62 BULLETIN 711; U. S. DEPARTMENT OE AGRICULTURE. 
tion to the distance, however, as a large part of the time is consumed 
in hooking, starting, unhooking, and the like, which is the same 
whatever the distance. 
The economic range, of course, varies with the style of yarding. 
The high lead affords its peculiar advantages only when confined 
to a distance of from 500 to TOO feet ; ground yarding is generally 
worked on & maximum of from 600 to 900 feet ; while the overhead 
systems are worked to best advantage on longer reaches, say from 
900 to 1,500 feet. Of course, it is sometimes necessary and advisable 
to use these systems, particularly the latter, at greater distances. 
The less of the total burden of transportation assigned to the rail- 
road, the more comes on the yarding, increasing the distance and 
lowering the output. So the topography of the country has a great 
deal to do with fixing the yarding distance. While it is possible to 
build railroads nearly everywhere, it is not always practical to clo so 
because of the high cost of grading and maintaining the track, the 
large investment, and the danger and high cost of operating trains 
on heavy grades. The volume of the stand affects the yarding dis- 
tance in much the same way, as more miles of spur railroad can 
economically be built where the stand is heavy than where it is light. 
(5) Size of crew. — Up to a certain point the output increases as 
the size of the crew is increased. On the other hand, a relatively 
large output due to a large crew is not necessarily the most economi- 
cal. Too much can be made of this factor, since, with any system of 
yarding, the bulk of the crew is largely fixed. For example, in the 
case of ground yarding, the crew, as a rule, consists of 11 men. 
This type of crew is more or less elastic in its makeup, however, as 
ground yarding crews consisting of as many as li are used; others 
contain as few as nine men. 
(6) Condition and care of equipment. — The output varies with the 
condition of the equipment, the way it is used, and the length of life 
expected of it. It is larger when up-to-date machines of the proper 
size rather than old machines of the wrong size are used, when 
machines are driven at practically their maximum speed instead of 
slowly for the purpose of prolonging their life and reducing the cost 
of maintaining them, and when lines, rigging, etc., are replaced as 
soon as the signs of wear indicate that they may break, instead of 
waiting for them to break a number of times before being replaced. 
There must, of course, be a nice balance between the output and the 
labor, equipment — maintenance and depreciation — and supply costs 
per thousand feet. Most operators, no doubt, get as close to this 
balance as is possible. There are some, however, who could reduce 
the total cost per thousand feet for yarding by taking better care of 
the equipment : others who could reduce the cost by speeding up the 
