Forest carbon sequestration changes in response to timber harvest

Forest succession contributes to the global terrestrial carbon (C) sink, but changes in C sequestration in response to varied harvest intensities have been debated. The forests of the Central Appalachian region have been aggrading over the past 100 years following widespread clear-cutting that occurred in the early 1900s and these forests are now valuable timberlands. This study compared the history of ecosystem C storage in four watersheds that have been harvested at different frequencies and intensities since 1958. We compared NPP. NEP, and component ecosystem C fluxes (g C m(-2) year(-1)) in response to the four different harvest histories (no harvest, clear-cutting, single tree selection cutting, and 43 cm diameter-limit cutting) Clear-cutting had short-term negative effects on NEP but harvest did not significantly impact long-term average annual C sequestration rates. Average plant C (g C m(-2)) since 1950 was about 33% lower in response to a clear-cut event than plant C in an un-harvested forest, Suggesting that the C sequestration associated with clear-cutting practices would decline over time and result in lower C storage than diameter-limit cut, selective cut, or un-harvested forests. Total C stored over a 55-year period was stimulated similar to 37% with diameter-limit cutting and selective Cutting relative to un-harvested forests. (C) 2009 Elsevier B.V. All rights reserved