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.


  • Recruiting 2018 Summer Interns, Hubbard Brook and Bartlett Experimental Forests
  • COOL new findings: Goswami S, M.C. Fisk, M.A. Vadeboncoeur, M. Johnston, R.D. Yanai, and T.J. Fahey. 2017. Phosphorus limitation of aboveground production in northern hardwood forests. Ecology, DOI: 10.1002/ecy.2100.
    • Tree growth responded more to P addition than to N addition in mid-aged and mature stands (p=0.02). These results are surprising because temperate forests on glaciated soils have been presumed to be N- limited, but they are consistent with predictions of the MEL model, parameterized for our experimental conditions (Rastetter et al. 2013). We can speculate that P limitation is a result of decades of anthropogenic N deposition.
  • Research opportunity for high school students. Sign up for a free research course, ESF296, and work with the Multiple Element Limitation in Northern Hardwood Ecosystems (MELNHE) project.
  • 44th Annual Rochester Academy of Sciences Fall Scientific Paper Session.  November 11, 2017, St. John Fisher College.

Hong, D.S., A.D. Wild, and R.D. Yanai.  Battle of the babies: Beech interference with maple regeneration. PDF

Lasser, G.A., M.T. Johnston, M.J. Mahoney,  V.A. Leimanis, and J.R. Stoodley.  An investigation of nutritional effects on causal organisms of beech bark disease in aftermath forests. PDF

Morley, M., C. Sosa, R.D. Yanai.  Time for tea: Nutrient affect on tea decomposition after three-month incubation in northern hardwood forest soils. PDF

Rice, A.M., M.T. Johnston, and R.D. Yanai.  Do nutrient additions affect sap flow in sugar maple trees? PDF

Young, A.R., R.D. Yanai, R. Minocha, and S. Long.   Specific leaf area and amino acids respond  to nutrient amendments and canopy depth. PDF


  • ASA Annual Meeting presentation. October 23, 2017. Yanai, R.D., Gonzales, K.E., Goswami, S., Li, S., Fisk, M.C., and Fahey, T.J. N vs P Limitation: A Factorial Fertilization Experiment in Temperate Hardwood Forests.

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