SECT. I. WOUNDS. 475 



all affected. For trees will continue to thrive though 

 subjected to this operation for many successive years ; 

 and the hole, if not very large, will close up again 

 like the deep incision, not by the union of the 

 broken fibres of the wood, but by the formation of 

 new bark and wood projecting beyond the edge of 

 the orifice, and finally shutting it up altogether. 



SUBSECTION III. 



Girdling. Girdling is an operation to which Employed 

 trees in North America are often subjected when the pi an t. 

 farmer wishes to clear his land of timber. It con- 

 sists in making parallel and horizontal incisions 

 with an axe into the trunk of a tree, and carrying 

 them quite round the stem so as to penetrate through 

 the alburnum, and then to scoop out the intervening 

 portion. If this operation is performed early in the 

 spring and before the commencement of the bleed- 

 ing season, the tree rarely survives it; though some 

 trees that are peculiarly tenacious of life, such as 

 Acer saccharinum and Nyssa infegrifolia, have 

 been known to survive it a considerable length of 

 time.* 



SUBSECTION IV. 



Fractures. If a tree is bent so as to break part 

 only of the cortical and woody fibres, and the stem 

 or branch but small, the parts will again unite by 



* Barton's Elem. of Rot. Part ii. 



