Polo oak. Chestnut tree is a deciduous tree, the fruit produced by the chestnut, can be grafted Polo oak, in late May end to early June, using a single bud cut grafting method, the survival rate is very high. Chestnut tree is a tree up to 20 meters high, the bark is dark gray, irregularly y cracked, with longitudinal grooves, the skin has many yellow-gray round lenticels.