84 IMPORTANT TIMBER TREES 



Checking and warping of some woods when seasoning 

 baffled manufacturers for a long time, and, until methods 

 were discovered whereby it was overcome, many woods were 

 esteemed of little value. But much has been gained in that 

 direction, and dry-kilns now obviate such difficulties to a 

 great extent. They suppress even the exudation of gums 

 and pitch from some woods so that they can be painted or 

 otherwise finished without danger of disfigurement from 

 that source. Experience shows that all wood can imbibe 

 moisture after being seasoned, some more than others, 

 whether it comes as a direct application of water or from 

 a humid atmosphere. Whenever that occurs the wood im- 

 mediately swells and, in common parlance, " will not stay 

 put." 



It is a singular fact, but one well known to woodworkers, 

 that no matter how long or how thoroughly a piece of wood 

 may have been seasoned, and notwithstanding it may practi- 

 cally have neither shrunk nor swelled during its use, yet to 

 dress off the surface with a plane or otherwise will cause 

 the piece to shrink again. Whether there is still moisture 

 in the wood which can escape after the thoroughly dried 

 surface is removed may be a question, but probably that is 

 the case. 



Decay. It is well known that some woods decay more 

 rapidly than others. As here used, decay does not include 

 wearing away of a surface when exposed to the action of 

 the winds, water, or frost, but a breaking-down of the cellu- 

 lar structure from and through diseases brought into it by 

 some of the various species of fungi. Wood of some spe- 

 cies of trees resists these attacks better than others, and 

 this power of resistance in a large measure establishes its 

 value for exposed situations. Were a fence post, telegraph 

 pole, or railroad tie cut from a Paper Birch capable of re- 

 sisting decay equal to that of a Locust or Catalpa, the value 

 of the Birch would be far above what it is. Thus a know- 

 ledge of the resistance to decay aids in determining what to 

 plant. 



