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Research Experience for Undergraduates

Dr.  Ruth Yanai requests for Research Experience for Undergraduates (REU) and Research Opportunity Award (ROA) have been recommended for funding this summer.  Through this funding, participants work with multiple investigators, assisting with on going research, and also developing individual projects that they will see to completion.

REU Proposal

The project on Multiple Element Limitation in Northern Hardwood Ecosystems (MELNHE) provides excellent opportunities for exposure to scientific research because it involves so many researchers and so many topic areas, with work centered in an attractive geographic location that promotes interaction.  In addition to the nine stands of three ages at Bartlett originally funded by NSF, we are working in young and mature stands at Jeffers Brook and Hubbard Brook, which provide a gradient in site fertility.  There were five PIs initially funded on collaborative proposals, and four more have written other proposals to fund their work in our sites. There are five graduate students currently funded on the main project and more are being recruited.  There are undergraduates on the field crew, each with responsibility for a project area, and there is a constant flow of visiting scientists, foreign exchange students, and visitors from other projects.  The center of activity is the White House at Bartlett, with the nearby dorm and lab.  Sharing housing, meals, and cooking responsibilities contributes to the chances for interactions with scientists at all levels of development.

Because of the large number of researchers involved, REU participants will have the opportunity to learn about and contribute to a wide variety of measurements at these sites, including tree inventory, herb and seedling inventory, root biomass, root imaging, soil sampling, soil respiration, nitrogen mineralization, leaf area, collecting litterfall, and shooting fresh foliage.  There are opportunities for laboratory experiments, for example on nitrogen mineralization and microbial respiration, as well as field experiments.  They will also have access to reams of data collected during the previous funding cycle at Bartlett ( and collected over decades at the Hubbard Brook Experimental Forest.

We hope to have additional REU students on our team at Bartlett, supported on the HBR LTER or by the REU Site at Plymouth State University, if renewed. Regardless of how they are funded, we treat all our team members as researchers, not just as grunt labor, and we give them the support they need to learn about experimental design, research planning, time management, project coordination, data analysis, and the scientific communication of results.  The integration of efforts across a range of backgrounds and experiences, from REU, to RET, to visiting professors, provides everyone an opportunity to better understand the process of scientific research, and everyone gains exposure to a wide range of subjects within the fields of forest ecology and ecosystem nutrient cycling.

Possible Projects

Participants in this year’s field operations will develop focused research projects in the context of the overall experimental design.  Some possible projects are listed here.

  • Impact of fertilization on soil nitrogen transformations using laboratory incubations: The student can examine questions relating to changes in decomposition rates and in nitrogen mineralization and nitrification rates resulting from N and P fertilization. We have pre-treatment results as well as results from similar factorial experiments where nutrients were added in the lab, and the student can compare their results to this previous work.
  • Filming minirhizotrons can tell us the effect of nutrient treatments on root production.  Calculations of root turnover can make use of root biomass measured in 2009 in power-cored samples at depths > 30 cm and soil cores for shallow root biomass (0-30 cm).   Root biomass and production can thus be compared by soil depth, forest age, and across sites.
  • Heterotrophic respiration: In 2009, we trenched plots in five stands to exclude roots.  This year, a comparison of soil respiration in the trenched plots and outside the plots permits an estimate of autotropic and heterotrophic respiration.  The four plots in each stand should be compared to see if there is already a response to nutrient additions in young and old stand in two contrasting sites.
  • The development of leaf area could be monitored using an LAI-2000.  We will be monitoring sap flow in some of our stands to test for an increased in transpiration in response to nutrient additions, as observed in the whole-watershed Ca addition at Hubbard Brook.  Differences in leaf area development with treatment could be important to explaining changes in transpiration following nutrient additions.
  • Northern red oak is an infrequent associate of northern hardwood species in our permanent plots. In a warming climate, we expect this species range to expand.  Monitoring oak regeneration could give us an early signal of response to climate change. We have regeneration data from the 1990s to which to compare current data.
  • Forest productivity: We will inventory trees on all our plots this year, the first year of treatment.  We need to test whether growth differs already by treatment compared to earlier inventories, or whether these data can be used as a baseline to detect future changes in productivity.  This project would include field work (with a large crew), data entry, documentation of methods and data, and statistical analysis.
  • Forest composition: The results of stand inventory can also be used to describe forest community structures through non-parametric multivariate analysis such as Canonical Correspondence Analysis or Non-Metric Multidimensional Scaling. We have data on environmental variables such as soil chemistry, soil depth, aspect, slope and elevation that could be used in the multivariate analysis to explore causes of the variation in forest structure.

Other Program Elements

We have developed a culture for mentoring students and developing skills essential to the conduct of scientific research and a spirit of cooperation in the field crew.  Some of the program elements are outlined below.  New this year will be a weekly seminar series, based on the successful Science Night tradition at Hubbard Brook.

  • Proposals for each research project will be developed by the leading student and reviewed by the team.  Approved proposals will be posted on our web site prior to initiation of the work.  Formal review of proposals can prevent many misunderstandings and errors in implementation.
  • Each REU will be mentored by a graduate student. They will be mentored in several areas relating to their individual research, including proposal preparation, data collection, organization, and documentation, and statistical analysis.
  • Each REU will give an oral presentation at the annual Hubbard Brook Cooperators meeting in July.  Many of our undergraduates have made presentations at this meeting, including three last year.
  • We take turns posting photos, results, and stories during the course of the summer. Last year’s blog is available at
  • An important component of the summer experience is the shared living experience, including cooking (in teams of two), eating together, and household chores. We have a wide variety of experience and cultural backgrounds represented on the team, and we learn from each other in professional, social, and personal arenas.
  • Thursday night discussion series:  Herb Bormann and Tony Federer have already agreed to give presentations; many other prominent researchers work at Bartlett who are not associated with our project (Scott Ollinger, Andrew Richardson, Dave Hollinger, Bill Leak), and we will schedule them to give presentations on their work in conjunction with their travel to Bartlett.  In alternation with these presentations, we will discuss reading of common interest, including topics such as the impacts of scientific research on society.

Results from previous REU Supplements

This is our first request on the current grant.  The previous grant for work on this project (DEB-0235650) supported several REU students.  Their projects included an analysis of change in forest floor depth, using long-term remeasurement; analysis of roots collected from quantitative soil pits, contributing to a publication; and a satellite project exploring the long-term effect of liming on N mineralization and P availability.  Most of these students made presentations at the annual Cooperators’ Meeting of the Hubbard Brook Ecosystem Study, and several used their research projects as the basis for Senior Theses.  


The crew leader at our field site is a woman, Corrie Blodgett (a veteran of our 2004 field crew, when she was an undergraduate).  The majority of our current graduate students (4 out of 5) are women.  Half of the 6 PIs are women, including two in leadership positions.  Thus the male and female students on the crew will be exposed to both female and male role models.  This is important for students from institutions such as ESF, which still has only 15% women on the faculty.  We also benefit from broad cultural diversity, with students hailing from Puerto Rico, China, and Korea, as well as the mainland US.  

Participant Selection

We will select students based on academic and career interests, previous academic course work and field experience, and aptitude for research.  We have contact with many potential students through teaching and academic year lab employment; where we don’t have first-hand knowledge of student ability and interests, we will interview their referees, rather than relying solely on written references.