THE WATER OF SOILS. 265 



and where surface roots are few or absent it may readily hap- 

 pen that the surface soil is moister than the subsoil. 



This was very strikingly shown by the investigations of Ototzky in 

 the South-Russian steppes, in comparing both the moisture contents and 

 the depth of bottom water as between forest land and the open plains. 

 On the steppe near Chipoff, Government of Voronej, he found the 

 ground water at from 3 to 5 meters (10-16 feet) depth ; under the forest 

 in the same region and in identical underground formations, the water 

 level stood at 15 meters. In the Black Forest near Cherson, the water 

 is found at about 15 feet beneath the surface ; under the steppe and in 

 cultivated ground it stood at 10 feet. At the same time the forest soil 

 was moister in the upper two feet than the soil of the steppe, where 

 surface evaporation (partly through shallow plant-roots, partly direct) 

 was greater than under the shadow of the forest ; under which, moreover, 

 there were few shallow rooted plants to draw upon the moisture of the 

 surface soil. 



The great evaporation from forests is a matter demonstrated 

 by actual measurement ; hence it is not surprising that certain 

 shallow-rooted trees should serve for the reclamation of wet 

 ground, as has been demonstrated on the large scale, c. g., in 

 the use of the eucalyptus in the Pontine Marshes of Italy, and 

 of the maritime pine in the Landes of western France. Thus 

 the sanitation of swampy districts through tree-planting has be- 

 come one of the established measures in their settlement. But 

 this refers only to the evaporation from the trees themselves; 

 for in the shade of the forest, a free water-surface is found to 

 evaporate on the average only one-third as much as in open 

 ground. Of course there must be a correspondingly great 

 diffence in the amounts of evaporation from the soil-surfaces 

 in the respective areas. 



The great draft made by the Eucalyptus globulus upon soil- 

 moisture has been also abundantly shown in California, where 

 on account of its rapid growth this tree has been largely used 

 for windbreaks. Tt was found that the trees deplete the 

 fields of moisture for from twenty to thirty feet on either side, 

 so as to materially reduce crops within that limit. For this 

 reason the pine and cypress has of late found greater accept- 

 ance for this purpose. 



