Wind and solar energy are recognized as environmentally friendly energies. Wind energy is generated from the surface of the earth by solar energy. While wind energy can be regarded as "free" energy, generating it entails high installation cost as well as a large land footprint and noise, which is deemed to be a nuisance. In addition, maintenance costs are high. In this study, we propose a novel tree-wrapped wind energy harvester, which is inexpensive and easy to manufacture. Triboelectric generators follow simple principles and can be of various generator types. Triboelectric generators running on wind energy have been studied by many researchers. Our design comprises light and flexible tree-wrapped triboelectric generator modules. Multiple generator modules can be connected in parallel to harvest electrical energy. We show that the proposed generator can potentially harvest sufficient wind energy and can even be used in an urban environment by mounting them on trees in cities.