Carbon based energy sources like coal, gas, and oil all originated from the conversion of

sunlight energy by plants. A dominant consideration for rebalancing the global carbon

cycle is to find ways to promote the increased growth of trees and shrubs. Agricultural

activities occur on approximately half of the land in the contiguous U.S., so much of the

opportunity to store carbon through afforestation will occur on farms and ranches. 

Agroforestry does not convert agricultural land to forests, but rather leaves land in production agriculture, while integrating trees into farm and ranch operations to accomplish 

economic, environmental, and social goals. Several agroforestry practices can lead to 

substantial storage of carbon and removal of atmospheric carbon dioxide:

Windbreaks – store carbon as they protect farmsteads, livestock, roads, people, soils, and

crops. Field windbreaks reduce evaporation and plant transpiration rates such that crop

yields per field are typically improved, even though a portion of the field has been converted to windbreaks. Optimal tree planting levels have been estimated at five percent of the

cropped field.

There are 185 million acres of tilled land in the Great/Central Plains. Planting only 2.5 

percent of this field area to 30-foot-wide tree windbreaks would span 1.3 million miles and

cover 4.6 million acres. As trees continue to grow, more carbon is stored. Carbon dioxide

removal, based on 20-year-old plantings, would exceed: 

80 million metric tons 

Additional CO2 reductions

would result from:

• Lower heating costs for 

farmstead homeowners 

• Lower cost of snow 

removal

• Reduced need for crop 

fertilizer 

• Lower feeding demands 

of winter livestock 

• Improved water use 

efficiency

W

Agroforestry: Using trees and shrubs to produce social, 

economic, and conservation benefits.

orking Trees

for Carbon Cycle Balance
Riparian Forest Buffers – Trees grow rapidly in riparian zones due to favorable moisture and nutrient conditions. When suitable trees and shrubs grow in these moist environments they also filter out excess nutrients,

pesticides, animal wastes, and sediments coming from adjacent agricultural or urban activities. 

• USDA has committed to planting 2,000,000 miles of conservation buffers. If one-fourth of these buffers 

were 100 foot wide forested riparian buffers, CO2 removal would exceed: 

110 million metric tons

Silvopasture – Timber/grazing systems managed on the same area of land can increase net carbon storage. In

areas like the Southeastern U.S., loblolly pine silvopasture systems are both economically and environmentally

attractive. When both the tree and grass components are properly managed, an increase in net carbon storage

versus pasture or forest alone, can be achieved. 

Short Rotation Woody Crops (SRWC) – Low prices for traditional crops have increased the interest of

farmers in fast-growing woody crops, like hybrid poplar trees, for fuel and fiber. These SRWC systems provide

a way of increasing on-farm income, while also being designed to treat agricultural, livestock, community, and

industrial wastes. The rapid growth of SRWC results in high rates of nutrient uptake and large amounts of carbon storage over rotation lengths as short as five to 15 years.

• SRWC systems increase on-farm income 

• SRWC systems can treat agricultural and municipal wastes 

• In the Pacific Northwest, 10-year-old irrigated plantations remove 180 to 330 metric tons of CO2 per acre

• Soil carbon levels during the first rotation increased by 40 or more tons per acre

• Net carbon benefits are realized if the wood fiber is used for solid wood products or fuel

References

Brandle, J.R., T.D. Wardle, and G.F. Bratton 1992. Opportunities to Increase Tree Planting in Shelterbelts and the Potential Impacts on

Carbon Storage and Conservation. In: Sampson, R.N. and D. Hair (eds.) Forests and Global Change, Vol. 1: Ch. 9. American Forests,

Washington D.C.

U.S. Dept. of Energy 1999. Carbon Sequestration, State of Science. Draft Report. Ch. 4: Carbon Sequestration in Terrestrial Ecosystems.

29 pgs.

Estimated Carbon Dioxide Removal in 35-year-old Loblolly Pine Stand

Metric tons CO2 per acre

(To convert CO2 to C, divide by 3.67)

Forest* Grassland* Silvopasture** 

Plant Carbon 345 180 525

Soil Carbon 176 345 261 

Total 521 525 786 

* U.S. Department of Energy 1999. 

**Louisiana State University, Hill Farm Research Station 1999.

The USDA National Agroforestry Center (NAC) is a partnership of the Forest Service (Research and

Development and State and Private Forestry) and the Natural Resources Conservation Service. It is

administered by the Forest Service, Southern Research Station; and its program manager and headquarters are located in Huntsville, AL, on the campus of Alabama A&M University, while its research, clearinghouse, and technology transfer staff are concentrated in Lincoln, NE, at the University of Nebraska. NAC’s

purpose is to accelerate the development and application of agroforestry technologies to attain more economically, environmentally, and socially sustainable land use systems. To accomplish its mission, NAC

interacts with a national network of partners and cooperators to conduct research, develop technologies

and tools, establish demonstrations, and provide useful information to natural resource professionals.

A partnership of