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Carbon

Illustrated graphic with title "Carbon in Time and Space, A spatial and temporal view". Carbon stocks in forests are always in flux due to variations in age, disturbance, and environmental factors. Detecting patterns and trends requires taking a broad view in both space and time.
A Spatial and Temporal View | Carbon in Time and Space

Carbon is the basic building block of forests. Trees and other vegetation naturally absorb carbon dioxide (CO2) through the process of photosynthesis and store it as biomass in the trunks, branches, roots, and leaves. Carbon absorbed by plants can be transferred to soil through decomposing roots, leaves, and wood, where a portion of it can remain for long periods of time. CO2 is an important greenhouse gas released into the atmosphere that contributes to rising global temperatures. This makes the absorption and storage of carbon within forests critical to mitigate climate change and limit the impacts on our ecosystems and communities.

Efforts to monitor carbon in forests and grasslands produces the authoritative research, analyses, and tools to estimate carbon stocks and track change over time across the nation. The estimates contribute to international reporting on National Greenhouse Gas Inventory to the United Nations Framework Convention on Climate Change, forest sustainability reporting for the Montreal Process, carbon assessments across national forests and grasslands, and beyond.

Carbon Stewardship

The Forest Service is a leader in the  integration of climate adaptation and mitigation in land management. Carbon stewardship highlights  the importance of managing climate risk through adaptation to stabilize carbon in plants and soil. Carbon Stewardship also aims to manage carbon uptake and storage, while balancing a wide range of other ecosystem benefits  on national forests and grasslands. 

Definition

The Forest Service defines carbon stewardship as actions that are informed by carbon science that increases carbon uptake or storage in biological matter such as plants or soil or increases stability through land-use and vegetation management strategies . Thoughtful carbon stewardship promotes ecosystem integrity and climate adaptation and does not maximize carbon at the expense of forest health or habitat. Carbon stewardship involves:

  • The intentional analysis of the effects of management actions on carbon uptake, storage, and stability

  • Considering carbon along with other ecosystem benefits.

  • The net enhancement of ecosystem carbon uptake and storage.

  • Avoided emissions from disturbance or tree mortality (carbon stabilization).

Description

Carbon stewardship requires a broad definition because ecosystem carbon responses to land management actions may be different. The following elements of carbon stewardship are described to help determine if proposed actions can reasonably be expected to provide carbon benefits over the life of a project.

Timescale of carbon benefits

Carbon benefits are not limited to immediate increases in carbon stocks but may be realized over a variety of time scales. Carbon responses may include near-term decreases in carbon stocks, where carbon benefits may take many decades to occur.

Carbon stability

Carbon stewardship actions may be in response to assessments that indicate current conditions are out of alignment with the carbon carrying capacity of the system. For example, overstocked forests that are a legacy of past fire suppression has resulted in elevated risk of tree mortality and severe wildfire. In these landscapes, reducing tree densities will decrease carbon to lower the risk of carbon losses from mortality and fire. These actions can provide carbon benefits since the remaining ecosystem carbon is expected to have greater stability and a longer residence time in the system. Carbon stewardship actions that increase carbon stocks in live vegetation, dead wood, and soils should not elevate the risk of disturbance that would cause widespread carbon emissions back to the atmosphere.

Climate adaptation

Actions that provide adaptation benefits through reduced risk of unintended climate impacts can provide carbon benefits through avoided carbon emissions. Some disturbances or forest health issues may also decrease carbon uptake through plant growth. While not all adaptation actions provide carbon benefits, there are many actions that address risks to ecosystem health that sustain or improve the capacity of systems to absorb atmospheric carbon dioxide through plant growth.

Integrated natural resource management

While national forests and grasslands can play an important role in mitigation of greenhouse gas emissions through land management, considering the numerous environmental benefits provided by healthy ecosystems is paramount to achieving our mission. Carbon stewardship aims to integrate the consideration of carbon in plants and soil called biogenic carbon  in a way that recognizes the importance of achieving other management objectives. Maximizing ecosystem carbon stocks can create undesirable tradeoffs with other environmental benefits, and in some landscapes may result in lower carbon benefits where carbon stability is compromised. Maximizing carbon is therefore not necessary, and is often counter to, achieving effective carbon stewardship.

Carbon Assessments

The Forest Service is the primary agency in the U.S. that collects and analyzes data on U.S. trees, the carbon they store, and emissions back to the atmosphere after they are harvested or die. Forest Service scientists study how land management, land uses, and land changes affect carbon in the landscape and ways to increase carbon storage. The Forest Service has always led efforts to practice, develop, and demonstrate sound and sustainable management of forest-based resources. The management of forest carbon is no exception.

An infographic showing the closed loop of Forest Service in the Atmosphere.
Management and Disturbance in Forest-Atmosphere Interactions | Carbon Cycle

The Forest Service Forest Inventory and Analysis (FIA) program is the basis of national greenhouse gas estimates from forest land use and land use change. FIA estimates on the carbon content among forest types are used by policy makers at local, state, and national levels to estimate the carbon benefits from land management activities and inform climate change mitigation measures.

The Forest Service has developed regional carbon assessment reports to help forest managers and the public understand how much carbon is stored in forest ecosystems and harvested wood products. The baseline forest carbon reports draw information from the FIA program to provide carbon stocks and trends. These reports also provide estimates of carbon stored in harvested wood products over longer time periods depending upon the availability of data. These assessments are provided as a nationally consistent data set with which we can better understand geographic differences and important trends.

Carbon stock and trend information, in conjunction with companion assessments on forest carbon disturbances, help inform forest managers and the public of the relationship between carbon storage and past management and disturbance impacts. This will help us begin to consider short and long-term carbon consequences of alternative forest management strategies.

Available Carbon Assessment Reports

Baseline Carbon Reports

Disturbance Carbon Reports

Tools for Carbon Inventory, Management, and Reporting

Several tools exist to help quantify forest carbon for planning and reporting, including:

Other tools include:

  • USDA Forest Service Carbon Dashboard – The carbon data in this dashboard help to: 1) visualize how forest carbon is distributed across the U.S.; 2) evaluate decades of carbon trend information on National Forest System lands; and 3) understand how climate change, socioeconomics, fire, and other factors affect forest carbon stocks in the future.

  • USDA Entity Scale Greenhouse Gas Methods Report (2024)

  • Forest Service Research & Development Carbon Monitoring

  • i-Tree is a suite of online tools and freely available software packages developed by the Forest Service and cooperators to support ecosystem service assessment, including carbon sequestration from urban and rural forest management.

  • Land Emissions and Removals Navigator (LEARN) tool is an interactive web mapping tool was developed to help communities in the United States estimate the local greenhouse gas (GHG) impacts of their forests and trees. It uses Forest Service FIA data to provide an approximation of annual GHG impacts over a given time period. GTR-NE-343 - Methods for calculating forest ecosystem and harvested carbon with standard estimates for forest types of the United States & accompanying spreadsheet-based carbon calculator: methods, sample calculations, and regional average carbon stocks as tables (aka ‘look-up tables’) for 51 major forest types across ten geographic regions in the conterminous U.S.

  • GTR-NRS-202 - Standard Estimates of Forest Ecosystem Carbon for Forest Types of the United States: updates ecosystem carbon stock methodologies and estimates developed previously in GTR-NE-343. These estimates are based on results from the Forest Vegetation Simulator.

  • The Forest Vegetation Simulator (FVS) is a suite of software incorporating forest growth simulation modeling that can quantify vegetation change and carbon flux in response to natural succession, disturbances, and management.

Carbon Resources

Forest Service Research and Development factsheets on carbon:

Other resources:

 

https://www.fs.usda.gov/managing-land/sustainability-and-climate/carbon