FIRE CASE STUDIES
SPECIES: Rubus idaeus | Red Raspberry 



CASE NAME : 
Elk Island Burn, Alberta



REFERENCE : 
Johnston, M.; Woodard, P. 1985 [52]



SEASON/SEVERITY CLASSIFICATION : 
May 5, 1980/variable


STUDY LOCATION : 
The study site is located in Elk Island National Park, approximately 23
miles (37 km) east of Edmonton, Alberta.



PREFIRE VEGETATIVE COMMUNITY : 
Preburn overstory vegetation was made up of quaking aspen (Populus
tremuoides) and balsam poplar (P. balsamifera), which ranged from 50 to
70 years of age.  Understory vegetation was dominated by red raspberry
(Rubus idaeus), beaked hazelnut (Corylus cornuta), strawberry (Fragaria
spp.), fleabane (Erigeron spp.), and reedgrass (Calamagrostis spp.).



TARGET SPECIES PHENOLOGICAL STATE : 
not reported.



SITE DESCRIPTION : 
     Soil - orthic gray luvisol
     Elevation - not reported
     Topography - not reported
     Size of treated area - 9.9 acres (4 ha)
     Weather conditions - dry



FIRE DESCRIPTION : 
Seven artificial fuel beds (24 x 24 inches [60 x 60 cm]) were
constructed of varying amounts of excelsior, or excelsior mixed with
white spruce slats.  The prescribed head fire did not spread to the beds
because of discontinuous fuels.  The beds were ignited with matches
after the passage of the flame front.  Specific weather and fire
behavior characteristics were as follows:

     Fire weather:

     Dry bulb temperature (C) - 14.5
     Relative humidity (%) - 33
     Wind speed at 10 m (kh/h) - 6
     Fine fuel moisture code - 88
     Duff moisture code - 57
     Drought code - 106
     Initial spread index - 4
     Buildup index - 58
     Fire weather index - 12

     Estimated fire behavior characteristics recorded for the seven
     fuel beds ignited with matches -
     
     fuel loading     flame length     frontal fire     residence time
     (kg/m sq.)       (m)              intensity        (minutes)
                                       (kW/m)
     0.17             0.5                  57            1.5
     0.87             1                   258            2
     0.87             1                   258            2
     3.94             1.5                 622            4
     3.94             1.5                 622            4
     9.65             1.5               1,162           10
     9.65             2.5               1,905           10     


FIRE EFFECTS ON TARGET SPECIES : 
All aboveground red raspberry stems were killed where fuels were added.
On fuel-free plots, only portions of the aboveground stems were killed.
Plants sprouted from underground regenerative structures where
aboveground mortality was complete, but from both aboveground and
belowground tissues where portions of the aerial stems were killed.
Depth of underground regenerative structures ranged from 0 to 2 inches
(0-5 cm), with mortality of tissues occasionally extending to 0.4 to 1.2
inches (1-3 cm) below the duff surface.  Portions of most deeper
"rhizomes" apparently survived.  Red raspberry also reproduces through
lateral buds located on small, shallow, succulent, poorly protected
roots which can be damaged by fires of high intensity.

The number of sprouts produced per plant did not vary according to burn
treatment.  Height growth and the number of leaves did vary by
treatment, indicating that red raspberry recovery may be affected by
fire intensity and severity.  Specific recovery rate data for red
raspberry were as follows:

  date     response                     fuel loading (kg/m sq.)
           parameter              0.00    0.17    0.87    3.94    9.65

  July 4   #sprouts/plot          5       4       4       4       5
           ht. growth/sprout(cm)  52.0    32.7    17.4    12.2    8.8
           avg. # leaves/sprout   --      8       6       5       3

  July 22  #sprouts/plot          6       4       5       4       7
           ht. growth/sprout(cm)  58.7    36.5    19.5    16.1    12.8
           avg. # leaves/sprout   --      8       6       5       5

  Aug. 1   #sprouts/plot          3       4       4       4       7
           ht. growth/sprout(cm)  58.4    36.8    19.1    16.2    13.5
           avg. # leaves/sprout   --      8       6       5       5

  Aug. 16  #sprouts/plot          3       4       5       4       7
           ht. growth/sprout(cm)  60.0    37.2    21.0    16.7    13.5
           avg. # leaves/sprout   --      7       7       6       6

  Aug. 30  #sprouts/plot          3       2       4       3       7
           ht. growth/sprout(cm)  60.2    37.0    20.8    16.8    13.8
           avg. # leaves/sprout   --      7       6       5       6

Mean abovegrd. ovendry biomass
           (grams/plot)           2.5     4.1     5.0     4.6     4.4


FIRE MANAGEMENT IMPLICATIONS : 
Red raspberry may be somewhat susceptible to high intensity fires
because of shallow, fairly poorly protected root buds.  This study
suggests that hot prescribed fires may be useful in reducing red
raspberry in some carefully selected instances.

Related categories for Species: Rubus idaeus | Red Raspberry