PRACTICAL FORESTRY. 



31 



the consequences began to be observed. The question of forests and 

 cHmate was then raised for the first time ; but questions of this kind 

 can not be answered without long and careful observations. Such 

 observations were begun by Becquerel in France and Krutsch in 

 Germany about the middle of the last century, 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 



Fig. 21. — The forest cover. Oregon. 



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 prob- 

 ably 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 affected by the forest, and 

 in what way. 



The climate of any place on the earth's surface results 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. Secondly, it depends 

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



358 



