Kirk Davies, Chad Boyd, and Tony

SvejcarUSDA-ARS, Burns, OR

Managing uplands in the sagebrush steppe

Prevention is keeping a good density of bunchgrasses

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

WINTER GRAZED

UNGRAZED

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

QUESTIONS?