202 LOGGING 
less the poles are on the same level, the tires will not travel on 
a flat surface and excessive tire wear results. 
On the one-pole road, timbers 18 inches or more in diameter 
are used with a hewed upper face 16 or more inches wide. These 
are laid on crossties spaced from 6 to 10 feet apart, depending 
on the solidity of the bottom and the weight of the load. Where 
two poles join, the under side of each is hewed flat for a distance 
of 4 feet on either side of the joint and an 8-foot timber placed 
under it. The stringers also are notched where they rest on the 
crossties and are drift-bolted to them. The timbers are bedded 
for about one-half their diameter and the center and sides of the 
grade are ditched and ample cross ditches must be provided to 
carry the water away from the grade. Either inside or outside 
guard rails may be used, and these are spiked to the poles. 
Concrete roads have been suggested as a substitute for pole and 
plank roads, but their high cost has deterred operators from using 
them. The life both of plank and fore-and-aft roads is from 
three to four years. 
Motor truck loading is done either with a crosshaul and animal 
draft, or with a loading donkey and a gin-pole. The latter 
method is preferred on extensive operations because the load can 
be placed in from five to ten minutes. Since the maximum 
daily output per truck can be secured only when the loading 
and unloading time is kept at a minimum a rapid loading rig is 
necessary. Winches operated by the truck engine have been 
put on the market but have not been extensively adopted by 
loggers. 
The most common unloading method is to elevate the outer 
side of the roadbed at the rollway from 18 to 24 inches which 
is sufficient to cause most of the logs to roll from the truck when 
the chock blocks are removed. 
The maximum practical grades for motor truck work do not 
exceed 6 per cent in the loaded direction and 12 per cent empty. 
Trucks have been operated on grades as high as 35 per cent by 
the use of a power snubbing device which lowers the loaded 
trucks down the incline and pulls the empty trucks to the top. 
The daily capacity of trucks is dependent on the size of truck, 
road regulations, grades, distance, and size of timber. A 5-ton 
truck with an 8^-ton trailer operating over private roads will 
haul an average load of 4000 board feet. The same truck on 
