FIRE CASE STUDIES
SPECIES: Eleocharis palustris | Common Spikerush 



CASE NAME : 
Malheur NWR, Oregon


REFERENCE : 
Young, R. P. 1986 [34]


SEASON/SEVERITY CLASSIFICATION : 
fall burn; information on severity unavailable



STUDY LOCATION : 
The fire was conducted on Malheur National Wildlife Refuge, 40
kilometers south of Burns in southeastern Oregon.  The common spikerush
(Eleocharis palustris) burn was located at
Martha Lake Field (T26S, R28E, S24, SE 1/4, & S25, NE 1/4).


PREFIRE VEGETATIVE COMMUNITY : 
The study sites consisted of five wetland habitats dominated by
monotypic communities of emergent macrophytes.  These sites ranged from
deep-water habitats to upland wet meadows.  All dominant species were
rhizomatous and included common spikerush (Eleocharis palustris),
hardstem bulrush (Scirpus acutus), American threesquare (S. americanus),
alkalai bulrush (S. maritimus), common cattail (Typha latifolia),
burreed (Sparganium eurycarpum), awned sedge (Carex atherodes), Nebraska
sedge (C. nebraskensis), and Baltic rush (Juncus balticus var.
montanus).


TARGET SPECIES PHENOLOGICAL STATE : 
dormant


SITE DESCRIPTION : 
Total area of the refuge is 72,219 ha and sits within a basin which
forms the northwest part of the Basin and Range Province of the western
United States.  Two major rivers, the Silvies and the Blitzen flow
through the refuge.  The climate is semiarid with moderate to cold
temperatures.  Annual precipitation averages between 25 and 30
centimeters, the majority of which falls in winter and spring.  Growing
seasons are shortened by cool springs, dry summers, and freezing in late
August or early September.


FIRE DESCRIPTION : 
The burn on the common spikerush site was conducted on 20 October 1981.
Test burns were used to evaluate fire behavior before burning the main
unit.  Fires were started with drip torches on the downwind boundaries
of all plots.  Strip headfires were used after backing fires created a
wide line.  Firelines were constructed where natural breaks did not
occur.  Preburn feuls and weather conditions at the time of the burn
were as follows:

        Preburn fuel loading:  389-805 gm2
        Fuel height:  12 cm
        Litter height:  6 cm
        Fuel moisture:  3.7 percent
        Temperature:  16-23 deg C
        Relative humidity:  13-17 percent
        Wind speed:  2-16 km/hr

Fire behavior and effects on fuels during the prescribed fire were as
follows:

                                                        Postburn
Rate of Spread    Flame length       Fire intensity    resid. fuels  
  (m min-1)           (m)              (kW m-1)           (g m-2)    Reduction 
-------------------------------------------------------------------------------
Headfire Backfire  Headfire Backfire  Headfire Backfire  mean range    (%)
-------------------------------------------------------------------------------
20-30    1-1.5     1.5-3.5  1-1.5     3031-6272 152-314   33   0-96     94


FIRE EFFECTS ON TARGET SPECIES : 
Fire effects were evaluated in terms of vegetative response, including
shoot height, density, weight, and growth rate; aboveground standing
crop; residual organic materials; and reproductive effort.  These
measurements were taken for two years following the burn.  Common
spikerush increased its aboveground standing crop and shoot densities.
Shoot weights decreased, although not significantly.  Residues after 2
years did not differ much.  All shoots produced inflorescences.  Shoot
height and rate of height-growth following burning and nonuse treatments
for the first postfire growing season follow:
                              Fall burn              Nonuse
                  Growth
                  period   Height  Growth rate   Height   Growth rate
   Date           (days)    (cm)     (cm/d)       (cm)      (cm/d)
-----------------------------------------------------------------------
 7 April 1982       --      3 (4)*     ---        2 (3)      ---
 2 May   1982       25      8 (7)      0.2        6 (4)      0.2 
 7 June  1982       36     30 (12)     0.6       27 (14)     0.6
 3 July  1982       26     46 (17)     0.6       44 (15)     0.6
29 July  1982       26     50 (15)     0.2       56 (12)     0.3
19 Aug   1982       21     49 (18)       0       55 (14)       0
 
* All shoot height values = mean + or - (standard deviation)


FIRE MANAGEMENT IMPLICATIONS : 
The purpose of this study was to provide information for wetland fire
management plans.  Fire can play an important role in rejuvenating these
emergent species; however, long-term effects and effects of repeated
burning need to be further investigated.

Related categories for Species: Eleocharis palustris | Common Spikerush