that varies from one species to another and is partially determined by different fuel structural traits such as surface-to-volume ratio of twigs and leaves, retention of standing dead twigs, canopy architecture and bulk density. Our aim was to assess the role of these fuel structural traits in modulating soil temperatures under patches of different species. The results showed that there were contrasting differences in the fuel-structure complex among different species patches in Mediterranean Basin shrublands. The differences in the fuel structure were important in modulating soil temperature because, regardless of the total fuel load, the highest temperatures were found under the species with the highest loads and densities of dead fine fuel. Surprisingly, temperatures under herbaceous species were high in relation to shrubby species; however, temperature residence times were shorter. Therefore, management strategies that promote species that accumulate low contents of fine dead fuel could be crucial for attaining less severe fires with a reduced effect on ecosystem functioning.