In either case the slashing can be given the advantage of the greatest
dryness with safety if it is surrounded by a cleared fire line from
which to work. Firing should be against the wind and if the wind
changes suddenly the opposite edge should be back fired. Previous
cutting of all dead trees and snags over 25 feet high is urgently
recommended. The camp crew should be held in readiness, well provided
with tools, as insurance against accidental escape.

Its probable restriction of insect breeding is a point of slash
burning likely to receive much future study. It is well known that
most forest-injuring insects prefer dying trees to vigorous ones;
also that the existence of an abnormal amount of such material
tends to abnormal breeding and consequent serious attack of vigorous
timber when the dead material becomes too dry to be inviting. It
is by no means impossible that 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,