Forests, wetlands and other ecosystems in the eastern United States naturally store close to 15 percent of the national emissions each year, a study finds.

The U.S. Geological Survey published a study showing eastern ecosystems can store 1.1 billion tons of carbon dioxide each year. That's about 15 percent of what the Environmental Protection Agency estimates the country emits each year, or roughly the annual emissions from U.S. automobiles.

"This landmark study by the U.S. Geological Survey provides yet another reason for being good stewards of our natural landscapes, as ecosystems play a critical role in removing harmful carbon dioxide from the atmosphere that contributes to climate change," U.S. Interior Secretary Sally Jewell said in a statement Wednesday.

The USGS report finds the eastern United States accounts for just under 40 percent of the total U.S. landmass but stores more carbon in its ecosystems than rest of the Lower 48 states combined.

Wetlands, which cover 9 percent of the eastern United States, accounted for about 13 percent of the carbon sequestration. Agricultural areas cover 31 percent of the eastern part of the country and stores 4 percent, the study finds.

Forested lands stored the most carbon through natural processes, though the USGS said that natural carbon sink may decline because of changes in land use.

Carbon sequestration is the process where CO2 is removed from the atmosphere and stored as carbon in vegetation, soils and sediment.