1G ELEMENTS OF SYLVICULTURE. 



A farther distinction is made, according to their 

 composition, between rich soils, which contain a large 

 proportion of vegetable mould, and poor soils, con- 

 taining little or none. 



Marl is an intimate mixture of lime and clay ; 

 when exposed to the air it crumbles, and according as 

 the clay or lime predominates, it is said to be 

 argillaceous or calcareous, forming in the former case 

 a stiff soil, in the latter case a light soil. Marl is a 

 first rate soil, nutritive in itself, and highly suitable 

 to every kind of cultivation. 



Rich sand is a mixture of sand and clay ; when 

 vegetable mould is added to it, it constitutes the 

 best soil for the growth of forest trees. 



FOREST TREES. The botanical description of forest 

 trees belongs to the department of natural history, 

 and will therefore find no place in this manual. 



But before giving the treatment of the more 

 important among them, we shall mention the climate 

 and soil that suit them best, their habitat in plains or 

 in mountainous regions, their manner of growth, 

 qualities and uses, the requirements of the young 

 plants, in a word, all that is capable of affecting 

 cultural operations. It will suffice to give heret he 

 characteristic features of the two grand divisions, 

 broad-leaved trees and conifers. 



The broad-leaved trees have annual leaves, with 

 the exception of a few southern species ; the cork, 

 western holm, and kermes oaks, &c. ; the leaves 

 have a well-developed blade, and there is a bud at the 

 axil of each. The result is an irregular ramification. 

 Their wood is always formed of vessels, fibres and 



