FIRE CASE STUDIES
SPECIES: Leymus cinereus | Basin Wildrye 



CASE NAME : 
Great Basin Rate-of-Spread Study


REFERENCE : 
Range, P.; Veisze, P.; Beyer, C.; Zschaechner, G. 1982 [58]
Zschaechner, G. A. 1985 [89]


SEASON/SEVERITY CLASSIFICATION : 
Horse Haven-1 - late summer/moderate
Horse Haven-2 - fall/moderate
Jackpot-1 - late summer/moderate
Jackpot-2 - fall/moderate


STUDY LOCATION : 
The Horse Haven site is located on BLM lands on the Ely District in the
upper end of Smith Valley, west of the Egan Range, between Secs. 27 &
28, T.  19 N, R. 62 E, MDB&M, or approximately 16 miles (10 km)
northwest of Ely, Nevada.

The Jackpot site is on the Elko District near the headwaters of
Cottonwood Creek watershed in portions of Secs. 3 & 10, T. 46 N, R. 63
E, MDB&M, or approximately 8 miles southwest of Jackpot, Nevada.


PREFIRE VEGETATIVE COMMUNITY : 
Horse Haven - Sagebrush-grass community.  Some associated plants
included big sagebrush (Artemisia tridentata ssp. vaseyana), low
sagebrush (A. arbuscula), green rabbitbrush (Chrysothamnus
viscidiflorus), antelope bitterbrush (Purshia tridentata), Utah
serviceberry (Amelanchier utahensis), bluegrass (Poa spp.), needlegrass
(Stipa spp.), bluebunch wheatgrass (Pseudoroegneria spicata), basin
wildrye (Leymus cinereus), tailcup lupine (Lupinus caudatus), arrowleaf
balsamroot (Balsamorhiza sagittata), stickseed (Hackelia spp.),
fiddleneck (Amsinckia spp.), and horsemint giant hyssop (Agastache
urticifolia).  The stand was approximately 35 years old.

Jackpot - Sagebrush-grass community.  Same associated plants as on Horse
Haven site.  The stand was approximately 45 years old.


TARGET SPECIES PHENOLOGICAL STATE : 
Horse Haven-1:  dormant
Horse Haven-2:  dormant
Jackpot-1:  dormant
Jackpot-2:  dormant


SITE DESCRIPTION : 
Horse Haven:  Elevation: 7,500 feet (2,285 m)
              Aspect: southwest
	      Slope: 12%
	      Mean annual temperature: 44 degrees F (6 degrees C)
	      Mean annual precipitation: 8.84 inches (22.45 cm)
	      Soils:  Derived from quartzite and volcanic rocks;
		Simme series (member of the loamy skeletal and mixed frigid
			family of Aridic Argixerolls)
		Mascump series (member of the loamy-skeletal and mixed frigid
			family of Aridic Lithic Argixerolls)
	      Depth to bedrock: 26 inches (66 cm)


Jackpot:  Elevation:  6,600 feet (2,010 m)
          Aspect:  north
          Slope: 7%
          Soils:  drainage bottoms - Torriorthentic Haplexerolls
                  (both loamy and clayey families)
                  lower sideslopes - Typic Argizerolls
                  rocky outcrops on ridges - Xerollic Haplargids


FIRE DESCRIPTION : 
Burning conditions were as follows:

                  Horse Haven-1   Horse Haven-2    Jackpot-1    Jackpot-2
--------------------------------------------------------------------------
Burn date           08/29/80        10/08/80       08/27/80     10/06/80  
Time                 1400            1300           1100         1130    
Air Temp (deg F)       89              74             74           70
Rel. Hum. (%)          14              16             24           27
Wind Speed (mph)        8               3              5            5
Fuel Moist (%)
      Live             92              77             92           77
      Dead              4               5              4            9
Fuel Depth (cm)        70              88             61           52
Fuel Load (lb/ac)       3.03            3.50           3.48        --- 
Soil Mois. (%)          7               ---            7            10


Horse Haven-1:  One basin wildrye plant was tagged prior to burning.
Preburn basal diameter was 25 cm with a height of 110 cm.  Litter depth
averaged 6 cm at the base.  Fire intensity and severity data were
recorded as follows:

Flame length:  6 feet
Rate of spread:  25 feet/min
Heat per unit area:  660Btu/ft sq
Maximum basal crown temperature recorded:  1,500 degrees Fahrehneit

Horse Haven-2:  Two basin wildrye plants were monitored on this site.
Preburn basal diameters were 65 cm and 59 cm.  Litter depth averaged 3
cm at plant bases.  Fire intensity and severity data were recorded as
follows: 

Flame length:  20 feet (3,770 Btu/ft/sec)
Rate of spread:  40 feet/min
Heat per unit area:  5,660 Btu/ft sq

Jackpot-1:  One plant was monitored.

Jackpot-2:  One plant was monitored.  Sudden shifts in wind speed and
direction in addition to fuel concentrations in the drainage bottoms
caused erratic fire behavior.


FIRE EFFECTS ON TARGET SPECIES : 
Horse Haven-1:  The one plant monitored was completely defoliated, and
only charred stubble remained.  This plant had resprouted by the
following July, but after 2 years it developed a dead center.  Dry soil
moisture conditions (6 percent at 15 cm) at the time of the fire
combined with adequate postburn precipitation probably enhanced
survival.  Postburn height recover was as follows:  110 cm preburn; 105
cm in 1980; 92 cm in 1982; 129 cm in 1983; 77 cm in 1984.  Evidence of
grazing was present all years.

Horse Haven-2:  This extremely intense fire only defoliated the two
tagged plants; immediatley after the burn, blackened stems and leaves 12
cm in length sitll remained over both plant bases.  Some resprouting
occurred the first postburn growing season.  By the second season, one
plant had regained 50 percent of its original height; however, basal
diameter was much reduced despite resprouting occurring from five areas
within the crown.  The other plant has recovered 100 percent of its
original height by the second postburn growing season but basal area was
reduced.  Four years after burning, both plants had regained 97 percent
of their preburn basal areas, and plant heights were 87 percent of
preburn measurements.

Jackpot-1:  The one basin wildrye plant monitored died.

Jackpot-2:  Fire initially decreased the basal diameter and burned the
coarse dead stems of the one basin wildrye plant monitored during this
prescribed burn.  By the second year basal diameter exceeded that of
preburn dimensions and height was 73 percent of preburn.  Four years
after the fire,  basal diameter has nearly doubled and plant height was
142 percent of the preburn measurement.


FIRE MANAGEMENT IMPLICATIONS : 
NO-ENTRY

Related categories for Species: Leymus cinereus | Basin Wildrye