Transboundary fire regimes in the sino–mainland southeast asia borderlands

Fire regimes increasingly reflect coupled human–natural dynamics, and where landscapes are contiguous, fire impacts and individual fire events can cross administrative boundaries. We quantified fire activity asymmetries across China–Myanmar, China–Laos, and China–Vietnam borders using 50-km bilateral buffers and satellite-derived fire events during 2003–2016. Fire counts were markedly higher on the Myanmar (6.26×), Laos (8.44×), and Vietnam (4.28×) sides than in adjacent China-side buffers, whereas mean event size, duration, and spread speed were broadly similar within each pair. Cross-border fires represented 1.0%, 2.3%, and 2.3% of all fire events affecting Myanmar, Laos, and Vietnam, respectively, but 6.2%, 17.2%, and 9.6% on the corresponding China sides, indicating pronounced cross-border exposure asymmetry. Despite broadly similar land cover backgrounds, ignition locations were more strongly associated with broadleaved forest on the China sides, and with shrubland on neighbouring-country sides, especially Myanmar and Vietnam. Fire seasonality peaked in February–April, with additional autumn activity on the China side. Together, these results reveal marked cross-border discontinuities in fire regimes that may reflect interacting differences in land use, accessibility, environmental conditions, and fire management contexts, highlighting the value of bilateral and regional coordination for fire risk reduction.