196 PRACTICAL TREE REPAIR 



over the opening. The tinning, of course, must 

 be just as well done as if the cavity had been 

 thoroughly excavated. 



For blocking a small hole at the base of a hol- 



Plug of concrete at base of 

 chimney cavity 



low tree, nothing is better than a plug of concrete, 

 held in place by nails driven into the wood a couple 

 of inches back from the opening. An incision 

 must be made, and the filling must be kept back 

 from the cambium line, just as in ordinary fillings. 

 It perhaps had better be said again that the 



