INFLUENCE OF WOODLANDS UPON STREAMS. 291 



Kansas, Nebraska, and Missouri, are not without precedent. It is re- 

 membered, in Central Kansas, that heavy rains occurred in August, 

 1858, and that destructive floods occurred in Juno and July, 1867. The 

 season of 18G8 was accounted a wet year. It is the general belief of 

 the inhabitants who have resided in that section since the first settle- 

 ment that the rains are on an increase in recent years. 



The dark-colored prairie soil of Kansas and Nebraska, when covered 

 with herbage, is not liable to erosion. Even after it has been broken 

 np, this soil when wet becomes pasty and somewhat impervious to water, 

 in heavy rains, and it is not until the surface has been worn away till 

 it reaches the subsoil, composed of a porous, sandy loam-, that these 

 erosions become serious, and, when once formed, difficult to repair. 



The absorption, retention, and delivery of water by the soil under 

 cultivation, or covered with forests, has long been a subject of obser- 

 vation, and has necessarily been an element in calculating the capacity 

 of streams for the maintenance of their supply, ever since the subject 

 has been reduced to exact rules. The following observations, nearly a 

 century old, are strictly' in accordance with modern experience: 



Countries baviog a level surface, and those where the soil is generally cultivated, 

 absorb relatively much more water than those where these conditions are different. 

 Ic is true that after the heaviest rains, bare and uncultivated laud will scarcely be 

 damp at a few inches below the surface, while the same soil, when finely divided by 

 cultivation, would be saturated by the water to the depth of several feet. * * * It 

 always takes water some time to penetrate the earth, even when there is nothing to 

 hinder its How, and every obstacle that tends to obstruct it favors infiltration. Wood- 

 lauds are therefore well adapted to hinder the waters from running off, and to favor 

 their passage into the soil. This they do with better eff"ect when they are more densely 

 covered. It is, moreover, certain that the leaves of trees, pump up and absorb a large 

 amount of water, and although the soil on which they grow is uncultivated, it is much 

 more susceptible of absorption of rains than bare and uncultivated land. 



Forests contribute so efiectually to the detention and preservation of the waters that 

 springs in some countries, flowing through the year, have entirely disappeared after the 

 woods had been burned, nor did they reappear until after the verdure had been re- 

 stored, their existence being closely dependent uxwu its presence.^ 



Mr. James Brown, of Stirling, Scotland, a standard authority upon 

 forestry, in speaking of the effect of tree-planting upon moisture, says: 



I have frequently been surprised to find (on examining woods which had been planted 

 some 10 or 12 years, all the land under which had been considered dry at the time the 

 plantation was made) wet spots, spreading wider and wider every year, and some of 

 them even beginning to throw out runs of water; thus proving that under the shade 

 of the trees the larger portion of the moisture of the land is retained, and therefore 

 accumulates in spots, according to the nature of the subsoil.- 



In a study of the influence of forests upon climate and springs of 

 water, by M. Jules Maistre de Villeneuvette, published at Montpelier in 

 1874:,^ this ob.server during eighteen months continued his experiments 

 in a wooded basin and in one that had been cleared, but otherwise sim- 

 ilar in soil and conditions. The former, with an area of 779 hectares, 

 delivered 110 liters of water very regularly; the other, with 6.786 hec- 

 tares, had a drainage of only 10 or 12 liters a second, and was very 

 irregular. He found the temperature of the open fields at least 10^ (C.) 

 above that in woods. Ho noticed that in the southern region, the culti- 

 vation of cereals is becoming more uncertain and less profitable, an«J. 

 that the injuries by the Phylloxera upon the vine-roots were more de- 

 structive; and concludes by urging upon his readers the necessity of 

 counteracting this growing tendency to drought by j)lanting and irri- 

 gating^ ^^ 



^Xouicaux Principcs d'HydmuUque. Par. M. Bernard, 4° (1787), p. 141. 



'Forester, 4th ed., p. 14. 



^Influence des Forcta sur les CUmats et les Sources, 8vo, pp. 60. 



