Forest fire severity in NW Spain: a case of study

Abstract

Wildfires have become a main forestry concern for pine stands in Galicia (NW Spain). Burned forested areas have patterns of varying burn severity as a consequence of various topographic, vegetation and meteorological factors. Determining the relative importance of these factors is necessary to predict fire severity in the canopy, and therefore, base decisions on fuel management. A spatial study of fire severity for a large wildfire (Oia, Pontevedra) is presented here. Pine stands within the fire were classified according to the fire severity. The effect of meteorological (simulated wind speed and direction), topographic (aspect, slope and combined variables) and canopy fuel structure (LIDAR data) variables was described and then modeled. The presence of high fire severity patches was significantly linked to areas of higher simulated wind speed, to lower height stands and to sunny slopes. Simulated wind speed was the most important variable determining the high intensity areas in the rank order of importance analysis, meanwhile slope and aspect were the second and third most important variables. Canopy structure presented low variability in the studied area, which leads to a low importance in classifying fire severity. Variables evaluating alignment of forces, slope and wind direction, have not been found to be important predictors.