92 PRACTICAL TREE REPAIR 



to succumb to the storms, prune it back severely, 

 perhaps brace it to its stronger neighbors, fertilize 

 it, and plant a young tree or two near by. The 

 chances are good that the old tree will become 

 a sturdy specimen and thrive for several decades. 

 The young tree, in the meantime, will grow to fair 

 size, and will be ready to take the veteran's place. 

 If the grove is to be permanent it must always con- 

 tain young trees as well as old ones. 



In the third place, expensive fillings should not 

 be put into trees in a region where there is a high 

 mortality rate (either among all trees, or simply 

 in the species to which the decaying tree belongs) 

 on account of gradual changes in the environment. 

 Such regions of high mortality are common near 

 cities. They are oftenest caused by the lowering 

 of the water level and the consequent drying of 

 the soil, as a result of draining, street-paving, the 

 destruction of the forest floor covering, and the 

 compacting of the surface soil. They are also 

 caused by the contamination of the atmosphere 

 by factories. When such a state of things exists, 

 or threatens to exist, it is obviously unwise to spend 

 money on work which cannot in any way diminish 

 the risk from the prevalent adverse conditions. 

 If there is money to be spent upon the trees in such 

 a locality, it should be spent, if at all, in an effort 

 to restore the natural conditions for want of which 

 the trees are dying, and preferably in improving 



