The fruit of the oak is called acorn. Acorns are used to save forests. They are collected in early autumn for later planting. Also, acorn is a good animal feed for pigs, sheeps and even chickens. Farmers bake bread from acorn flour, soak it in water and then give to chickens. Moreover, people eat some types of acorn which are similar to chestnut. For example, in Korea people use acorn to cook jelly.