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Harvard Forest REU Symposium Abstract 2014

  • Title: Assessing seasonal photosynthetic function of dominant species post-clearcut
  • Author: Kyle A Boyd (Smith College)
  • Abstract:

    Large-scale forest disturbance affects the exchange of carbon, water and energy between the ecosystem and the atmosphere. Clearcutting is one of the most dramatic disturbances due to the impacts on ecosystem processes and vegetation structure. Due to the complexity in these processes, it is not well understood how the physiology and vegetation structure will change post-clearcut. In the fall of 2008 Christopher Williams’ lab commercially clearcut an eight-hectare area in Harvard Forest to study the forest recovery. We studied photosynthetic function and nutrient content in six of the most common species located at the clearcut study site. During June and July a portable photosynthesis system (LI-6400xt) was used to measure leaf-level CO2-response curves and light-response curves of Prunus pensylvanica, Prunus serotina, Acer rubrum, Quercus rubra, Rubus idaeus and Dennstaedtia punctilobula. Additionally, leaf tissue samples were analyzed for carbon and nitrogen content. Previous work from the Williams lab during the summer of 2012 provided the basis for comparing changes in photosynthetic capacity. Taken together, this allowed us to measure the photosynthetic capacity, understand potential limitations to photosynthetic capacity, and determine how these change over time. The data suggested similar photosynthetic rates for most species over the past two years. However, preliminary results showed that Prunus pensylvanica appeared to be the most efficient in both years, while Acer rubrum had the highest C:N ratios. Results from this work will allow us to understand changes in photosynthetic capacity of the most dominant species and how they play a role in ecosystem productivity.

  • Research Category: Group Projects