|Brauer, David - Dave|
Submitted to: Forest Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/11/2009
Publication Date: 2/15/2010
Citation: D.K. Brauer, D.E. Brauer, A. Ares, A.L. Thomas, D. Burner and J. Idassi. Effects of seedling type on the establishment, growth and precocity of eastern black walnuts (Julgans nigra L.) for nut production. 2009. The Open Forest Sci J. 3: 1-8. Interpretive Summary: Many landowners in the United States have limited access to knowledge of the potential economics returns from eastern black walnut agroforestry practices and this lack of knowledge may be limit the establishment of walnut plantings. There are indications that grafted varieties of eastern black walnut selected for improved nut quality may produce flowers and nuts sooner tha non-grafted seedling trees; however data are lacking to fully support this hypothesis. ARS scientists from Booneville AR and cooperating scientists from Oregon State University observed the production of flowers by grafted and non-grafted seedling trees over a three year period at three different locations. Almost all of the grafted trees produced flowers whereas none of the non-grafted trees did. Results from this study clearly demonstrated that grafted trees of named varieties produced flowers, thus nuts, sooner than non-grafted trees. Landowners planting eastern black walnuts for nut production will be interested in these results because they identify a management option, i.e. planting a grafted tree, which promotes nut yields sooner. Nursery producers who produce grafted seedling trees will be interested in these results also because they demonstrate a beneficial characteristic of these seedlings trees warranting their higher retail prices.
Technical Abstract: Eastern black walnut (Juglans nigra L.) has potential for agroforestry practices in the eastern United States because of its value for nuts and timber; however, practices for optimum nut production are poorly defined. Studies were conducted to determine the type of planting material that can assure successful establishment of black walnut for nut production. The first study compared the survival and growth of bare root and container seedlings. Survival exceeded 95% with both stock types four years after planting. Bare root seedlings grew less during the first year after planting compared to container stock. No differences in annual growth increment were observed in the next three years. A study was conducted to compare flower production by commercially available open-pollinated seedlings derived from cultivars versus grafted cultivars at three locations in Arkansas and Tennessee. Seventy-two to 87% of the grafted cultivars flowered during the first four years compared to a maximum of 30% for the open-pollinated seedlings by the fourth year. A third study verified a previously reported relationship between trunk diameter and nut yields for grafted cultivars. These results suggest that landowners seeking to establish black walnut plantings for nut production should consider using container stock of grafted cultivars selected for improved nut quality.