Quick! Identify this fern!

Walking into the forest, I never imagined it was comparable to a human body. There are processes occurring constantly that can be both seen and heard, such as birds singing in the trees or spiders spinning webs between the trees. And then there are the ones you cannot see or hear, such as photosynthesis and respiration. My job this summer is to take notice of some of these unseen activities in order to gain a better understanding of the understory, or the plants that sprinkle the forest floor, to assess how their presence affects northern latitude forests.

I begin every day at 7.30 a.m. in order to start up the core equipment of my research: The Li-Cor 6400XT Portable Photosynthesis System. As it buzzes and whirs to get ready for the field, I prepare the giant metal frame it will be strapped to that makes me look like a Ghostbuster. (I try to hide these pictures, sorry). Wearing the Li-Cor is like taking a two-year-old to Disneyland because I have to carry around a massive amount of its necessities in order to keep it happy for a full day. When I finally get to the field after an hour of warm-up, it is show time. I visit each species in a plot that is on my list of prominent understory plants, which includes anything from fuzzy cinnamon ferns to hefty sarsaparilla leaves. I choose a single, healthy leaf and clamp the leaf chamber over it while carefully monitoring the conditions of the leaf on the screen.

When I refer to leaf conditions, I am talking about the rates at which photosynthesis and transpiration are occurring. The leaf chamber works by exposing the leaf to carbon dioxide and light once the gasket is tightly sealed in order to keep it from switching into respiration mode. The carbon dioxide is essentially a reference value to go by so that the value of the sample can be compared.

When I have obtained 2-3 replicates of each species from a plot, I bring it back to the lab where I measure the leaf area in order to adjust the data for plants that did not fill the entire gasket. After, the samples are dried and put in a grinder so that they can be sent off for carbon:nitrogen analysis.

Once I have plenty of data from a range of both deciduous and coniferous plots, I hope to obtain results by the end of this program that will signify how exactly the understory is relevant to the forest. Does it store most of the carbon in the forest? How does each species independently affect the ecosystem? I am very excited to see my results because the understory is generally understudied in aboveground measurements, with most research focusing on the canopy.

I will be comparing my results with data obtained in 1992, and by doing so may provide a better understanding of how the forest itself functions, especially in relation to carbon storage. Additionally, I may be able to predict which understory species will become dominant in the Harvard Forest as global warming progresses and hypothesize what their contribution will be to global climate change.

While you are most likely to see us REU students working crazy hard in the field and in the lab, we can also be spotted out in the open! We recently visited the Harvard Museum of Natural History and are currently planning weekend trips to Cape Cod and Mount Greylock. If you someday become a part of this awesome program, you will not only test the limits of your mind, but you will get an adrenaline rush!