Carbon Pools and Fluxes in Southern Appalachian Forests

An estimated 35 percent of the global terrestrial carbon is stored in soil and biotic carbon pools, such as forests. These pools can store or release carbon. Because forests store immense amounts of carbon, forest management is becoming part of efforts to increase carbon sequestration and mitigate greenhouse gas emissions. Long-term research from the USDA…  More 

Black Locust & Drought

With its symbiotic bacteria, black locust (Robinia pseudoacacia) makes its own nitrogen fertilizer – and can share it with other tree species. “In early successional temperate forests, symbiotic nitrogen fixation is often the main source of new nitrogen,” says USDA Forest Service scientist Chelcy Miniat. But drought could slow the rate of symbiotic nitrogen fixation,…  More 

Forests, Farms, or Houses?

Molecules relentlessly cycle from one form to another. “Simple human activities, such as building homes, can affect these cycles,” says U.S. Forest Service research soil scientist Jennifer Knoepp. For example, trees growing near streams affect the way nitrogen and other nutrients move from the land to the water. “Riparian zones play a critical role in…  More 

Chemical Clues to a Forest’s Past in Nitrogen Isotope Ratios

From the depths of the soil to the top of the atmosphere, nitrogen is everywhere. It is also indispensable to plants and animals. The vast majority of nitrogen atoms contain the same number of uncharged particles. However, a few atoms are ‘stable’ isotopes that have one extra uncharged particle. Although the extra particle adds a miniscule…  More