Hubbard Brook Experimental Forest: Soil Freezing Study (SFS) In Situ Measurements of Snow and Soil Frost Depth

Climate models for the northeastern United States (U.S.) over the next
century predict an increase in air temperature between 2.8 and 4.3 °C
and a decrease in the average number of days per year when a snowpack
will cover the forest floor (Hayhoe et al. 2007, 2008; Campbell et al.
2010). Studies of forest dynamics in seasonally snow-covered
ecosystems have been primarily conducted during the growing season,
when most biological activity occurs. However, in recent years
considerable progress has been made in our understanding of how winter
climate change influences dynamics in these forests. The snowpack
insulates soil from below-freezing air temperatures, which facilitates
a significant amount of microbial activity. However, a smaller
snowpack and increased depth and duration of soil frost amplify losses
of dissolved organic C and NO3- in leachate, as well as N2O released
into the atmosphere. The increase in nutrient loss following increased
soil frost cannot be explained by changes in microbial activity alone.
More likely, it is caused by a decrease in plant nutrient uptake
following increases in soil frost. We conducted a snow-removal
experiment at Hubbard Brook Experimental Forest to determine the
effects of a smaller winter snowpack and greater depth and duration of
soil frost on trees, soil microbes, and arthropods. A number of publications have been based on these data: Comerford et al. 2013,
Reinmann et al. 2019, Templer 2012, and Templer et al. 2012. 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. Campbell JL, Ollinger SV, Flerchinger GN, Wicklein H, Hayhoe K, Bailey AS. Past and projected future changes in snowpack and soil frost at the Hubbard Brook Experimental Forest, New Hampshire, USA. Hydrological Processes. 2010; 24:2465–2480. Comerford DP, PG Schaberg, PH Templer, AM Socci, JL Campbell, and KF
Wallin. 2013. Influence of experimental snow removal on root and
canopy physiology of sugar maple trees in a northern hardwood forest.
Oecologia 171:261-269. Hayhoe K, Wake CP, Huntington TG, Luo LF, Schwartz MD, Sheffield J, et al. Past and future changes
in climate and hydrological indicators in the US Northeast. Climate Dynamics. 2007; 28:381–407. Hayhoe, K., Wake, C., Anderson, B. et al. Regional climate change projections for the Northeast USA.
Mitig Adapt Strateg Glob Change 13, 425–436 (2008). https://doi.org/10.1007/s11027-007-9133-2. Reinmann AB, J Susser, EMC Demaria, PH Templer. 2019. Declines in northern forest tree growth
following snowpack decline and soil freezing.  Global Change Biology 25:420-430. Templer PH. 2012. Changes in winter climate: soil frost, root injury,
and fungal communities (Invited). Plant and Soil 35: 15-17 Templer PH , AF Schiller, NW Fuller, AM Socci, JL Campbell, JE Drake,
and TH Kunz. 2012. Impact of a reduced winter snowpack on litter
arthropod abundance and diversity in a northern hardwood forest
ecosystem. Biology and Fertility of Soils 48:413-424.