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). These data were gathered as part of the Hubbard Brook
Ecosystem Study (HBES). The HBES is a collaborative effort at
the Hubbard Brook Experimental Forest, which is operated and
maintained by the USDA Forest Service, Northern Research
Station.