Performing Department
Ecosystem Science & Management
Non Technical Summary
Natural disturbances in part determine the carbon carrying capacity of a given forest by limiting the amount of carbon that can be sustained (Keith et al. 2009). Wildfire is a natural disturbance that contributes the equivalent of 4-6% of annual anthropogenic emissions in the United States (Wiedinmyer and Neff 2007) and has legacy effects on carbon sequestration that can persist for years (Dore et al. 2008, Meigs et al. 2009). Fire severity and the resultant emissions can be influenced by forest management (Hurteau et al. 2008, North et al. 2009) with treatments that improve the resistance of forest carbon to loss by fire, thereby increasing the permanence of the forest carbon stock (Hurteau et al. 2008, Hurteau and North 2009, North et al. 2009). However, the carbon balance of wildfire risk mitigation depends on forest type. In mesic forests of the Pacific Northwestern US, where historic mean fire return intervals are long, fuels reduction treatments yield a net reduction in forest carbon stocks (Mitchell et al. 2009). In dry temperate forests, such as ponderosa pine or Sierran mixed-conifer forest, fuels reduction treatments can actually increase carbon storage by reducing wildfire emissions and reducing tree mortality (Finkral and Evans 2008, Hurteau and North 2009, Mitchell et al. 2009). Regardless of forest type, wildfire risk mitigation treatments incur immediate carbon costs. Tree removal and prescribed fire emissions are a function of the treatment implemented on a given site and represent the largest emissions sources, with equipment related emissions representing less than 1-3% of the forest carbon (North et al. 2009). While thinning does reduce carbon stocks, it can serve to consolidate the remaining carbon in fewer larger trees that continue to sequester carbon. Additionally, in some forested systems prescribed fire emissions can be quickly re-sequestered by the remaining trees on site (Hurteau and North 2010). In many of these dry forest types, past land management including grazing and fire suppression has fundamentally altered the forest structure. Although some research suggests that this has led to increased tree density and forest carbon stocks (Hurtt et al. 2002), recent studies comparing forest inventories from the 1930s with current forest inventory data in the Sierra Nevada found that while forest density has increased, carbon stocks have decreased (Fellows and Goulden 2008). If generally true, this suggests that structural manipulations targeted at restoring fire in these systems may sequester more carbon by favoring retention of fewer, larger trees that are resistant to loss from high-severity fire (Hurteau et al. 2008, Hurteau et al. 2009). This type of forest management, designed to reduce fuels and facilitate fire reintroduction, may best emulate natural disturbance patterns. Forest productivity is a function of many abiotic and biotic factors, including climate. Recovery from past disturbance, including land-use and land-use change, has yielded a net increase in the amount of forest carbon sequestered over the past century (Hurtt et al. 2002). The increase in net primary productivity has been further enhanced by anthropogenic emissions of carbon dioxide and nitrogen. As anthropogenic emissions continue to alter the climate, forest productivity and distribution is likely to be impacted. Since high-severity wildfire and other disturbances can reset the successional stage of a forest, these disturbances could act as a catalyst for landscape and regional change in the distribution of forests (Hurteau and Brooks 2011). Yet, there is uncertainty surrounding many aspects of how forests will respond to changing climate, disturbance regimes, and management actions. Natural disturbances in part determine the carbon carrying capacity of a given forest by limiting the amount of carbon that can be sustained (Keith et al. 2009). Wildfire is a natural disturbance that contributes the equivalent of 4-6% of annual anthropogenic emissions in the United States (Wiedinmyer and Neff 2007) and has legacy effects on carbon sequestration that can persist for years (Dore et al. 2008, Meigs et al. 2009). Fire severity and the resultant emissions can be influenced by forest management (Hurteau et al. 2008, North et al. 2009) with treatments that improve the resistance of forest carbon to loss by fire, thereby increasing the permanence of the forest carbon stock (Hurteau et al. 2008, Hurteau and North 2009, North et al. 2009). However, the carbon balance of wildfire risk mitigation depends on forest type. In mesic forests of the Pacific Northwestern US, where historic mean fire return intervals are long, fuels reduction treatments yield a net reduction in forest carbon stocks (Mitchell et al. 2009). In dry temperate forests, such as ponderosa pine or Sierran mixed-conifer forest, fuels reduction treatments can actually increase carbon storage by reducing wildfire emissions and reducing tree mortality (Finkral and Evans 2008, Hurteau and North 2009, Mitchell et al. 2009). Regardless of forest type, wildfire risk mitigation treatments incur immediate carbon costs. Tree removal and prescribed fire emissions are a function of the treatment implemented on a given site and represent the largest emissions sources, with equipment related emissions representing less than 1-3% of the forest carbon (North et al. 2009). While thinning does reduce carbon stocks, it can serve to consolidate the remaining carbon in fewer larger trees that continue to sequester carbon. Additionally, in some forested systems prescribed fire emissions can be quickly re-sequestered by the remaining trees on site (Hurteau and North 2010). In many of these dry forest types, past land management including grazing and fire suppression has fundamentally altered the forest structure. Although some research suggests that this has led to increased tree density and forest carbon stocks (Hurtt et al. 2002), recent studies comparing forest inventories from the 1930s with current forest inventory data in the Sierra Nevada found that while forest density has increased, carbon stocks have decreased (Fellows and Goulden 2008). If generally true, this suggests that structural manipulations targeted at restoring fire in these systems may sequester more carbon by favoring retention of fewer, larger trees that are resistant to loss from high-severity fire (Hurteau et al. 2008, Hurteau et al. 2009). This type of forest management, designed to reduce fuels and facilitate fire reintroduction, may best emulate natural disturbance patterns. Forest productivity is a function of many abiotic and biotic factors, including climate. Recovery from past disturbance, including land-use and land-use change, has yielded a net increase in the amount of forest carbon sequestered over the past century (Hurtt et al. 2002). The increase in net primary productivity has been further enhanced by anthropogenic emissions of carbon dioxide and nitrogen. As anthropogenic emissions continue to alter the climate, forest productivity and distribution is likely to be impacted. Since high-severity wildfire and other disturbances can reset the successional stage of a forest, these disturbances could act as a catalyst for landscape and regional change in the distribution of forests (Hurteau and Brooks 2011). Yet, there is uncertainty surrounding many aspects of how forests will respond to changing climate, disturbance regimes, and management actions.
Animal Health Component
0%
Research Effort Categories
Basic
20%
Applied
80%
Developmental
(N/A)
Goals / Objectives
1. Quantify the effects of forest management and disturbance on forest carbon dynamics using empirical and simulation based approaches. 2. Simulate the effects of changing climate on forest growth and distribution and how climate and disturbance will interact to influence forest carbon dynamics.
Project Methods
Objective 1: Using data from a range of forest types (light limited to water limited) forest growth will be modeled with the implementation of management actions targeted at achieving specific outcomes. Data were gathered at three US Military installations (Fort Benning, GA; Camp Navajo, AZ; Joint Base Lewis Mchord, WA) to parameterize a growth-and-yield model and a biogeochemical model. Using the parameterized models, we will simulate management actions to maximized forest carbon sequestration, minimize wildfire risk, and maximize threatened/endangered species habitat. We will evaluate these different management acitons in terms of carbon trade-offs. We will develop spatial data products to facilitate management planning at the three installations. We will also run workshops at each installation to train natural resource managers on how to use the models. Using data from the Teakettle Experiment, established at the Teakettle Experimental Forest in the Sierra Nevada, we will quantify how wildfire risk mitigation treatments and insect-induced mortality influence the distribution of carbon within this mixed-conifer forest. The Teakettle Experiment includes three 4 ha replicate treatment units of six different treatments. This full factorial experiment includes a no-thin control, understory thinning, overstory thinning and prescribed burning. All trees within each treatment unit have been stem-mapped and numerous other measurements have been made to facilitate quantification of the distribution of carbon. This work builds on our previous efforts (North et al. 2009, Hurteau and North 2010) and provides a longer-term characterization of the effects of treatment on forest carbon. Additionally, we will also gather data on charcoal formation resulting from the prescribed buring treatments. This recalcitrant carbon pool is poorly understood and determining the effects of fuel size on charcoal formation will provide a better understanding of the contribution of prescribed burning to long-term carbon storage. Objective 2: Using Forest Inventory and Analysis data and other spatial data products (e.g. LANDFIRE), we will parameterize a growth-and-yield model and a biogeochemical model to determine the influence of projected changes in climate on the forest carbon sequestration and forest type distribution. This research will use downscaled climate projections from three general circulation models and two emission scenarios (B1 and A2). This research will partition the effects of different drivers (e.g. climate and management) on forest growth and distribution. Using the projected forest growth and distribution simulation outputs, we will intersect these data layers with a prognostic fire model to examine feedbacks between wildfire and forests under different climate projections. The specific feedbacks include quantifying the effect of wildfire on forest growth and distribution under altered climate and quantifying the effect on prior wildfire events on the probability of successive large wildfire occurrence. Outputs from the intersection of forest and fire data layers will be used in the FINN model framework to estimate emissions from wildfire, including emissions with human health impacts such as PM2.5 and PM10. This research will occur in the Sierra Nevada and US Rocky Mountains. Using Forest Inventory and Analysis data and other spatial data products, we will parameterize a landscape scale forest model to quantify the effects of changing climate, insects and pathogens, and management activities on forest species diversity and productivity. This research will also include a common garden experiment using southern species to determine establishment and survivorship rates to better inform model simulations. This research will use downscaled climate projections from three general circulation models and two emission scenarios. This simulation domain for this research will be the Mid-Atlantic region, with the common garden experiment occurring in Pennsylvania. Implementation of this research is contingent upon external funding. Stakeholder Engagements: Outreach to ensure the results of this research will include workshops, research briefs, and a web tool to present model results. Additionally, work on objective 2 will involve an iterative stakeholder data product evaluation process for a sub-region of the modeling domain. This iterative process will involve researchers presenting results to a core stakeholder group and provide an opportunity for the stakeholders to influence the format of the final data products to ensure their usability for management planning. Literature Cited: Dore S, Kolb TE, Montes-Helu M et al. (2008) Long-term impact of a stand-replacing fire on ecosystem CO2 exchange of a ponderosa pine forest. Global Change Biology, 14, 1-20. Fellows AW, Goulden ML (2008) Has fire suppression increased the amount of carbon stored in western U.S. forests? Geophysical Research Letters, 35, L12404. 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, 493-498. Hurteau M, 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. Hurteau MD, Hungate BA, Koch GW (2009) Accounting for risk in valuing forest carbon offsets. Carbon Balance Manag, 4, 1. Hurteau MD, North M (2010) Carbon recovery rates following different wildfire risk mitigation treatments. Forest Ecology and Management. Hurteau, M.D., Brooks, M.L., 2011. Short- and long-term effects of fire on carbon in US dry temperate forest systems. BioScience 61, 139-146. Hurtt GC, Pacala SW, Moorcroft PR, Caspersen J, Shevliakova E, Houghton RA, Moore B, Iii (2002) Projecting the future of the U.S. carbon sink. Proceedings of the National Academy of Sciences, 99, 1389-1394. Keith H, Mackey BG, Lindenmayer DB (2009) Re-evaluation of forest biomass carbon stocks and lessons from the world's most carbon-dense forests. Proceedings of the National Academy of Sciences, 106, 11635-11640. Meigs GW, Donato DC, Campbell JL, Martin JG, Law BE (2009) Forest fire impacts on carbon uptake, storage, and emission: the role of burn severity in the Eastern Cascades, Oregon. Ecosystems, 12, 1246-1267. Mitchell SR, Harmon ME, O'connell KEB (2009) Forest fuel reduction alters fire severity and long-term carbon storage in three Pacific Northwest ecosystems. Ecological Applications, 19, 643-655. North M, Hurteau M, Innes J (2009) Fire suppression and fuels treatment effects on mixed-conifer carbon stocks and emissions. Ecological Applications, 19, 1385-1396. van Mantgem, P.J., Stephenson, N.L., 2007. Apparent climatically induced increase of tree mortality rates in a temperate forest. Ecol. Lett. 10, 909-916. Wiedinmyer C, Neff JC (2007) Estimates of CO2 from fires in the United States: implications for carbon management. Carbon Balance Manag, 2, 10. Westerling, A.L., Hidalgo, H.G., Cayan, D.R., Swetnam,T.W., 2006. Warming and earlier spring increase western U.S. forest wildfire activity. Science 313, 940-943.