A seven-row shelterbelt approximately one-half mile in length was started in the spring of 1938. The rows of the belt were planted north and south for about three-fourths of their length, and east and -west for the remainder. The outer row on the west and north was Caragana followed by Russian olive, green ash, American elm, green ash, American elm and Ponderosa pine. The rows were all spaced six feet apart, and the Caragana about three foot part in the row.
Agricultural Experiment Station, South Dakota State College
Davis, L.L. and Snyder, L.C., "Tree Growth as Affected by Cover Crops" (1943). Agricultural Experiment Station Horticulture Pamphlets (1943-1950). 2.