It is estimated that approximately 48 percent of the net area of the forest is covered with timber, and supports a stand of some 2¼ billion board feet. Lodgepole pine, Douglas fir, and Engelmann spruce are the principal timber species; alpine fir, Rocky Mountain red cedar, and several minor broadleaved species also occur. Mature timber may be purchased, and when sales are made the cut is so regulated that a perpetual supply of timber will be available without destroying the forest cover. There are more than 20 different timber operations within the forest which provide lumber, posts, poles, and other timber products for the communities and residents of the Big Horn Basin and adjacent territory, and provide a living for approximately 100 families. These operations also supply such special products as railroad ties and mine timbers and props. Hundreds of ranchers and farmers obtain directly such material as corral poles, fence posts, and fuel from the forest. Water Resources.—The vast coniferous forests of the Shoshone are important as a ground cover in regulating the flow of streams having their headwaters inside its boundaries. By retarding the run-off from melting snows and rains, the forests help to prevent erosion and floods in the spring and conserve the flow of water through the summer when it can be used for irrigation. The development of agriculture and, in fact, the future growth of Wyoming and other Western States are absolutely dependent upon irrigation water. Two large irrigation projects, the Shoshone and Sunshine, are dependent upon the forest watersheds, as are many cooperative and individual users. Without doubt the greatest social and economic contribution of the forest to those living within and adjacent to it, and the State at large, is water for irrigation and domestic use. The Shoshone project waters 73,000 acres, on which agricultural crops having a value of approximately $2,000,000 are raised annually. With the completion of the Hart Mountain Division of this project, the area under water will be increased by approximately 41,000 acres. Local enterprise in the form of cooperative and individual projects has brought under irrigation more than 60,000 acres additional. The Sunshine project provides supplemental water for a part of the land included in the last figure given. If the Shoshone project is developed to capacity, it is estimated that approximately 163,000 acres of land will be under water.