HAND LOGGING AND ANIMAL SNAKING 
155 
hibitive of speed and cuts down the daily output. Steep grades 
increase the number of logs and the volume which can be handled 
at one time for relatively long distances. This is shown in P^ig. 
35 in which a comparison is made of the gross output per hour 
for a horse team on slopes ranging from 10 to 25 per cent, and on 
slopes ranging from 30 to 50 per cent.^ The graph indicates that 
the output per hour is greater on the gentler slopes for distances 
not exceeding 500 feet, and less for greater distances. This is 
due to the ability of the horses to traverse the distance from stump 
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Fig. 37. — Graph showing the Effect of Slope on Skidding Output, Animal 
Logging, under Winter Condition.s. Inland Empire. 
to skidway on the more gentle slopes in a shorter time than on 
the steep slopes, and also to the tendency to skid maximum 
loads on steep slopes only for the longer distances. Teamsters 
are not inclined to make up maximum loads for short distances 
and on the operations at which these data were taken the average 
load for the gentler slopes exceeded those on the steep slope up 
to a distance of 500 feet. 
The influence of the character of the bottom on the skidding 
output is shown in Fig. 36 for slopes ranging from 15 to 30 per 
1 From data contained in Inland Empire Sawing and Skidding Studies, 
by James W. Girard. Timberman, Sept. 1920, pp. 36 to 38. 
