Forest Carbon

Forest growth provides and important carbon sink. As the National Climate Assessment reports, the amount of carbon taken up by U.S. land is dominated by forests, which have annually absorbed 7% to 24% of fossil fuel carbon dioxide (CO2) emissions in the U.S. over the past two decades. The efficient management of forests for carbon sequestration is closely related to sustainable and ecological forestry practices that use nature as a model.

As the Forest Guild notes, forests and forest products capture and store about 10 percent of all annual U.S. carbon emissions and could capture and store additional amounts by increasing excellent forestry practices. Carbon management on existing forests can include practices that increase forest growth, such as fertilization, irrigation, switching to fast-growing planting stock, shorter rotations, and weed, disease, and insect control. In addition, forest management can increase average forest carbon stocks by increasing the interval between harvests, by decreasing harvest intensity, or by focused density/species management. Mitigating climate change by enhancing forest carbon sequestration is increasingly acknowledged to be a relatively low-cost option and would likely yield other environmental benefits. However, forest carbon sequestration faces challenges: measuring the additional carbon stored (over and above what would occur naturally); monitoring and verifying the results; and preventing leakage.

A variety of models can be used for estimating carbon level changes. The two basic approaches are:

  • a “land-based” approach, which begins by identifying the acceptable activities for sequestering carbon and estimating the carbon consequences of those activities, and then monitors the lands to determine the extent to which those activities occur; and
  • an “activity-based” approach, which also begins by identifying the acceptable activities for sequestering carbon and estimating the carbon consequences of those activities, and then monitors the activities to determine the extent to which those activities occur.

The approach taken affects the intensity and spatial scale of the monitoring required, and different models impose different requirements for data, boundary conditions, carbon stocks, and more. However, the Intergovernmental Panel on Climate Change contends that, regardless of the approach and model, “a well-designed carbon accounting system would provide transparent, consistent, comparable, complete, verifiable, and efficient recording and reporting of changes in carbon stocks and/or changes in greenhouse gas emissions by sources and removals by sinks from applicable land use, land-use change, and forestry activities and projects” is necessary to properly quantify gains in forest carbon management. Fortunately, numerous tools and guidance are being developed to support these efforts throughout the United States.

Discussing emergent best practices in forest carbon emissions reductions, Nature4Climate describes numerous “pathways” in forest management that can lead to significant greenhouse gas reductions.  These include avoided conversion, reforestation, and improved forest management. By identifying carbon mitigation management opportunities across biomes, land trusts can connect emerging best practices to long-standing stewardship approaches to further conservation objectives locally that yield critical global carbon reduction achievements.

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