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Summer Research Project 2018

  • Title: Group Project (Megaplot): Size-Energy Partitioning in a Temperate Forest
  • Summer Supervisors: John Grady; Sydne Record
  • Researchers: John Grady; Sydne Record
  • Project Description:

    One of the most conspicuous and ecologically important traits of a tree is its size. Within a species, trees can vary in size by many orders of magnitude, from tiny seedlings to multi-ton adults. This intraspecific variation in tree size has important consequences for forest structure and function, as it governs patterns of tree abundance, growth rate and energy flux. Recent theoretical models make predictions about size-energy patterns of forests, but light limitation has been hypothesized to cause deviation from predictions for the smallest trees. The demographic data needed to test this hypothesis, however, is limited, as small saplings are typically overlooked in forest censuses. The goal of this project is to examine seedling demography and growth at Harvard forest and explore their theoretical implications. We will track seedling recruitment and production with boots-on-the-ground measurements at in the Harvard Forest ForestGEO megaplot. Students will gain valuable field experience and be exposed to new methods in data analysis. They will also grapple with current theoretical issues that are being hotly debated in the ecological literature.

    The students selected for this project will be co-mentored by Drs. John Grady and Sydne Record of Bryn Mawr College, who will both be present during the summer. A typical week for the student will entail the majority of the time in the field with some time at the computer doing data entry and analysis. For a portion of the summer, students will also perform destructive collections of tree seedlings and saplings, which we will be dried and weighed in the lab for biomass estimates. Drs. Grady and Record will meet with the students a minimum of three times per week. Dr. Grady will assist the summer students in database compilation, locating transects, ID and tagging of seedlings, biomass collections, and recording demographic and canopy data. The students will learn identification of forest tree species, experimental protocol, as well as theoretical issues motivating the research. The students will analyze data using R statistical software and will present their findings in a symposium at the final week at HF. This project is part of a larger group project/collaboration with another group of students who will also be working on ants in the megaplot with Dr. Aaron Ellison. There will be opportunities throughout the summer to collaborate with the ant group. There will also be opportunities to develop an independent project that can be extended into a year-long independent study or a senior thesis. On average the students can expect to spend about 80% of the time doing field work and 20% of the time doing data entry, data analysis, and lab work.

    General Requirements: The students working on this project must be willing to
    1. Participate actively in field studies, including ~8 hours per field day crouching in a forest environment to measure seedlings with biting insects and hot, humid conditions.
    2. Be able to hike with scientific gear (30-45 lb. pack) in rough, forested terrain. The field site is ~ 1 mile one way from the main buildings at Harvard Forest.
    3. Be willing to collect seedlings and sapling for biomass estimation and weigh the dried materials in the lab.
    4. Be willing to collaborate with the ant megaplot group on field work and data analyses.
    5. Have, or be willing to develop, a basic understanding of Excel and R for graphical and statistical analysis.
    6. Think critically about theoretical issues in forest demographics and community ecology and link them to field work and data analyses.

  • Readings:

    Farrior, C., Bohlman, S., Hubbell, S. & Pacala, S. Dominance of the suppressed: Power-law size structure in tropical forests. Science 351, 155-157 (2016).

    Ruger, N., Condit, R. Testing metabolic theory with models of tree growth that include light competition. Functional Ecology, 26, 759-765 (2012).

    Shingleton A. W. Allometry: The study of biological scaling. Nature Education Knowledge 3 (10): 2. (2010).

    West, G. B., Enquist, B. J. & Brown, J. H. A general quantitative theory of forest structure and dynamics. Proceedings of the National Academy of Sciences 106, 7040-7045 (2009).

    Westoby, M. The self-thinning rule. Advances in Ecological Research 14, 167-220. (1984)

  • Research Category: Physiological Ecology, Population Dynamics, and Species Interactions, Large Experiments and Permanent Plot Studies, Group Projects