I'm actually quite curious if mega-herbivores would help reduce fire risk on a warming planet. If can be done with mechanical thinning or controlled burns but I don't see how we get the money and manpower to do this over the massive forested areas of western North America.

But if there was an animal that ate and/or destroyed smaller trees and brush while leaving larger ones, they could reduce fuel loads for free. We know elephants do this in Africa so perhaps mastodons and mammoths did the same thing in the ancient American ecosystem.