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Wildfire Rehabilitation in Utah
Linda MacDonald
Abstract-The magnitude of the fire problem on arid rangeland in
Utah was addressed, and effectiveness of common fire rehabilitation practices was compared. In lower elevations, and over much of
Utah's arid environment, cheatgrass and other weedy species readily
invade burned areas when the site specific reseeding mixture used
is not planted (drilling) or covered (chaining). Aerial seeding followed by single chaining to cover the seed proved to be a very
effective method of establishing perennial vegetation, maintaining
species diversity, and inhibiting the spread of weedy species. It
was noted that old seedings, containing fire resistant and fire
tolerant species of vegetation, remained green longer into the fire
season, and made natural fire-breaks, thereby helping to contain
the wildfire.
Land administered by the Bureau of Land Management
(BLM) in Utah is generally arid, receiving 8-12 inches of
precipitation per year. Acres ofBLM land burned by wildfire
has increased from 4,549 acres in 1991, to 308,457 acres in
1996 as shown in the following tabulation:
Year
1991
1992
1993
1994
1995
1996
BLMacres
burned
4,549
7,439
11,928
116,021
127,900
308,457
The increase in number of acres burned is due in part to the
invasion of introduced winter ap.nuals such as cheatgrass
(Bromus tectorum), and past fire suppression activities.
Cheatgrass not only changes the fire frequency of a site, but
also the fire volatility, intensity and extent of the area likely
to burn in the future.
Objective
The purpose of the Emergency Fire Rehabilitation program is to: Protect life, property, soil, water and/or vegetation resources; Prevent unacceptable on-site and off-site
damage to the watershed (erosion control); Reduce invasion
and establishment of undesirable or invasive species of
vegetation, and; Facilitate meeting Land Use Plan objectives. The purpose of this study was to compare various
In: Monsen, Stephen B.; Stevens, Richard, comps. 1999. Proceedings:
ecology and management of pinyon-juniper communities within the Interior
West; 1997 September 15-18; Provo, UT. Proc. RMRS-P-9. Ogden, UT: U.S.
Department of Agriculture, Forest Service, Rocky Mountain Research
Station.
Linda MacDonald is a Range Management Specialist, Bureau of Land
Management, Utah State Office, P.O. Box 45155, Salt Lake City, UT 84145.
410
treatment methods of wildfire rehabilitation for meeting
the stated objectives, keeping in mind the cost associated
with each method of treatment.
Methods and Results
In all seeding methods, mixtures of grasses, forbs and
shrubs that are adapted to the site were used. Exception: On
some sites with State listed noxious forbs, a mixture of
native and introduced grasses adapted to the site was used.
Forbs and shrubs will be seeded after the noxious weed
problem is controlled by spraying.
Preci pitation following the seeding was above normal, and
winter temperatures were warmer than normal. Results
described, therefore, are from the best possible climatic
conditions to be expected in the area.
Natural Revegetation, No Seeding
(Control Area)
Control areas were examined to determine their natural
recovery. In higher elevations where sufficient moisture and
a diverse population of perennial vegetation exists, these
areas recovered sufficiently to protect the watershed, especially on the north and east facing slopes. Response of native
vegetation was not as good on south and west facing slopes,
which are typically drier.
Below 6,000 ft elevation, and in much of Utah's arid
environment, cheatgrass and other weedy species readily
invaded the burned areas. These areas did not respond
naturally with sufficient perennial vegetation to protect the
watershed from wind and water erosion, and weed invasion.
Seed by Aerial Application Only Without
Coveri ng the Seed
Seed was flown over 102,100 burned acres in the rehabilitation area. Ofthis number, 55,200 acres were aerial seeded
only, with no disturbance to the soil. These areas were then
compared with areas that were not seeded (control areas),
areas where seed was planted by drill, and with areas that
were seeded and then chained to cover the seed.
While a small percent of the uncovered seed germinated
and became established, it was not in sufficient quantity to
protect the soil from erosion. In areas of high winds, the seed
was blown to unburned islands, and roadside gullies. There
it was covered with topsoil lost from the site due to wind
erosion. The seed became established in these disturbed
areas. Pedestaling of the exposed plant roots, showed that
up to four inches of topsoil was lost due to wind erosion in
some areas that had been seeded, where the seed was not
covered.
USDA Forest Service Proceedings RMRS-P-9. 1999
Seed by Aerial Application Followed by
Chaining to Cover the Seed
broadcast seeding without covering the seed was not cost
effective over large areas in Utah's arid environment.
The seed mixture was flown on the treatment area, followed by one-time chaining to cover the seed. In addition, in
some areas, seed dribblers were placed so that shrub seeds
were planted by the action of the heavy equipment in areas
being chained. In 1996, some areas suitable for drilling seed
were aerial seeded instead because of the vast acreage
needing immediate treatment following wildfire. More than
twice as many acres could be covered per day, by using this
method.
Covering the seed with one-time chaining, proved to be
very effective in establishing perennial vegetation to protect
the site from wind and water erosion. This seeding method
helped establish and maintain species diversity, and inhibit
the spread of cheatgrass and other- weedy species.
Aerial Seeding Followed by Chaining to
Cover the Seed
Drill Seeding
Sixteen thousand one hundred fifty acres were seeded by
rangeland drills. Most exhibited a high germination response, the exception being the sand dunes at Little Sahara
Recreation Area. In most cases, drilling effectively planted
the seed mix, and inhibited the spread of cheatgrass and
State listed noxious weeds.
This method of covering the seed proved to be a very
effective in establishing perennial vegetation on areas with
slopes and gullies, rocky outcrops, and areas with dead tree
stumps and debris. This treatment is highly effective in
protecting the site from wind and water erosion. These
seedings helped establish and maintain species diversity,
and inhibit the spread of cheatgrass and other weedy species.
Aerial seeding followed by one-time chaining to cover the
seed also proved to be a practical and relatively inexpensive
method to use when large acreage needs to be treated (over
300,000 acres of BLM land burned in 1996). With this
method, 250 acres could be treated per day, as compared to
drilling the seed at 100 acres per day.
Drill Seeding
Areas that were seeded by drilling had the highest germination response. But drilling could only be used on level
areas free from obstacles. Therefore drilling wasn't possible
in pinyon-juniper sites, rocky outcrops, and areas with
washes or channels, and on slopes.
Discussion __________
Study plots have been identified for long term monitoring
of the treatment areas, by BLM and by the U.S. Forest
Service Shrub Laboratory. Observations discussed below
pertain to results of rehabilitation, the first year following
treatment.
Natural Revegetation
In higher elevations (above 6,000 ft) where sufficient
moisture and a diverse population of perennial vegetation
exists, reseeding is often not needed, especially on the north
and east facing slopes. However south and west facing
slopes, which are typically drier, would likely benefit from
seeding.
Below 6,000 ft elevation, and over much of Utah's arid
environment, cheatgrass and other weedy species readily
invade burned areas. The dominance of cheatgrass shortens
the fire cycle, and increases the volatility and extent of the
fire. Also because cheatgrass does not catch and hold snow
like a diverse perennial stand ofvegetation, the site becomes
drier (desertification). On sites dominated by cheatgrass,
the normal revegetative process is interrupted resulting in
loss of native perennial species, and lack of diversity.
Dense stands ofpinyon-juniper often lack a diverse understory. When wildfire removes the canopy, there is not sufficient perennial seed available in the soil to protect the site
from wind and water erosion.
Aerial Seeding Without Covering the Seed
This method did not result in adequate perennial vegetation to protect the watershed. Invasive introduced weeds
such as cheatgrass and State listed noxious weeds readily
invaded the sites. In areas with highly erosive soils, wind
and water erosion is evident. It was also determined aerial
USDA Forest Service Proceedings RMRS-P-9. 1999
Additional Benefits of Seeding
Where wildfire burned into old seedings, it's advance was
slowed or stopped in that direction, in spite of strong winds.
The seedings, which contain fire resistant and fire tolerant
species of vegetation, remain green longer into the season.
There are numerous examples where old seedings make
natural fire-breaks, thereby helping to contain the wildfire.
Acknowledgments
The author expresses appreciation to the personnel at the
BLM Fillmore Field Office who did all the on-the-ground
work, and to Glenn Foreman and Kelly Rigby, Utah State
Office for photographs and assistance in preparing the
poster.
References ___________________
Clary, Warren P. Plant density and cover response to several
seeding techniques following wildfire. Research Note INT-384,
6 pp. U.S. Department of Agriculture, Forest Service, Intermountain Research Station.
Everett, Richard; Clary, Warren. Fire effects and revegetatio!l on
juniper-pinyon woodlands. Rangeland fire effects: a symposIUm,
Boise, ID.1984November 27-29. Idaho State Office, D..S. Department of Interior, Bureau of Land Management, BOIse, Idaho.
1985. (33-37).
Farmer, Mark E.; Harper, Kimball T.; Davis, James~. 19.97 .. The
influence of anchor-chaining on watershed health m a Jumperpinyon woodland in central Utah. In: Ecology and management of
pinyon-juniper communities within the interior west symposium; proceedings; 1997 September 15-18;. Provo, UT.
Monsen, Stephen B.; Pellant, Mike. 1997. Seedmg burned shrublands
by aerial broadcasting and a~ch?r chaining. 1~~7. In; E~ology
and management of pinyon-Jumper commumtIes wlthm the
interior west symposium; proceedings; 1997 September 15-18;
Provo, UT.
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