62 ECONOMICS OF FORESTRY. 



out. Now, although with the expenditure of more 

 than $40,000,000 only a small part has been recu- 

 perated, the efficiency of a forest growth in hold- 

 ing the soils of the slopes and retarding the 

 run-off water seems experimentally demonstrated 

 beyond peradventure. 



In Germany the greatest exponent of natural 

 philosophy, Alex, von Humboldt, from observa- 

 tions in many parts of the globe, came to the 

 conclusion that forest conditions and climatic 

 conditions are intimately related. Among the 

 causes which tend to lower the mean annual 

 temperature, he cited in his " Cosmos," " extensive 

 woods, which hinder the insolation of the soil by 

 the vital activity of their foliage, producing in- 

 tense evaporation owing to the extension of these 

 organs, and increasing the surface that is cooled 

 by radiation, and acting consequently in a three- 

 fold manner, by shade, evaporation, and radia- 

 tion ; " and in another place he gives expression 

 to his conviction of the relation of forest cover 

 and water conditions in the often-cited words, 

 " How foolish does man appear to me in destroy- 

 ing the mountain forests, for thereby he deprives 

 himself of wood and water at the same time." 



In the beginning of this century, when the 

 tendency of dismembering and selling the forest 

 property accumulated by the state governments 

 began to spread, in part as a consequence of 

 Adam Smith's doctrine, those opposed to such a 





