SAP-STAIN, MOLD, AND DECAY IN GREEN WOOD. 
27 
Kiln drying reduces shipping weight; makes the lumber fit for 
almost immediate use; eliminates or reduces losses due to insects, 18 
or to checking, rotting, staining, or molding; improves the quality 
of the lumber; reduces the amount of yard space; and saves the 
tying up of capital and carrying costs (Tiemann, 51, p. 4, 5). 
It is possible that where several producers are located within a 
few miles of one another, a battery of modern dry kilns, operated 
according to the most approved methods (possibly on the community 
plan) might solve the problem of cost of installation and operation. 
In dry kilns, stripping or cross piling the stock and providing 
means to prevent stagnation of the confined air are absolutely neces- 
sary if the develop- 
ment of mold is to be 
avoided. The water 
spray kiln devised at 
the Forests Products 
Laboratory represents 
one of the latest de- 
velopments in the tem- 
perature and humidity- 
controlled type of 
kiln. 19 
During the first few 
weeks of kiln drying, 
when the humidity is 
high and the tempera- 
ture ranges from 80° 
to 105° F., an abundant 
growth of white mycelium occasionally forms between the courses 
and interferes more or less with the circulation of the air in the kiln. 
This "is due to the presence of mold fungi, and it usually indicates 
stagnation in the kiln (PL I, fig. 4). Steaming for one hour at a 
temperature of 160° to 180° F. has been found effective in destroy- 
ing or at least checking the growth of this mold (Tiemann (51), 
P- 187). ■ V 
18 Powder-post beetles, however, are said to cause considerable damage at times in 
seasoned stock ; in fact, these beetles do not work in green stock. 
18 A complete description of this kiln is given in Bulletin No. 509, United States Depart- 
ment of Agriculture (52), a copy of which may be procured from the Superintendent of 
Documents, Government Printing Office, Washington, D. C, for 5 cents. Further infor- 
mation concerning the design and installation of this kiln is given in Bulletin No. 894, 
United States Department of Agriculture (50), to be procured from the same source at 
10 cents a copy. 
Fig. 8.— Split billets loosely piled in the areaway between 
the doors of a box car. The doorways are loosely 
boarded up to allow for ventilation of the car and at 
the same time prevent the stock from working out 
while in transit. 
