They do not normally burn, and can be very badly damaged by fire. Burning causes organic matter to decompose rapidly into mineral components which cause plants to grow fast, and it recycles essential nutrients, especially nitrogen. Some tree species cannot survive without periodic blazes. Lodgepole and jack pines are serotinous species - their cones open and their seeds germinate only after they have been exposed to fire. In Australia, the mountain ash, a flowering tree which grows in temperate areas, needs a site to be thoroughly burnt and to be exposed to full sunlight before it can regenerate.
Forests adapt themselves to relatively small intermittent fires.
But when policymakers try to suppress fires altogether, they encourage the accumulation of dead growth and allow new species to establish themselves. When a fire does start, it finds more fuel to sustain itself than would normally be there. This is true of the forests in the 11 US states that are burning now. But people have been interfering there for almost a century, preventing the fires which would have broken out naturally every two to seven years. The result is plain - fires 10 times stronger than they would otherwise have been, with 10 times more impact on nature, and 10 times harder to control.