THE RELATION OF THE SMALLER FOREST AREAS 
IN NON-FORESTED REGIONS TO EVAPORA- 
TION AND MOVEMENT OF SOIL WATER 
IRWIN T. BODE 
The importance of the climatic and edaphic relations of forests 
has been the basis for wide discussion and study. The scope of 
this field is shown in a condensed way in a report of the Sub- 
Committee on Forest Investigations to the Fifth National Con- 
servation Congress/ which discusses studies undertaken up to 
the time of the report (1913) and presents in general results 
obtained. Recently, Zon,^ in a paper, “Forests and Water in the 
Light of Scientific Investigation,” has presented a much more 
comprehensive view of the subject and the literature. He has 
attempted to bring together “all the well established scientific 
facts in regard to the relation of forests to the water supply.” 
The work includes an extensive bibliography. 
It is not necessary in the present discussion, therefore, to at- 
tempt to review the whole field or all of the literature with 
reference to these edaphic and climatic relations. Such citations 
are made as are pertinent to the particular phases of the present 
studies. 
In connection with the management of the timber-lands in the 
Southwest, Pearson ^ has presented considerable data as the result 
of studies to determine the influence of forest cover upon local 
climate. The efifects upon air temperature, soil temperature, 
precipitation, atmospheric humidity, and wind are included. Only 
meager information, however, is presented as to the relation of 
forests to soil moisture and evaporation. With regard to evapo- 
ration, Pearson states that the influence of the forest in decreasing 
the same is 30 per cent greater in Europe than it was found to 
be in his studies for New Mexico and Arizona. 
1 The relation of forests to water, Rept. Sub-committee on Forest Investigations 
to Fifth National Conservation Congress. November, 1913. 
2 Zon, Raphael, Forests and water in the light of scientific investigation. Final 
Rept., National Waterways Commission, Appendix V, 
3 Pearson, G. A., A meteorological study of parks and timbered areas in the 
western yellow-pine forests of Arizona and New Mexico. Reprinted from Monthly 
Weather Rev., 41, 1615-1629. 1913. 
