It won't make much sense. When you chop down a tree, does the tree magically disappear? No, it leaves a stump. And realistically, you won't get rid of a stump that easily. So you'll still be bumping into the trees as you drive your ATV... Just the lower half of them.
I'd personally rather have the outside area of the main base completely inaccessible for any player modifications except adding "outer layer" things like placing boxes and ramps to jump across the river. It'll leave more room for the dev to make cool/scary things without constantly keeping in mind that the player might do something in this exact coordinate that would ruin the event.