![[logo] US EPA](http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
Representative Carbon Sequestration Rates and Saturation Periods for Key Agricultural & Forestry Practices |
 |
Activity |
Representative carbon sequestration rate in U.S.(Metric tons of C per acre per year) |
Time over which sequestration may occur before saturating (Assuming no disturbance, harvest or interruption of practice) |
References |
Afforestation a) |
0.6 – 2.6 b) |
90 – 120+ years |
Birdsey 1996 |
Reforestation c) |
0.3 – 2.1 d) |
90 – 120+ years |
Birdsey 1996 |
Changes in forest management |
0.6 – 0.8 e) |
If wood products included in accounting, saturation does not necessarily occur if C continuously flows into products |
Row 1996 |
0.2 f) |
IPCC 2000 |
||
Conservation or riparian buffers |
0.1 – 0.3 g) |
Not calculated |
Lal et al. 1999 |
Conversion from conventional to reduced tillage |
0.2 – 0.3 h) |
15 – 20 years |
West and Post 2002 |
0.2 i) |
25 – 50 years |
Lal et al. 1999 |
|
Changes in grazing land management |
0.02 – 0.5 j) |
25 – 50 years |
Follet et al. 2001 |
Biofuel substitutes for fossil fuels |
1.3 – 1.5 k) |
Saturation does not occur if fossil fuel emissions are continuously offset |
Lal et al. 1999 |
| a) | Values are for average management of forest after being established on previous croplands or pasture. |
| b) | Values calculated over 120-year period. Low value is for spruce-fir forest type in Lake States; high value for Douglas Fir on Pacific Coast. Soil carbon accumulation included in estimate. |
| c) | Values are for average management of forest established after clearcut harvest. |
| d) | Values calculated over 120-year period. Low value is for Douglas Fir in Rocky Mountains; high value for Douglas Fir in Pacific Coast. No accumulation in soil carbon is assumed. |
| e) | Select examples, calculated over 100 years. Low value represents change from 25-year to 50-year rotation for loblolly pines in Southeast; high value is change in management regime for Douglas Fir in Pacific Northwest. Carbon in wood products included. |
| f) | Forest management here encompasses regeneration, fertilization, choice of species and reduced forest degradation. Average estimate here is not specific to U.S., but averaged over developed countries. |
| g) | Assumed that carbon sequestration rates are same as average rates for lands under USDA Conservation Reserve Program. |
| h) | Estimates include only conversion from conventional to no-till for all cropping systems except for wheat-fallow systems, which may not produce net carbon gains. Estimates of changes in other greenhouse gases not included. |
| i) | Assumed that average carbon sequestration rates are same for conversion from conventional till to no-till, mulch till or ridge till. Estimates of changes in other greenhouse gases not included. |
| j) | See Improve/Intensify Management section in Table 16.1 of Follett et al. (2001). Low end is improvement of rangeland management; high end is changes in grazing management on pasture, where soil organic carbon is enhanced through manure additions. Estimates of flux changes in other greenhouse gases not included. |
| k) | Assumes growth of short-rotation woody crops and herbaceous energy crops, and that burning this biomass offsets 65-75% of fossil fuel in CO2 emissions. Estimates of changes in other greenhouse gases not included. |
Full reference citations:
Birdsey, R.A. (1996) Regional Estimates of Timber Volume and Forest Carbon for Fully Stocked Timberland, Average Management After Final Clearcut Harvest. In Forests and Global Change: Volume 2, Forest Management Opportunities for Mitigating Carbon Emissions, eds. R.N. Sampson and D. Hair, American Forests, Washington, DC.
Lal, R., J.M. Kimble, R.F. Follett and C.V. Cole (1999) The Potential of U.S. Cropland to Sequester Carbon and Mitigate the Greenhouse Effect. Lewis Publishers.
Follett, R.F., J.M. Kimble and R. Lal (2001) The Potential of U.S. Grazing Lands to Sequester Carbon and Mitigate the Greenhouse Effect, Lewis Publishers.
IPCC (2000) Special Report on Land Use, Land-Use Change, and Forestry, R.T. Watson et al. (eds.), Intergovernmental Panel on Climate Change, Cambridge University Press, p. 184.
West, T.O. and W.M. Post (2002) Soil Carbon Sequestration by Tillage
and Crop Rotation: A Global Data Analysis. Soil Science Society of America
Journal. Available at DOE CDIAC site.