RELATIONS OF TREES TO WATER 297 



surrounded by a rampart of woods, it was sheltered 

 from the force of the winds and pleasantly open to 

 the sun. But when men began to fell the woods to 

 supply the demands of towns and cities for fuel and 

 lumber, these clearings were gradually deprived of 

 their shelter, by levelling the surrounding forest 

 and opening the country to the winds from every 

 quarter. But the clearing of the wood from the 

 plains, while it has rendered the climate more 

 unstable, has not been the cause of inundations or 

 the diminution of streams. This evil has been pro- 

 duced by clearing the mountains and lesser elevations 

 having steep or rocky sides; and if this destructive 

 work is not checked by legislation or by the wisdom 

 of the people, plains and valleys now green and fertile 

 will become profitless for tillage or pasture, and the 

 advantages we shall have sacrificed will be irre- 

 trievable in the lifetime of a single generation. The 

 same indiscriminate felling of woods has rendered 

 many a once fertile region in Europe barren and 

 uninhabitable, equally among the cold mountains 

 of Norway and the sunny plains of Brittany. 



Our climate suffers more than formerly from 

 summer droughts. Many ancient streams have 

 entirely disappeared, and a still greater number are 

 dry in summer. Boussingault mentions a fact that 

 clearly illustrates the condition to which we may be 

 exposed in thousands of locations on this continent. 

 In the Island of Ascension there was a beautiful 



