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

Timing of spring leaf-out of red maple and sugar maple
saplings experiencing combinations of soil warming and winter
freeze-thaw cycles was assessed weekly in 2014 and 2015 from
late April (when growing season warming began) through early
June when leaves were fully expanded. 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.