Hubbard Brook Experimental Forest

Climate

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

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.

Vegetation

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.

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

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.