INFLUENCE OF FOKESTS ON CLIMATE 5 



This shows that at elevations of less than 300 feet the 

 rainfall was the same as in the open country ; but that with 

 increasing elevations the rainfall in the forest exceeded 

 more and more that in unforested localities ; thus at 3000 

 feet elevation the rainfall was 84 per cent more in the 

 forest. 



The effect of local afforestation is to increase the rainfall 

 in the district. This has been proved by observations taken 

 in several localities, one being a moorland in Hanover, and 

 another a considerable area in the southern steppes of liussia, 

 which were planted with trees. Eain-gauges were placed 

 inside the planted tracts and in the surrounding country; 

 and as the plantations were increased year by year, the 

 rainfall recorded in them was found to be gradually 

 augmented. 



3. Tlic Influence of Forests upon Melting of Snow. — Prof. 

 J. E. Church (5), Director of the Mount Kose Observatory, 

 Nevada, U.S.A., has made interesting researches into the 

 restraining effect of forests on the melting of snow. He has 

 devised new methods of rapidly and economically measuring 

 large areas of snow at high altitudes. In the Sierra Nevadas 

 a larger quantity of snow accumulates in forests than on 

 bare slopes, the forests that retain snow best being those 

 with open narrow glades. There can be no longer any 

 question of the direct influence of forests in delaying the 

 melting of snow and in retarding stream-flow at the very 

 time when floods normally occur. The forested slope 

 contains an average water-content (the snow being converted 

 into an equivalent amount of water) one-fifth greater than 

 the bare but protected slope above it, nearly twice as much 

 water as the cornice at the edge of the mountain, over 

 fourteen times the moisture conserved by the wind-swept 

 slope, and more than twice the average water-content of all 

 three areas combined. Prof. Church advocates the planting 

 of timber screens at strategic points on exposed slopes in 

 order gi'eatly to increase their capacity to store more snow. 

 There are thus two types of reservoirs : the snow reservoirs 

 formed by the forest to hold the snow in its original form, 



