4 CARNEGIE INSTITUTION 



C. The establishment and maintenance, in the region, of a botan- 

 ical station, laborator)', and garden for the solution of problems re- 

 quiring such equipment. 



Explanation of Plan. 



I. Relation of Vegetation to Environment in the United States. 



A. The function and effect of the forest with regard to atmospheric 

 jnoisture, precipitation, and run-off, and the converse effect on the forest. 



The relation of forests to atmospheric moisture, precipitation, and 

 run-off is one of the largest economic problems of forestr^^ It is 

 directly concerned with the water supply for dry and irrigation farm- 

 ing, for water power, and for navigation, and with the control of 

 floods. Although it is the text for continual di-scussion, we do not 

 yet know whether forests influence rainfall or not, or what is the 

 exact relation of the forest to run-off. 



More than seventy thousand square miles of national forest re- 

 serves have been created, chiefly with a view to the protection of the 

 water supply in the arid and semi-arid west, without adequate scien- 

 tific demonstration of their effectiveness. It may be noted also that 

 the flood loss along streams which rise in the Southern Appalachian 

 Mountains, during the last twelve months, was upwards of eighteen 

 million dollars. The lack of precise information on a topic so funda- 

 mentally important requires to be remedied, and is capable of remedy. 

 The failure of previous investigations has had much to do with the 

 neglect of a technical knowledge of the nature of the forest and of 

 the differences between forest types. The opportunity to reach re- 

 sults of great value is an admirable one. These results will not be 

 reached, at least for many years, by any agency other than the Car- 

 negie Institution, since no other is capable of cooperating at the 

 same time with all the indispensable members of this inquir3\ A 

 suitably conducted study will substantially solve this problem ; it 

 will not be undertaken unless by the Institution, and it is thoroughly 

 worthy of investigation along the following general lines : 



The investigation should be in charge of a trained forester, assisted 

 by a meteorologist, a hydrographer, a plant physiologist, and an 

 authority on plant distribution, each to be of the first rank. A 

 Greek and Latin scholar, with some knowledge of the general sub- 

 ject under investigation, should be employed during one year to 

 examine and sift the historical evidence for climatic change following 

 deforestation. 



