Some trees actually need fires
I think it's one of the giant redwoods whose cones require a fire to activate the seeds. Giant redwoods or sequoias (one of those), with their branches far in the air and resistant bark, are pretty much immune to all but the largest fires.
SDG is right that with people in the picture, it isn't as easy to just let nature go its way. Besides, what major difference if you chop down trees every decade or so versus letting them burn down?