`AU Buck II` is a new and distinct Chinese chestnut cultivar that is blight resistant, precocious and prolific. It produces a large nut. Nut drop begins about September 15 and continues for a 6 7 week period. A large percentage of the nuts drop during the first three weeks after the beginning of nut drop. `AU Buck II` nuts mature and start dropping during the early phase of the normal ripening period that most Chinese chestnut cultivars mature and drop nuts in the area. `AU Buck II` is a large tree that was 9.14 meters tall, with a canopy area of 101.36 square meters at 15-years of age. `AU Buck II` is the second cultivar to mature and drop nuts in a series of four Chinese chestnut cultivars that will provide for a continuous nut drop of a high energy wildlife food source from late August through mid-to-late November.