Here is another picture of what I called sweaters on trees. It is called yarn bombing. These trees are found on Hulen Street. The students from the FW Academy of Performing Arts did the crochet work then wrapped them around the tree. To connect the ends, they used yarn to lace it together kind of like lacing a corset. Interesting huh?
I've seen that here in Finland, too. Here we call it "knit graffiti", and I've mostly seen smaller works (just today I spotted one, tied around the railing of a bridge) but what you captured - yarn bombing is certainly a great term for that! Pretty cool! :)