THE AIR SEASONING OF WESTERN SOFTWOOD LUMBER 21 
common, particularly in yards of large area. Both gas and electric 
surtace carriers, which actually carry the lumber rather than merely 
haul it, are gaining in popularity. Auto trucks, especially con- 
structed to permit automatic loading at the green chain and unload- 
ing upon scaffolds or sawhorses at destination are also used. 
Wagons and dollies propelled by tractors or horses are still employed 
to a considerable extent, and a new development, rather limited as 
yet, is the use of monorails or cranes in the yard. 
Such a wide range of methods is in some measure attributable to 
differences in local conditions. Topography, surface conditions, size 
and layout of the yard, species and sizes of stock, and similar ele- 
ments may have an influence upon the type of transportation selected. 
These must necessarily be correlated with such factors as cost of 
actual moving operations, effect of the transportation system upon 
the efficiency of related yard operations, and influence of the system 
upon seasoning conditions. It is not within the scope of this bul- 
letin to attempt a full discussion of the many and complicated phases 
of .efficient yard transportation. However, some reference to its 
relation to other yard operations and to seasoning conditions is 
pertinent. 
The relation to other yard operations can be well illustrated by 
some comparisons between two very different types of transporta- 
tion. The use of wagons and horses in the yard is a most inflexible 
method. Stock must immediately be unloaded by dropping it on 
the ground. If not in the proper location for piling, it is difficult 
and costly to move. When hand piled, one-third to one-half of 
the lumber in each pile must be handled twice, once on to scaffolds 
and once on to the pile. Despite care in unloading, the stock comes 
in contact with dust and mud. During the dry season dust raised 
by the teams penetrates the piles. Dirt and grit thus accumulating 
on the lumber not only increase the liability of blue-stain infection 
but later have an appreciable effect on planer knives. 
The track system, on the other hand, is a most flexible method of 
transportation. Stock can be held on the trucks until piled, allow- 
ing temporary storage, when necessary, in any part of the yard and 
avoiding congested working conditions in the alleys. Stored trucks 
can later be moved easily to the final location. Since the loads are 
high and conveniently moved, and all piling can be done directly 
from the trucks, work on one high and one low pile can be carried 
on at the same time. The stock never comes in contact with the 
ground; dust is of little consequence in tracked yards; and the 
lumber handlers lose no time waiting for teamsters. 
The movement of lumber to and from the drying yard is often 
considered merely as a physical operation, without its being realized 
that the transportation method employed may materially influence 
seasoning. The direction of the yard alleys may be fixed by the 
transportation system rather than by seasoning considerations. 
Transportation by certain methods can very materially add to depre- 
clation losses through incidental breakage and damage. The influ- 
ence of these methods upon the height of hand piling may result 
in congested yard conditions, in low foundations, and poor piling 
practice. Some methods of transportation can definitely increase 
the liability of stain infection in pine yards. 
