This is an easy great idea. I also park under trees and see a lot stuff fall down there as I'm trying to pick it out. Sucks. I'm gonna try this. ThanksThanks. . Yes, the folded over top 3.5" to 4" is 2.5" thick, so, it wedges in nicely and holds in place. I could even pull it up a it more and it would be even snugger.
I also thought, it it didn't hold, I would apply some double sided carpet tape to the back side of it against the inner fender well sheet metal.
So far,it is working well. We'll see how it goes through the Fall. I park outside some with a lot of trees in our Fall travels.