170 STUDIES OF TREES 



insignificant, but, if negloctod, it will soon commence to 

 decay antl thus to carry disease and insects into tlie tree. 

 The tree then becomes hollow and tlangerous and its life 

 is doomed. 



Injury to the cambium layer, resulting in surface wounds, 

 may be due to the improper cutting of a branch, to the 

 1 ite of a iiorse, to the cut of a knife or the careless wielding 

 of an axe, to the boring of an insect, or to the decay of a 

 fungous disease. (See Fig. 117.) Whatever the cause, 

 the remedy lies in cleaning out all decayed ivuod, removing 

 the loose bark and covering the exposed wood with coal tar. 



In cutting off the loose bark, the edges should be made 

 smooth before the coal tar is applied. Loose bark, put 

 back against a tree, will never grow and will only tend to 

 harbor insects and disease. Bandages, too, are hurtful 

 because, underneath the bandage, disease will develop more 

 rapidly than where the wound is exposed to the sun and wind. 

 The application of tin or manure to w^ounds is often indulged 

 in and is eciually injurious to the tree. The secret of all 

 wound treatment is to keep the wound smooth, clean to the 

 live tissue, and well covered with coal tar. 



The chisel or gouge is the best tool to employ in this 

 work. A sharp hawk-billed knife will be useful in cutting 

 off the loose bark. Coal tar is the best material for cover- 

 ing wounds because it has both an antiseptic and a pro- 

 tective effect on the wood tissue. Paint, which is very 

 often used as a substitute for coal tar, is not as effective, 

 because the paint is apt to peel in time, thus allowing 

 moisture and disease to enter the crevice between the 

 paint and the wood. 



Cavities: Deep wounds and cavities are generally the 

 result of stubs that have been permitted to rot and fall out. 

 Surface wounds allowed to decay will deepen in course of 



