Five summers after being planted, the trees have grown. Many of them have outgrown their white plastic trunk protectors. I've taken quite a few off that were tight and we'll see how the trees do without them. Below is an image of the trunk of one maple tree that got attacked by the field mice last winter. The ant is crossing the new growth that has partially filled in the wound. The tree had a plastic trunk protector on but it didn't stop the rodent. I'm going on the theory that at a certain point, the bark gets so thick that rodents no longer find the older trees very tasty. When the spirals are removed though, the trunk that was protected looks younger than the parts of the trunk that had been exposed to the weather so I am a bit worried that the field mice will attack the trees that have been newly uncovered.