Fire Prevention as a GHG Mitigation Strategy

Presented by Robert Beach, RTI International

Brent Sohngen, The Ohio State University

Presented atForestry and Agriculture Greenhouse Gas Modeling Forum

March 6-8, 2007Shepherdstown, West Virginia

RTI International is a trade name of Research Triangle Institute

3040 Cornwallis Road ■ P.O. Box 12194 ■ Research Triangle Park, NC 27709Phone 919-485-5579 e-mail rbeach@rti.orgFax 919-541-6683

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Introduction

Heightened concern in recent years that intensive human intervention may have made forests more susceptible to negative effects of wildfires

Evidence that fire management interventions such as prescribed burning and thinning can reduce potential hazards related to wildland fires by removing smaller materials that can act as ladders for fires

Healthy Forests Restoration Act called for widespread thinning in US forests in order to help make them less susceptible to the negative effects of fires

Potential for reduction in the impacts of fires suggests that additional short-term carbon emissions could lead to smaller emissions in the future if large fires are reduced Implications for carbon sequestration in fire-prone stands

This is an exploratory study to examine the net carbon effects (accounting for time) of thinning using the Forest Vegetation Simulator-Fire and Fuels Extension (FVS-FFE) model

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Study Region and Plots

Representative ponderosa pine stands in the Eastern Cascades region of OregonRegion has been identified as having high build-up

of fuels in forests, that could potentially lead to large-scale consequences if fires break out

Ponderosa pine is the dominant species in the Eastern Cascades

Plot data obtained from the US Department of Agriculture, Forest Service, Forest Inventory and Analysis

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Models

Used FVS-FFE model to assess biomass stocks, thinning options, and simulated fire effects

FVS models stand dynamics, including growth of forests, mortality, and other attributes

The Fire and Fuels Extension can be used to model changes in biomass in different pools over time and to simulate the effects of a fire on these pools as well as modeling residual stand growth. FFE can be used to simulate the effects of fires under

different weather conditions

Examined carbon storage and emission profile over a 100-year period with and without thinning and with and without a fire

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Models (2)

Fuel Reduction Cost Simulator (Fight et al., 2006) was used to estimate costs of extracting materials from thinning operations

Used cut list from FVS to identify the trees that were thinned

Benefits of extracting marketable materials were estimated using price data from the OR Dept of Forestry

Estimated non-CO2 emissions (methane, nitrous oxide) from wildfire using EPA emission factors

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Assumptions

Thinning from below until 50 sq ft basal area

Material in the range of 5"-7" is used for pulp and material >7" dbh is used for sawtimber

All remaining material is assumed to be chipped and burned onsite, leading to an immediate emission

Calculate carbon stock in standing biomass using factors from Smith et al (2003)

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Representative Stand

Stand Identifier =>

4120040202990513

Stand "90513" Latitude; Longitude 42.4100; 122.5800

Sampling Weight 15,968

Month/Year Measured 07/2004

Elevation (ft)/Slope 2105/40%

Age 70

ft3 per acre /site class

1792/20 – 50 ft3/acre/year

Trees per acre 319

Crowning Index (MPH)

47.5

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Change in Carbon Stock with Thinning

0

10

20

30

40

50

60

70

80

90

100

2000 2020 2040 2060 2080 2100

tC/h

a

No Thinning Thinning w/o Products Thinning w/Products

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Unthinned Stand with Fire in 2010

0

10

20

30

40

50

60

70

80

90

100

2004 2014 2024 2034 2044 2054 2064 2074 2084 2094

t C

/ha

Base Forest w/o Fire Small Fire Larger Fire

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Change in C Storage from Thinning Relative to Baseline

-0.40

-0.35

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

2004 2014 2024 2034 2044 2054 2064 2074 2084 2094

Year

ton

ne

s/h

a/y

ea

r

Thinning w/o fire

Thinning w/ fire

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Thinning without Fire

Immediate release of carbon from thinning

Thinned stand slowly begins to approach carbon storage of unthinned stand over time

PV of carbon change over 100 years from case study stand is -4.12 tC/ha without fire

PV of carbon change with fire is actually even more negative in this case at -4.95 tC/ha

Harvesting operation cost: $678/acre

Value of wood harvested: $498/acre

Net value: -$180/acre

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Other Stands

Across the 487 ponderosa pine stands in the Eastern Cascades of OR available from FIA dataOver half had lower carbon emissions from fires

when they had been thinnedHowever, only in a minority of cases (<20%) were

the lower emissions from fire sufficient to offset the higher emissions from thinning

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Timing of Thinning and Fires

We also examined a number of scenarios that varied the timing between thinning and the fire

Initially we thought that the findings may be related to the fire occurring shortly after thinningHowever, it made relatively little qualitative

difference in changes in carbon storage

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Conclusions

Based on our simulations and assumptions, thinning tended to result in lower discounted net carbon storage In the absence of wildfires, carbon storage is

reduced relative to baseline due to the removal of carbon during thinning

With wildfires, the majority of plots examined did have lower emissions if they had been thinned, but not sufficiently lower to offset the emissions from thinning

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Future Research/Extensions

Alternative fire models FOFEM, CONSUME, others

Accounting for interactions with other stands

Prescribed burning

Quantify factors impacting effectiveness of thinning in reducing emissions

Include harvesting

Stochastic wildfires

Examination of climate effects