FILLING TREES 91 



a tree belonging to a species which, locally or 

 generally, is doomed to destruction by the attacks 

 of insects or fungous diseases. In some parts of 

 New England this principle would rule out work 

 on old elms, on account of the havoc wrought by 

 the elm-leaf beetle and the leopard moth. The 

 rapid spread of the chestnut bark disease makes 

 it almost foolhardy to put much money into chest- 

 nut trees within two hundred and fifty miles of 

 New York. Even beyond that radius, it is doubt- 

 ful whether work is admissible which looks for- 

 ward fifteen or twenty years. 



The second rule is to the effect that it is usually 

 unwise to spend much money filling trees that 

 stand in a grove or woods, where the mass of the 

 foliage counts for more than the individual trees. 

 In such a case the grove should be handled as a 

 whole. Its effect as a whole, the thickness and 

 the color of the foliage and the thriftiness of the 

 trees, is likely to be improved far more by enrich- 

 ing the soil, by installing a watering system, or 

 by planting young trees, than by the expenditure 

 of the same amount of money in filling cavities 

 in one or two of the trees. In this connection it 

 must be remembered that in the absence of the 

 elementary requirements of tree life, water and 

 good soil, the other trees in the grove will one 

 by one need more or less expensive doctoring. If 

 a veteran of the grove becomes weak and threatens 



