Climate Change Across Seasons Experiment (CCASE) Sapling Study at the Hubbard Brook Experimental Forest: Photosynthesis

Rates of leaf-level photosynthesis of red maple and sugar maple saplings
experiencing combinations of soil warming and winter freeze-thaw cycles was
measured biweekly on fully expanded, intact leaves from June through August 2014
and June through September 2015 using a LI-6400.

There were seven treatments for each species of maple. For each species, ten saplings experienced ambient
temperatures (reference), ten experienced growing season warming with no induced freeze-thaw cycles in
winter (warmed), ten in each of four groups experienced warming in the growing season coupled with two, four,
six, or eight soil freeze-thaw cycles in winter (warmed + 2 FTC, warmed + 4 FTC, warmed + 6 FTC, warmed + 8 FTC),
and ten experienced snow removal in winter with ambient temperatures in the growing-season (snow removal).