Northern Forest Futures Project

Global Carbon Cycles

[image:] Birch logs bundled for firewood

Maintenance of Forest Contribution to Global Carbon Cycles

People rely on forests, directly and indirectly, for a wide range of goods and services. Measures of forest productive capacity are indicators of the ability of forests to sustainability supply goods and services over time. An ongoing focus on maintaining productive capacity of forests can help ensure that the use of forest resources does not impair long term forest productivity even though the goods and services expected from forests may change over time due to social, economic, or technological trends.


Key Findings

  • Forests sequester large amounts of carbon in soil organic matter and in the wood of living trees.
  • As new forests grow over time the amount of sequestered carbon rapidly increases and then the rate of increase levels off as forests mature.
  • The total amount of sequestered carbon in U.S. forests is equal to approximately 27 years of carbon dioxide emissions for the United States.
  • The annual net increase in carbon sequestered in U.S. forests from tree growth is equivalent to about 10 percent of the annual emissions of carbon dioxide and associated greenhouse gasses.
  • When trees are harvested and converted to wood products, the carbon in those products remains sequestered until the products eventually decompose or are burned.
  • Using woody biomass to replace fossil fuels for energy production avoids the release of carbon from the fossil fuels that would be used instead and creates opportunities for carbon sequestration if the harvested forests are regenerated.
  • In 2007, the equivalent of 2 percent of the energy consumed in the U.S. came from wood combustion by industrial (1.3 percent), residential (0.4 percent), utility (0.2 percent), and other (0.1 percent) users.
  • Less than 1 percent of U.S. electric power is generated from wood.

From Forests of the Northern United States, NRS-GTR-90, 2012.

Indicators

Number Indicator Current condition ratinga Recent trend condition ratinga Rating explanation
18 Carbon sequestered
in forests
    The quantity of sequestered carbon in forests generally increases as the volume of live trees increases. The volume of timber in the region has increased substantially in the past 50 years. (See also Wood volume, item 10.)
19 Carbon sequestered in
forest products
    Carbon is sequestered in forest products. Regionally about 1.5 billion cubic feet of wood is converted annually to long-lived products. Another 0.9 billion cubic feet is used to produce pulp and paper products. This is a substantial quantity of wood products and associated sequestered carbon, but it is below the region’s capacity. Since 1986, the annual volume of roundwood products has decreased. (See also Wood volume and Wood growth and removals, items 10 and 11.)
20 Using woody
biomass for energy
    Annually about 0.6 billion cubic feet of wood harvested in the region is used for fuelwood (including residential heating). This is a small part of the region’s energy needs, but utilization of woody biomass for energy is increasing. Use of fuelwood often offsets consumption of fossil fuels that would be used instead.



Highly Positive 


Positive 


Neutral 


Negative 


Highly Negative 


Comments

Maps and Figures

[map:] When and where carbon occurs in a typical forest
When and where carbon occurs in a typical forest—a composite summary for all northern forests showing average carbon by forest age and forest component; note that about 16 percent of live tree carbon is coarse roots
[map:] Aboveground live tree biomass for Northern States
Aboveground live tree biomass for Northern States
[map:] Location and amount of avoided carbon dioxide emissions from electric utilities that were using wood as a power source, 2007, based on expected emissions from using coal.
Location and amount of avoided carbon dioxide emissions from electric utilities that were using wood as a power source, 2007, based on expected emissions from using coal.

For additional detail, see Criterion 5: Maintenance of forest contributions to global carbon cycles in the Forests of the Northern United States.