FIRE EFFECTS
SPECIES: Alnus viridis ssp. sinuata | Sitka Alder 



IMMEDIATE FIRE EFFECT ON PLANT : 
Severe fires can completely remove organic soil layers leaving alder
roots exposed and charred, thus eliminating basal sprouting.  Low to
moderate severity fires kill only aboveground plant parts [21,52].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Sitka alder is generally favored by fire.  It often increases in
frequency and extent in the early seral communities that follow a fire.
Although aboveground plant parts may be killed by fire, plants usually
recover by sending up several new shoots from their root crown, which
often increases stand density [16].  Sitka alder's wind-dispersed seeds
quickly colonize soils exposed by fire, and seedlings often become an
important part of the first postfire generation [47].

Throughout northern Idaho, Sitka alder is more common on burned lands
than on unburned.  On sites repeatedly burned over a 30-year period both
frequency and cover have increased.  In unburned climax coniferous
stands, Sitka alder attained a frequency of less than 1 percent, but on
nearby areas burned more than once, it had a frequency of 30 percent
[37].

In another northern Idaho study, Sitka alder sprouts originating from
root crowns following a wildfire flowered 5 years after the fire.
Seedlings were first detected during the 8th postfire year with a 5
percent frequency, and 2 years later increased to a frequency of 75
percent [47].

Sitka alder, in the Kamloops Forest Region of British Columbia,
reportedly takes 5 to 7 years to "recover" from broadcast burns of
moderate to severe intensity [20].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
In the subalpine fir zone of British Columbia, Sitka alder stands are
common in some drier areas.  Pojar and others [41] speculate that this
may be related to fire history.  Since Sitka alder is a nitrogen-fixing
species, it may be a more successful invader in these drier areas where
fires were hotter and removed much of the surface organic matter.


FIRE MANAGEMENT CONSIDERATIONS : 
NO-ENTRY

Related categories for Species: Alnus viridis ssp. sinuata | Sitka Alder