By Dryw Jones, Andy Gray, and Taylor Lucey
The forests of the Pacific Northwest have the potential to play a role in mitigating the effects of climate change by reducing carbon emissions and enhancing carbon stores that are associated with activities, such as forest products use, bioenergy, and land conservation and management.
Jurisdictions of the Pacific region of North America (from Hawaii to Alaska) have either enacted or have considered a range of carbon policy options to mitigate climate change. Many of the policy options directly or indirectly affect land management, in particular forests, and these options include carbon offsets in cap and trade programs; energy from wood residue, which counts as clean energy; taxes on carbon-emitting fossil fuels; increasing ecosystem carbon stores; maintaining forested area; and increasing the proportion of harvested material used for long-lived products.
The success of any of these policies requires understanding their impact on forest carbon and understanding the underlying forest carbon science research. As a result, there is a growing need for legislators, land managers, conservation organizations, and the wood products industry to understand how policies and management choices affect carbon dynamics in the forest, in wood products, and in overall emissions to the atmosphere. This need is best addressed with good science and even better data.
Navigating carbon science
The current literature on carbon science comes in many flavors with some studies appearing to contradict others. For example, one paper might find net emissions of carbon from a thinning treatment, while another finds net sequestration. To understand why similar studies on carbon dynamics may come to different conclusions one must understand what exactly these research papers are looking at, and what assumptions they make.
To help make sense of the forest carbon science, there are a series of questions to ask when reviewing forest carbon studies.
- What policies or land management options are being considered in the study? A wide variety of options are available that might affect the amount of carbon stored in forests and wood products. Few papers can address all of them, and many only evaluate one or a few management options.
- What carbon cycle pools and fluxes are included in the carbon dynamics analysis? The “forest sector” as defined by international assessments includes the live, dead, and soil carbon in the forest and the harvested wood derived from that forest. In contrast, life cycle analyses may assess the fossil fuels used when managing the forest and when transporting, manufacturing, and consuming resulting products, usually in comparison to alternative (non-wood) building materials. A paper that only looks at in-forest carbon dynamics will come to different conclusions about the carbon implications of management than one that looks at the whole forest sector, or one that includes actual or avoided fossil fuel emissions.
- Are estimates of carbon stores or fluxes? A focus on carbon flux (the rate of sequestration or emission) tells you what is happening now but does not tell you how carbon stores compare to a baseline level. Stores represent the overall amount of carbon removed from the atmosphere, but some stores, like belowground biomass, soil carbon, and landfills, can be difficult to measure.
- Are there discount rates and time horizons? What rates are being used and what assumptions do those rates imply about future conditions? Projections used to calculate carbon credits for specific parcels of forested lands may apply to different baselines, time horizons, and discount rates for emissions and sequestration.
- Are disturbances included? Studies that do not include estimates of disturbances—like wildfire, windstorms, or insect and disease outbreaks—or that assume current disturbance patterns won’t change will have different estimates of future carbon stores than studies that assume disturbance patterns will change under future climates.
- What is the scale of the study? While the carbon in a managed stand may fluctuate greatly over 100 years, carbon from aggregated stands (e.g., a watershed) might fluctuate much less, making it harder to assess the impact of a given silvicultural treatment. Conversely, small-scale studies may not apply to the variety of vegetation types and management strategies that occur at larger scales.
- Does the study track all components of change? Analyses that focus on tree growth will come to different conclusions than those that include mortality and harvests. Studies focused on forest ecosystems might treat all removals as emissions, whereas studies that track carbon through wood products might conclude that managed forests are carbon neutral, or net carbon sinks. Carbon in harvested wood used for bioenergy could be double counted if the carbon was considered a loss from the forest ecosystem and then also counted as an emission when burned.
- What carbon price is used? Does the paper assume that carbon prices will go up in the future or does it use current values or an assumed range? To a large degree, carbon prices dictate modeled landowner behavior with respect to carbon credits. Understanding why a carbon price was chosen gives critical insight into the paper’s conclusions.
Advancing carbon science in the PNW
As these questions suggest, there are many ways to approach carbon research and there is still much we need to learn. The complexity of quantifying carbon stocks and flows and the variety of policy options proposed to mitigate climate change point to a growing urgency to better understand the interaction between carbon dynamics and land management.
To improve our understanding of carbon dynamics, the USDA Forest Service’s Pacific Northwest Research Station launched a Carbon Research Initiative in September 2019 in a coproduction effort with agency partners in Hawaii, California, Oregon, Washington, British Columbia, and Alaska. The four-day workshop concluded with attendees converging on four high priority carbon research topics for the region:
- Carbon science synthesis that outlines the current state of knowledge for carbon sequestration scenarios;
- Land management scenarios and alternatives that best represent stakeholders’ interests with respect to carbon dynamics;
- Socio-economic incentives and drivers of forest management that stakeholders see as viable course of action; and
- Synthesize and assess carbon models to enable evaluation of the scenarios and policies identified above.
The carbon science synthesis effort is collecting existing literature on landbased carbon dynamics within the Pacific region of North America. The data from available studies will allow us to describe what we know about the carbon consequences of specific management activities, and where are the gaps in knowledge that lead to uncertainty. We are working with land managers and agencies to ensure that concepts and data are provided to help people understand what is and is not known about managing natural resources for carbon. The planned outputs of this effort include: 1) an online searchable database of relevant literature (currently at 760 publications); 2) a manuscript synthesizing the literature; and 3) presentations and workshops to communicate the results of the research.
The land management scenario effort is focused on identifying and understanding the management strategies and policies that might be effective at mitigating the effects of a changing climate. We do not fully understand the ecological and socioeconomic trade-offs associated with a given management strategy, nor is there a clear understanding of how to assess the impacts on net carbon flux when new management or policies are implemented. This effort will apply carbon projection models to understand: 1) future changes to forest and harvested wood carbon pools resulting from different land management and policy scenarios; 2) the effectiveness of government policies and regulations to sequester and store carbon; and 3) the ramifications of climate change and carbon-focused policies on other ecosystem services and human social and economic well-being.
We are prioritizing land management scenarios of highest interest to our broad stakeholder groups and that appear to be most viable from a social and biophysical perspective. The planned outputs from this effort include: 1) incorporation of timber flow and harvested wood products analysis into a regional carbon report; and 2) a publication and interactive web application demonstrating different scenarios and projections.
The socio-economic incentives and drivers of management effort is focused on understanding how and why diverse public, private, and Tribal landowners are currently managing their forests in order to evaluate the effects of different management and policy scenarios to them. This will provide a “business as usual” trajectory for comparison with potential alternative approaches. We will also investigate whether forest landowners would be able and willing to adopt alternative management scenarios in response to various policy or program incentives designed to increase carbon sequestration and storage in forests, and how this would impact their other management goals. We will survey and interview forest owners/managers to determine: 1) what their current management strategies are and how carbon fits into those strategies; 2) how compatible carbon-oriented objectives are with their other management goals; 3) what drives their forest management decisions; and 4) what would be needed for them to alter current forest management in ways that enhance carbon sequestration and storage. Planned outputs include a manuscript summarizing results, and promising scenarios for modeling by the other Initiative efforts.
The carbon model synthesis effort is assessing the conceptual frameworks, mechanisms, and data requirements for different types of forest sector models so stakeholders can make informed decisions about which projection models are best suited to the scenarios they wish to evaluate. We are reviewing models identified by stakeholders and scientists and will identify options for projecting: 1) behavior of landowners and land managers in response to price or regulatory incentives and requirements; 2) response of forest ecosystem and harvested wood product carbon pools to different management practices; 3) implications of different uses of harvested forest materials for carbon stores, energy and material substitution, as well as leakage effects from changes in harvest patterns; 4) effects of climate change and natural disturbance regimes on ecosystem carbon balance and changes in land cover types; and 5) effects of modeled ecosystem changes and uses on wildlife habitat, water quality, recreation, and local economies.
Planned project outputs include: 1) a report providing decision support for the selection and development of modeling approaches to address stakeholder needs; 2) publication of initial forest simulation results; 3) improved models of soil carbon cycling in terrestrial ecosystems and improved linkages between terrestrial and aquatic productivity; and 4) comparison of carbon footprints of traditional and new wood products versus common non-wood materials to quantify potential substitution benefits.
Gaining a better understanding of climate change and climate change mitigation strategies is a complex global challenge that is inherently linked with socioeconomic hurdles. Through the PNW Research Station’s Carbon Research Initiative, ecologists, social scientists and coproducers are working together to assist policy makers, land managers, and other stakeholders in creating and assessing tools to maintain the resilience of our ecosystems now and into the future. The coproduction approach the Initiative is founded on helps us meet stakeholders’ goals by directly integrating feedback from collaborators into the Initiative process.
In addition to providing valuable information and tools to the public, we hope to use our findings to identify the research topics needed to fill in knowledge gaps along the way. With the support of outside agencies and partners, we will pursue those research topics in the future.
Dryw Jones is a research forester with the PNW Research Station in Olympia, Wash. He can be reached at email@example.com. Andy Gray, an SAF member, is a research ecologist, and Taylor Lucey is a ORISE research fellow with the PNW Research Station in Portland, Oregon. Gray can be reached at firstname.lastname@example.org, and Lucey can be reached at Taylor.Lucey@ usda.gov. For more information about the Carbon Research Initiative, visit https://tinyurl.com/yx8o925x.