Q.Animals and Madrone tree
Hi
I am having a major battle with some kind of ghost-like animal in my backyard. Squirrels or birds are chewing off my large Madrone tree leaves and young-shoots, so much so, that there are bare branches on the tree and at times bushels full of leaves on the ground. As the attached page shows, to prevent anything to crawl up the tree, I wrapped a 40” wide 1/8” clear and slippery plastic around the trunk… but still, by each morning there are freshly cut leaves on the ground. At least I like to know if other people are having the same problem. And if there is a solution?
Thanks,
Leafless in Seattle.

Not sure, it is not characteristic of squirrel or bird activity, or racoons; porcupine is not likely with your barrier, but do you possibly have parrots?
http://parkways.seattle.gov/2014/03/25/peru-natives-make-annual-trip-to-seward-park/