A chichi is a type of fungal growth that forms on the bark of some trees, especially beeches. Chichis are also known as "wood ears" or "tree ears" because they resemble the shape of human ears. Chichis are not harmful to the trees, but rather live in a symbiotic relationship with them. Chichis help the trees by decomposing organic matter and releasing nutrients into the soil, while the trees provide chichis with a moist and shady habitat. Chichis are edible and are often used in Asian cuisine, especially in soups and stir-fries.