A Forest Fire is a natural disaster in Civilization VI, introduced in the Maya & Gran Colombia Pack. Any tile with Woods or Rainforest can catch ablaze. The fire burns hot for three turns, destroying (e.g. lumber mills) or pillaging (e.g. plantations) any improvements on the tile, reducing the owning city's Population, and damaging units that walk through it. On the second and third turns, the fire can spread to any adjacent Woods or Rainforest tiles.
- Burns a tile with Woods or Rainforest, pillaging improvements, damaging units walking through it, and reducing owning city's Population.
- Burns for 3 turns.
- On the second and third turns, the fire can spread to any adjacent Woods or Rainforest tiles.
- Once the fire has burned out, the Woods and Rainforest is replaced with a Burnt variant, boosting the tile's Food yield.
- Over the next 3 turns, it regrows until it returns to its normal state, at which point it also boosts the tile's Production yield.
Note that the affected city will lose population even if it is not working any of the tiles that might catch fire in future turns. This means that the only counterplay is to not have a lot of adjacent forests. You could in theory also choose which city to lose the population by swapping tiles between cities where possible.