Overview

Researchers in the Multiple Element Limitation in Northern Hardwood Ecosystems (MELNHE) project are studying N and P acquisition and limitation through a series of nutrient manipulations in northern hardwood forests.  This project is supported by the National Science Foundation, and builds upon the Northern Hardwood Forest Calcium Cycling Project, which established our sites at Bartlett. The project is also affectionately called the Shoestring Project, for the continued effort prior to continued funding.

Although temperate forests are generally thought of as N-limited, resource optimization theory predicts that ecosystem productivity should be co-limited by multiple nutrients.  These ideas are represented in the Multi-Element Limitation (MEL) model, developed by Ed Rastetter at the Marine Biological Laboratory in Woods Hole, Massachusetts. To test the patterns of resource limitation predicted by MEL, we are conducting nutrient manipulations in three study sites in New Hampshire: the Bartlett Experimental Forest, the Hubbard Brook Experimental Forest, and Jeffers Brook in the White Mountain National Forest.  

At Bartlett, we have three replicate stands of three ages (~20, 30, and > 100 years).  At Hubbard Brook and Jeffers Brook, there are two stands at each site, corresponding to the mid-aged and mature stands at Bartlett (total 13 stands).  In each stand, there are four treatment plots, each 1/4 ha (50 m x 50 m), treated with N (30 kg N/ha/yr as NH₄NO₃), P (10 kg P/ha/yr as NaH₂PO₄), N+P, or control, beginning in spring 2011.  At 5 of the 13 stands, we also have a Ca treatment plot (1150 kg Ca/ha in the form of CaSiO₃).  

We are monitoring stem diameter, leaf area, sap flow, foliar chemistry, leaf litter production and chemistry, foliar nutrient resorption, root biomass and production, mycorrhizal associations, soil respiration, heterotrophic respiration, N and P availability, N mineralization, soil phosphatase activity, soil carbon and nitrogen, nutrient uptake capacity of roots, and mineral weathering.  Results will be posted as they develop.

MELNHE is led by 6 principal investigators: Ruth Yanai, SUNY College of Environmental Science and Forestry, Syracuse, NY; Melany Fisk, Miami University of Ohio, Oxford, OH; Tim Fahey  and Christy Goodale, Cornell University, Ithaca, NY; Joel Blum, University of Michigan, Ann Arbor, MI, and Ed Rastetter, Marine Biological Laboratory, Woods Hole, MA; with a host of additional collaborators, including graduate students, technicians, undergraduate students, high school teachers and visiting scientists. 

Research Highlights:

Sap Flow Results.  Virginia Hernandez-Santana and Heidi Asbjornsen measured sap flow summer 2011 in beech, maple, and birch trees at Hubbard Brook (mature) and Bartlett (C8) in control, N, P, and N+P treatments.  Posted 3/20/12 More Info

Soil N&P Availability.  Melany Fisk provides the initial assessments of nutrient availability HERE.  Stay tuned for the narrative!

Recruiting Interns and Graduate Students.  Revised 2/21/12.   More Info

Northern Forest Research featured at U Ohio-Miami.  Dr. Melany Fisk, Associate Professor of Zoology, and Ph.D. candidate Shinjini Goswami describe their research in the New Hampshire's northern hardwood forest in September, 2011.   Posted 2/17/12.   Video and Transcript

Differentiating soil respiration between roots and decomposers.  Kikang Bae compared the soil respiration between trenched and untrenched plots in Jeffers Brook (most fertile), Hubbard Brook (intermediate), and Bartlett (C6 and C9, least fertile) in the White Mountains of New Hampshire.  Posted 12/21/11 More Info

Wollastonite application, and installation of soil moisture probes:  The last of the wollastonite was applied Friday, November 11, 2011-- right on schedule.   More Info

Evaluating rotary cores for sampling exchangeable cations, carbon, and nitrogen in rocky soils.  A summary of Carrie Rose Levine's thesis project.    December 06, 2011 More info

Previous Highlights are available here

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