Those strange metal strips wrapped around tree trunks are usually there for a practical reason: they act as barriers to animals and crawling pests. Smooth sheets of aluminum or galvanized metal make it difficult for squirrels, rats, raccoons, and other climbing animals to grip the bark and reach branches, nests, fruit, or nearby rooftops. Similar metal flashing has been recommended specifically as a way to stop squirrels and other animals from climbing trees.
Tree bands can also be used as part of insect control. Certain caterpillars and other pests travel up tree trunks to reach the canopy, and slippery or sticky barriers can interrupt that journey. For pests such as spongy moth caterpillars, extension specialists recommend bands around trunks to prevent them from climbing back into the tree.
