Yes! Necessary for a number of trees to reproduce. Morelle mushrooms are another example, their spores are fire activated. Look fo them in burn areas the following spring.

West coast trees evolved to drop their lower branches. They naturally won't have branches for 20 to 40 feet off the ground. They need to grow old enough to do that. Most forests have already been chopped down a few times over though in the last 150 years.

Yep, they've always happened. The Summers are very dry and hot, then the thunderstorms come...

There's a number of plants that have actually evolved to take advantage of the fires.

The ecosystem managed by indigenous peoples through proscribed burns, yes. Nowhere humans have lived escaped humans altering the ecosystem to serve our needs.