THE AIR SEASONING OF WESTERN SOFTWOOD LUMBER 15 
Drying conditions surrounding the lumber pile are improved by 
the north-and-south alley in the seasons of greatest humidity. Snow 
does not accumulate as rapidly or remain as late in the spring at 
the front or rear of the piles. Fog is cleared with less delay. 
Even if the prevailing winds come from the east or west, their 
effect on yard circulation need not be lost if the narrow spacing 
between the sides of the piles is made continuous from alley to alley 
across the entire yard. 
_ Apparently little thought has been given to direction of layout 
in the construction of most western yards. Both north-south and 
east-west arrangements are found very generally in the several pro- 
ducing regions. In the building of new plants and the extension of 
existing yards, the definite merits of north-and-south alleys should 
be given recognition. The decision as to the direction of the main 
alleys will of course settle as well the direction of the other openings 
in the yard. 
Main alleys are seldom so narrow as to restrict unduly either lum- 
ber handling or the movement of air currents in the yard, and yet 
the maximum drying benefits from the direct rays of the sun are not 
to be obtained with a minimum width of less than 16 feet. ‘The 
width should preferably be 20 feet, especially where drying is natu- 
rally slow. ‘“hroughout the West, main alleys are commonly 16 to 
18 feet wide but range from 12 to 26 feet. (Pl. 2, A.) Strangely, 
the narrower alleys are usually found in yards where general sea- 
soning conditions would dictate the maximum. 
REAR ALLEYS 
Rear alleys are sometimes utilized for lumber handling, but their 
real function is to improve drying conditions. Their effectiveness is 
dependent, as is that of the main alleys, upon direction and width. 
In view of the very general necessity for economy of yard space, a 
width of 12 feet is recommended. However, where rapid drying is 
sought, rear alleys 16 feet wide are more effective. If an extremely 
open layout is essential, the rear alleys should bear a greater propor- 
tion of the increase in width than the main alleys. The need for sur- 
face improvements in the main alley, which must be suitable for 
transportation, ordinarily prohibits a width of more than 20 feet. 
In western softwood yards rear alleys 8 to 12 feet wide are very 
common, but variations from 2 to 80 feet are found. ‘That the sea- 
soning benefits from adequate spacing are not fully appreciated is 
evident in the use of narrow rear alleys in some of the locations most 
unfavorable for drying. 
CROSS ALLEYS 
Cross alleys, openings at right angles to the main alleys, serve a 
number of purposes. They reduce the fire hazard, facilitate trans- 
portation and general movement about the yard, and influence the air 
circulation. Local conditions naturally have an important bearing 
on the interval between cross alleys. An ideal arrangement, which 
some yards boast, is a cross alley every 200 to 300 feet, although this 
is not always practicable. In the average yard there should at least 
be 8 or 10 with a minimum width of 20 feet. Sixty feet is very de- 
