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Land Resources Forest recreation is an important resource. Forest land provides habitat for many species of wildlife. Urban Lands. - In addition to cities, towns, and village communities, urban land includes land for industrial purposes in the Pacific Southwest. Most of the urban lands have been developed in areas that were developed previously for irrigation. In general, urban land developments are not compatible with other uses except for incidental agricultural, nongame wildlife, recreation, and water yield uses. Other. - Lands grouped as "other" include the land not encompassed by the four preceding cate- gories, such as salt flats, rock exposures, dunes, beaches, and many other landscape types. Vegetal Cover Ninety percent of the area has vegetation. General- ly, the desert vegetation tends to be sparse and to offer little protection to the soil. Figure 4 shows acreages by vegetal cover types, and certain noncover categories, by regions. land Use Figure 5 shows the distribution of major land uses. Areas such as salt flats that have no specific major use have been eliminated from consideration. This graphic presentation does not account for multiple uses. Recreation and watershed use and fish.and-wildlife occupancy, for example, are counted only if the land has been dedicated to them, limiting , or excluding other uses. Management The management use and treatment of the land resource varies with ownership as well as with physical characteristics. For this reason, ownership affects the quality and quantity of natural runoff as well as the location and magnitude of water use. With 57 percent of the Pacific Southwest federally owned, the major portion of Federal land is managed by the Department of the Interior (Bureau olLand Manage- ment), and the Department of Agriculture (Forest Service). Management of the national forests and public domain lands has been directed toward the maintenance and improvement of the total pro- ductive capacity of these lands. This culminated in full multiple-use management of national forests through passage of the Multiple-Use Sustained Yield Act of 1960 and of Bllreau of Land Management lands through passage of the Classification and Multiple.Use Act of 1964 (expired December 31, 1970). Other public land managing agencies and many private landowners have endorsed and are applying 28 the principle of multiple use under slightly different standards. For the most part, however, privately owned lands are managed at the discretion of the owners and under the constraints, if any, of local or county ordinances. land Resource Problems Problems related to land occur because of two broad categories of erosion - that erosion which occurs naturally by wind, rain and snow, tempera- ture, and other natural phenomena; and that erosion caused by man which accelerates the process in many ways. Cultivation, especially under dry-farming condi. tions, has resulted in localized soil loss. Under irrigation, soil movement is seldom significant. Broad areas,' however, have been subjected to heavy grazing use, some fo'r well over a century. Many range areas are in critical condition which show distinct deterioration .. Timber harvest methods have occasionally led to accelerated erosion over relatively small areas and to less critical forms of land deterioration over broader areas. Wildfire burns the protective cover from large areas almost every hot dry season, leaving them susceptible to erosion. At least 60 percent of burned area is in cover types that require many years to recover their soil protecting capability. Flooding is another catastrophic event that destroys parts of the land resource through streambank erosion, land scouring, or overwash of sediment. Disturbance of the land through construction activity generates sediment and often alters the surface drainage pattern, concentrating the runoff. A new element in the land destruction process is the use of vehicles in desert recreation. The fragile balance between tenuous desert or alpine cover and no cover at all can be upset by a small amount of traffic. Growing popularity of "dune buggies," motorcycles, and similar vehicles is hastening the defacement of dunes and shrubs and even destruction of desert "pavement" that has developed over centuries. Vehicles and equipment are widely used in, pros. pecting for minerals and cause land deterioration. Actual mineral extraction takes place on only a small percentage of the land area, but in some locations large open pits and extensive tailing dumps are exposed. Expanded irrigation has brought about a different kind of land deterioration caused by waterlogging and by the resultant salt buildup in the soil. Part of the problem is due to application of too much irrigation water directly to the affected lands, and in other cases delivery-canal seepage or similar phenomena also may contribute to the deterioration.