134 Staten Island Association of Arts and Sciences 



This phase of the subject has been exhaustively treated by Pro- 

 fessor Willis L. Aloore, chief of the Weather Bureau, and a sum- 

 mary of his conclusions may be of interest, as tending to disprove 

 certain very widely circulated impressions. He points out that 

 climatic changes are slow, extending through long periods of time, 

 and that increase or diminution in the forest area is the result, 

 not the cause, of such changes. This is shown by observation of 

 conditions in such high latitude countries as Alaska, where the 

 density of the forest has not been appreciably diminished although 

 the climate has undergone a gradual change, due to the retreat of 

 the glaciers. In desert regions the existence of dead forests, 

 often petrified, as in New Mexico and Arizona, indicates that the 

 climate became arid long before the forest succumbed. Certainly 

 in these cases no human agency could have compassed the destruc- 

 tion of the forests and by this means converted the land into a 

 desert. 



It has been observed that rain gauges placed in a forest always 

 catch more water than those exposed in open fields. This might 

 seem' to indicate that precipitation is greater on such areas, but 

 as a matter of fact, the construction of the gauges is such that 

 when sheltered from the wind they invariably catch more rain 

 drops. This accounts wholly for the differences in record be- 

 tween the two situations. So also, while the temperature of a 

 forest is lower and its relative humidity higher than in an adjoin- 

 ing field, this is purely a local condition, and the general climate 

 of the state or even of the county in which such a forest was 

 situated would not be appreciably affected by its removal. In 

 other words, destruction of the forests cannot be said to result in 

 any marked decrease in precipitation or any alteration in the mean 

 annual temperature; and this is amply demonstrated by the 

 records of the Weather Bureau. In the Ohio Valley, for exam- 

 ple, where deforestation has been extensive, the curve chart cov- 

 ering a period from 1834 to the present time shows a steady 

 average, while in New England, where deforestation began even 

 earlier in our history, there has been an actual increase in pre- 

 cipitation during the same period. 



