The preliminary report from the Institute for the Conservation of Nature and Forests (ICNF), covering the period from January 1 to August 31, states that among the investigated fires, the most frequent causes were “arson – imputed” (31%), followed by slash-and-burn practices (25%) and re-ignitions (10%).
The ICNF reports that out of the 7,042 rural fires recorded by the end of August, 4,786 were investigated, with 68% of the cause investigations being concluded.
The provisional report indicates that from January 1 to August 31, 7,042 rural fires ignited, resulting in 254,296 hectares of burned area, including forest stands (118,127 ha), shrublands (107,881 ha), and agricultural land (28,288 ha).
“Comparing the figures for 2025 with the historical data from the previous 10 years, there was a 23% reduction in rural fires but a 259% increase in the burned area relative to the annual average” since 2015, the document highlights.
The ICNF further points out that “the year 2025, up to August 31, presents the fifth lowest number of fires and the highest burned area since 2015.”
The report also reveals that by the end of August, there were 83 “large fires” resulting in 245,014 hectares of burned area. The largest fire began on August 13 and lasted 11 days in the municipality of Arganil (Piódão), consuming 65,417 hectares of forest. This was followed by fires in the municipalities of Trancoso (Guarda), with 46,325 hectares, and Sátão (Viseu), with 13,769 hectares.
The report further indicates that Porto (1,697) recorded the highest number of fires by August 31, followed by Braga (698) and Viana do Castelo (590). The ICNF notes that these are mostly small fires with less than one hectare of burned area.
Conversely, the district most affected by the burned area is Guarda, with 79,060 hectares, approximately 31% of the total, followed by Viseu, with 39,298 hectares (15% of the total), and Castelo Branco, with 39,228 hectares (10% of the total).
