What a High-Tech Forest Can Teach us About Global Warming

There are no secrets in the Harvard Forest. Cameras strapped to study towers hover above the canopy of this 3,750-acre wooded plot in central Massachusetts, taking snapshots of the foliage to record the exact moment when buds begin to form or leaves start to turn. Sensors measure the invisible exchange of carbon and water between the trees and the atmosphere. Breezes, birdsong, even human footsteps—nothing slips through unnoticed. 

Forests are among Earth’s most efficient carbon sinks—2.5 acres of trees can hold up to 50 times more carbon than a similarly sized plot of grass or crops. So researchers like Andrew Richardson, an evolutionary biology professor at Harvard University, are conducting arboreal surveillance, working to document how carbon cycles fluctuate on a changing planet. Decoding how trees are responding to climate change now could give scientists insight into what lies ahead. “Harvard Forest has unbelievably rich, long-term data,” says Meghan Blumstein, a Ph.D. student in Richardson’s lab, “which is really essential for understanding long-term change.” For example, working with scientists from the Woods Hole Research Center and other institutions, Richardson’s team discovered that the forest uses less water and conducts more photosynthesis than it has in the past, which suggests that as the climate changes, trees might adapt to store even more CO2.

While Richardson’s crew is recording the forest’s responses to climate change in real time, elsewhere in the Harvard Forest, scientists are pressing the fast-forward button. A group of biologists from North Carolina State University led a project that involved building heated chambers to see how ants reacted to rising air and soil temperatures (they duplicated that experiment down in North Carolina, in Duke University’s own research forest). Other projects have involved knocking down trees to simulate the effects of climate-aggravated disasters, like hurricanes and invasive species. 

This kind of work takes patience, but the data captured through this web of research tease out the shifting rhythms of a forest in flux. The constant photographing of the foliage, for example, has revealed that climate change is causing spring to hit the forest more than two weeks earlier than it did about 150 years ago, Blumstein explains. “Year to year you can look at photos,” she says, “and actually see the difference.”