Kirk Davies, Chad Boyd, and Tony
SvejcarUSDA-ARS, Burns, OR
Managing uplands in the sagebrush steppe
Competitive Ability of Cheatgrass Relative to Native Grasses
native
Cheatgrass after 6 weeks
Bluebunch Wheatgrass after 6 weeks
Increase in wildfires is a global and local issue
Most models suggest fire will become more frequent and severe
Fuel management is critical to limiting fire risk and severity
Rangelands are expansive, thus limiting options
Grazing is the only treatment that is feasible across large landscapes
Northern Great Basin Experimental Range
Not grazed since 1937
Both grazed and ungrazed plots burned in 1993
Long-Term Grazing Exclosures
3 times fuel loads on PG
Increased fuel depth
Current year’s biomass equal
Native perennial grass
Ungrazed
Grazed
Grazed Burned 15 yrs post-fire Ungrazed Burned 15 yrs post-fire
Native perennial grasses
Light colored vegetation is cheatgrass
Grazed in Nov –March for 4 years.
Compared to adjacent non-grazed sites .
Burned in Sept 2014
Winter grazing study
Date
July August September
Fue
l mo
isture (%
) 0
20
40
60
80UngrazedWinter grazed
*
*
* *
*Fuel moisture of extinction
Area burned (%
)
0
20
40
60
80
G
UG
a
bA.
Rate of spread (m
· sec-1
)
0.0
0.1
0.2
0.3
0.4
a
b
B.
Treatment
Flam
e height (m)
0
1
2
3
4
a
b
D.
Treatment
Flam
e depth (m)
0
1
2
3
4
a
b
C.
Are
a B
urn
ed
(%
)F
lam
e d
ep
th (
m) R
ate
of
Sp
read
(m
sec1
-1)
Fla
me H
eig
ht
(m)
GrazedUngrazed
Grazing can decrease wildfire riskAlso increase resilience to wildfire
Lower temperatureMore unburned patches
Grazed areas are more suppressible
Slower moving fireReduced flame lengthsAllows for direct attack
Effect will vary by community composition and fire weather
Needs to be a strategic and flexible
plan
Grazing decreases fire risk and severity