skip to main content


Title: Hubbard Brook Experimental Forest: Soil Freeze Study - Tree Growth
The climate is changing in many temperate forests with the amount of forest area dominated by sugar maple experiencing an insulating snowpack expected to shrink between 49 and 95% compared to 1951-2005 values. A reduced snowpack and increased depth and duration of soil frost can injure or kill fine roots, which are essential for plant water and nutrient uptake. These adverse impacts on tree roots can have important impacts on tree growth and ecosystem carbon sequestration. We evaluated the effects of changing winter climate, including snow and soil frost dynamics, by using tree cores to measure sugar maple radial growth rates in the Soil Freezing Study plots at the Hubbard Brook Experimental Forest. 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. Analysis of these data are published in: Reinmann AB, Susser JR, Demara EMC, and Templer PH. 2019. Declines in northern forest tree growth following snowpack decline and soil freezing. Global Change Biology. 25(2):420-430. https://doi.org/10.1111/gcb.14420  more » « less
Award ID(s):
1637685
NSF-PAR ID:
10316991
Author(s) / Creator(s):
; ;
Publisher / Repository:
Environmental Data Initiative
Date Published:
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. 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. 
    more » « less
  2. Abstract

    Changes in growing season climate are often the foci of research exploring forest response to climate change. By contrast, little is known about tree growth response to projected declines in winter snowpack and increases in soil freezing in seasonally snow‐covered forest ecosystems, despite extensive documentation of the importance of winter climate in mediating ecological processes. We conducted a 5‐year snow‐removal experiment whereby snow was removed for the first 4–5 weeks of winter in a northern hardwood forest at the Hubbard Brook Experimental Forest in New Hampshire,USA. Our results indicate that adverse impacts of reduced snowpack and increased soil freezing on the physiology ofAcer saccharum(sugar maple), a dominant species across northern temperate forests, are accompanied by a 40 ± 3% reduction in aboveground woody biomass increment, averaged across the 6 years following the start of the experiment. Further, we find no indication of growth recovery 1 year after cessation of the experiment. Based on these findings, we integrate spatial modeling of snowpack depth with forest inventory data to develop a spatially explicit, regional‐scale assessment of the vulnerability of forest aboveground growth to projected declines in snowpack depth and increased soil frost. These analyses indicate that nearly 65% of sugar maple basal area in the northeastern United States resides in areas that typically experience insulating snowpack. However, under theRCP4.5 and 8.5 emissions scenarios, we project a 49%–95% reduction in forest area experiencing insulating snowpack by the year 2099 in the northeastern United States, leaving large areas of northern forest vulnerable to these changes in winter climate, particularly along the northern edge of the region. Our study demonstrates that research focusing on growing season climate alone overestimates the stimulatory effect of warming temperatures on tree and forest growth in seasonally snow‐covered forests.

     
    more » « less
  3. Soil atmosphere fluxes of the trace gases; carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) have been measured at several locations at the Hubbard Brook Experimental Forest (HBEF) including 1) the “freeze” study reference plots that provide contrast between stands dominated (80%) by sugar maple versus yellow birch and low and high elevation areas, 2) the Bear Brook Watershed where trace gas sampling is coordinated with long-term monitoring of microbial biomass and activity and 3) watershed 1 where trace gas sampling locations were co-located with long-term microbial biomass and activity monitoring sites that are located near a subset of the lysimeter sites established for the calcium addition study on this watershed. This dataset contains the Freeze study data. Watershed 1 and Bear Brook trace gas data can be found in: https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-hbr&identifier=116. 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. These data have been published in: Groffman, P. M., Hardy, J. P., Driscoll, C. T., & Fahey, T. J. (2006). Snow depth, soil freezing, and fluxes of carbon dioxide, nitrous oxide and methane in a northern hardwood forest. Global Change Biology, 12, 1748–1760. 
    more » « less
  4. In 1997, as part of a study of the relationships between snow depth, soil freezing and nutrient cycling (http://www.ecostudies.org/people_sci_groffman_snow_summary.html), we established eight 10 x 10-m plots located within four stands; two dominated (80%) by sugar maple and two dominated by yellow birch, with one snow reduction (freeze) and one reference plot in each stand. In 2001, we established eight new 10-m x 10-m plots (4 treatment, 4 reference) in four new sites; two high elevation, north facing and two low elevation, south facing maple-beech-birch stands. To establish plots for the “freeze” study, we cleared minor amounts of understory vegetation from all (both freeze and reference) plots (to facilitate shoveling). We then installed soil solution samplers (zero tension lysimeters), thermistors for soil temperature monitoring, water content (time domain) reflectometers (for measuring soil moisture), soil atmosphere sampling probes, minirhizotron access tubes, and trace gas flux measurement chambers (described below). All plots were equipped with dataloggers to allow for continuous monitoring of soil moisture and temperature. Treatments (keep plots snow free by shoveling through the end of January) were applied in the winters of 1997/98, 1998/99, 2002/2003 and 2003/2004. Measurements of soil nitrate (NO3 -) and ammonium (NH4 +) concentrations, microbial biomass carbon (C) and nitrogen (N) content, microbial respiration, potential nitrification and N mineralization rates, pH, and denitrification potential were measured on these plots at multiple time points during these studies. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES) using funding from the U.S. National Science Foundation. 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. 
    more » « less
  5. The valley-wide plots are a grid of 431 sites along fifteen N–S transects established at 500-m intervals spanning the entire Hubbard Brook Valley. The plot network was designed by Paul Schwarz for spatial analysis of tree species distribution patterns within the valley. Multiple above- and below-ground attributes have been measured on these plots. This dataset includes forest inventory data at 10 year intervals, for 1995, 2005, and 2015. The full survey takes three seasons to complete, with the datatable listing the exact measurement interval for each tree. Data are included for both trees and saplings on 371 core plots (all surveys) and 60 densified plots (1998, 2008). Locations of plots in this study can be found in the following dataset: Hubbard Brook Experimental Forest Valleywide Plots: GIS Shapefile (2022.) https://doi.org/10.6073/pasta/440b176372e0cdeb341731aea816b67c 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. These data have been used in a number of publications including: Schwarz, P.A., Fahey, T.J., Martin, C.W., Siccama, T.G., and Bailey, A. 2001. Structure and composition of three northern hardwood–conifer forests with differing disturbance histories. For. Ecol. Manage. 144(1–3): 201–212. doi:10.1016/S0378-1127(00)00371-6. Schwarz, P.A., Fahey, T.J., and McCulloch, C.E. 2003. Factors controlling spatial variation of tree species abundance in a forested landscape. Ecology, 84(7): 1862–1878. doi:10.1890/0012-9658(2003)084[1862:FCSVOT]2.0.CO;2. van Doorn, N.S., Battles, J.J., Fahey, T.J., Siccama, T.G., and Schwarz, P.A. 2011. Links between biomass and tree demography in a northern hardwood forest: a decade of stability and change in Hubbard Brook Valley, New Hampshire. Can. J. For. Res. 41(7): 1369–1379. doi:10.1139/X11-063. Cleavitt, NL; AB Clyne and TJ Fahey. 2019. Epiphytic macrolichen patterns along an elevation gradient in the White Mountain National Forest, New Hampshire. J. Torrey Bot. Soc. 146(1): 8-17. Cleavitt, NL; Battles, JJ, Fahey, TJ, and Blum, J. 2014. Determinants of survival over seven years for a natural cohort of sugar maple seedlings in a northern hardwood forest. Can. J. For. Res.44 (9): 1112-1121. 
    more » « less