FIRE CASE STUDIES
SPECIES: Deschampsia cespitosa | Tufted Hairgrass 



CASE NAME : 
Kings Canyon National Park, CA/Subalpine Wildfire/Tufted Hairgrass Response


REFERENCE : 
DeBenedetti, S. H.; Parsons, D. . 1979 [24]
DeBenedetti, S. H.; Parsons, D. J. 1984 [25]


SEASON/SEVERITY CLASSIFICATION : 
summer (early August)/light to severe


STUDY LOCATION : 
Vegetation response was studied following a lightning-ignited fire in
Ellis Meadow, a 30-acre (12 ha) subalpine meadow within the Roaring
River drainage of Kings Canyon National Park, California, in the
southern Sierra Nevada.


PREFIRE VEGETATIVE COMMUNITY : 
The prefire community was subalpine meadow vegetation within forest
dominated by Sierra lodgepole pine (Pinus contorta spp. murrayana).  The
meadow community was dominated by beaked sedge (Carex rostrata), tufted
hairgrass (Deschampsia cespitosa), Idaho bentgrass (Agrostis
idahoensis), and Mexican rush (Juncus mexicanus).  Other common
herbaceous species were primrose monkeyflower (Mimulus primuloides),
Parish's yampah (Perideridia parishii), small white violet (Viola
macloskeyi), and several species of fireweed (Epilobium spp.).


TARGET SPECIES PHENOLOGICAL STATE : 
NO-ENTRY


SITE DESCRIPTION : 
The study site is at 9,154 feet (2,790 m) elevation.  The area is a
generally flat, basin-type meadow.  The meadow surface consists of
low-lying troughs between hummocks formed by the root crowns of tufted
grasses and sedges.  An organic layer up to 12 inches (30 cm) deep
overlays a loamy sand soil.  The water table usually remains within a
few inches of the surface throughout the summer.  However, precipitation
had been 45 to 50 percent below the normal average of 41.1 inches (1,044
mm) for each of the 2 years before the fire.  The summer of the fire was
very dry.

On September 30, 1977, immediately following the fire, two permanent
transects were established on a severely burned portion of the meadow.
Severely burned sites were differentiated by the extent to which the
organic layer was consumed; meadow surfaces were lower in the more
severely burned areas than in other areas, and ash depth exceeded 0.8
inch (2 cm).


FIRE DESCRIPTION : 
A lightning storm in early July 1977 ignited several fires in the
vicinity of Ellis Meadow.  These were allowed to burn, and fire reached
Ellis Meadow in early August.  By late summer, large contiguous areas of
the sedge-tallgrass community within Ellis Meadow had burned.  About 60
percent of the meadow had burned by the end of September, when autumn
precipitation extinguished the fire.

The fire smoldered where it was severe, spreading at a rate of less than
2 inches per minute (5 cm/min).  In these areas the fire burned nearly
all the organic layer, including subsurface and aboveground organic
matter.  Fire consumed some tufted hairgrass plants entirely by a
combination of surface and subsurface fire.  In some cases subsurface
fire combined with sporadic surface flare-ups, resulting in nearly
complete consumption of the root mass and organic matter in the surface
soil layer while leaving portions of the aboveground vegetation intact.

Ash depth where present ranged from 0.4 to 8 inches (1-20 cm), averaging
3.5 inches (9 cm).  Mean ash depths were significantly (p<.05) greater
when charred vegetation remained at the surface in association with ash
than when only ash was present.


FIRE EFFECTS ON TARGET SPECIES : 
Where fire was of light to moderate severity, most of the dry
above-surface tufted hairgrass material and some of the green biomass
were burned.  However, subsurface fire was light or absent and ash depth
rarely exceeded 0.8 inch (2 cm).  A distinct pattern was observed on
hummocky microtopography.  Where fires were of low severity, fire was
largely confined to the troughs between hummocks.  Tufted hairgrass,
common on hummocks, was not seriously injured by these fires, and was
seldom observed to have suffered damage to the root crown even when the
tops were heavily burned.

Where fire was severe and smoldered for some time, both troughs and
hummocks were burned.  Here fire burned nearly all of the organic layer,
including tufted hairgrass subsurface and aboveground matter, and tufted
hairgrass was killed.  The surface of the meadow in these areas was
lowered between 4 and 10 inches (10-25 cm) relative to adjacent
vegetation.

During the final week of September or the first week of October each
year between 1978 and 1981 the two transects were sampled by measuring
the foliar cover of individual plant species.

Immediately after fire:  42.7 percent of all vegetation on the lengths
of the transects had been reduced to ash.  Ash segments on the transects
included prefire spaces between root crowns as well as individual plants
consumed entirely by a combination of surface and subsurface fire.  On
another 41.1 percent of the total transect lengths the root mass and
upper soil layer had been completely burned by subsurface fire, though
partially burned aboveground herbage remained.  These transect sections
corresponded to the prefire root crowns of sedges, rushes, and tufted
grasses of which tufted hairgrass was a dominant.  Only about 2.3
percent of the original vegetation survived on the lengths of the two
transects.

Postfire year 1:  Tufted hairgrass was widely distributed throughout the
severely burned portions of the meadow; it was generally more abundant
than in the measured transects.  Tufted hairgrass appeared to have
established from seeds and also reestablished vegetatively.  In less
severely burned areas tufted hairgrass aboveground biomass and cover
appeared comparable to that on unburned sites, even where tops had been
charred or removed by fire.

Tufted hairgrass percent cover on transects over the 4 years following
fire was as follows:

                          Percent Cover

              1978        1979        1980        1981

               0.2        11.1        18.5        17.8

The lack of prefire vegetation data prevents precise comparison, but
tufted hairgrass cover on the most severely burned portions of Ellis
Meadow seemed to be succeeding toward that which had been characteristic
of the prefire state.


FIRE MANAGEMENT IMPLICATIONS : 
Tufted hairgrass root crowns in subalpine meadows generally survive all
but very severe fires.  Tufted hairgrass regenerates from the root
crowns and also from seed in the seedbank.

Related categories for Species: Deschampsia cespitosa | Tufted Hairgrass