170 TRANSACTIONS OF THE ILLINOIS 



historical period, so we can now proceed to show what has been and ever 

 must be the effect of deforestation. These effects may be treated under 

 three different heads: fii"st, amehoration of chmate, where the forest is too 

 dense; second, degradation, where deforestation is carried beyond due 

 Umits; and third, permanent aridity and steriHty where the destruction is 

 total. First, then, examples of amelioration. 



It can not be controverted that the climate of northern and central 

 Europe has been greatly ameliorated within the last two thousand years. 

 VaiTO speaks of the climate of southern France as unfavorable to the growth 

 of the vine and the olive. Virgil describes the Crimea as subject to the 

 rigors of an eight months' winter. Diodorus Siculus narrates how whole 

 armies crossed the frozen Rhine, Rhone, and Danube. In fact, all ancient 

 authors are agreed as to the rigors of the climate of central Europe at 

 their time. 



America affords a similar example of amelioration. The early set- 

 tlers of New England and Virginia speak of the severity, length, but 

 equability of American winters, which is irreconcilable with their 

 comparative mildness, shortness, but extreme variability now. Jefferson, 

 in his notes on Virginia, records this testimony of the old settlers, which 

 he says is coiroborated by his own observation and experience. He says 

 within the recollection of the living generation, the climate has been much 

 modified. The snows are fewer and less in quantity, and remain a 

 shorter time on the ground. Streams that were formerly closed for 

 weeks with ice, now seldom freeze over. The changes from warm to 

 cold and vice versa are now more sudden, frequent, and extreme. 

 "When spring then came, it came to stay, and not as now relapse 

 suddenly back into winter." 



Jefferson gave it as his opinion that these changes have been caused 

 by clearing away the forests, exposing the soil to the warming influences 

 of the sun, and by giving freer passage to air currents, whether warm 

 or cold. In Europe the amelioration of climate is attributed to the 

 same cause; and there can be no question as to the correctness of the 

 inference. 



Who has not observed that the snows and ice of winter lie longer in 

 the forests than in the open fields.^ Europe two thousand years ago, and 

 America when discovered, were covered with an almost unbroken 

 wilderness of forest. The ice and snow then melted not so soon, and 

 consequently the winters were longer than now. Deforestation whenever 

 carried on within due limits has been a benefit, shortening the winters 

 and producing a general amelioration of climates. 



Let us now give a few instances of degradation of climate. The 

 stringent forest regulations of the Tezcucans and Aztecs have already 

 been mentioned. The effects of these regulations and of their abroga- 

 tion by the conquerors.are thus described by Prescott, the historian : 



" In the time of the Aztecs, the land was thickly covered with larch, 

 oak, cypress, and other forest trees, the extraordinary dimensions of some 

 of which remaining to the present day, show that the curse of barren- 

 ness in later times is chargeable more on man than on nature." And 



