The need for trees in the Great Plains was recognized during settlement in the late 1800's. The Timber Culture Act of 1873 provided for planting a timber culture entry of 40 acres for each quarter section (160 acres) of homestead. The act was amended several times to reduce acreage planted to trees. The Clarke-McNary Act of 1924 provided Federal assistance that made it possible for landowners to purchase planting stock at cost. Governmental programs were developed in the 1930's to help relieve the effects of drought in the Great Plains. The Shelterbelt Program of 1935-1942 (later known as the Prairie States Forestry Project) was one of these programs. The purpose of the Shelterbelt Program was twofold: (a) the planting of windbreaks throughout the eastern plains to reduce wind erosion and (b) to provide relief employment. The program was administered by the U.S. Forest Service until 1942, when responsibility was transferred to the Soil Conservation Service. The purpose of the study was to inventory 20 Prairie States Forestry shelterbelts in Cass, Barnes and Ransom counties of southeastern North Dakota. The inventory would include tree and shrub species, growth data, vigor and the incidence and types of diseases and insects. The shelterbelts were chosen at random to obtain variation in species, orientation and planting sites. These belts ranged in length from one-quarter mile to one-half mile and from three to 20 rows in width.