Carbon Dynamics with Links to Growth and Mortality of Trees and Ground Vegetation

The functioning of boreal forest ecosystems is based on the ecosystem structure and functioning, which involves carbon cycling through its uptake in photosynthesis to retention in biomass and soil organic matter. Atmospheric carbon is bound in the ecosystem through the growth of biomass, which synthesizes new tissue in trees and ground vegetation. Soil carbon input includes litter, exudates from roots and mycorrhizal fungal mycelia, and bodies of the soil biota. In decay, litter is converted into partly decayed organic matter and further humus. The difference between gross primary production (GPP) and autotrophic respiration (RA) yields the net primary production (NPP), the rate at which energy and carbon are accumulated and maintained in the form of mass in trees and other green plants. NPP declines in aging trees, i.e., GPP declines more rapidly than the increase in RA. Finally, carbon departs the ecosystem in carbon dioxide emitted into the atmosphere and in dissolved in surface and ground water flows.