Yosemite NP, especially the iconic valley, looked vastly different when the Europeans first arrived in the nineteenth century. It was sparsely forested and had lots of meadows. After a 150 years of no controlled burns, it's a dense forest down there. It turns out the native peoples were managing the forest, after all.

The national park service does controlled burns in Yosemite and has for a couple decades at this point. You can argue they don't do enough but they're limited by bureaucracy, safe conditions, and manpower rather than willingness.