EFFECTS OF DESTRUCTION OF FORESTS. 4()9 



of fields, or tlie ground. In order to do this, it is of course abso- 

 lutely necessary to denude the soil ; that is, the trees must be cut 

 down and destroyed. This, however, is no argument in favor of 

 that kind of destruction, against which it is designed to speak. 

 For it may be safely asserted that if only so much soil in the 

 United States were judiciously denuded, and the trees destroj'ed, 

 as would produce not only food enough to support one hundred 

 million inhabitants, and still afford a large surplus for exportation, 

 there would remain still, in immense forests and scattered groves 

 and thickets, an amount of trees sufficiently abundant to subserve 

 all those natural purposes for which they were undoubtedly 

 intended. 



After the field has been prepared and tilled, manured and planted, 

 there come two all important conditions, temperature and moisture 

 of the soil, — that is, there must be neither too much, nor too little, 

 but just enough of sunshine, which supplies light and heat, and of 

 rainfalls which supply the moisture, A great excess of either of 

 these conditions tends very greatly to diminish the results of the 

 husbandman's labor, if it does not render that labor entirely un- 

 availing. In proof, witness the effects of a season of severe drouth, 

 and also one of cold drenching. , 



The temperature of the soil is affected by various causes. First 

 the surfaces of the open fields are heated by the full and unob- 

 structed rays of the sun. The heat thus derived penetrates to a 

 greater or less degree according to the nature of the soil. Then 

 again, temperature is affected by the winds from various quarters, 

 which either assist the sun's rays, or cool the surface by dispersing 

 and carrying off the natural radiations of heat. Still further, we 

 have an artificial cause of increased warm temperature, in drainage. 

 By a series of careful experiments, it has been with certainty as- 

 certained, that drained land is considerably warmer than undrained. 

 And still another cause of a modification of the temperatui-e of the 

 soil in the open fields, is the proximity of forests of tall trees. In 

 the absence of the sunlight during cold storms, these forests pro- 

 tect the bare soil and the vegetable growths from the cold north- 

 erly and easterly winds ; and, since trees are bad conductors of ^ 

 heat, they give out an equally beneficial cooling radiation, during 

 the heated seasons, and under the rays of the noonday sun. These 

 indisputable facts, it will be observed, intimately connect the sub- 

 ject matter of this paper with Temperature, the first of the two 

 important conditions above mentioned. 



