274 On the Plantiiuj of Forest-Trees. 



the common lime grows spontaneously on the lias shale in the 

 west of England^ and perhaps would succeed in most moist or 

 cool soils. It flowers in June and July; and is generally propa- 

 gated by layers. 



The birch (Betula alba). J'here are two native varieties; one 

 growing w^th straight firm boughs, and the other called the weep- 

 ing-birch, from its beautifully pensile spray. The young plants 

 resemble each olher ; but the weeping-birch may be distinguished 

 from the other by the numerous tubercles on the stem. The 

 birch is a very hardy tree, and is the last that yields to the rigour 

 of climate on the frozen plains of the north, and the elevated sides 

 of mountains. It is found on most poor soils, and frequently 

 occurs in coal shales in South Britain ; and such is its general 

 adaptation^ that it may be considered the forlorn-hope of the 

 planter. 



The horse -chesnut (Esculus hippocastcinum) must be con- 

 sidered merely as an ornamental tree, but one of such remarkable 

 beauty, both of foliage and blossom, as to demand a place in 

 every treatise on forest-trees, however brief. The wood is of 

 no value except for fuel. It grows in almost any kind of soil; 

 but arrives at its largest size on deep and healthy sands and loams. 

 It flowers in May.; and the seeds may be planted in October or 

 November. 



Resinous or Cone-beariug Trees. 



Of these trees it may be obseiS ed generally, that they occupy 

 the colder portion of the temj^erate zone, whether the climate be 

 owing to high latitude, or elevation, or to those causes which effect 

 a variation of temperature in different countries under the same 

 parallel. In the north-west of Europe, the region where the 

 pine tribe prevails, is more limited towards the South than in 

 North America, where the lines of equal temperature descend 

 many degrees as they traverse that continent ; and the same takes 

 place in the opposite direction across Asiatic Russia, where pines 

 prevail in much lower latitude than on the shores of the Baltic 

 and of Western Europe. Besides temperature, and those causes 

 before noticed, which effect the distribution of trees, there is an- 

 other which must exercise great influence. The hard, firm leaves 

 of the pine tribe exhale much less than the soft leaves of deci- 

 duous trees ; and therefore such trees are enabled to grow in 

 situations where less rain falls, and in soils less retentive of 

 moisture, such as the dry, sandy levels in the interior of con- 

 tinents, and the thin soil on the elevated slopes of mountains. 

 There can be no doubt that each of the causes mentioned has its 

 effect in varying the prevalence of one or the other kind of trees, 

 in proportion to the degree in which it exists. The sides of 



