FELLING AND LOG-MAKING 113 
stances of 160,000 feet. From fifteen to seventeen men would 
be required to secure the same output with hand labor, and the 
labor charge would considerably exceed the cost of operation and 
maintenance of the machine. Some difficulty is experienced in 
operating during cold weather because the moisture freezes on 
the cylinder and piston and interferes with the action of the 
latter. 
An endless chain saw is used to cut logs into shingle-bolt lengths 
in the redwood forest region and also to cross-cut logs at the mill. 
It is especially adapted for the former work, where very large 
timber is to be cut into short lengths, because several cuts can 
be made at each set-up of the machine. 
WASTE IN LOG-MAKING^ 
Inefficient saw crews under improper supervision often cause 
a waste of timber by careless selection of log lengths. 
Crook or Sweep. — Waste nearly always occurs in the division of 
a bole having crook or sweep. It is more serious in small than in 
large timber because the percentage of loss in slabbing at the mill is 
much greater. Pronounced sweeps should be cut from the bole 
and left in the woods and when it is not deep it should be left 
on the end of the log where there will be the minimum loss in 
manufacture. Logs with crook or sweep are more expensive 
to handle both in the forest and at the mill than straight logs of 
the same diameter and length because more time is required to 
skid, to load on to the log cars and to handle them in the mill. 
The actual yield of lumber is from 12 to 75 per cent less depending 
upon the per cent relation between the depth of sweep or crook 
and the diameter of the log.^ 
Forked Trees. — Another source of waste is the cutting up of 
forked trees. The chief faults of the sawyers in this regard are: 
(1) Felling the tree so that the lower fork is either imbedded 
in the ground or so placed that it is difficult to saw it properly. 
The line of least resistance is followed and the lower fork is left 
or a portion of it sacrificed. (Fig. 22.) 
^ See Prolonging the Cut of Southern Pine, by H. H. Chapman and R. C. 
Bryant. Yale University Press, New Haven, Conn., 1913. 
2 See Forest Mensuration, by H. H. Chapman. John Wiley and Sons, 
Inc., New York, 1921. 
