30 PRACTICAL TREE REPAIR 



to deal with quite different affairs from ordinary 

 pruning wounds. Suppose a large wound is 

 painted. In a year or two season checks form in 

 the wood and the inelastic paint fractures. Bor- 

 ing insects find little crevices in which to deposit 

 their eggs. The larvae burrow back and forth in 

 the wood, returning as adults to the wound to 

 emerge. At the surface the paint may stop them 

 temporarily, but the strong jaws of the insects 

 soon break it down. Each hole thus left, with a 

 moist mass of sawdust extending back into the 

 wood, is an ideal germinating bed for fungus 

 spores. In four or five years more the wood is 

 quite rotten, large cracks appear in its surface, 

 ants and other insects have free access. Soon the 

 wound is beyond any cure but a more or less ex- 

 pensive cavity treatment. Repeated observation 

 of this process has lead the writer to conclude that 

 a single coat of paint is a positively dangerous 

 dressing for large wounds, concealing, as it does, 

 the disintegration which goes on underneath it 

 almost as rapidly as if the wound had not been 

 dressed at all. 



A very permanent dressing is the plastic ce- 

 ment used by slaters. It is applied in a thick 

 layer with a spatula. It does not become hard 

 nor crack if it is properly made. It has no anti- 

 septic quality and must be preceded by an applica- 

 tion of carbolineum. It is probable that the use 



