FIRE CASE STUDIES
SPECIES: Berberis nervosa | Dwarf Oregon-Grape 



CASE NAME : 
Clearcut/burned western redcedar-western hemlock forest, BC


REFERENCE : 
Lafferty, R. R. 1972 [58]


SEASON/SEVERITY CLASSIFICATION : 
Plot 6 - May 22, 1969/high
Plot 7 - September 9, 1968/moderate


STUDY LOCATION : 
The study site was located approximately 33 miles (53 km) east of
Vancouver and 14 miles (22 km) north of Mission City, British Columbia.


PREFIRE VEGETATIVE COMMUNITY : 
Douglas-fir (Pseudotsuga menziesii) dominated the overstory, with
scattered western redcedar (Thuja plicata) and western white pine (Pinus
monticola) on the south and west aspects, and western hemlock (Tsuga
heterophylla) and western redcedar on the north and east aspects.  Dwarf
Oregon-grape (Berberis nervosa), red elderberry (Sambucus racemosa),
willow (Salix spp.), mountain ash (Sorbus sitchensis), vine maple (Acer
circinatum), alder (Alnus spp.), bigleaf maple (Acer macrophyllum), red
and ovalleaf huckleberry (Vaccinium parviflorum, V. ovalifolium),
thimbleberry (Rubus parviflorus), trailing blackberry (R. ursinus),
salal (Gaultheria shallon), fireweed (Epilobium angustifolium),
twinflower (Linnaea borealis), deer fern (Blechum spicant), and mosses
were common in the preburn community.


TARGET SPECIES PHENOLOGICAL STATE : 
Not reported.


SITE DESCRIPTION : 
Elevation - 500 feet (152 m).  
Parent materials - bedrock was composed of quartz diorite and diorite,
                overlain with glacial till, outwash, and minor
                lacustrine and aeolian deposits.
Soils - mixture of colluvium, loess, and ablation till; loamy with mixed
                gravel throughout.
Climate - marine and cool.  no distinct dry season.
                average of 203 frost-frees days per year.


FIRE DESCRIPTION : 
                rate of spread     residence time     total fuel
                (ft/min)           (minutes)          loading (g/m sq)

Plot 6                22                85               15,840
Plot 7                15                50               30,308

                energy released     
                (cal/m sq x 1,000)
Plot 6               22,709   
Plot 7               45,799

                initial duff     residual duff    % duff reduction
                wt. (g/m sq)     wt. (g/m sq)     by weight

Plot 6            6,700              3,750            44
Plot 7           10,000              6,710            33

                avg. initial     avg. initial     fuel consumed
                fuel             loading          (g/m sq x1,000)
                (g/m sq x1,000) (g/m sq x1,000)

Plot 6              8.322            15.022             3.058
Plot 7             20.321            30.308             7.946

                total energy
                cal/m sq x 1,000,000

Plot 6            22.709 x 10                   
Plot 7            45.799 x 10

                % moisture content of slash prior to ignition

             fine           medium       large
          (.04-2.5 in)   (.43-3.9 in)   (4.0 in  or >)      
          (.01-1.0 cm)   (1.1-10 cm)    (10.1 cm or >)

Plot 6       12.5             6.6         40.3
Plot 7       17.4            16.3         21.4

         % moisture content of organic fuel components prior to ignition

                litter          fermination             humus

Plot 6          21.8            102.7                   120.8
Plot 7          11.8            146.1                   197.8


FIRE EFFECTS ON TARGET SPECIES : 
Dwarf Oergon-grape recovery was as follows:

                        Plot 6 -
                
                1968       1969      1970     1971
              (prefire)  (postfire)

% freq.         49.0        11.4      --       1.1
% canopy cover   6.9         1.1      --       ---

                        Plot 7 -

                1969        1970        1971
              (postfire)  (postfire)   (postfire)   

% freq.         6.8          6.8         6.8
% cover         0.3          0.2         0.6

On plot 7, dwarf Oregon-grape had not regained vigor within 3 years
after fire.


FIRE MANAGEMENT IMPLICATIONS : 
Dwarf Oregon-grape and others shrubs are more likely to dominate early
seral stages after fires of low intensity.  Damage or destruction of
underground regenerative structures is more probable after severe fires
and can result in a slow recovery.  Shrubs in general are less severely
harmed by fires in early spring or late fall when carbohydrate reserves
are still concentrated in the roots than by fires occurring during
growth periods.

Related categories for Species: Berberis nervosa | Dwarf Oregon-Grape