`AU Buck I` is a new and distinct Chinese chestnut cultivar that is precocious, produces a large crop annually of small to medium sized nuts that mature early and the nuts start dropping about August 28. Nut drop continues for a 4-5 week period. The nuts mature and start dropping 3-4 weeks before most cultivars. The early nut drop and small to medium nut size of `AU Buck I` make it ideal for use as a food source for wildlife. `AU Buck I` is a medium to tall tree with a height of 8.53 meters and a smaller canopy area (62.74 square feet) than most Chinese chestnut trees. `AU Buck I` is the first 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.