If you look around at the trees in Seoul, you’ll notice that a lot of them are wearing luau skirts, hay sweater belts or cozies. They serve as a low-tech and environmentally-safe way to manage tree pests. How? When it’s cold and leaves drop off, pests rush down the trunk of a tree and burrow in the roots, causing damage all winter. Pests find warmth quicker and forget to go further down — reducing the pest population and need for pesticides. Right before spring the “tree cozy” is removed and burned.


Tree cozy, as seen in Gangnam.