Land-use change and large wildfires

A new paper published in the Italian journal "Annals of Silvicultural Research" explores the relationships between land use change and large wildfires.

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Photo: Luca Tonarelli.

The effects of climate change on wildfires are widely studied around the world. However, another key process contributing to changing fire regimes in many regions has not received so much testing. This “ingredient” is land-use change, also referred to by its acronym LUC, or the conversion of pieces of land from one purpose to another. Land abandonment is a major driver of land-use changes because human control over land (for instance, agricultural activities and livestock grazing) decreases and the land is left to natural dynamics.

Land abandonment in southern Europe accelerated in the 20th century and new shrubs and trees occupied the former forests, agricultural and grazing lands left by the local population, who moved from rural regions to cities. This process is still going on nowadays and has changed rural landscapes dramatically. These shifts pose a critical question for wildfires: is the encroachment of tall grasses, shrubs and forests due to natural succession resulting in landscapes that are more flammable than in previous decades?

A new article in the Annals of Silvicultural Research, “Land use change towards forests and wooded land correlates with large and frequent wildfires in Italy”, examines the hypothesis that Italian wildfires selectively burn areas characterised by a more intense land abandonment, especially in the case of areas affected by large fires and areas that burn repeatedly. The authors estimated the specific land-use changes that occurred between 1990 and 2008, using data from the Italian Land Use Inventory (IUTI), inside areas that burned between 2007 and 2017 and areas that did not burn in the same period.

The advance of new forests and especially new wooded vegetation such as shrublands, as well as the reduction of grasslands and pastures, is more evident within burned areas than in the rest of the unburned territory; this can be interpreted as a fire preference for these particular land-use changes. Large fires (> 500 ha) affected areas with higher rates of forest expansion, and recurrent fires tended to occur in areas with higher transitions from abandoned pastures and grasslands towards shrublands. Interestingly, buffer areas of 200 m along large fire perimeters experienced lower levels of land abandonment and higher increases in orchards and vineyards, suggesting that continuous management of agroforestry territories limits large fires by increasing the accessibility and effectiveness of fire-fighting.

Fire suppression will continue to be a fundamental part of fire management in the future. Nonetheless, extreme weather associated with climate change, and trends in land-use change have inevitably increased the fire proneness of Italian landscapes to the point that human lives and assets are continuously at risk during each fire season. Rural development policies must be better aligned to fire policies to manage the increasing fuel amount and connectivity. This means that fire prevention should be fully integrated into land-use planning in order to counter the effects of land-use change on fire hazard and risk.

REFERENCE

Ascoli D, Moris JV, Marchetti M, Sallustio L. 2021. Land use change towards forests and wooded land correlates with large and frequent wildfires in Italy. Annals of Silvicultural Research 46 (2). DOI: 10.12899