FORESTRY AND CONSERVATION 397 



THE PRESERVATIVE TREATMENT OF FARM TIMBERS. 



In many localities the need for the preservative treatment of 

 farm timbers is imperative. Throughout wide areas the advisa- 

 bility of using creosoted posts is indisputable. In spite of these 

 facts it is often difficult for a farmer efficiently to treat his own mate- 

 rial with preservatives. This, however, does not indicate that the 

 work should be neglected. Rather it points to some different means 

 of securing the desired result. There are two practical methods of 

 doing this. One is for some individual to undertake the work for 

 the neighborhood. A small wood-preserving plant could be profit- 

 ably operated in connection with a thrashing outfit, a feed mill, or 

 sawmill. The other plan is for several farmers to cooperate in estab- 

 lishing and operating the plant. As an indication of the success 

 which should attend such an undertaking the cooperative creameries 

 of various sections of the country may be cited. The means, then, 

 may vary, but it can not be too strongly emphasized that every 

 agricultural district should possess the facilities for increasing, by 

 preservative treatment, the durability of farm timbers locally used. 

 The decay of farm timbers is caused by the destruction of the 

 wood tissues by low forms of plant life. It follows that the object 

 of all preservative treatment is to prevent the development of these 

 organisms, and that the most effective treatment is the one that 

 accomplishes this for the longest period. 



These organisms require for their best development a certain bal- 

 ance between the air and the moisture content of the wood, and a 

 favorable temperature. Thorough seasoning, on the one hand, or 

 thorough saturation with moisture on the other, alters this balance to 

 such an extent that the growth of the organism is either retarded 

 or prohibited. Air seasoning only retards the growth. 



There are several methods by which timbers may be given 

 more thorough preservative treatment. The surface of the wood 

 may be soaked with paint or some similar substance. Such a coating 

 keeps the wood dry, and more or less effectually excludes the 

 entrance of the decay-producing organisms. Such coatings, however, 

 should be applied only to well-seasoned material, since they will 

 also tend to retard the escape of such moisture as may be already 

 within the timber. Better preservatives are the products of the dis- 

 tillation of coal tar and petroleum tar, which, in addition to possess- 

 ing the advantages of paint, are antiseptics and poisonous to fungi. 

 The deeper such antiseptics penetrate the wood the more lasting is 

 their effect. 



It is well known that wood decays most rapidly when placed 

 in contact with the surface of the ground, because the wood-destroy- 

 ing organisms find there more uniform conditions of heat and mois- 

 ture to encourage their development. For this reason the ground 

 line of a post must be thoroughly treated, whereas portions of the 

 post above and below this point require less treatment. The climate 

 of the locality should also be considered. In the warm Gulf States 

 or in a moisture-laden atmosphere posts require more thorough 



