Rebecca Sanders-DeMott

What seemed impossible only a few weeks ago has finally happened – the snow has melted! It’s true! The snow is gone from the forest, the soils are soft and very wet, and slowly but surely the trees are making their way to full canopy! This ephemeral period of time between snowmelt and leaf out by trees is really interesting from an ecology and biogeochemistry perspective. As scientists, we are really interested to know how all the important components of the ecosystem start working together at the end of winter so that by the middle of summer, they are a complex coupled system that is completely in sync (most of the time…). Does the early part of the season impact how things will go later on?

To get at some of these questions, I’ve been back out in the field this week sampling roots from our climate change plots. My goal is to assess whether the roots in all our different treatments are equally healthy as the growing season begins. If the temperature manipulations over the winter have harmed some of the roots more than others, this might impact how well the trees grow over the next few months.

A new experiment is currently being constructed at Hubbard Brook. This is a collaboration of Lindsey Rustad of the USDA Forest Service, Heidi Asbjorsen of UNH, and Pam Templer of Boston University.  The idea is to manipulate the amount of precipitation reaching the forest floor and to explore how this change impacts forest ecosystem function.  The amazing team at Hubbard Brook just completed the frame infrastructure last week!  There will be gutters placed on top of these boards to divert rainwater as it falls through the forest canopy. This will reduce the actual amount of precipitation experienced by the forest within the plots.  So cool!

Happy and dry in my rain gear!

Today was a rainy day up at Hubbard Brook and I was out digging up data on how much nitrogen is moving down through the soil, past the roots, and likely out of the ecosystem.  To do this, we bury ion-exchange resin bags in the soil below the rooting zone.  These are water permeable nylon bags filled with small beads that have been chemically charged to attract positive and negative ions.  As water flows through the soil, it moves through these bags and the ions in the water get trapped on the beads.  We can then bring the bags back to the lab and analyze the chemicals that have been intercepted.

A resin bag being excavated from the soil. The location of the bag is marked by a flag and we tie fishing line to the bag to help retrieve it.

For this project, we are interested in how our temperature treatments impact the amount of inorganic nitrogen moving through the soil.  Tomorrow morning, I will extract the ions from the beads and then analyze for ammonium and nitrate content. These particular bags were first placed in the field back in June.  They will provide us with an estimate for the rate of nitrogen leaching from June - October.

BU Today has written a great profile of two of our undergraduate research assistants who have been collecting data for our climate change projects at Hubbard Brook.  Check it out!

Both Risa McNellis and Taylor Barrow worked with us this summer through BU's Undergraduate Research Opportunities Program (UROP), along with Darian Marinas from Ohio State.  They'll all present their findings from this summer next week at the annual BU UROP Symposium.

BU Today: Wiring the Woods

Photo Credit: Cydney Scott

Photo credit: Cydney Scott

Photo credit: Cyndey Scott