STREET TREES. 49 



the bottom and the concrete poured in from above. The 

 zinc and the edges of the wound should be painted or tarred 

 to render them less conspicuous. 



BRACES FOR CROTCHES. 



Acute angled crotches in trees of large size often split. 

 To prevent this, or to repair a break, let iron braces be put 

 in of size sufficient to withstand the strain. See Fig. 20. 

 Do not let bands be used, many trees have D n't use 

 been rained by them. If the weight of limbs bands - 

 is not very heavy a solid rod with screw threads on both 

 ends can be used. Ordinarily, however, it is best to use hook 

 bolts and a chain, or eye bolt, so that there may be some move- 

 ment when the wind blows. Whether a single rod or a com- 

 bination is used let a neat hole be bored entirely through each 

 limb and as high above the crotch as is prac- 

 ticable. If a rod is used these holes must be in 

 line, if a chain or eye bolt it does not matter. 

 On the outer side of each hole countersink a seat for a washer 

 at least 4 inches in diameter and for the nut. When the 

 brace is in place make the whole taut by screwing up the nuts. 

 If the tree has been split and the gap cannot be closed by the 

 power of the screws rig a tackle higher up. Let the hook ends 

 of the bolts project several inches so that they will not be 

 buried as the tree grows, but see that the washer, nut and 

 end of bolt are left so that they will be overgrown. 



WHAT TO DO WITH OLD TREES. 



Xothing that has been said about the choice of trees should 

 be construed as a recommendation to remove a poor tree be- 

 fore it can be replaced by a better one. A ragged old silver 

 maple is often better than none. When systematic tree 

 planting is decided upon accommodate the plan to existing 

 trees and provide for a gradual replacement of undesirables. 



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