Interesting stuff there, Justin. As to what might be tearing down your clubhouse, I really couldn't say. Are there any other kids in your area that might do it? The reason I ask is because when I was your age, several of us kids in the neighborhood got quite a bit of pleasure out of finding someone else's clubhouse and tearing it down. (Yeah, I know. We were all mean as snakes.

)
About the clear-cut area. It always surprises me the number of people that will look at a clear-cut and think of it as a "dead" area since all the trees are gone. But when you really get to studying a clear-cut, you'll find just the opposite to be true. When the overhead canopy is removed on a piece of land, it gives all the plants at ground level a chance to attempt to thrive. Go take a look around that clear-cut and you'll find new grass starting to grow, the bushes will be putting out new shoots, and there will still be a fair amount of cover for smaller animals.
With all the new growth coming in, it provides quite a bit of food for rabbits, turkeys, deer, squirrels, etc. Once those animals start using the clear-cut, the predators like coyotes, bears and cougars (not to mention humans and probably sasquatch) begin to frequent the area because more of their food sources are there. It's a perfect example of the food chain on a smaller scale.
I agree with your mom that the squatch probably don't stay in a clear-cut area but I have no doubt that if they're around, they'd sure stay near the cut.
Good luck, Justin. And happy squatchin'!