How it starts vs how it can continue are two different things.
As it gets hotter, forests get drier. Prolonged drought periods make for more leaves, more brush - more fuel for fires on the ground.
Most wildfires these days start out due to something caused by people - a flaming car is one example, along with less blatant things like poorly handled campfires, poorly maintained or damaged power lines, burning off brush, even a tossed cigarette in the right conditions.
Climate change is increasing the scope of wildfires regardless of cause.