FIRE EFFECTS
SPECIES: Artemisia cana ssp. cana | Plains Silver Sagebrush 



IMMEDIATE FIRE EFFECT ON PLANT : 
Burning causes complete top-kill of plains silver sagebrush regardless
of the degree to which aerial plant parts are consumed.  The extent to
which plants survive burning, however, is directly related to fire
intensity.  Totally consumed plants sustain higher mortalities than
those less thoroughly burned.  This trend is further accentuated by
season of burning as it relates to fire severity and plant phenology.
More plants survive spring burns than fall burns [39,40].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
Silver sagebrush mortality is directly related to fire intensity, fire
severity, and season of burning.  White and Currie [39] conducted spring
and fall burns under comparable site conditions on a mixed-grass prairie
in eastern Montana.  Mortality differed significantly (p<.01) between the
two seasons.  Fall burning produced the greatest overall mortality.
Over 75 percent of totally consumed plants died; another 40 percent of
less thoroughly burned plants also died.  In comparison, only 33 percent
of totally burned plants died following spring burning; less than 10
percent of the rest were killed.  These studies indicate that fall burns
are extremely effective at plant control on sites where diminished soil
moisture conditions result in higher severity fires.  Mortality can be
further increased by increasing fire intensities; fuels can be
supplemented by deferring grazing prior to burning.


PLANT RESPONSE TO FIRE : 
Plains silver sagebrush reestablishes via root sprouting and rhizomes
following burning [1,42,43].  Plant size prior to burning has little
effect on subsequent survival or regrowth.  Burn intensity tends to
retard rather than change the location of bud development.  Preburn
levels are quickly restored following most spring burning.  The majority
of plants survive and resprout vigorously due to the combined effects of
reduced fire severities and favorable moisture conditions.  Fall burning
is usually associated with adverse growing conditions and higher fire
severity and results in significant decreases in plant numbers and has a
more lasting effect upon plant coverages [39].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
Most fire effects information on plains silver sagebrush indicates that
densities are rapidly regained and typically enhanced following burning
[6].  White and Currie [39] report that plains silver sagebrush exhibited
a differential growth response with reference to season of burning.
Following spring burning silver sagebrush plants produced relatively few
(3 to 4) sprouts per plant; stem elongation was rapid, however.
Severely burned plants reached heights of at least 8 inches (20 cm)
within 3 months of burning, while less severely burned plants grew to
over 12 inches (30 cm).  Most plants were characterized by dense foliage
and a bushy growth form.  In contrast, fall burning resulted in plants
which produced more sprouts per plant but which had little regrowth.
Lightly burned plants had an average of 10 sprouts per plant but failed
to reach 8 inches (20 cm) within 3 months of breaking dormancy.  Plants
which were severely burned had only four sprouts per plant and averaged
less than 2.4 inches (6 cm).

These results suggest that burning can be used to achieve a range of
management objectives.  On winter ranges where this subspecies is a
palatable forage, spring burning can be used to enhance plant coverages
and rejuvenate stands.  Where plant control is deemed necessary, fall
burning can drastically reduce coverages.  Apparently silver sagebrush
is under greater moisture stress as the season progresses, and this
stress is compounded in thick stands [40].


FIRE MANAGEMENT CONSIDERATIONS : 
NO-ENTRY

Related categories for Species: Artemisia cana ssp. cana | Plains Silver Sagebrush