ELi5 How does forest or grassland catch fire, does it always need a spark or can drying out cause spontaneous combustion?

Question

ELi5 How does forest or grassland catch fire, does it always need a spark or can drying out cause spontaneous combustion?

In: 3

Answer 1

Lightning can spark a fire, as can campfires, cigarette butts, sparks from power lines. Arson is also a cause way too often.