METHODS OF PREVENTING THE DECAY. 27 



The food supply can be effectively recjulated by cutting the timber 

 at the time when the trees either have their stored footl materials in 

 smallest quantity or else have them in the least available form, 

 namely, late summer, autumn, and winter (Zon, 1909); but local 

 conditions may modify the time of cuttmg to some extent. The 

 supply of air can be regulated to some extent, the floating of timber 

 being one of the most practical methods of such regidation. The 

 water supply is probably the most easily regulated of any factor, 

 the seasoning of timber being the most practical method of regulatmg 

 it before it is placed in service. While in service, a number of methods 

 are available, according to the location of the timber; for railroad 

 ties, a well-drained roadbed (Dudley, 1887; Fernow, 1890; Yon 

 Schrenk, 1902) ; in other locations the seasoning of timber followed 

 by painting or external coating with preservative substances (Dud- 

 ley, 1887; Roth, 1895; Von Schrenk, 1902); the use of composite 

 timbers instead of single large ones, leaving beams without boxing 

 them in, and similar expedients are all thoroughly practicable methods 

 of keeping the water content below the danger point. 



SEASONING OF TIMBER. 



It is a well-known and imquestioned fact that well-seasoned tim- 

 ber is much more durable than green timber of the same kind. The 

 most important result of seasoning is the marked reduction of the 

 water content to a point unfavorable for the rapid growth of wood- 

 rotting fungi. Green coniferous timber contains 40 to 50 per cent of 

 water (calculated on the dry weight of the wood) under ordinary 

 conditions. Air-seasoned coniferous timber contains 10 to 25 per 

 cent of water (Smith, 1908; Eastman, 1908; Sherfesce, 1908c; Hatt, 

 1907; Tiemann, 1907; Grinnell, 1907; Fernow, 1897). Air seasoning 

 removes one-half to two-thirds of the total water content, lowers the 

 water content especially of the outer layers of wood, and to a large 

 extent prevents the infection of a sound timber; but there is danger 

 of such infection occurring at any time when the timber becomes wet 

 and absorbs enough water to very decidedly raise the water content.'' 



Seasoning is eflicient as a method of preventing decay b}^ Lenzites 

 sepiaria. It must be done as rapidly as possible, es})ecially in the 

 Gidf States. To this end, open piling (Von Schrenk and Hill, 1903) 

 is far better than the usual close method. It is necessary in eastern 

 Texas to assist seasoning as much as possible, as green timbers will 

 rot in five or six months if piled closely. In the Northern States sea- 

 soning progresses more slowly, but with less danger from this fungus. 



Kiln (hying is here considered as a rapid method of seasoning, the 

 result being identical by either kiln drying or air diying. 



«Falck, Die T.enzitesfaule dos Coniferenholzes. 1000. s^tatps that the myc-eliiim 

 of Lenzites sepiaria will remain alive in a dry decayed timber for two to three years. 

 214 



