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Soil Warming Experiments

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Models of climate change predict a global mean temperature increase of 2-5°C during the next century.

Our longest-running soil warming experiment assesses forest response to warming with an emphasis on soil processes (e.g., decomposition, trace gas fluxes) that could alter ecosystem function, atmospheric chemistry, and global climate.

Initial treatments included:

  • soil temperature raised 5°C above ambient with heated cables
  • soils with cables but no heating (disturbance control)
  • control plots

Fluxes of soil gases (CH4, N2O, and CO2) and N availability have been measured monthly since initiation of the project in 1991.

In 2003 we added two large (30x30m) plots (heated and control) to this experiment in order to evaluate the effect of warming on tree root processes.

In 2006, we added 24 3x3m plots, each assigned one of four experimental treatments with six replicates per treatment: control, warming (5°C above ambient with heated cables), nitrogen addition (applied in equal doses during the May – October growing season as an aqueous solution of NH4NO3 at a rate of 50 kg N per hectare per year), and warming x nitrogen. 

These projects are supported by the Harvard Forest Long-Term Ecological Research Program.