I mean, I know trump is just an idiot repeating things he's been told or has heard somewhere on repeat but there is something credible to that idea.
It's the one downside in my opinion to protected areas and parks. No one is allowed to do anything in them that is seen as unnatural. I wouldn't suggest logging a park but selectively removing and cleaning up debris / dead trees should definitely be a thing.
They are a giant fire hazard.
A natural forest has regular fires to clear out the underbrush and dead debris. Parks never allow fires to occur and that dead debris builds up to a point that if a fire did happen, absolutely nothing would survive the heat whereas smaller more regular fires would allow for some of the older and stronger trees to survive and repopulate, depending on the forest ecosystem.