Tree planting goals must account for wildfires

Grassroots movements such as the Trillion Tree Campaign (1) and international policies such as the EU Biodiversity Strategy for 2030 (2) aim to mitigate climate change through ambitious tree planting objectives. However, tree planting targets could produce counterproductive side effects (3), including an increase in the amount and continuity of fuels, a key driver of large fires in a warming world (4, 5). Drier weather, coupled with afforestation dominated by extensive, dense, even-aged, monospecific conifer or eucalypt plantations, has already promoted megafires in places like Chile and Portugal (6), and burnt areas are more likely to reburn when postfire management includes extensive reforestation instead of natural regrowth (7). Reforestation programs should prioritize the mitigation of fire risks.