MECHANICAL AND
PRESCRIBED FIRE
FUEL TREATMENTS:
The Fire and Fire Surrogate
Study
at
Blodgett Forest
Research Station
Professor Scott Stephens, P.I. &
Jason Moghaddas, Fire Ecologist,
Plumas National Forest
The Fire Surrogate Study Research Team
U.C. Berkeley Fire Science Laboratory
Presentation Outline:
1. Blodgett History and Fire
Surrogate Study Overview
2. Vegetation, Fuels, & Fire
Behavior Results
3. Summary and Discussion
BLODGETT FOREST
RESEARCH STATION
Georgetown, CA
Management History (4400 acres):
¾ 1849-1900: Grazing, removal of some
sugar and ponderosa pine; more
intensive logging by oxen in the
1890’s
¾ 1900-1913: Extensive railroad logging
over most of forest. UC in 1933. Fire
Suppression is policy
¾ 1960-1970: Removal of most residual
old trees
¾ 1849-1970: Common practice in
Sierra
¾ 1975 on: Range of silvicultural
treatments implemented; regular
inventory plots and procedures
implemented- HIGH SITE QUALITY
Project Overview Æ Treatment Methods Æ Results Æ Summary
BLODGETT FIRE
HISTORY ANALYSIS
(Stephens & Collins, 2004)
¾Over 60 fire scars cross
dated.
¾Mean fire interval 4.7
years
¾Fire interval range 4-28
years
¾Most fires occurred in
dormant season
(September-October)
¾Fires stop after 1910
Project Overview Æ Treatment Methods Æ Results Æ Summary
Fire Surrogate Study:
What Types of Questions Are We Trying to
Answer?
¾Can forest structure and process (fire) be altered in a way that
will measurably reduce fire related mortality within a given stand?
¾Can “standard treatment practices” (thinning, burning) available
locally be utilized to achieve this goal?
¾Can these practices be used to effectively modify fire behavior?
¾What are the ecological effects and economic costs of using
these practices?
Project Overview Æ Treatment Methods Æ Results Æ Summary
Where Is the Study Taking Place?
Eastside Cascades
Northern Rockies
Blue Mountains
Southern Cascades
Ohio Hills
Central Sierra
Southern Sierra
• Southern
Piedmont
Appalachians
Southwest Plateau Jemez Mountains
• Southern Alabama
Coastal Plain
VISIT YOUR LOCAL FFS SITE!
Site locations for the National Fire and Fire Surrogate Study
Core response variables
- economics & wood product
utilization
- fire behavior, fuels, smoke
- insects
- pathogens
- soil & forest floor
- vegetation
- wildlife
Project Overview Æ Treatment Methods Æ Results Æ Summary
Treatment Goals & The “Desired Future Condition”
“Each non-control treatment shall be designed to
achieve stand and fuel conditions such that, if impacted
by a head fire under 80th percentile weather conditions,
at least 80 percent of the basal area of over story
(dominant and co-dominant) trees will survive.”
Project Overview Æ Treatment Methods Æ Results Æ Summary
“Future of the Forest”
“The Old Forest of the west slope of the Sierra will have been cut
away,
And the young growth will consist largely of red fir, white fir,
and incense cedar” (Leiberg, 1902)
Photo From R.S. Polkinghorn-”Pino Grande”
What should the “desired future condition” look like?
Project Overview Æ Treatment Methods Æ Results Æ Summary
Blodgett Site “Desired Future Conditions”
AVERAGE:
¾Crown cover………………~45%; 15-20%
overlap of dominant & co-dominant trees
¾Basal area…………………~125ft2/acre
¾Height to crown base……..~10 feet
¾Surface fuel load………….~10 tons/acre
¾Duff/litter cover……………~75%
¾Duff/litter depth……………~2-3 inches
¾Snags >12”DBH/acre……..~3-5
¾LWD >12” diam/acre……..~5-7 pieces
Project Overview Æ Treatment Methods Æ Research Æ Results Æ Summary
How do we achieve
the “desired future
conditions?
12 Treatment Units
¾Replicated, randomized
design with controls.
¾3 controls
¾3 mechanical only
¾3 mechanical plus fire
¾3 fire only
¾All units 40-70 ac in size
¾All units are in “group
selection” silvicultural system
Project Overview Æ Treatment Methods Æ Research Æ Results Æ Summary
Blodgett Forest Study
Site:
Treatment Unit
Details
Matrix
¾25-acre measurement area
¾Plots on 3-chain spacing
¾3 age classes of groups
¾100 foot buffer area around
treatment unit
Project Overview Æ Treatment Methods Æ Research Æ Results Æ Summary
Groups
What Tool Does FFS Use To Achieve DFC’s?
¾Control: No treatment of vegetation during the study period
¾Mechanical only: Commercial harvest followed by mastication
of 90% of material less than 10 inches DBH
¾Mechanical plus fire: Identical to mechanical only but followed by
a prescribed burn treatment of surface fuels
¾Fire only: No mechanical treatments;
prescribed burn treatment of surface fuel only
Project Overview Æ Treatment Methods Æ Research Æ Results Æ Summary
Post Treatment Vegetation Structure
PO ST T R E AT M EN T : C anopy C ov e r
100
a
80
b
ab
b
%
60
40
20
¾Canopy cover was (P <0.05)
reduced in mechanical only and
mechanical plus fire treatment
types
0
CONTROL MECH ONLY
600.0
FIRE
MECH + FIRE
PO ST T R EAT M EN T : T re e s pe r Acre >1
Inch D B H
a
500.0
TPA
400.0
300.0
¾Trees per acre > 1 inch DBH
were reduced (P <0.05) in all
active treatment types
b
b
200.0
b
100.0
0.0
CONTROL MECH ONLY
FIRE
MECH + FIRE
Project Overview Æ Treatment Methods Æ Results Æ Summary
Post Treatment Fuel Loading
POST TREATMENT: Litter and Duff Load per Acre
40.0
a
a
Tons Per Acre
30.0
20.0
b
10.0
0.0
10
CONTROL MECH ONLY
b
MECH + FIRE
POST TREATMENT: 1, 10, and 100 Hour Fuel Load per
Acre
a
Tons Per Acre
FIRE
a
5
b
b
0
CONTROL MECH ONLY
FIRE
¾Litter and duff loads were
reduced (P <0.05) in fire only
only and mechanical plus fire
treatment types
¾1, 10, & 100 hour fuel loads
were reduced (P <0.05) in fire
only and mechanical plus fire
treatment types.
¾1,000 hour sound and rotten
reduced (P <0.05) in fire only
and mechanical plus fire
treatment types (not shown)
MECH + FIRE
Project Overview Æ Treatment Methods Æ Results Æ Summary
Post Treatment Crowning and Torching Index:
90th Percentile Weather Conditions
POST TREATMENT: Crowning Index (Miles per Hour)
40
b
b
¾Crowning index was
increased (P <0.05) in
mechanical only and
mechanical plus fire
treatment types
Miles per Hour
30
a
a
20
10
0
CONTROL MECH ONLY
FIRE
MECH + FIRE
POST TREATMENT: Torching Index (Miles per Hour)
500
c
Miles per Hour
400
b
300
¾Torching index was
increased (P <0.05) in fire
only and mechanical plus
fire treatment types
200
100
a
a
0
CONTROL MECH ONLY
FIRE
MECH + FIRE
Project Overview Æ Treatment Methods Æ
Results Æ Summary
Predicted Probability of Mortality:
90th Percentile Weather Conditions
100
POST TREATMENT: Percent Probability of Mortality,
Trees >1 Inch DBH
b
80
b
%
60
a
40
a
20
0
CONTROL MECH ONLY
FIRE
MECH + FIRE
¾Percent probability of
mortality of trees >1”
DBH was reduced (P
<0.05) in fire only and
mechanical plus fire
treatment types
¾Predicted mortality
similar (<8%) for trees
>20” DBH for treated
units
Project Overview Æ Treatment Methods Æ Results Æ Summary
No Treatment- tradeoffs
¾Retains Canopy Cover
¾Retains all surface fuels and CWD
¾Retains all ladder fuels
¾Does not reduce probability of torching and crowning
¾Which stand type would you want next to your house (all tx) ?
Harvest + Mastication- tradeoffs
¾Can decrease canopy cover- depends on treatment intensity
¾Can increase surface fuels and CWD
¾Reduces ladder fuels
¾Reduces probability of torching and crowning
¾Reduction in annual volume growth
Harvest + Mastication + rx fire- tradeoffs
¾Can decrease canopy cover- depends on treatment intensity
¾Kills existing regeneration
¾Decreases surface fuels and CWD, especially rotten CWD
¾Existing snags may be burned up but new ones created
¾Reduces ladder fuels
¾Reduces probability of torching and crowning
¾Risk of escape
¾Potential for smoke impacts to local and regional air shed
¾Less need for re-burn as there are fewer dead small trees
Fire only- tradeoffs
¾Can maintain overstory canopy cover;
¾ Kills understory trees and existing regeneration
¾Decreases surface fuels and CWD, especially rotten CWD
¾Existing snags may be burned up but new ones created
¾Reduces ladder fuels
¾Reduces probability of torching and crowning
¾Risk of escape
¾Potential for smoke impacts to local and regional airshed
¾Will likely need re-entry to burn deadfall created from scorch
related mortality
How do we verify our modeled results?
¾Study behavior of treatments in “real” burns (i.e. Cone Fire,
Hayman Fire).
¾Talk to fire management personnel- they have EXTENSIVE
experience observing real fire behavior under almost all
fuel loadings, extreme weather conditions, and in the WUI.
¾Research which “captures” the knowledge of experienced fire
personnel should be funded- many are retiring soon!
Above photo by Karen Wattenmaker;
All photos posted by the National Interagency
Fire Center, http://www.nifc.gov
Acknowledgements
•Funded by Joint Fire Science Program &
The Resource Legacy Fund Foundation
•Scott Stephens, P.I.
•Fire Surrogate Study Research Team
•Center for Forestry, Blodgett Forest Research Station
•2001-2003 field technicians
¾We know how to create a “fire
safe” stand structure in mixed
conifer forests- many “fire safe”
structures seen on field tour
¾Each forest has shared and
unique constraints
QUESTIONS?
•http://www.fs.fed.us/ffs/
-Fire Surrogate Study
•http://nature.berkeley.edu/stephens-lab/ -U.C. Fire Science Lab
•http://www.cnr.berkeley.edu/forestry/
-U.C. Center For Forestry