462 Forestry Quarterly. 



30 per cent., and even more for some species, with a correspond- 

 ing decrease in the cost of transportation. Thorough seasoning is 

 essential if the poles are to be treated with preservatives. 



"In general, poles cut during the spring and summer lose 

 weight most rapidly. Poles cut during autumn and winter lose 

 weight less rapidly but more regularly. Too rapid seasoning may 

 be detrimental to the timbei" by causing excessive checking. 



"Shrinkage of poles during seasoning is very slight and does 

 not exceed one per cent, on the circumference. 



"A simple and inexpensive way of using a preservative con- 

 sists in applying it to the surface of the pole with a brush. 

 Treatments made in this manner with a good preservative may be 

 expected to add two to three yeafs to the life of the poles and 

 more than repay their cost, but are not as effective as impregnat- 

 ing the wood with the preservative. 



"Impregnation of many pole timbers, especially the sapwood 

 of round timbers, may be successfully accomplished in open tanks, 

 without the use of artificial pressure, by immersion in hot and 

 cold preservative, the cold following the hot. 



"The open-tank process for the treatment of poles has the ad- 

 vantage that it is possible to apply the preservative to the butts 

 only, with a great saving in the amount used. Plants for butt 

 treatments may be constructed in a simple and inexpensive man- 

 ner. 



"Preservative treatment is profitable financially, the increased 

 durability of the timber decreasing the annual service charge. 

 Relatively greater benefits are derived from the treatment of non- 

 durable woods than from the treatment of those which possess 

 great natural durability. 



"Preservative treatment makes possible the use of poles of 

 smaller butt circumference, since allowance usually made for de- 

 terioration need not be considered, when it is certain that the full 

 size and strength of the poles will be retained through a long 

 period of years. 



"By the application of preservative treatment, many species of 

 timber not naturally durable and formerly not considered suitable 

 for poles may be used for this purpose, thus opening up new 

 sources of supply, and greatly relieving the pole situation from the 

 threatened exhaustion of those woods now most commonly used." 



S. J. R. 



