SYLVICULTURE 27 



must be taken into account. The height above sea-level 

 reached by trees is to a great extent regulated by climatic 

 conditions warmth particularly. The greatest altitudes are 

 reached by Spruce and Mountain Pine (Pinus montana} ; follow- 

 ing them, in order, come the Cembran Pine (Pinus cembra) 

 and Mountain Alder (A Inns viridis\ Larch, Sycamore, 

 White Alder (Alnus incana), and Rowan or Mountain Ash. 

 Cembran Pine and Mountain Alder are practically confined 

 to the Alps. As failing to reach any considerable altitude 

 Sweet Chestnut, Poplar, Acacia, and Osier Willows may 

 be mentioned. 



Tree Growth in Relation to Light 



For the raising of woods and the management of them, 

 it is most necessary to understand the requirements for light 

 of the various trees. 



A few species, especially Silver Fir and Beech, do not 

 demand a full degree of light in order to grow well. The 

 Yew tree possesses this faculty of toleration to a wonderful 

 extent. On the other hand, there are species for whose 

 growth, and life itself, much light is absolutely essential. To 

 this latter class belong Birch, Larch, Oak, and Scots Pine. 



Trees that have been allowed to grow in free positions, 

 and to develop their natural character, can be judged in their 

 relation to light by the foliage of their crowns. 



Under like conditions of shade, the twigs and crowns of 

 shade-bearing species are alive and healthy, while those of the 

 light-demanders are languishing or dead. The crowns of 

 the individual trees, as well as of the wood as a whole, 

 appear thick and close- in the case of the former, but light 

 and open in that of the species intolerant of shade. That 

 shade-bearing trees can also develop to perfection in open 

 positions must be evident to all who have observed their 

 growth in any of our wooded parks. 



The habit of growth characteristic of the various species, 

 as shown in the development of their crowns and in the 



