|
If you ask the Roads End Prescribed Fire
Burn Boss how the fire burned, she would say it was “light
and spotty.” Under some circumstances, this would be
a disappointing outcome, but in this case, it was exactly
what the fire managers at Sequoia and Kings Canyon National
Parks wanted.
The Roads End Prescribed Fire in May 2005
was designed to restore the pattern of fire on the landscape
while minimizing the impacts of an invasive plant species:
cheatgrass. This highly flammable plant from Europe and Asia
has invaded forests across the western United States changing
the way fires burn and choking out native plant species.
No one knows for sure how cheatgrass was
originally introduced into the area, but one likely method
was inside hay for stock animals. Cheatgrass increased dramatically
in the parks after prescribed burns were conducted in the
1980s and 1990s. In 1998, the parks suspended the prescribed
fire program in Cedar Grove to conduct a research project.
Fire managers and researchers wanted to know the combined
role that fire may be playing in spreading or limiting cheatgrass.
Funding was acquired through the Joint Fire Sciences Program
and researchers from the United States Geological Survey (USGS)
designed the methods. In 2001 and 2002, scientists and fire
crews conducted experiments at a variety of sites to analyze
the success or failure of cheatgrass given different levels
of nutrients, fuel, seed, shade, or fire.
Although many of the treatments had only
mild effects on cheatgrass, one seemed to offer some hope.
Scientists found that in unburned plots, a two-inch layer
of pine needles was very effective at eliminating cheatgrass.
Adapting this information for burn management, the parks could
choose to build-up pine needles by allowing more time between
fires and then conducting periodic low-intensity fires to
protect the trees that produce needles and reduce soil disturbance.
Can it be this simple? Unfortunately, no.
If the parks allow too much material to buildup on the ground
in order to control cheatgrass, fire intensities would change.
The historic low-intensity fires characteristic of ponderosa
pine forests would be replaced by high-intensity fires. Cheatgrass
researchers found that when plots with heavy litter burned
intensely, few cheatgrass seeds survived, but those that did
formed vigorous plants.
So, what is the balance? For now, fire managers
will apply what was learned and burn less frequently and under
cooler conditions to control intensity. The Roads End Prescribed
Fire was the first burn that was planned using information
from the research project. It was conducted in late-spring
to achieve lighter burning conditions and the whole unit was
surveyed for cheatgrass prior to burning. This baseline information
will help managers understand if the effort was successful
when the area is resurveyed in the future.
Have the parks been able to “cheat”
cheatgrass? Time will tell. Cheatgrass will never be completely
eliminated from the area, but fire personnel and researchers
will keep looking for ways to minimize its impacts on native
plants.
For more information about this cheatgrass
study, contact Tom McGinnis (tmcginnis@usgs.gov)
or Jon Keeley (jon_keeley@usgs.gov).
Contact: Jody
Lyle ; Fire Education and Information Specialist
Phone: (559)
565-3703 |
