FOREST INFLUENCE ON CLIMATE. 57 



FORESTS AND CLI3IATE. 



The discussion of forest influence on climate began 

 in this way. AVhen the French revolution broke out 

 in 1789, the old restrictions on the manag-ement of pri- 

 vate forests were done awa3^ A wholesale cutting of 

 these timberlands prompt!}^ followed, and as earh^ as 

 1792 the consequences began to be observed. The 

 question of forests and climate was then raised for the 

 lirst time: but questions of this kind can not be an- 

 swered without long and careful observations. Such 

 observations were begun b}^ Becquerel in France and 

 Krutsch in Germanv about the middle of the last cen- 

 turv, but it was not until 1867 that a satisfactory way 

 of making them was devised. This was the system of 

 double stations — one within the forest, the other at a 

 distance in the open. It was first put in operation by 

 Professor Ebermayer, now of the Bavarian Forest 

 School. By this means the amount of moisture and 

 heat in the forest may be compared with that in the 

 open, and in the end a full and satisfactory answer will 

 probably be reached. 



In order to find how great the influence of forests on 

 climate may be, we must first see what are the factors 

 which make climate. Then we may ask which of these 

 factors can be afiected by the forest, and in what way. 



The climate of an}' place on the earth's surface re- 

 sults from the action of the sun's heat upon it. Climate 

 is the average condition of the weather. It depends, 

 first of all, on the distance of a place from the equator 

 and its elevation above the sea. Secondh\ it depends 

 on the distribution of land and water, the relief of the 



