This study was initiated with the selection of representative open-grown walnut trees throughout the Tennessee Valley. In 1940, 96 sample trees were selected and 36 trees were added to the study in 1942. These 132 trees are located in 42 counties and afford a good representation of age, size, and growth quality of open-grown black walnut. Each sample tree has been visited annually. Entire crops were collected, carefully weighed and sampled: tree diameters and other measurements were taken for the tree growth phase of the study. When convenient, nuts were hulled in the field with a corn sheller, but more often they were brought to Norris and run through a hulling machine. After hulling, the nuts were dried until cured, then a sample for each tree was tested for percentage of filled nuts, nut weight, and cracking quality. Yield Results on nut yield and nut quality for the 132 sample trees have been condensed to the presentation in Table 1. For the six-year period the average tree in this study had a diameter of 13.3 inches and yielded 33 pounds of hulled, dry nuts a year. The yield of common black walnut trees in the Tennessee Valley is characterized by extreme variation. Tree size, of course, influences nut yield. One-half of the yields from a 6-inch diameter tree ranged from no crop to 4 pounds of hulled, dry nuts; whereas half the yields from a 22-inch tree ranged from 40 to 100 pounds. A yield of less than one-half pound of hulled, dry walnuts was considered "no crop". Some individual trees had unusually high or low yields. The outstanding bearer was tree 117. It had the highest average yield for the six-year period, and the heaviest crop of hulled, dry nuts for any single year. During the six years this tree yielded 953 pounds of dry, hulled nuts and 194 pounds of kernels--truly outstanding production for a common black walnut tree. Another notable bearer, tree 100, yielded 916 pounds of nuts and 189 pounds of kernels. However, this tree was almost 11 inches larger in diameter than tree 117. The exceptional bearers in each diameter class also had the highest single nut crops. The other extreme is characterized by low yields. Crops were lacking or insignificant for trees 60, 63, 211, and 221. Tree 37, with a 19.7-inch diameter, bore only one crop of 31 pounds during the entire six-year period. This tree has no value for nut production but would yield a good sawlog. Variation of yield by seasons and locality was examined by grouping the 132 sample trees into six localities of 22 trees each. Greater variation in averages by crop years existed than averages by tree location groups. However, some variation was found between the eastern and western portions of the Tennessee Valley.