FIRE EFFECTS
SPECIES: Thuja plicata | Western Redcedar 



IMMEDIATE FIRE EFFECT ON PLANT : 
Western redcedar is commonly killed by fire.  Because of their large
size, however, old western redcedar trees can often survive if they are
not completely girdled by fire [21].  Shallow roots under the duff layer
are often scorched when the duff layer burns and even surface fires may
kill western redcedar [51].  Fire injury to roots can lead to fungal
infection, chronic stress, and growth losses [65].  The most common
causes of fire mortaility are root charring and crown scorching [70].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
After fire, western redcedar will readily establish on bare mineral soil
seedbeds via off-site wind dispersed seeds [22,26].  Although unburned
soil benefits western redcedar regeneration more than soil that has been
scorched, slash burning favors western redcedar by creating more mineral
soil surfaces in cutover areas [50].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
Riparian stringers supporting western redcedar may act as firebreaks
because the moist duff does not readily burn [21].  Old-age western
redcedar stands have heavy fuel loads, but a large proportion of this
material is in the form of deep duff layers and downed, rotting log
material.  These stands could support slow moving fires at best; once
ignited, however, such heavy fuel materials could support long-lasting
fires [29].
 
Fire-killed western redcedar often shows little deterioration even after
5 years.  The bark usually remains intact on dead tree for 5 years.
Fire mortality produces no immediate reduction in strength of western
redcedar poles, and some large trees remain salvageable for almost 100
years after being killed by fire [51].

When slash from decadent western redcedar-western hemlock stands was
burned, a greater proportion of western redcedar than of western hemlock
slash was consumed.  This was a result of greater longitudinal and
horizontal fracturing of the western redcedar.  When fracturing does not
occur, western hemlock slash is at least as flammmable as western
redcedar slash.  Fire spreads faster in western redcedar when the slash
from both species is 1 year old.  Western redcedar slash does not drop
its foliage.  The slash of western redcedar is less flammable when
chipped.  One study showed that the fire hazard normally associated with
cutting of western redcedar poles was reduced by skidding entire
pole-size trees to the landing, where the slash was chipped and blown
over the edge [51].

Slash from western hemlock-western redcedar-Alaska-cedar forests produce
greater nutrient losses to the atmosphere when the slash composition has
a greater proportion of Alaska-cedar and western redcedar.  One can
expect smaller nutrient losses when western hemlock makes up the
majority of the slash [23].  For further details on slash burning of
western redcedar refer to the fire case study in the Alaska-cedar Fire
Effects Information System species writeup.

Related categories for Species: Thuja plicata | Western Redcedar