Modelling the effects of landscape fuel treatments on fire growth and behaviour in a Mediterranean landscape (eastern Spain)

Abstract

The number of large fires increased in the 1970s in the Valencia region (eastern Spain), as in most northern Mediterranean countries, owing to the fuel accumulation that affected large areas as a consequence of an intensive land abandonment. The Ayora site (Valencia province) was affected by a large fire in July 1979. We parameterised the fire growth model FARSITE for the 1979 fire conditions using remote sensing-derived fuel cartography. We simulated different fuel scenarios to study the interactions between fuel spatial distribution and fire characteristics (area burned, rate of spread and fireline intensity). We then tested the effectiveness of several firebreak networks on fire spread control. Simulations showed that fire propagation and behaviour were greatly influenced by fuel spatial distribution. The fragmentation of large dense shrubland areas through the introduction of wooded patches strongly reduced fire size, generally slowing fire and limiting fireline intensity. Both the introduction of forest corridors connecting woodlands and the promotion of complex shapes for wooded patches decreased the area burned. Firebreak networks were always very effective in reducing fire size and their effect was enhanced in appropriate fuel-altered scenarios. Most firebreak alternatives, however, did not reduce either rate of fire spread or fireline intensity.

Landscape – wildfire interactions in southern Europe: Implications for landscape management

“…This can be explained by several factors, namely the lower priority given for fire fighting in shrublands (on the assumption that they are the least valuable land cover), the number of human-caused ignitions (e.g. burning for rangeland management purposes, such as creating pastures) and the higher rate of fire spread in this LULC (Duguy et al, 2007;Fernandes, 2009;Moreira et al, 2009). Additionally, as a consequence of shallower soils that prevent dense forest to establish (Garcia-Fayos et al, 1998) and abandonment of hard to mechanize terrace cultivation (Tatoni et al, 1994), shrublands are a common land cover type in steeper slopes where the rate of fire spread is higher.…”

“…Other studies applied fire resistance rules to LULC types at the scale of fire events (Viedma et al, 2009) or at both stand and landscape scales (Gonzalez et al, 2005(Gonzalez et al, , 2008 and showed that landscape resistance to fire was negatively influenced by the spatial contiguity of LULC, and positively influenced by the diversity resulting from fuel contrast at fire edges. Simulation models also showed that fire spread and behaviour were greatly influenced by fuel spatial distribution (Duguy et al 2007). …”

“…the landscape structure), so that when a wildfire ignites in a well managed landscape, it spreads more slowly, burns with less intensity and severity, and is less costly to suppress (e.g. Duguy et al, 2007). However, the management implications of understanding the landscape-fire relationships are not restricted to fuel break design, but they also enable the definition of land use management rules and the design and implementation of policies leading to specific landscape goals (in terms of overall fuel patterns), ranging from forest and agricultural and rural development, to urban development policies.…”

Wildfire Assessment Using FARSITE Fire Modeling: A Case Study in the Chihuahua Desert of Mexico

“…A FARSITE study conducted by Duguy et al (2007) in the Spanish Mediterranean found firebreaks to be highly effective in the reduction of fire size. The study also suggested that FARSITE was a highly effective model for testing fuel treatments, including firebreaks.…”

“…Fuel treatments are another common and highly effective tool to minimize fire hazard. Fuel treatments are considered to be any kind of change in the spatial arrangement of fuel to retard or cease the propagation of fire (Duguy et al, 2007). Common fuel treatments include the creation of water points, firebreaks, or various techniques of vegetative thinning (Van Wagtendonk, 1996;Stephens, 1998).…”