WWETAC Projects

Project Title: Landscape-level effects of fuel treatments on wildfire risk and carbon in central Oregon

Status: Ongoing

Principal Investigators: Nicole Vaillant and Alan Ager, WWETAC

Collaborators: Mark Finney, USDA Forest Service, Rocky Mountain Research Station, Missoula Fire Sciences Laboratory, Missoula, MT; Andrew McMahan, SofTec Solutions, Inc., Ft. Collins, CO

E-mail Contact: Nicole Vaillant, nvaillant[at]fs.fed.us

Key Issues: Several studies have investigated the tradeoffs from implementing fuels reduction treatments for the purpose of reducing wildfire severity and their effect on carbon stocks, CO2 emissions from treatment, and avoided wildfire emissions as a result of treatments (i.e. Finkral and Evans 2008, Hurteau et al. 2008, Hurteau and North 2009, Reinhardt and Holsinger 2010).  Although informative, these studies are limited to stand-level assessments where the probability of fire is 1.  We propose to look at landscape-level fire simulations to calculate carbon pools and emissions for expected (where burn probability is <<1) and conditional (where burn probability is 1) scenarios for both treated and untreated landscapes.

Study Objectives and Goals:

  1. Quantify the effectiveness of fuel treatments to reduce modeled wildfire risk (fire size, burn probability and conditional flame length) by vegetation type in 2010;
  2. Quantify simulated treatment C emissions by vegetation type;
  3. Quantify carbon emissions by vegetation type from modeled wildfires in 2010;
  4. Quantify carbon pools by vegetation type, with and without fire, for untreated and treated landscapes for 2010 (immediately after wildfire simulations) and 2020; and
  5. Compare outcomes of 3 & 4 for expected (calculated for a random ignition and a single wildfire event in the study area) and conditional (where all points on the landscape are burned) scenarios.

General Description: This project is taking place on the Deschutes National Forest in central Oregon.  The project includes simulation of thousands of fires using a command line version of FlamMap to determine wildfire risk coupled with stand-level runs of the Forest Vegetation Simulator with the Fire and Fuels Extension (FVS-FFE) to calculate expected and conditional standing carbon. Simulations occur on both treated and untreated landscapes.  Treatments are only allowed to be simulated in general forest matrix, deer habitat, visual corridors, and late successional reserves only when none of the area is or has potential to be northern spotted owl (Strix occidentalis caurina) habitat.  Simulated treatments include three year process including: a thin from below to a vegetation specific basal area, a fuel move, and an underburn. Treatments were simulated on about 20% of the landscape (Figure 1).  More specifically:

  1. Estimate p(Fi), the probability of every stand burning at a given fire intensity i;
  2. Estimate the loss of carbon for a given fire intensity, ΔCi. This is accomplished by burning each stand in FVS-FFE while varying the flame length;
  3. For each pixel, calculate Expected standing carbon, E(C) = C – Σ(p(Fi) * ΔCi), where C is the carbon before the fire, and Σ(p(Fi) * ΔCi) is the expected carbon given a random ignition on the landscape and a severe fire event.
  4. For each pixel, calculate Conditional expected standing carbon, CE(C) = Σ(p(Fi)/p(F) * ΔCi), where conditional expected carbon is the amount of carbon given that the distribution of fires occurs (i.e. burn probability = 1).
  5. Simulate fuel treatments and re-calculate values described in #1, #2, #3, and #4 above for the treated landscape.

fuel treatment locations

Figure 1. Fuel treatment locations on the Deschutes National Forest.

preliminary results

Figure 2. Preliminary results of expected and conditional total stand carbon and above ground live carbon for 2010 and 2020. Total stand carbon includes live trees, understory vegetation, snags, surface fuels, ground fuels, and harvested carbon stored in manufacturing products (if applicable). Above ground live carbon includes live trees and understory vegetation. Expected stand carbon is remaining carbon given a random ignition and a single wildfire event in the study area. Conditional stand carbon is remaining carbon given every pixel in the landscape burns.

 

Deliverables and Citations:

Ager AA, Finey MA, McMahan AM. In press. Measuring the effect of fuel treatments on forest carbon using landscape risk analysis. Natural Hazards and Earth System Sciences.

Cathcart J, Ager AA, McMahan AM, Finney MA. In press. Carbon offsets from fuel treatments using a risk analysis. Proceedings of the 2009 National Silviculture Workshop, Boise, ID.  June 15-18. Rocky Mountain Research Station, General Technical Report RMRS-P-X.

Finkral AJ, Evans AM. 2008. The effects of a thinning treatment on carbon stocks in a northern Arizona ponderosa pine forest. Forest Ecology and Management 255: 2743–2750

Hurteau MD, Koch GW, Hungate BA. 2008. Carbon protection and fire risk reduction: toward a full accounting of forest carbon offsets. Frontiers in Ecology and the Environment 6(9): 493–498

Hurteau MD, North M. 2009. Fuel treatment effects on tree-based forest carbon storage and emissions under modeled wildfire scenarios. Frontiers in Ecology and the Environment 7:409-414

Reinhardt E, Holsinger L. 2010. Effects of fuel treatments on carbon-disturbance relationships in forests of the northern Rocky Mountains. Forest Ecology and Management 259(8): 1427-1435

Project ID: FY10AA75