ON QUALITY OF SOIL. 



Ill 



height at which the Scots fir grows in Scotland, even 

 of the size of a large shrub, is said to be 2000 feet. 

 In most places, however, it does not ascend half so 

 far. I should conceive 700 or 800 feet to be the 

 greatest altitude to which it attains any where with- 

 in twelve miles of the sea-coast. Assuming 900 feet, 

 as the medium height attained by it and the birch, 

 we may assign 600 feet for the oak and larch, and 400 

 for the beech, with the other trees that belong to its 

 zone. Even at the extreme points of these eleva- 

 tions, we must look in general for nothing but dwar- 

 fish scragginess. Wood is said to thrive in Perth- 

 shire, at a greater height than any where else in 

 Scotland. This may be accounted for, partly by 

 the distance from the sea, and partly from the 

 mountains, in many places of that county, being 

 piled so closely together, as to reflect back the rays 

 of the sun upon each other, and afford mutual shel- 

 ter. 



