A NATIONAL PLAN FOE AMERICAN FORESTRY 329 



tion and reforestation, mainly of protection forests, have been under 

 consideration in a number of countries. Shortly before her recent 

 revolution, Spain appropriated $19,000,000 for this purpose. France 

 has been considering an even larger program. 



Public forests that have protective value are, of course, almost 

 universally managed so as to preserve and increase their protective 

 effect. Soviet Russia has excepted forests that lie along or on the 

 headwaters of important streams from the present policy of liquida- 

 tion of timber values which is said to be applied to other forests. 

 Just as in the United States, a large proportion of the public forest 

 area in many countries, particularly that belonging to provincial 

 or national governments, is in mountain regions and consequently of 

 high protective value. The less accessible mountain forests naturally 

 were the last to be sought by private owners. This is less true of the 

 communal forests, which are generally located fairly close to settle- 

 ments. Forests belonging to mountain communes, however, such 

 as many of those in Switzerland, Austria, France, and Spain, also 

 have high protective value and are managed accordingly, generally 

 under the supervision of the national governments. 



More detailed information on the foreign legislation dealing with 

 protection forests is given in the section on "Public Regulation of 

 Private Forests." 



CLASSIFICATION OF WATERSHED PROTECTION INFLU- 

 ENCE OF FORESTS OF THE UNITED STATES 



With a view to determining the relative importance of forests in 

 the regulation of stream flow, in water supplies, in erosion control, or 

 in influencing other watershed values, the forest areas of the United 

 States have been classified into three groups: (1) Those of major 

 influence; (2) those of moderate influence; and (3) those of slight 

 to no influence. It is recognized that adequate scientific data and 

 results are not available for an absolute classification. In classifying 

 the forest lands, however, the possible application of such research 

 data as are available has been considered for all areas, and these data 

 have been supplemented by field observations and study of all avail- 

 able records. In order that the interpretations would be most use- 

 ful, general observational surveys were supplemented by specific 

 examination of representative areas. The classifications represent the 

 best combined judgment that the Forest Service could bring to bear 

 on them. 



Forests considered as of major influence included those occurring 

 on steep slopes subject to heavy or concentrated rainfall; on areas 

 with excessive and rapid snow melt; and on areas having unusually 

 erosible soils, where in the absence of the forest cover serious damage 

 would be apt to be done to soil or other values of the watershed itself, 

 or to land, improvements, navigation, or other values. In a number 

 of localities, particularly hi the West, where the demand for water is 

 unusually great and where because of scant rainfall it is necessary to 

 conserve as much of the stream run-off as possible, the forest cover, 

 even though far from a complete canopy, has been classed as of major 

 influence. These forests include many areas of the woodland type, 

 where disturbance of the forest cover has caused or would cause 

 abnormal erosion and endanger water conservation through the exces- 



