susceptible to serious erosion whenever the ground cover is disturbed. The former is largely under Federal administration in the Wichita National Forest, but the latter is not subject to any Government regulation. If care is taken to employ those agricultural methods best suited to the prevention of soil wash; if fire protection is given, and overgrazing prohibited, no detrimental influence as regards soil erosion on these areas should result. Under present conditions, the Wichita-Mountain region is classed as beneficial and the Arbuckle Mountain as detrimental in their influence on erosion and run-off.

The Ouachita Mountains mark the most extensive area of rough topography to be found in the watershed. As long as a protective cover of timber, brush, or grass is kept on these steep slopes there will be little danger of excessive run-off and erosion. This will

entail methods of logging whereby a stand of trees is kept continuously on the land through selective logging, an adequate system of fire prevention, and, on cultivated lands, the employment of agricultural practices best suited to the prevention of erosion. Some headway has already been made in fire protection and selective cuttings on the Ouachita National Forest and by a few of the progressive lumber companies controlling extensive holdings in this region, by leaving a vegetative cover on the ground at all times (by diameter limit cuttings) and by instituting fire-control measures. These measures have not gone far enough to make this region of beneficial influence in its effect on flood control, and it has been classed as detrimental except for a portion in Arkansas, including the Ouachita National Forest and adjoining areas which have been classed as of neutral influence.

Parts of the rich agricultural region of northeastern Texas have suffered from erosion on those soils which are particularly susceptible to washing if preventative measures are not taken. The solution is to keep the steeper slopes in timber, to guard against the use of wasteful methods of tilling the soil, and to prevent fires. At present the influence of this region is neutral.

The hilly country of northern Louisiana, generally better suited to forestry than to agriculture, has suffered severe losses in its producing capacity through clear cutting of the virgin stands of pine, and until recently by receiving practically no protection from annually recurring fires. This land should be kept in forest cover, and fire protection is absolutely essential for that. Some planting of denuded areas will be necessary, but the natural reforestation of much of this region will follow after fire protection is obtained.

The relative protective value of the watershed has been rated according to the influence of the factors of soil, physiography, precipitation, and general character of cover (including forest cover) on erosion and run-off. This gives an indication of the relative importance of this watershed in respect to flood control when compared with other drainages. Separate ratings for each cover type and by kind of land used have been made and averaged by minor drainages and for the major basin as a whole. Forest cover ratings appear in an accompanying table (II), but a brief summary of all the ratings for each watershed is as follows:

1 Character of cover includes not only forest cover, shown separately in this table, but also improved and unimproved lands.

2 Average.

The designation of certain areas as critical and the detailed recommendation of certain forestry measures to be applied on them and elsewhere, must not obscure the fact that excessive run-off and erosion occur also in other places and can be prevented by other than forestry measures. Minor losses on cultivated land throughout the basin are, in the aggregate, probably far greater than on the worst of the critical areas designated in this report. Except in the eastern bottom lands and in the areas of deficient rainfall in the western end of the drainage, the erosion of roadside ditches is in its entirety another problem of staggering proportions. It is the cumulative effect of many small contributions of silt or water which makes these problems important. Fortunately they can be handled in the same way, piecemeal, by the cumulative effect of many small corrections, such as sodding ditch banks, increasing the organic matter in plowed fields, planting waste land to grass or trees, and covering cuts and

FIGURE 3.--Pure longleaf pine land on upper coastal plain soil.

Devastated by Buchanan Lumber Co., Red River drainage. Near White Surphur Springs, below Jena, La.

FIGURE 5. Ten-inch cottonwood buried by 6 feet of silt from Red River during 1927 flood. New roots have developed near surface of deposit. Rapids Parish, La. Outside levee. Bottom-land hardwoods. Red River drainage

fills with honeysuckle or other vegetation. The solution of these problems is essential to the completion of any program of flood control, and all available agencies must cooperate in the work.

SUMMARY

Because of the importance of the Red River-Ouachita drainage area from a flood standpoint, no less than from one of erosion, it is necessary that a complete and continuous forest cover should be maintained and developed. Not only is it necessary that a forest cover be maintained at all times, but it is imperative that the management of forest lands in this region take strictly into account the effect that these lands have upon the situation in the Mississippi Basin. Proper forest management, therefore, is essential.

Particularly is proper forest management necessary in the Ouachita Mountains where most slopes are unsuited for cultivation. The effect of clearing or clean cutting is shown on many of the slopes in erosion that has resulted. Clear cutting therefore should be avoided wherever possible and a system of cutting used which will permit a continuous cover upon the area at all times. With protection and with careful cutting methods, regeneration of the prevailing forests should be comparatively easy. Without an adequate fire protection this will be difficult or impossible, even with any system of management. Because removal of all or a major portion of the timber on the slopes at one time will result in a serious loss of soil and a reduction in the protective value of the cover against rapid run-off, it is evident that some system of selective logging must be used. Under such a system only that portion of the merchantable timber, such as for example the trees above a certain diameter class or trees possessing certain characteristics, would be removed. This would provide for the quick reestablishment of a forest and maintain all forest litter in as productive a state as is possible.

Proper forestry methods, however, should result in adequate yield and income from the forest cover and at the same time maintain to the utmost the advantage of full soil protection. Throughout this drainage, methods of harvesting the timber crops should be adapted to the individual situation. Any logging methods used should so be adapted to the conditions that they would bring about the least possible disturbance to the soil and to the forest cover. In this way the maximum protection to the soil would be assured.

As indicated, full protection from forest fires is necessary. Not alone is it necessary to guard against the fires which commonly follow logging operations, but it is also necessary to guard against the customary "light burning" or "woods burning" practice which is prevalent in the region. Largely through ignorance of the damage that fires do, local residents are accustomed to setting fire to the forests for a variety of reasons, believing that thereby they benefit grazing, remove obnoxious insects or animals, or make progress through the woods relatively easy. Thousands of acres are thus wantonly burned each year with little or no justification for the practice. The result of these fires is detrimental to the best interests of the lower Mississippi in that the removal of the litter paves the