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Show Engineering measures for control of erosion.-To combat erosion in those sections of the valley which have been traditionally devoted to intertilled crops, terracing is proceeding in addition to readjustment of crop cover. The first erosion control program of TVA was on eroding areas bordering the reser- voirs. This involved constructing check dams, building diversion ditches, plowing in gully banks, and mulching sheet eroding areas. Power grading machines have been purchased and used extensively by farmer associations, co- operatives, and private contractors. The largest acreage has been in Alabama, with a sizable amount in Mississippi and Tennessee. In the 114 counties of the valley for which data are available the miles of terraces have increased from 11,415 in 1935 to 128,000 in 1947. Strip cropping has in- creased from 6,200 to 17,600 acres in the same period. Contour tillage is practiced on nearly all of the more than 1 million acres that have been terraced and strip cropped. This accomplishment has been stimulated by the efforts of other Federal, State, and local agencies as well as TVA. Forest protection.-About half the area of the Tennessee Valley is woodland. Its abuse has re- sulted in extensive erosion. Repeated cuttings, in which successively the largest and most valuable trees have been taken, have greatly depleted the forest, especially as they are often followed by fire and grazing. Repeated efforts to cultivate steep lands have also been a source of erosion and flash floods. The TVA has undertaken to retire some of the submarginal land to forest, and to obtain a good forest cover. In its effort to prevent the sedimen- tation of reservoirs and channels, the TVA early launched a reforestation program and cooperated with the Federal Forest Service in fire control measures. The TVA has undertaken a series of forestry measures designed to protect and improve the for- est. Included are such measures as reforestation, stand improvement, forest fire control, and "hill culture" or the planting of trees for their fruits or other specialty products as well as timber. Sub- marginal land was put into forest production to eliminate erosion as well as to obtain a profitable crop. Some acquired lands, after being improved, were turned over to the Forest Service for inclu- sion within the national forest system. In the early years of the program, reforestation was used, with the active cooperation of the Forest Service, to establish a protective strip around reser- voirs. Forest-tree nurseries were established at Norris, Clinton, and Muscle Shoals. The highest production of these nurseries in the past has been about 25 million 1-year seedlings annually. This reforestation program was extended to eroding privately owned lands. By 1942, about 150 million trees had been planted from TVA nurseries. Two-thirds of these were planted on about 78,000 acres of private land. By 1950 the total number of trees planted exceeded 200 million. In 1949 nearly 4,500 landowners planted more than 15 million seedlings from TVA nurseries on 13,900 acres of land. Fire control measures have been established to protect this resource. State-organized cooperative forest fire control established with Forest Service and TVA assistance has been extended to 88 coun- ties. Of the 14 million acres of forest land in the valley, nearly 10 million, or 70 percent, now have organized fire protection. TVA also cooperates with State forestry agen- cies as does the Forest Service in assisting forest and farm woodland owners to adopt better practices of timber management and in helping forest indus- tries and operators to use better methods of logging, milling, and processing wood products. 737 |