Land use change towards forests and wooded land correlates with large and frequent wildfires in Italy

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It is commonly believed that wildfires in southern Europe have been favored by the encroachment of flammable vegetation on cultivated and grazed areas no longer managed as a consequence of deep socio-economic changes in rural areas. Using the whole of Italy as study case, this paper explores the hypothesis that wildfires selectively burn areas with specific land use changes (LUC) characteristic of agricultural land abandonment, especially in large (> 500 ha) and recurrent burnt areas. Additionally, we examined LUC within 200 m buffer areas around perimeters of large fires to explore if active land management may hamper the growth of large fires. To investigate the study hypotheses, pre-fire LUC were compared within six different geographic domains defined according to the burnt areas from 2007 to 2017 across Italy. Estimates of LUC between 1990 and 2008 came from the Italian Land Use Inventory (IUTI), which is based on photointerpretation of 1,206,198 sample points on high-resolution aerial images. The analyses reveal that LUC in all geographical domains reflect typical trends of agricultural land abandonment in southern Europe during the last decades: expansion of forests, shrubland and new settlements at the expense of agricultural land, grasslands and pastures. However, results show higher rates of pre-fire LUC in burnt areas than in the rest of territory considered available for burning. We found that higher rates of forest expansion and shrub encroachment on abandoned grasslands and pastures are related to a higher incidence of large and recurrent fires, respectively. Furthermore, areas surrounding large fires were less affected by pre-fire land abandonment than burnt areas and show higher increases in vineyards and orchards. Our findings suggest that land abandonment have probably increased fire proneness at national scale by expanding shrub and tree encroachment, and thus increasing fuel connectivity and fuel build-up. Therefore, we urge for a greater integration between fire management and rural development policies.