Distribution characteristics of vegetation fires in border areas of China from 2001 to 2022 based on MODIS fire spot data.

Due to natural factors and influences from neighboring countries, wild fires frequently occur in China's border areas. To quantify the activities of wild fires in border areas, we analyzed the regime of wild fires within a 2 km buffer zone on both sides of China's land borders based on MODIS fire spot data, including fire types, fre-quency, seasonality, and spatial distribution. Between 2001 and 2022, a total of 25918 vegetation fires occurred in China's border regions, with forests, cropland, and grasslands accounting for 42.0%, 30.4%, and 14.4% of the fire incidents, respectively. Forest fires were most common in broadleaved forests. Cropland fires mainly resulted from traditional farming practices and the lack of fire prevention awareness among border residents, which often caused fires to spread to nearby forests, leading to forest fires. Among grassland fires, meadow steppe posed the highest risk, and grassland fires in forest-grassland ecotones were likely to trigger forest fires. There were significant differences in fire types and seasonal distribution across regions. In the northeastern border region, grassland fires, deciduous broadleaved forest fires, and cropland fires were predominant, with spring and autumn being the primary seasons for fire occurrences, especially in April and October. In the southwestern border region, evergreen broadleaved forest fires and cropland fires were predominant, with spring and winter being peak periods for fires, especially in March and December. In the northwestern border region, grassland fires and cropland fires were predominant, with more vegetation fires occurring in summer and autumn, peaking in September. Within a 2 km range on both sides of the border, the number of fire spots outside the country far exceeded those within, particularly in the border areas of Inner Mongolia, Jilin, Yunnan, and Guangxi, increasing the risk of cross-border fires in these regions. Fire spots showed significant clustering, with major clusters found in the border region of Xishuangbanna Dai Autonomous Prefecture in Yunnan, Hulunbuir City in Inner Mongolia, Huma County and Jiamusi City in Heilongjiang, and Hunchun City in Jilin. Different fire prevention strategies should be developed based on the characteristics of vegetation fires in different border regions, targeting vegetation types, seasonal periods, and clustering areas prone to fires, to implement effective vegetation fire prevention and control measures in border areas.