110 



ON QUALITV OF SOIL. 



spect to the trees found in regions of various degrees 

 of heat or cold, we may form a pretty accurate esti- 

 mate of the heights at which they will thrive rela- 

 tively to one another. 



Now, we are told that the trees which reach 

 nearest to the limit of perpetual snow, and within a 

 very few degrees of it, are the Scots fir and the 

 birch, reduced, in their nearest approach to this in- 

 hospitable region, to the stature of scragged shrubs. 

 A degree or two farther south than this utmost 

 verge of vegetation, the spruce is found at first in a 

 very diminutive state. After it, still farther south, 

 succeeds the oak, then the beech, and, last of ail, 

 the Spanish chesnut. The ash, elm, lime, &c. be- 

 long to the zone of the beech. In like manner we 

 are told that, at the foot of the Alps, the chesnut 

 flourishes, the beech continues after the former dis- 

 appears, and the oak rises to a height where there 

 are found no beeches. After the oak itself has va- 

 nished, the pine continues diminishing regularly in 

 size, till it approaches the boundary of perpetual 

 frost. 



These observations furnish us with the elevations 

 at which trees will thrive, relatively to one another, 

 in all countries ; as to absolute heights, they must, 

 of course, vary in different climates. The utmost 



