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 has also been called the Shoestring Project, during the period of unfunded effort between major research grants.

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 (Rastetter et al. 2012). To test the patterns of resource limitation predicted by MEL, we are conducting nutrient manipulations in three study sites in New Hampshire: Bartlett Experimental Forest, Hubbard Brook Experimental Forest, and Jeffers Brook in the White Mountain National Forest.

At Bartlett, we have three replicate stands of three ages, young (~20 y), mid-aged (30), and mature (>100 years). We have identified stands at Hubbard Brook and Jeffers Brook that corresponds to the mid-aged and mature stands at Bartlett, for 4 more stands. Each of the 13 stands has four 1/4 ha (50 m x 50 m) treatment plo ts, treated annually beginning in spring 2011, with N (30 kg N/ha/yr as NH4NO3), P (10 kg P/ha/yr as NaH2PO4), N+P, or nothing (an untreated control). Five stands 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. Although it is too early to see a response of forest productivity to the modest rates of N and P application, we have seen synergistic effects of P addition on soil N availability, and foliar resorption of P is highest at high N, which indicates nutrient co-limitation.

This material is based upon work supported by the National Science Foundation under Collaborative Grant Nos. #DEB- 0949324 (ESF), 0949420 (MBL), 0949317 (Miami U), 0949854 (Cornell) and 0949550 (U Mich), and supplements thereto, with cooperation from the Northeastern States Research Cooperative, the LTER site grant to Hubbard Brook, the Hubbard Brook Research Foundation, and the McIntire-Stennis Cooperative Forestry Research Act. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of any of these agencies.

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, Cornell University, Ithaca, NY;
  • 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.


ASA Annual Meeting presentation: N vs P Limitation: A Factorial Fertilization Experiment in Temperate Hardwood Forests. October 23, 2017.


54th Annual HB Cooperators Meeting. July 11-13, 2017. Slideshows available.

Spotlight on Student Research, April 25, 2017:


  • Congratulations Kara! Watch Kara Gonzales' capstone presentation: Effects of CA, N and P fertilization on foliar nutrient dynamics of three northern hardwood tree species. January 26, 2017.
  • Shoestrings at the 53rd Annual HB Cooperators meeting. July 13-14, 2016.


Poster Presentations

ESF undergraduate Madison Morley presents at SUNY ESF and Cobleskill

Presentation at the 2015 Soil Science Society of America meeting:

During the Biological Weathering Symposium, Dr. Ruth Yanai gave a presentation entitled "Comparison of Current and Long-Term Ca Weathering Rates in the White Mountains of New Hampshire."

RAHSS featured in the ESF2014-15 Annual Report, Oct 22, 2015

Research Program for High School Students enrolling for the 2015-16 School Year, for students attending ESF in the High School partner schools. While enrollment is a rolling basis, 40 hours in the ESF's Forest Ecology Lab must be completed by the end of the academic year. Work sessions are scheduled most weekends, and during a number of school breaks. Participants work with Dr. Ruth Yanai, her graduate students and undergraduate Research Aides, and with students in city and suburban districts.

Former Tech puts MELNHE background to work in Home School Program.

MELNHE featured at 2015 Central New York Science & Engineering Fair, Mar 22, 2015. Max Charlamb, a 9th grader at Manlius Pebble Hill School in Dewitt, NY, has been working with Dr. Ruth Yanai, through a Research Assistantship for High School Students supplement to analyze project data. His poster entitled "Is phosphorus more limiting than nitrogen to foliar production in Northern Hardwood Forests" earned High Honors in the Senior Division (grades 9-12). He concluded that data do not support the hypothesis that foliage production would increase with P application more than with N. At the older sites, litter production seemed limited by N availability. The CNYSEF accepts projects from students in grades 4-12 from public, private and independent schools and homeschooled students in Onondaga, Madison, Oswego, Cayuga and Cortland counties. The Fair is one of several annual STEM competitions administered through the Museum of Science and Technology, located in downtown Syracuse's historic Armory Square.

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