198 GENEEAL EESULTS. 



There are, in the constitution and action of the forest, many 

 forces, organic and inorganic, which unquestionably tend power- 

 fully to produce meteorological eflEects, and it may, therefore, be 

 ^assumed as certain that they must and do produce such effects, 

 unless they compensate, and balance each other, and herein lies 

 the difficulty of solving the question. To some of these elements 

 late observations give a new importance. For example, the ex- 

 halation of aqueous vapor by plants is now behoved to be much 

 greater, and the absorption of aqueous vapor by them much less, 

 than was formerly supposed, and Tyndall's views on the relations 

 of vapor to atmospheric heat give immense value to this factor in 

 the problem. In like manner the low temperature of the surface 

 of snow and the comparatively high temperature of its lower 

 strata, and its consequent action on the soil beneath, and the great 

 condensation of moisture by snow, are facts which seem to show 

 that the forest, by protecting great surfaces of snow from melting, 

 must inevitably exercise a great chmatic influence. If to these 

 influences we add the mechanical action of the woods in obstruct- 

 ing currents of wind, and diminishing the evaporation and re- 

 frigeration which such currents produce, we have an accumula- 

 tion of forces which must manifest gr^at climatic effects, unless — 

 which is not proved and can not be presumed — ^they neutralize 

 each other. These are points hitherto Httle considered in the 

 discussion, and it seems difficult to deny that as a question of 

 a/rgument^ the probabihties are strongly in favor of the meteoro- 

 logical influence of the woods. The evidence, indeed, is not satis- 

 factory, or, to speak more accurately, it is non-existent, for there 

 really is next to no trustworthy proof on the subject, but it ap- 

 pears to me a case where the burden- of proof must be taken by 

 those who maintain that, as a meteorological agent, the forest ia 

 inert. 



The question of a change in the climate of the Northern 

 American States is examined in the able Meteorological Report of 

 Mr. Draper, Director of the IlTew York Central Park Observatory, 

 for 1871. The result arrived at by Mr. Draper is, that there ia 

 no satisfactory evidence of a diminution in the rainfall, or of any 

 other climatic change in the winter season, in consequence of 

 clearing of the forests or other human action. The proof from 

 meteorological registers is certainly insufficient to estabhsh the 



