A Scientific Laboratory 170 Feet High in the Sky

Grand-scale ecology brings a Virginia forest under unprecedented scrutiny by Smithsonian researchers

McShea (in Posey Hollow): “Nobody has tried anything nearly as comprehensive.” Stephen Voss

Deep in the heart of Posey Hollow, on the grounds of the Smithsonian Conservation Biology Institute in Front Royal, Virginia—past the straight, sturdy hickories and a gnarled, 250-year-old black gum, the oldest tree in a forest that was clear-cut for farming in Colonial times—a galvanized steel tower rises 170 feet into the sky. When construction was completed, in late July, it became the tallest structure for at least an hour’s drive in any direction. When scientists install an array of instruments on the tower next month, the surrounding forest will become one of the most closely studied in the world.

The tower is one of 60 to be built across the United States as part of the National Ecological Observatory Network (NEON), a massive monitoring project, sponsored by the National Science Foundation, that will take the pulse of the nation’s environment. For 30 years starting in 2017, when the network is due to be completed, the towers will continuously measure temperature, carbon-dioxide concentration, moisture and many other variables in 20 different types of ecosystems. Posey Hollow is representative of a second-growth Eastern forest, there being virtually no old-growth forest left in the Eastern United States. Another tower will be installed at a Smithsonian research center on the shore of the Chesapeake Bay, to capture a Mid-Atlantic coastal ecosystem. At each NEON site researchers also will monitor soil conditions and collect insects, birds, plants and small animals. Once a year or so, airplanes carrying laser equipment will fly over the forests to create high-resolution digital scans of the tree canopy so scientists can track its density and growth. The NEON project will also incorporate data from 46 aquatic sites to paint a more complete picture of our ecosystem nationwide. “Ecology is going big-scale. If you want to understand how the environment works, you need to sample widely and bring in as many variables as possible,” says Bill McShea, a Smithsonian wildlife ecologist. “But so far, nobody has tried anything nearly as comprehensive as this.”

The Conservation Biology Institute was founded to conduct research on endangered animals, and it is still home to such creatures as cheetahs, red pandas and gazelles. But over the past five years researchers have taken a magnifying glass to a 63-acre section of Posey Hollow to better understand a forest that is growing without the pressures of encroaching development. “Every tree in here with a diameter of over a centimeter we’ve mapped, measured and identified,” McShea told me in early June as we hiked into the forest to see where the tower would be built. That comes to 41,031 trees of 65 species.

The scientists say the data gathered by the tower instruments will shed new light on the critical role that forests play in the greater environment. “What I’m most excited about is a sensor that makes continuous measurement of the exchange of carbon dioxide and water vapor between the forest and the atmosphere,” says Kristina Teixeira, a forest ecologist at the institute. “From this, you can get the total amount of carbon dioxide being taken up by the forest on a daily or annual time scale.” By comparing the rate of carbon dioxide absorption with surveyed tree growth, scientists will be able to calculate how effectively forests like this one mitigate greenhouse-gas emissions—an increasingly important issue as the climate changes. Other data will help researchers model how forests are affected by drought, rising temperatures and other factors, and could help them determine how certain native trees, such as that ancient black gum, withstand invasive species.

One of the most innovative aspects of NEON, though, has less to do with gathering information than with distributing it: The data will be made publicly available in real time over the Internet, so everyone with a stake in the ongoing changes to our environment will have a chance to monitor them. As Teixeira says, “Anyone with a good idea can just go in there and test their hypothesis.”

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