PLANTING AND CARE OF TREES 143 



the filling into two or more sections by cutting into it with a 

 knife in about the same way that sidewalk builders section off 

 their concrete walks. (See figs. 64 and 65). This precaution 

 obviates the irregular cracking of the concrete due to the swaying 

 of the tree by the wind. By reinforcing the concrete, also, with two 

 or more steel uprights, by numerous steel rods, or by iron pipes, 

 the danger from cracking the filling is greatly reduced. Even 

 though no cracks are made in the concrete there is likely to be a 

 crack between the wood and the filling, where water is likely to en- 

 ter. For this reason some prefer to cover the concrete with zinc, 

 tacking it down on a freshly-painted surface as previously de- 

 scribed. 



Bolting and Cliaining — Some trees with bad crotches, like the 

 Elm and Silver Maple, are very liable to split down, unless protect- 

 ed in some way. Any tree with a cavity in its tmnk, no matter how 

 small, is likely to split open, due to the freezing of the accum- 

 ulated water. Trees affected in this way, of course, should first 

 have their cavities filled and the water prevented from accumu- 

 lating. Any tree that shows a tendency to split should be sup- 

 ported by bolting or chaining. It is also well to preclude damage 

 by bracing all trees with bad crotches, even when there is no indi- 

 cation of splitting. A sudden storm often tears large branches 

 from the trees that are least suspected of being injured. When 

 the branch is completely severed there is no hope, and all that can 



Fig-. 68. The result of improper methods 

 of supporting- a weak crotch. 



be done is to trim up and dress the wound. If the branch is not 

 completely severed and if it may be readjusted without injuring the 

 connecting tissue, the chances are favorable for saving the limb. 



