98, DEPARTMENT BULLETIN 1425, U. S. DEPT, OF AGRICULTURE 
CROSSERS 
The crossers, or strips or boards placed between the courses of 
stock at right angles to the stock to facilitate drying, affect not only 
the horizontal air circulation in the pile but the horizontal alignment 
of the stock as well. The method of crossing employed has a far- 
reaching effect upon general pile construction, upon operating costs, 
and upon depreciation of both stock and crossers. The crossing or 
“ sticking” of lumber is therefore a matter of utmost importance in ~ 
air seasoning. Solution of many perplexing drying problems will 
be found in the adoption of proper methods of crossing. . 
NUMBER OF LAYERS OF STOCK TO THE COURSE 
Western softwood lumber is very largely piled one layer to the 
course, each layer of stock being separated from those above and 
below by crossers. Because of its tendency to stain, pine is always 
piled in this manner. ‘ Larch-fir,” or western larch and Douglas fir, 
which is handled and sold as a single product in the Inland Empire, 
is, however, very generally piled two layers to the course and some- 
times three. In the same region, white fir, cedar, and spruce are occa- 
sionally “ double-decked.” Certain grades of redwodd and the white 
fir of the California pine territory are often dried two layers to the 
course. Double-decking is also used to a limited extent at some plants 
in the Douglas fir region. 7 
Apparently the objects in view in double-decking, particularly in 
the Douglas fir region and to some extent in the others, are primarily 
to increase the capacity of already congested yards and to facilitate 
more rapid piling. However, to a considerable degree, the practice 
of piling more than one layer to the course is prompted by the desire 
to reduce depreciation from the checking and loosening of knots that 
occur at times of the year favorable to very rapid drying. Although 
the average rate of seasoning is cut down by this means and probably 
some forms of degrade are reduced during very brief periods of the 
year, this system of piling has very real disadvantages and very 
largely defeats its own ends. 
The drying time is necessarily increased greatly. Uniformly 
dried stock is out of the question, and the uneven drying of the 
two faces causes serious depreciation from checking and cupping, 
both during and after seasoning. Careful tests have been made to 
determine the relative amounts of degrade resulting when the single- 
layer method and the double-layer method were used. In white fir, 
double-decking resulted in a 75 per cent greater depreciation than 
that from single piling—almost entirely due to cup and check. Fur- 
ther, double-decking produced, for the same drying period, a mate- 
rially higher moisture content. As might be expected, the difference 
in degrade is not so pronounced with stock 8 inches or less in width. 
Although it must be granted that the seasonal piling of certain 
woods by the multiple system may at times actually have some merit, 
any unforeseen contradiction of weather conditions, such as a late 
wet spring followed by an early dry season, very often precludes 
the success anticipated. Everything considered, excessively rapid 
drying can be avoided more effectively by other changes in pile 
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