Site suitability and economic aspects of black walnut (Juglans nigra L.) in Mississippi

A site suitability study and economic analysis were conducted for naturally occurring black walnut (Juglans nigra L.) in Mississippi using 60 fifth-acre plots established during 2000. Soil, site, and tree measurements were used to: (1) construct site index (SI) curves and a nondestructive method for predicting walnut age; (2) classify diameter growth potential; (3) characterize suitable planting sites; and (4) project monetary returns. Bottomland fronts, flats, and ridges and upland toe slopes were the most frequently occurring natural black walnut sites and produced average diameter growth of 0.5 in./year. Growth was not significantly (P > 0.1) influenced by soil nutrients, pH, or site factors; however, a small portion of variation was positively correlated to silt percentage (P = 0.01-0.09; R2 = 0.05-0.12) and negatively correlated to sand percentage (P = 0.01-0.09; R2 = 0.05-0.11). Clay textured soils were absent at all sampling depths. Land dedicated to black walnut management yielded up to 5.4 times the land expectation values of loblolly pine (Pinus taeda L.) where SIs for both species were 100. Favorable growth rates and monetary returns demonstrated that black walnut production has substantial economic potential for forest landowners in Mississippi.