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Harvard Forest Symposium Abstract 2010

  • Title: The effect of soil warming on the decomposition of woody debris
  • Primary Author: Minda Berbeco (Tufts University)
  • Additional Authors: Jerry Melillo (Marine Biological Laboratory); Colin Orians (Tufts University)
  • Abstract:

    Woody debris is a recalcitrant carbon pool, storing carbon in complex molecules for extended periods of time. It has been shown that temperature and moisture are major drivers in decomposition from this pool. Additionally, under certain circumstances, both species and size can influence decomposition. It is not known, however, how the woody debris carbon pool in the moist, temperate forests of New England will respond to climate change, specifically soil warming. An increase in decomposition of woody debris could cause a pulse of carbon dioxide to exit the forest thus greatly reducing its storage potential.

    We looked at the decomposition of woody debris after two years under a soil warming scenario using the soil warming plots at Harvard Forest in Central Massachusetts. We placed debris of two size classes (2 cm diameter and 4 cm diameter) and four New England tree species (Tsuga canadensis, Quercus rubra, Acer Saccharum and Betula lenta) in the soil warming and control plots and measured mass loss over two years ending in the Fall of 2009.

    We found a significant effect of warming on decomposition across all four species of woody debris and the two size classes. Though warming drove decomposition to be faster in all species, there remained a species difference independent of treatment, with the more recalcitrant species, T. Canadensis and Q. rubra, losing less mass over time. In addition, though there was a trend for both the smaller and larger debris having a higher moisture content in the soil warming plots, no statistical difference was seen between the two plots. Overall, the smaller debris held more moisture independent of treatment. These results suggest that soil warming could result in an increase in decomposition of woody debris across species and size.

  • Research Category: Large Experiments and Permanent Plot Studies
    Soil Carbon and Nitrogen Dynamics