Effect of Fertilization on Carbon in Boreal Ecosystems

In boreal forest ecosystems, carbon and nitrogen cycles interact with impacts on carbon sink/source processes and balance between above- and belowground carbon stocks. The addition of nitrogen increases primary production in the above- and belowground organs of trees and ground vegetation, with a consequent increase of carbon in the ecosystem. The carbon stocks in soil are also linked to plant growth through the subsequent input of aboveground plant/tree litter (e.g., litter from foliage and branches) onto the soil surface and of root litter (e.g., coarse roots, fine roots) deeper within the soil profile. On the other hand, nitrogen addition may reduce the decay of organic compounds by reducing microbial activity. This reduces carbon dioxide emissions (efflux) from soil, thus increasing soil carbon stocks.