VII] FUNCTIONS OF BARK 99 



This is also true of other trees at the margins of 

 plantations injudicially thinned e.g. Oaks, Maples, &c. 

 because although such trees grown from the first in the 

 open, are sufficiently protected in our climate, growth in 

 dense woods is apt to induce the formation of a bark which 

 is thinner and more succulent than the normal. 



On the other hand, thin barked trees if grown exposed 

 from the beginning, in ordinary situations, are often effi- 

 ciently protected by being covered from top to toe by 

 foliage shoots, as is often seen in Beeches, Spruce, 

 Lime, &c. 



The same properties which render the non-conducting 

 tegumentary coverings such efficient protectors against 

 insolation, are also effective in protecting trees against the 

 effects of spring frosts, the Birch an especially frost- 

 resisting tree being a good example. It has been 

 observed that while the younger parts of Scots Pines, 

 Larches and Spruces, &c., on which the bark-coverings 

 are still thin frequently suffer from frost, the older portions 

 of the stem being better protected suffered no injury. 



All these matters are important in forest-operations in 

 deciding how gradually trees grown in close forest shall be 

 exposed. 



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