Guys, I don't like to get preachy and all, but this needs to be said.
DO NOT COZY TREES.
DO NOT WRAP YOUR TREES IN KNITTING.
DO NOT PUT "KNITFITTI" AROUND LIVING THINGS, including but not limited to trees! (People are ok. And some dogs.)
If you absolutely MUST do this sort of thing as an "art project" of some sort, take it down after a day or two.
Disclaimer: I don't know anything about this particular project, I just swiped it off google image to illustrate what I meant by tree-cozying. For all I know, this one was taken down in a responsible amount of time.
If the cozy is tight, it can stunt the tree's growth and cause limbs to fall off. Moisture can build up behind the cozy and cause the bark to rot (and a number of other fun, nasty things to happen, like fungal infections.) Insects can take up residence underneath them and eat the tree to death. Trees have DIED from being "lovingly cozied". Acrylic is especially guilty, since it will practically never rot off, or breathe, for that matter. Don't do it.
Plus, there are a million and ten ugly things you could cozy- poles, railings, door handles, statues (ok, not ALL statues are ugly, but they could use scarves, don't you think?) You don't need to take on something already attractive. Leave the damn trees alone.