Why is deforestation a threat to Yellowstone National Park?

Deforestation causes loss of animal and plant species due to their lack of habitat. A huge portion of animals and plant species live in forests so if we take that away from them how are they supposed to survive? Not only does deforestation threaten species known to us, but also threatens species we haven't even discovered yet.

Explanation:

This isn't necessarily for Yellowstone but for all national parks ^