142 PRACTICAL TREE REPAIR 



back of the cambium depends on the thickness of 

 the dressing with which the surface of the concrete 

 is to be protected. There is a natural tendency 

 to rub the surface of the filling down smooth, but 

 the subsequent surface dressing sticks better to the 

 surface which results from cutting or paring down 

 the cement with a trowel. The conformation of 

 the filling should be graceful, following the curves 

 of the trunk, but no effort should be made to imi- 

 tate the bark or ridges of the natural tree. The 

 curve from one side of the cavity to the other 

 should not be full, but rather incline toward flat- 

 ness. 



CONCRETE: WET METHOD 



The method, which will now be described, of 

 filling cavities in trees with wet concrete mixture, 

 depends on the closing of the opening with a dam 

 of waterproof fabric (such as oil-cloth) held in 

 place by strips of canvas across the opening, the 

 dam being carried up the opening as fast as the 

 mixture is deposited. The work is performed in 

 the following way, a basal cavity of very moder- 

 ate difficulty being taken as an example. Having 

 completed the excavation and treated the interior, 

 fill the lower part, up at least to the surface of the 

 soil, with wet concrete. Then, if the tree is a 

 large one, tie two poles to the trunk, one each side 

 of the opening and six or eight inches from it. 



