[spott]

I think part of the issue is that one of the consequences of killing tons of trees is creating a lot of dry, dead, flamable wood. So the weakest trees get killed off by the beatles, but then all the nearby trees are killed in the resulting forest fire, which hurts the evolution argument a little.

On the other hand, part of the reason that this kind of thing is so bad is that we fight forest fires so aggressively. In the historic past, as trees are killed off en-masse by the beatles, a forest fire would ravage the area, decimating the beatles population. Because these fires aren't allowed to go unchecked anymore, the beetle population can continue to grow.