t the supposed immunity of Douglas
fir from insect injury may be largely due to the almost universal
destruction by fire of logging debris which would otherwise afford
ideal breeding places.

FIRE LINES

The division of mature forest into compartments separated by fire
lines is seldom practicable in this country. Nevertheless slashings,
deadenings and similar fire traps can very often be profitably
confined by the cleaning of strips which will not only stop or
retard the progress of a moderate fire but also facilitate patrol,
fire fighting or back firing. On favorable ground, where some choice
is offered, much may be done by falling timber inward so as to leave
few tops near the uncut timber and by the location of skidroads.
So far as practicable fire lines should be on the tops of ridges,
for, being slower to go downhill than up, fire is more easily
discouraged just as it reaches a crest. Bottoms of gulches are next
in strategic value, and midslopes least.

SAFEGUARDING EQUIPMENT

The most fruitful source of fires is spark-emitting locomotives
and logging engines. Much data has been collected showing that with
oil at a reasonable price its use is economical from a labor-saving
point of view as well as from that of safety. It reduces expense
for watchmen, patrol, fuel cutting, firebox cleaning and firing.
And since it is an absolute prevention, while all other measures
merely seek to minimize the risk, it is probable that even where
the cost of the oil more than balances these savings it will save
in the long run by averting a costly fire.

Where the use of oil cannot be considered, spark arresters are
essential. The argument that they prevent draft is not worth attention.
It is greatly exaggerated by engineers and firemen prejudiced against
innovation or too inattentive to keep their fires up properly and
consequently unnecessarily dependent on occasional forced draft.
The slight disadvantage involved by the modern improved arrester
is not to be compared with the importance of the safety acquired.

In addition to spark arresters, which may fail or be out of order,
logging engines using fuel other than oil should be provided with
a constant tank or barrel supply of six to twelve barrels of water
and 100 feet of hose with proper pumping attachment. With this a
spark fire can be promptly soaked out beyond danger of invisible
smouldering in rotten wood or duff. When conditions are dangerous,
careful loggers send a