hubbard brook experimental forest conclusion

The Experimental Forest Where Scientists First Recognized Acid Rain

A patch of new hampshire woods has served as a living laboratory since 1955..

Nestled in the White Mountains of New Hampshire is a forest. It sits in its own little valley, full of wispy birch trees, beeches, and grand sugar maples. The skies are a cobalt blue and cold, clear streams run down into a small, mirror-like lake. It might seem like a great place for a hike.

But if you do go there one day, you might notice a few mysterious things out in those New Hampshire woods—trees dotted with tiny metal tags that jingle like the collars of a pack of dogs; someone off in the distance, shovelling snow from a seemingly nondescript patch of forest floor; a handful of trees coated in ice, as if just hit by the world’s most specific blizzard.

All of these seemingly mysterious goings-on have a purpose. Because this isn’t just a patch of woods. It’s the Hubbard Brook Experimental Forest—a 63-year-old, 7,800-acre living laboratory that’s helping scientists understand the world around us.

“We currently have about 60 different collaborators at Hubbard Brook,” says site manager Ian Halm. The collaborators are working on a wide variety of projects, from learning and monitoring how nutrients move through an ecosystem, to tracking animal populations over time, to learning how northern forests might respond to events like drought or climate change.

A forester by training, Halm’s been working here since 1990. His office is full of moose antlers he’s picked up while hiking or snowmobiling through the forest.

“Moose drop their antlers once a year,” says Halm, joking the animals always seem to drop them right in his path. “I have to pick them up, otherwise I’d trip on them.”

When he’s not picking up antlers, you might find Halm clearing away a fallen tree, plowing snow away from the roads, or helping set up and maintain the various data collectors, remote cameras, and wireless equipment the scientists depend upon.

“When I started it was all pretty manual, with strip charts and charts on drums,” says Halm. “Now it’s all electronic.” Every hour data is wirelessly uploaded to headquarters. And if something goes wrong, Halm knows almost immediately. Before, if something broke you might not know until you hiked up to check on it. “Now every morning we look at a computer screen.”

Not that that stops him from getting out into the forest. Halm’s favorite place, he says, is a gorge the brook runs through, with a good swimming hole at the bottom.

Though Hubbard Brook is open to the public (it’s technically part of the White Mountain National Forest), for more than 60 years, it’s primarily been a place of learning. In 1955, the U.S. Forest Service set it aside to study hydrology, ecology, and forest management and almost immediately, the site began to reveal surprises.

In 1963, a handful of scientists began to look at rain samples collected in the forest. It was immediately obvious something was wrong. The rain was incredibly acidic. One sample came back with a pH level roughly the same as vinegar. Eventually, the scientists were able to trace the cause back to industrial air pollution, and in 1972, they published their results in a scientific paper—the first official documentation of acid rain in North America. Their work would go on to spark public discussion and influence decision-makers and in 1990 President George H. W. Bush would amend the Clean Air Act to specifically address the dangers of acid rain.

Since then, scientists have continued to monitor water quality, air pollution, and a host of other variables in Hubbard Brook, accumulating decades of continuous data. A data set this old and complete makes Hubbard Brook extremely valuable from a scientific perspective.

“You really need to have places where you can look at long-term trends,” says Halm. A single year or two worth of data might be valuable, but if you want a complete picture of what’s been happening over the decades, you need decades worth of data. “It really helps us gauge what we’re doing to the environment.”

About 60 scientists, researchers, and students currently work at Hubbard Brook—including Boston University’s Dr. Pamela Templer.

Templer has her own set of experiments at Hubbard Brook. In one spot of the woods, not too far away from the red wooden headquarters, Templer and her team are using snow shovels and heating cables to study not acid rain, but another important long-term trend that may be affecting our forests: climate change.

“The idea was to create conditions that the forests are likely to experience in the coming century,” says Templer. Studies have predicted the Northeast may warm by as much as 10 degrees Fahrenheit by 2080 , which could result in warmer growing seasons and less winter snow cover. By using the buried cables like underground space heaters to warm the soil and by manually clearing away the snow, Templer is simulating that warmer future world.

In previous experiments at Hubbard Brook, Templer found a potentially surprising nugget of information—less snow might actually make frosts worse . It turns out, the blanket of snow can act like an igloo, protecting the soil (and tree roots) from the freezing air.

“So in a world where you have less snow, you might actually end up with colder winter soils,” says Templer. Her team’s work, combined with monitoring the trees health and productivity, make up an experiment known as CCASE, which stands for Climate Change Across Seasons Experiment .

Many of the experiments, like Templer’s, purposefully manipulate aspects of the forest in order to learn more information, but there are also more observational studies, such as water quality sampling and the monitoring animal populations. “Forests provide a whole suite of wonderful resources for us, including clean water, clean air, habitat for animals and plants,” says Templer. We need to know how they might change in the future if we want to preserve and manage them. Whether through logging, urbanization, or climate change, humans have been making an impact. Now we need to understand the true extent of it, and the Hubbard Brook Experimental Forest is one place to find out.

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Hubbard Brook Experimental Forest

The Hubbard Brook Experimental Forest was established in 1955 as a major center for hydrologic research in New England. Located in the White Mountain National Forest in central New Hampshire, the 3,138-ha bowlshaped Hubbard Brook Valley has hilly terrain, ranging in elevation from 222 to 1,015 m. The Hubbard Brook Ecosystem Study was established by a cooperative agreement in 1963. In 1988 the Hubbard Brook was designated as a Long-Term Ecological Research site by the National Science Foundation.

Annual precipitation at Hubbard Brook averages about 1,400 mm, with one-third to one-quarter as snow. The month of January averages about -9 °C and the average July temperature is 18 °C. The average number of days without killing frost is 145. The estimated annual evapotranspiration is about 500 mm.

Soils at the Hubbard Brook are predominantly welldrained Spodosols (Typic Haplorthods) derived from glacial till, with sandy loam textures. They are acidic (pH about 4.5 or less) and relatively infertile (base saturation of mineral soil ~ 10 percent). Soil depths, including unweathered till, average about 2.0 m surface to bedrock, though this is highly variable. Depth to the C horizon averages about 0.6 m. At various places, the C horizon exists as an impermeable pan.

The present second-growth forest is even-aged and composed of about 80 to 90 percent northern hardwoods and 10 to 20 percent spruce-fir.

Facilities Information

The Robert S. Pierce Ecosystem Laboratory located at Hubbard Brook provides 835 m2 of space, including six offices, four laboratories, a conference room, six dormitory rooms, and a kitchen, baths, and showers. There is also a sample archive building and maintenance, storage, garage, and shop facilities.

Lat. 43°56′ N, long. 71°45′ W

Visitor Information

Contact information.

Hubbard Brook Experimental Forest USDA Forest Service Northern Research Station 271 Mast Road Durham, NH 03824

Contact: Lindsey Rustad

Research, Past and Present

At Hubbard Brook, the following topics are being studied:

• The role of calcium supply in regulating the structure and function of base-poor forest and aquatic ecosystems
• Animal populations and communities
• Colder soils in a warmer world: a snow manipulation in a northern hardwood forest ecosystem
• Stream ecosystems
• A spatial model of soil parent material
• Modeling effects of acid deposition, forest disturbance, and soil chemistry on forest production and streamwater quality
• Remote sensing for measurement of canopy nitrogen and calcium content, and estimation of forest production and stream chemistry
• Landscape-scale controls on N retention and N gas fluxes in the Hubbard Brook Valley
• Nutrient uptake at the ecosystem scale
• Carbon and calcium controls on microbial biomass and invertebrate grazers
• Comparison of δ 15N and nitrification potential across a nitrate-loss gradient
• Response of northern hardwood forests to nutrient perturbation
• Edaphic controls on the structure and function of the northern hardwood forest
• Vegetation dynamics and primary productivity

Major Research Accomplishments and Effects on Management

At Hubbard Brook, the following subjects have been researched:

• Small watershed technique for studying biogeochemistry
• Factors regulating nutrient flux and cycling in northern hardwood forests
• First documentation of acid rain in North America
• Effects of forest harvesting disturbance on water quality and quantity
• Long-term effects of acid rain on soil nutrient pools and streamwater chemistry
• Relationship of interior forest bird populations and communities to forest structure and development
• Development and application of ecosystem process models: 1) hydrological, 2) forest growth and development, and 3) soil nutrient processes

Research Opportunities

The Hubbard Brook staff welcomes new studies and collaboration on existing ones. There is a need for expanded cooperative research in the fields of soil physics and forest hydrology.

Key Personnel

Project leader, keith nislow, collaborators.

Scientists from other Forest Service research units

Institute of Ecosystem Studies

Brown University

Dartsmouth College

Syracuse University

Cornell University

University of Michigan

Yale University

Appalachian State University

State University of New York-Environmental Science and Forestry

USDI Geological Survey

Wellesley College

University of New Hampshire

Smithsonian Institution

Symphony of the Forest: WaterViz Camp Makes Science Accessible to All

Clearing the Air: Hubbard Brook’s Legacy in the Fight Against Acid Rain

Related programs.

Northern Forest Science and Applications

Publications.

• John L. Campbell, Lindsey E. Rustad, Scott W. Bailey, Emily S. Bernhardt, Charles T. Driscoll, Mark B. Green, Peter M. Groffman, Gary M. Lovett, William H. McDowell, Kevin J. McGuire, Emma J. Rosi. 2021. Watershed studies at the Hubbard Brook Experimental Forest: Building on a long legacy of research with new approaches and sources of data
• Mark B. Green, Linda H. Pardo, Scott W. Bailey, John L. Campbell, William H. McDowell, Emily S. Bernhardt, Emma J. Rosi. 2021. Predicting high‐frequency variation in stream solute concentrations with water quality sensors and machine learning
• Mahnaz Valipour, Chris E. Johnson, John J. Battles, John L. Campbell, Timothy J. Fahey, Habibollah Fakhraei, Charles T. Driscoll. 2021. Simulation of the effects of forest harvesting under changing climate to inform long-term sustainable forest management using a biogeochemical model
• John L. Campbell, Lindsey E. Rustad, Sarah Garlick, Noah Newman, John S. Stanovick, Ian Halm, Charles T. Driscoll, Brian L. Barjenbruch, Elizabeth Burakowski, Steven D. Hilberg, Kristopher J. Sanders, Jason C. Shafer, Nolan J. Doesken. 2020. A Comparison of Low-Cost Collector Configurations for Quantifying Ice Accretion
• Olivia L. Fraser, Scott W. Bailey, Mark J. Ducey, Kevin J. McGuire. 2020. Predictive modeling of bedrock outcrops and associated shallow soil in upland glaciated landscapes
• Christopher F. Hansen, Paul G. Schaberg, Allan M. Strong, Shelly A. Rayback, Gary J. Hawley. 2020. LiDAR Helps Differentiate Stand Health and Productivity Levels within a Northern Hardwood Forest
• Angela R. Possinger, Scott W. Bailey, Thiago M. Inagaki, Ingrid Kögel-Knabner, James J. Dynes, Zachary A. Arthur, Johannes Lehmann. 2020. Organo-mineral interactions and soil carbon mineralizability with variable saturation cycle frequency
• Sujit K. Sahu, K. Shuvo Bakar, Jinran Zhan, John L. Campbell, Ruth D. Yanai. 2020. Spatio-temporal Bayesian modeling of precipitation using rain gauge data from the Hubbard Brook Experimental Forest, New Hampshire, USA
• Craig R. See, Mark B. Green, Ruth D. Yanai, Amey S. Bailey, John L. Campbell, Jeremy Hayward. 2020. Quantifying uncertainty in annual runoff due to missing data
• Geoffrey Wilson, Mark Green, John Brown, John Campbell, Peter Groffman, Jorge Durán, Jennifer Morse. 2020. Snowpack affects soil microclimate throughout the year
• Ruth D. Yanai, Yang Yang, Adam D. Wild, Kevin T. Smith, Charles T. Driscoll. 2020. New Approaches to Understand Mercury in Trees: Radial and Longitudinal Patterns of Mercury in Tree Rings and Genetic Control of Mercury in Maple Sap
• Alan A. Ager, Michelle A. Day, Palaiologos Palaiologou, Rachel M. Houtman, Chris Ringo, Cody R. Evers. 2019. Cross-boundary wildfire and community exposure: A framework and application in the western U.S.
• Scott W. Bailey, Robert P. Long, Stephen B. Horsley. 2019. Comment on "Long-term decline of sugar maple following forest harvest, Hubbard Brook Experimental Forest, New Hampshire"
• N.J. Casson, A.R. Contosta, E.A. Burakowski, J.L. Campbell, M.S. Crandall, I.F. Creed, M.C. Eimers, S. Garlick, D.A. Lutz, M.Q. Morison, A.T. Morzillo, S.J. Nelson. 2019. Winter Weather Whiplash: Impacts of Meteorological Events Misaligned With Natural and Human Systems in Seasonally Snow‐Covered Regions
• Timothy J. Fahey, Paul G. Schaberg. 2019. Forest physiology and phenology
• Julie N. Weitzman, Peter M. Groffman, John L. Campbell, Charles T. Driscoll, Robert T. Fahey, Timothy J. Fahey, Paul G. Schaberg, Lindsey E. Rustad. 2019. Ecosystem Nitrogen Response to a Simulated Ice Storm in a Northern Hardwood Forest
• Mark B. Green, John L. Campbell, Ruth D. Yanai, Scott W. Bailey, Amey S. Bailey, Nicholas Grant, Ian Halm, Eric P. Kelsey, Lindsey E. Rustad. 2018. Downsizing a long-term precipitation network: Using a quantitative approach to inform difficult decisions
• Peter M. Groffman, Charles T. Driscoll, Jorge Durán, John L. Campbell, Lynn M. Christenson, Timothy J. Fahey, Melany C. Fisk, Colin Fuss, Gene E. Likens, Gary Lovett, Lindsey Rustad, Pamela H. Templer. 2018. Nitrogen oligotrophication in northern hardwood forests
• Patrick J. Minogue, Brent V Brodbeck, James H. Miller. 2018. Biology and control of cogongrass (Imperata cylindrica) in southern forests
• Mahnaz Valipour, Charles T. Driscoll, Chris E. Johnson, John J. Battles, John L. Campbell, Timothy J. Fahey. 2018. The application of an integrated biogeochemical model to simulate dynamics of vegetation, hydrology and nutrients in soil and streamwater following a whole-tree harvest of a northern hardwood forest
• Yang Yang, Ruth D. Yanai, Charles T. Driscoll, Mario Montesdeoca, Kevin T. Smith. 2018. Concentrations and content of mercury in bark, wood, and leaves in hardwoods and conifers in four forested sites in the northeastern USA
• Paolo Benettin, Scott W. Bailey, Andrea Rinaldo, Gene E. Likens, Kevin J. McGuire, Gianluca Botter. 2017. Young runoff fractions control streamwater age and solute concentration dynamics
• Rebecca R. Bourgault, Donald S. Ross, Scott W. Bailey, Thomas D. Bullen, Kevin J. McGuire, John P. Gannon. 2017. Redistribution of soil metals and organic carbon via lateral flowpaths at the catchment scale in a glaciated upland setting
• Lynn Christenson, Hannah Clark, Laura Livingston, Elise Heffernan, John Campbell, Charles Driscoll, Peter Groffman, Timothy Fahey, Melany Fisk, Myron Mitchell, Pamela H. Templer. 2017. Winter Climate Change Influences on Soil Faunal Distribution and Abundance: Implications for Decomposition in the Northern Forest
• Jorge Durán, Jennifer L. Morse, Alexandra Rodríguez, John L. Campbell, Lynn M. Christenson, Charles T. Driscoll, Timothy J. Fahey, Melany C. Fisk, Myron J. Mitchell, Pamela H. Templer, Peter M. Groffman. 2017. Differential sensitivity to climate change of C and N cycling processes across soil horizons in a northern hardwood forest
• John P. Gannon, Kevin J. McGuire, Scott W. Bailey, Rebecca R. Bourgault, Donald S. Ross. 2017. Lateral water flux in the unsaturated zone: A mechanism for the formation of spatial soil heterogeneity in a headwater catchment
• Pamela H. Templer, Andrew B. Reinmann, Rebecca Sanders-DeMott, Patrick O. Sorensen, Stephanie M. Juice, Francis Bowles, Laura E. Sofen, Jamie L. Harrison, Ian Halm, Lindsey Rustad, Mary E. Martin, Nicholas Grant, Christian Rixen. 2017. Climate change across seasons experiment (CCASE): A new method for simulating future climate in seasonally snow-covered ecosystems
• John Campbell, Ruth D. Yanai, Mark B. Green, Gene E. Likens, Craig R. See, Amey S. Bailey, Donald C. Buso, Daqing Yang. 2016. Uncertainty in the net hydrologic flux of calcium in a paired-watershed harvesting study
• Jorge Durán, Jennifer L. Morse, Peter M. Groffman, John L. Campbell, Lynn M. Christenson, Charles T. Driscoll, Timothy J. Fahey, Melany C. Fisk, Gene E. Likens, Jerry M. Melillo, Myron J. Mitchell, Pamela H. Templer, Matthew A. Vadeboncoeur, D. P. C. Peters. 2016. Climate change decreases nitrogen pools and mineralization rates in northern hardwood forests
• Afshin Pourmokhtarian, Charles T. Driscoll, John L. Campbell, Katharine Hayhoe, Anne M. K. Stoner. 2016. The effects of climate downscaling technique and observational data set on modeled ecological responses
• Tamir Puntsag, Myron J. Mitchell, John L. Campbell, Eric S. Klein, Gene E. Likens, Jeffrey M. Welker. 2016. Arctic Vortex changes alter the sources and isotopic values of precipitation in northeastern US
• Paolo Benettin, Scott W. Bailey, John L. Campbell, Mark B. Green, Andrea Rinaldo, Gene E. Likens, Kevin J. McGuire, Gianluca Botter. 2015. Linking water age and solute dynamics in streamflow at the Hubbard Brook Experimental Forest, NH, USA
• Rebecca R. Bourgault, Donald S. Ross, Scott W. Bailey. 2015. Chemical and morphological distinctions between vertical and lateral podzolization at Hubbard Brook
• Timothy J. Fahey, Pamela H. Templer, Bruce T. Anderson, John J. Battles, John L. Campbell, Charles T. Driscoll, Anthony R. Fusco, Mark B. Green, Karim-Aly S. Kassam, Nicholas L. Rodenhouse, Lindsey Rustad, Paul G. Schaberg, Matthew A. Vadeboncoeur. 2015. The promise and peril of intensive-site-based ecological research: insights from the Hubbard Brook ecosystem study
• Colin B. Fuss, Charles T. Driscoll, John L. Campbell. 2015. Recovery from chronic and snowmelt acidification: Long-term trends in stream and soil water chemistry at the Hubbard Brook Experimental Forest, New Hampshire, USA
• John P. Gannon, Scott W. Bailey, Kevin J. McGuire, James B. Shanley. 2015. Flushing of distal hillslopes as an alternative source of stream dissolved organic carbon in a headwater catchment
• Cody P. Gillin, Scott W. Bailey, Kevin J. McGuire, John P. Gannon. 2015. Mapping of hydropedologic spatial patterns in a steep headwater catchment
• Mark B. Green, Bethany K. Laursen, John L. Campbell, Kevin J. McGuire, Eric P. Kelsey. 2015. Stable water isotopes suggest sub-canopy water recycling in a northern forested catchment
• Joshua M. Halman, Paul G. Schaberg, Gary J. Hawley, Christopher F. Hansen, Timothy J. Fahey. 2015. Differential impacts of calcium and aluminum treatments on sugar maple and American beech growth dynamics
• Ruth D. Yanai, Naoko Tokuchi, John L. Campbell, Mark B. Green, Eiji Matsuzaki, Stephanie N. Laseter, Cindi L. Brown, Amey S. Bailey, Pilar Lyons, Carrie R. Levine, Donald C. Buso, Gene E. Likens, Jennifer D. Knoepp, Keitaro Fukushima. 2015. Sources of uncertainty in estimating stream solute export from headwater catchments at three sites
• Scott W. Bailey, Patricia A. Brousseau, Kevin J. McGuire, Donald S. Ross. 2014. Influence of landscape position and transient water table on soil development and carbon distribution in a steep, headwater catchment
• John R. Butnor, John L. Campbell, James B. Shanley, Stanley Zarnoch. 2014. Measuring soil frost depth in forest ecosystems with ground penetrating radar
• John L. Campbell, Andrew B. Reinmann, Pamela H. Templer. 2014. Soil freezing effects on sources of nitrogen and carbon leached during snowmelt
• John L. Campbell, Anne M. Socci, Pamela H. Templer. 2014. Increased nitrogen leaching following soil freezing is due to decreased root uptake in a northern hardwood forest
• Kaelin M. Cawley, John Campbell, Melissa Zwilling, Rudolf Jaffé. 2014. Evaluation of forest disturbance legacy effects on dissolved organic matter characteristics in streams at the Hubbard Brook Experimental Forest, New Hampshire
• John P. Gannon, Scott W. Bailey, Kevin J. McGuire. 2014. Organizing groundwater regimes and response thresholds by soils: A framework for understanding runoff generation in a headwater catchment
• Gerald J. Gottfried, Peter F. Ffolliott, Kenneth N. Brooks, Randall K. Kolka, Carol B. Raish, Daniel G. Neary. 2014. Contributions of studies on experimental forests to hydrology and watershed management [Chapter 14]
• James W..Hornbeck, Amey S. Bailey, Christopher Eagar, John L. Campbell. 2014. Comparisons with results from the Hubbard Brook Experimental Forest in the Northern Appalachians
• J.L. Morse, S.F. Werner, C.P. Gillin, C.L. Goodale, S.W. Bailey, K.J. McGuire, P.M. Groffman. 2014. Searching for biogeochemical hot spots in three dimensions: soil C and N cycling in hydropedologic settings in a northern hardwood forest
• R.D. Semlitsch, K.M. O'Donnell, F.R. III..Thompson. 2014. Abundance, biomass production, nutrient content, and the possible role of terrestrial salamanders in Missouri Ozark forest ecosystems
• Sarah K. Wexler, Christine L. Goodale, Kevin J. McGuire, Scott W. Bailey, Peter M. Groffman. 2014. Isotopic signals of summer denitrification in a northern hardwood forested catchment
• Richard L. Boyce, Paul G. Schaberg, Gary J. Hawley, Joshua M. Halman, Paula F. Murakami. 2013. Effects of soil calcium and aluminum on the physiology of balsam fir and red spruce saplings in northern New England
• Andrzej Bytnerowicz, Mark Fenn, Steven McNulty, Fengming Yuan, Afshin Pourmokhtarian, Charles Driscoll, Tom Meixner. 2013. Interactive effects of air pollution and climate change on forest ecosystems in the United States: current understanding and future scenarios
• John L. Campbell, Amey S. Bailey, Christopher Eagar, Mark B. Green, John J. Battles. 2013. Vegetation treatments and hydrologic responses at the Hubbard Brook Experimental Forest, New Hampshire
• Mark B. Green, Amey S. Bailey, Scott W. Bailey, John J. Battles, John L. Campbell, Charles T. Driscoll, Timothy J. Fahey, Lucie C. Lepine, Gene E. Likens, Scott V. Ollinger, Paul G. Schaberg. 2013. Reply to Smith and Shortle: Lacking evidence of hydraulic efficiency changes
• Joshua M. Halman, Paul G. Schaberg, Gary J. Hawley, Linda H. Pardo, Timothy J. Fahey. 2013. Calcium and aluminum impacts on sugar maple physiology in a northern hardwood forest
• L.H. Pardo, P. Semaoune, P.G. Schaberg, C. Eagar, M. Sebilo. 2013. Patterns in δ 15 N in roots, stems, and leaves of sugar maple and American beech seedlings, saplings, and mature trees
• Kevin T. Smith, Walter C. Shortle. 2013. Calcium amendment may increase hydraulic efficiency and forest evapotranspiration
• Margaret A. Zimmer, Scott W. Bailey, Kevin J. McGuire, Thomas D. Bullen. 2013. Fine scale variations of surface water chemistry in an ephemeral to perennial drainage network
• Peter M. Groffman, Lindsey Rustad, Pamela H. Templer, John Campbell, Lynn M. Christenson, Nina K. Lany, Anne M. Socci, Matthew A. Vadeboncoeur, Paul Schaberg, Geoffrey F. Wilson, Charles T. Driscoll, Timothy J. Fahey, Melany C. Fisk, Christine L. Goodale, Mark B. Green, Steven P. Hamburg, Chris E. Johnson, Myron J. Mitchell, Jennifer L. Morse, Linda H. Pardo, Nicholas L. Rodenhouse. 2012. Long-term integrated studies show complex and surprising effects of climate change in northern hardwood forests
• Colin A. Penn, Beverley C. Wemple, John L. Campbell. 2012. Forest influences on snow accumulation and snowmelt at the Hubbard Brook Experimental Forest, New Hampshire, USA
• Afshin Pourmokhtarian, Charles T. Driscoll, John L. Campbell, Katharine Hayhoe. 2012. Modeling potential hydrochemical responses to climate change and rising CO 2 at the Hubbard Brook Experimental Forest using a dynamic biogeochemical model (PnET-BGC)
• Andrew B. Reinmann, Pamela H. Templer, John L. Campbell. 2012. Severe soil frost reduced losses of carbon and nitrogen from the forest floor during simulated snowmelt: A laboratory experiment
• Lindsey E. Rustad, John L. Campbell. 2012. A novel ice storm manipulation experiment in a northern hardwood forest
• Ganapathi Sridevi, Rakesh Minocha, Swathi A. Turlapati, Katherine C. Goldfarb, Eoin L. Brodie, Louis S. Tisa, Subhash C. Minocha. 2012. Soil bacterial communities of a calcium-supplemented and a reference watershed at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA
• Pamela H. Templer, Andrew F. Schiller, Nathan W. Fuller, Anne M. Socci, John L. Campbell, John E. Drake, Thomas H. Kunz. 2012. Impact of a reduced winter snowpack on litter arthropod abundance and diversity in a northern hardwood forest ecosystem
• Ruth D. Yanai, Carrie R. Levine, Mark B. Green, John L. Campbell. 2012. Quantifying uncertainty in forest nutrient budgets
• John L. Campbell, Charles T. Driscoll, Afshin Pourmokhtarian, Katharine Hayhoe. 2011. Streamflow responses to past and projected future changes in climate at the Hubbard Brook Experimental Forest, New Hampshire, USA
• Chris A. Jannusch, Sudeep Chandra, Tom Dudley, Jeanne C. Chambers, Wendy Trowbridge. 2011. Meadow-stream processes and aquatic invertebrate community structure [chapter 6]
• L. E Riley, D. L. Haase, J. R. Pinto. 2011. National Proceedings: Forest and Conservation Nursery Associations - 2010
• Paul G. Schaberg, Rakesh Minocha, Stephanie Long, Joshua M. Halman, Gary J. Hawley, Christopher Eagar. 2011. Calcium addition at the Hubbard Brook Experimental Forest increases the capacity for stress tolerance and carbon capture in red spruce ( Picea rubens ) trees during the cold season
• Salim Belyazid, Scott Bailey, Harald Sverdrup. 2010. Past and future effects of atmospheric deposition on the forest ecosystem at the Hubbard Brook Experimental Forest: simulations with the dynamic model ForSAFE
• John L. Campbell, Scott V. Ollinger, Gerald N. Flerchinger, Haley Wicklein, Katharine Hayhoe, Amey S. Bailey. 2010. Past and projected future changes in snowpack and soil frost at the Hubbard Brook Experimental Forest, New Hampshire, USA
• Sean K. Carey, Doerthe Tetzlaff, Jan Seibert, Chris Soulsby, Jim Buttle, Hjalmar Laudon, Jeff McDonnell, Kevin McGuire, Daniel Caissie, Jamie Shanley, Mike Kennedy, Kevin Devito, John W. Pomeroy. 2010. Inter-comparison of hydro-climatic regimes across northern catchments: snychronicity, resistance and resilience
• Rakesh Minocha, Stephanie Long, Palaniswamy Thangavel, Subhash C. Minocha, Christopher Eagar, Charles T. Driscoll. 2010. Elevation dependent sensitivity of northern hardwoods to Ca addition at Hubbard Brook Experimental Forest, NH USA
• Paul G. Schaberg, Gary J. Hawley. 2010. Disruption of calcium nutrition at Hubbard Brook Experimental Forest (New Hampshire) alters the health and productivity of red spruce and sugar maple trees and provides lessons pertinent to other sites and regions
• Amy L. Riscassi, Todd M. Scanlon. 2009. Nitrate variability in hydrological flow paths for three mid-Appalachian forested watersheds following a large-scale defoliation.
• Jean-Luc E. Cartron, David L. Hawksworth, Deborah M. Finch. 2008. First records of the Brown Creeper breeding along the middle Rio Grande in central New Mexico
• Kas Dumroese, L. E. tech. coords..Riley. 2008. National Proceedings: Forest and Conservation Nursery Associations-2007
• Joshua M. Halman, Paul G. Schaberg, Gary J. Hawley, Christopher Eagar. 2008. Calcium addition at the Hubbard Brook Experimental Forest increases sugar storage, antioxidant activity and cold tolerance in native red spruce ( Picea rubens )
• Byung Bae Park, Ruth D. Yanai, Timothy J. Fahey, Scott W. Bailey, Thomas G. Siccama, James B. Shanley, Natalie L. Cleavitt. 2008. Fine Root Dynamics and Forest Production Across a Calcium Gradient in Northern Hardwood and Conifer Ecosystems
• John L. Campbell, Charles T. Driscoll, Christopher Eagar, Gene E. Likens, Thomas G. Siccama, Chris E. Johnson, Timothy J. Fahey, Steven P. Hamburg, Richard T. Holmes, Amey S. Bailey, Donald C. Buso. 2007. Long-term trends from ecosystem research at the Hubbard Brook Experimental Forest
• John L. Campbell, Myron J. Mitchell, Bernhard Mayer, Peter M. Groffman, Lynn M. Christenson. 2007. Mobility of nitrogen-15-labeled nitrate and sulfur-34-labeled sulfate during snowmelt
• Brett A. Huggett, Paul G. Schaberg, Gary J. Hawley, Christopher Eager. 2007. Long-term calcium addition increases growth release, wound closure, and health of sugar maple ( Acer saccharum ) trees at the Hubbard Brook Experimental Forest
• Gary J. Hawley, Paul G. Schaberg, Christopher Eagar, Catherine H. Borer. 2006. Calcium addition at the Hubbard Brook Experimental Forest reduced winter injury to red spruce in a high-injury year
• Stephanie M. Juice, Timothy J. Fahey, Thomas G. Siccama, Charles T. Driscoll, Ellen G. Denny, Christopher Eagar, Natalie L. Cleavitt, Rakesh Minocha, Andrew D. Richardson. 2006. Response of sugar maple to calcium addition to northern hardwood forest
• Michael I. Haverty, R. Joseph Woodrow, Lori J. Nelson, J. Kenneth Grace. 2005. Identification of Termite Species by the Hydrocarbons in their Feces
• Bongghi Hong, Dennis P. Swaney, Peter B. Woodbury, David A. Weinstein, David A. Weinstein. 2005. Long-term nitrate export pattern from Hubbard Brook Watershed 6 driven by climatic variation
• James D. Nichols, Scott T. Sillett, James E. Hines, Richard T. Holmes. 2005. Approaches for the Direct estimation of rate of increase in population size (λ) using capture-recapture data
• Linda H. Pardo, Carol Kendall, Jennifer Pett-Ridge, Cecily C.Y. Chang, Cecily C.Y. Chang. 2004. Evaluating the source of streamwater nitrate using d15N and d18O in nitrate in two watersheds in New Hampshire, USA
• Amey Schenck Bailey, James W. Hornbeck, John L. Campbell, Christopher Eagar. 2003. Hydrometeorological database for Hubbard Brook Experimental Forest: 1955-2000
• Scott W. Bailey, Donald C. Buso, Gene E. Likens. 2003. Implications of sodium mass balance for interpreting the calcium cycle of a forested ecosystem
• Richard K. Kobe, Gene E. Likens, Christopher Eagar. 2002. Tree seedling growth and mortality responses to manipulations of calcium and aluminum in a northern hardwood forest
• Gene E. Likens, Donald C. Buso, James W. Hornbeck. 2002. Variation in chemistry of stream water and bulk deposition across the Hubbard Brook Valley, New Hampshire, USA
• M.J. Mitchell, B. Mayer, S.W. Bailey, J.W. Hornbeck, C. Alewell, C.T. Driscoll, G.E. Likens. 2001. Use of stable isotope ratios for evaluating sulfur sources and losses at the Hubbard Brook Experimental Forest
• David A. Post, Julia A. Jones. 2001. Hydrologic regimes of forested, mountainous, headwater basins in New Hampshire, North Carolina, Oregon, and Puerto Rico
• Diane M. Sanzone, Jennifer L. Tank, Judy L. Meyer, Patrick J. Mulholland, Stuart E.G. Findlay. 2001. Microbial incorporation of nitrogen in stream detritus
• Donald C. Buso, Gene E. Likens, John S. Eaton. 2000. Chemistry of precipitation, streamwater, and lakewater from the Hubbard Brook Ecosystem Study: a record of sampling protocols and analytical procedures
• Richard T. Holmes, Gene E. Likens. 1999. Organisms of the Hubbard Brook Valley, New Hampshire
• Paul N. Courant, Ernie Niemi, Ed. Whitelaw. 1997. The Ecosystem-Economy Relationship: Insights from Six Forested LTER Sites
• Gregory B. Lawrence, Mark B. David, Walter C. Shortle. 1996. Aluminum mobilization and calcium depletion in the forest floor of red spruce forests in the northeastern United States
• Richard M. DeGraaf, Mariko Yamasaki. 1992. A nondestructive technique to monitor the relative abundance of terrestrial salamanders
• Anthony C. Federer, Louise D. Flynn, Wayne C. Martin, James W. Hornbeck, Robert S. Pierce. 1990. Thirty years of hydrometeorologic data at the Hubbard Brook Experiment Forest, New Hampshire
• C. Wayne Martin, Hornbeck James W., Hornbeck James W. 1989. Revegetation after strip cutting and block clearcutting in northern hardwoods: a 10-year history
• J.W. Hornbeck, C.W. Martin, R.S. Pierce, F.H. Bormann, G.E. Likens, J.S. Eaton, J.S. Eaton. 1987. The Northern hardwood forest ecosystem: ten years of recovery from clearcutting
• James W. Hornbeck, Gene E. Likens, John S. Eaton. 1976. Seasonal patterns in acidity of precipitation and their implications for forest stream ecosystems
• Gene E. Likens, F. Herbert Bormann, John S. Eaton, Robert S. Pierce, Noye M. Johnson. 1976. Hydrogen ion input to the Hubbard Brook Experimental Forest, New Hampshire, during the last decade
• C. Anthony Federer. 1973. Annual cycles of soil and water temperatures at Hubbard Brook
• C. Anthony Federer. 1965. Sustained winter streamflow from groundmelt
• Raymond E. Leonard. 1961. Interception of precipitation by northern hardwoods
• Richard S. Sartz. 1957. Snow and frost measurements in a watershed-management research program

Understory Publications

Hubbard brook experimental forest - panels, hubbard brook experimental forest - west thornton, new hampshire, external publications.

Yong, Wang; Finch, Deborah M. 1999. Response. Wilson Bulletin. 111(4): 589-592

General Research Overview

Home > General Research Overview

Explore the topics below for a general overview of some of the major research themes at Hubbard Brook.

For more detailed and comprehensive information, please visit the Online Book: A Synthesis of Scientific Research at Hubbard Brook .

Climate Change

Using long-term records of air temperature, precipitation, stream temperature, streamflow, snowpack, and lake ice cover we study how the forest ecosystem at Hubbard Brook is responding to a changing climate.

Changing Atmospheric Chemistry

We study how forests and streams respond to changes in the chemistry of the atmosphere, particularly declines in air pollution brought about by federal restrictions on emissions.

We study the quantity and quality of water moving through the ecosystem by measuring precipitation, stream flow, and water chemistry at each control and treated watershed.

Nutrient Dynamics

We study how nutrients cycle through forests and streams, examining the roles of both geologic and biological factors in element fluxes.

Stream Ecology

We study streams as discrete ecosystems within the broader Hubbard Brook landscape, and we study how stream ecosystems interact with the terrestrial ecosystems that surround them.

We study the structure and composition of the forest at Hubbard Brook, tracking the predominant forest vegetation types by decadal measurements of all trees greater than 10 cm in diameter on 371 permanent plots.

We study the biodiversity and food webs of the forest and streams at Hubbard Brook. We have one of the longest running studies of migratory songbirds in the world, initiated in 1969.

We study the development of forest soils, soil fertility, soil biology, and soil carbon sequestration.

Ecosystem Disturbance

We study how forests and streams respond to disturbances, both natural and human-caused.

• News & Insights

Hubbard Brook: Lessons from the Forest

From acid rain to the decline of songbirds, new book tells the fascinating story of one of the most intensively studied landscapes on Earth

• Acid Rain ,

For more than half a century, scientists have converged on the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire to explore how forest ecosystems work, from the flow of water and nutrients to the ecology and behavior of forest animals. HUBBARD BROOK: The Story of a Forest Ecosystem   captures the rich history of research at the site, including how it has transformed environmental policy, resource management, and forestry practices – locally, regionally, and nationally.

Ecologists Richard T. Holmes of Dartmouth College and Gene E. Likens of the Cary Institute of Ecosystem Studies coauthored the book. Longtime members of the Hubbard Brook research community, they provide an insider’s view of this unique forest-turned-laboratory. Readers will discover the natural history of the site, the guiding role of the watershed-ecosystem concept, long-term studies of disturbance (natural and human made), the role of animals in ecosystem processes, and challenges for the future.

Hubbard Brook is best known for being the site where Likens and colleagues first discovered acid rain in North America, and the home of pioneering studies that have advanced our understanding of how acid rain and other atmospheric pollutants impact forests and adjacent freshwaters. This work has informed a range of policy measures, including the 1990 Amendments to the Clean Air Act. 

Another distinguishing feature of Hubbard Brook research has been the experimental manipulations of whole watersheds, which have revealed how environmental stresses ripple through the forest ecosystem, influencing everything from soil fertility and the growth of trees to the survival of animals and the quality of water delivered downstream. Other notable findings from the 50 years of inquiry include the ecological effects of clear-cutting and other forestry practices, causes of population change in forest birds and mammals, and how pests, pathogens, extreme weather, and climate change affect forests and nearby streams and lakes.

Likens comments, “The most enduring lesson we can learn from Hubbard Brook is the critical role that sustained, place-based ecological studies play in diagnosing environmental problems and setting and assessing management and policy solutions. We are much more effective stewards when we have long-term monitoring to guide us, but the reality is that such studies are quite rare.”

The Hubbard Brook Experimental Forest was established by the U.S. Forest Service to explore the relationship between forests and New England’s water supply. In 1963, while a professor at Dartmouth, Likens and faculty colleagues F. Herbert Bormann and Noye M. Johnson partnered with U.S. Forest Service scientist Robert S. Pierce to initiate the Hubbard Brook Ecosystem Study, broadening research at the site to include ecology, hydrology, and biogeochemistry. In 1969, Holmes and his colleagues began studies of birds and other animals living in the forest, thus widening the scope of the project even further.

Hubbard Brook has inspired collaborations among federal agencies and academic scientists. Research has resulted in more than 1,500 peer-reviewed publications exploring everything from ice storms and air pollution to the impact of reduced snow cover on forest soils. Today, 50 investigators from more than 20 institutions conduct research at Hubbard Brook, making it one of the longest running and most comprehensive ecosystem investigations in the world.

Offered by Yale University Press, HUBBARD BROOK: The Story of a Forest Ecosystem  provides an accessible review and synthesis of how researchers have used a living forest as an experimental laboratory. In the beautifully illustrated 270-page volume, Holmes and Likens showcase the role that long-term, collaborative ecological studies play in informing the protection of air and water resources, sustainable forestry practices, and wildlife conservation. 

Holmes is a research professor of biology at Dartmouth College in Hanover, NH. He is also the Ronald and Deborah Harris Professor of Environmental Biology emeritus at Dartmouth. Likens is founder and president emeritus of the Cary Institute of Ecosystem Studies in Millbrook, NY. He is also Distinguished Research Professor at the University of Connecticut.

Praise for HUBBARD BROOK: The Story of a Forest Ecosystem   

“A classic volume that brings a captivating story of scientific research with great policy implications up to date and challenges us to envision the future of this and all forest ecosystems.”—David Foster, author of Hemlock

“The authors have elegantly packaged a 50-year history of the Hubbard Brook project into a very readable book that will be of interest to a wide variety of disciplines.”—James Galloway, University of Virginia “A tremendous accomplishment. The work is original and the scholarship is excellent. It is extremely important and it absolutely will be a cherished book.”—Andrew Friedland, Dartmouth College “An essential addition to the bookshelves of professional ecologists, natural history buffs, and New England armchair ecologists.”—Meg Lowman, California Academy of Sciences “This beautifully illustrated and wonderfully written book presents a comprehensive summary of 50 years of research at Hubbard Brook, perhaps the most iconic and influential long-term ecological research program ever conducted.”—Scott L. Collins, University of New Mexico “Many important lessons have been learned in this fabled forest laboratory. By telling the Hubbard Brook story, Holmes and Likens give a gift to all who treasure the northern hardwood forest.”—Stephen Long, author of Thirty-Eight .

The Cary Institute of Ecosystem Studies is an independent, nonprofit environmental research organization located on 2,000 acres in New York’s Hudson Valley. A world-premier center for ecosystem science, areas of expertise include disease ecology, forest and freshwater health, climate change, urban ecology, and invasive species. Since 1983, our scientists have produced the unbiased research needed to inform effective management and policy decisions. Our science program is complemented by education and outreach initiatives. 

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Sustainable Forests: Tools, Technology, and Science for Tomorrow’s Forest

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