FIRE EFFECTS
SPECIES: Vaccinium vitis-idaea | Mountain Cranberry 



IMMEDIATE FIRE EFFECT ON PLANT : 
Underground regenerative structures of mountain cranberry generally survive
light fires [102,115].  Plants often survive even when aerial portions are
consumed by fire [92].  However, plants may be killed by moderate to heavy,
duff-consuming fires [115].  Survival is related to many factors including
soil moisture levels, season of burn, fire severity and intensity, and rhizome
depth [38].

Rhizomes can sometimes survive soil surface temperatures of 820 degrees
F (438 degrees C) [102].  In arctic tussock communities, plants often
survive severe fires which remove all aboveground material [116].  The
heat-sensitive seeds of mountain cranberry are usually destroyed by fire
[115].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Mountain cranberry commonly sprouts from rhizomes or buds located on
surviving portions of aerial stems after fire damages or consumes
aboveground material [115,116].  Sprouting from stumps, or "rootstocks"
has also been reported [13,65].  Reestablishment through seed is
extremely rare [102].  Surviving portions of the aerial stems sprout
within a short time, but rhizome sprouting may be delayed until the
following year [115].

The speed of reestablishment varies according to the season of burn,
site characteristics, and fire intensity and severity.  Reestablishment
is generally rapid after light fires [27]; plants are often common on
lightly burned sites [102].  Regeneration may be slow after hot fires
that damage or destroy underground regenerative structures [27,102,111].
In northern spruce communities, intense, stand-destroying, late summer
fires which consume the organic layer [110] can be particularly damaging
to mountain cranberry [65].

On some sites, plants may sprout within months after a light burn and
regain preburn cover within a few years [102].  Mountain cranberry
generally appears within the first 6 years after fire in black
spruce-lichen, jack pine-lichen, and white spruce-birch communities
[38].  Residual survivors were observed at the end of the fifth growing
season in black spruce communities of southeastern Manitoba [16].  In a
severely burned black spruce community of interior Alaska, it became
abundant within 5 years after fire but set little fruit [117].  Viereck
[109] observed slow recovery after fire in a black spruce/feathermoss-
lichen community of interior Alaska.  Recovery was as follows:

                        percent cover (1971 fire)
        unburned        1972       1975      1980
           18             1          1         7

Mountain cranberry was present within 1 to 5 years after fire in white
spruce communities of Alaska [34].  Mountain cranberry is a common early
colonizer in jack pine communities, although reestablishment generally
takes at least several years [13].  In North America, postfire recovery
may be more rapid in moister, eastern boreal forests [68].

Reestablishment of mountain cranberry is often slow in tundra
communities [85].  Plants attained preburn coverage by the end of two
full growing seasons in arctic tussock communities [116].  In
northwestern Alaska, production was still significantly lower on sites
burned 13 years earlier than on unburned sites [33].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
Fire severity:  Recovery is typically much more rapid after light fires.
Postfire recovery in Alaska has been documented as follows [111]:

                                  percent cover
                  1971        1972        1973        1974        control

heavy burn         .05         .50         .30         .90         ----
light burn        3.45        3.55        1.65        6.10        20.35
heavy burn        0            .15         .20         .35         6.90

In sedge-shrub tundra on the Seward Peninsula of Alaska, little or no
sprouting was observed within 2 years on severely burned sites where
mountain cranberry was a preburn dominant.  After light to moderate
severity burns in sedge-tussock communities, mountain cranberry
resprouted and recovered relatively quickly.  Shoot densities increased
significantly on two of the four sites, from 43 shoots per meter square
to 126 per meter square and from 25 per meter square to 43 per meter
square.  However, sprouts were generally located on the surface or sides
of tussocks, suggesting that they escaped burning within the tussock
mass [84].

Recovery of mountain cranberry may be relatively slow in many types of
tundra shrub communities.  Recovery of mountain cranberry by tundra
community was as follows [84]:

                  sedge tussock-shrub tundra (burned 1977)
         Frequency (no. of plots)*               Cover (%)      
           1973    1978     1979           1973     1978     1979
site 2       10      10       10            6.9      0.8      1.3
site 3       --      10       10            ---      0.5      0.5
site 4       --      10       10            ---      0.5      0.5
site 5       --       9        9            ---      0.5      0.5

*Number of 1-m2 plots in which species occurs (ten plots sampled)

                birch and ericaceous shrub tundra (burned 1977)             
                     1973               1978                  1979
                        Cover               Cover                 Cover
                         _                   _                     _
               Freq.*   (x %)     Freq.*    (x %)       Freq.*    (x %)
nonfrost boils   10       7           0       0             0       0
frost boils      10       4           0       0             0       0    

*Number of 1-m2 quadrats in which species occurs/no. of quadrats on that
site X 10

                        sedge-shrub tundra (burned 1977)
         Prefire (1973)      1 yr after (1978)          2 yrs after (1979)
        Freq.*  Cover**  Freq.*   Cover**  Dens.***  Freq.*  Cover**  Dens.***
site 8   10     2.8        3       0.2       2        4        0.2     3 
site 9   10    15.5        6       0.3       2        7        0.3     5

*   Number of 1-m2 plots in which the species occurs (ten plots sampled)
**  Mean percent cover averaged over 10 plots
*** shoots/m2

Posfire frequencies of mountain cranberry 1 year after a summer fire in
sedge tussock-shrub communities of the Seward Peninsula of Alaska were
greatly reduced [119]:
   
sampling date       late May 1978        mid-June 1978   
                      freq. %               freq. %
burned                0.23                  0.05
unburned              1.00                  1.00 


FIRE MANAGEMENT CONSIDERATIONS : 
Postfire biomass:  Postfire reduction in mountain cranberry production
was as follows after a fire in an arctic tussock community [116]:

          mean annual production (g/m sq)
          burned            unburned
site 1      0.1               5.8
site 2      0.6               7.5
site 3      0.6               1.8
site 4      4.0               9.5

Biomass:  Biomass following a late June wildfire in interior Alaska was
measured at 0.04 grams per square meter during postfire year 1, 0.08
grams per square meter during postfire year 2, and 1.4 grams per square
meter during postfire year, compared to a control measurement of 5.1
grams per square meter [108].

Fuels and flammability:  Engelmark [30] reported that Vacciniums are
highly flammable due to specific chemical properties.  In northern
Sweden, species such as mountain cranberry can serve as ignition points
and as a continuous fuel mat for surface fires.  In many black spruce
stands of Alaska and northern Canada, an open, highly flammable,
ericaceous shrub layer can carry a fire [110].  However, Quintilio and
others [82] observed that an extensive mat of mountain cranberry and
alpine bearberry served as an effective fire barrier in a jack pine
stand near Darwin Lake, Alberta.  Fire seldom penetrated more than a few
centimeters into the vegetative mat.  The extensive ground mat
noticeably reduced the fire spread rate and coverage [82].

Related categories for Species: Vaccinium vitis-idaea | Mountain Cranberry