Virginia Tech expands research capacity to investigate forests from the atmospheric perspective

Virginia Tech has increased its capacity to study forests and how such landscapes influence climate by adding Thomas O’Halloran to the forest resources and environmental conservation research faculty in the College of Natural Resources and Environment.

O’Halloran, formerly assistant professor of environmental science at Sweet Briar College, brings access to the land-atmosphere research station he founded at Sweet Briar. The move to Virginia Tech was facilitated by Quinn Thomas, assistant professor of forest dynamics and ecosystem modeling at Virginia Tech since 2013, who had begun collaborating with O’Halloran at the research site in February of this year.

“The facility offers a new perspective on forests, enabling them to be viewed from the atmosphere’s perspective,” Thomas said.

O’Halloran originally designed the site to quantify the role of forests in regulating climate, particularly trees’ production of aerosols, which contribute to haze and interact with clouds. “This new collaboration with Quinn Thomas and Virginia Tech has significantly increased the scope and impact of the processes we can study at the site,” O’Halloran said.

Thomas and O’Halloran are interested in similar questions and instrumentation but have different backgrounds — Thomas in ecosystem science and O’Halloran in meteorology — which they combine to study land-atmosphere interactions.

The Sweet Briar Land-Atmosphere Research Station features a 120-foot tower with an array of instruments to measure forest-atmosphere interactions across a 67-acre pine plantation. Measurements include the movement of carbon, water, and energy between the forest and the air above, which affect climate.

For example, forests alter how dark the Earth is, which influences how much heat is absorbed or reflected — the energy balance. Whether forests make the Earth hotter or cooler is one of the questions being studied. Forests also absorb carbon, another factor in the energy balance.

“We are looking at the combination of these influences to answer questions on how forests influence climate,” O’Halloran said.

When it appeared in early 2015 that Sweet Briar College would close, the project’s future was uncertain, so Virginia Tech stepped in.

“Everything is still moving forward as it was,” Thomas said. “And Virginia Tech has strengthened its role at this exciting research site that combines forestry with micrometeorology.”

Now that Sweet Briar College remains open, work at the site continues as a collaboration between the two schools.

“The site is busier than ever. It makes me pleased to see undergraduate and graduate students from both schools working together,” O’Halloran said.

The research station contributes to an international network of “flux towers” — sites that measure exchanges of carbon dioxide, water vapor, and energy between large landscape areas, such as forests, and the air above them.

“These sites are in many ecosystems across the globe, including large networks in the U.S., Europe, and China,” Thomas said. “No site is exactly like ours but a lot are similar so that we can contribute to research at the global scale.”

Thomas describes “a few of the exciting ongoing research activities” at the atmosphere research station.

“There is a camera at the site that tells us to the day when the leaves fall. It is one of a chain of cameras, called PhenoCams, nationwide that monitor when leaves come on and off,” he explained. “Over time, these types of measurements help us determine the seasonality of plants and the effect of climate change. The research station also allows the study of the influence of cloudiness on plant growth and how much carbon dioxide is being absorbed by the forest.”

Instrumentation on the tower measures the properties of forests similar to ways they can be seen from space, so ground-based measurements can be linked to satellite measurements.

It will be another year before the first results are in. Meanwhile, in addition to gathering data, the atmosphere research station continues to be a resource for graduate student projects and undergraduate classes at both Virginia Tech and Sweet Briar College from several disciplines, such as forest resources, environmental informatics, and meteorology.