A report by Danica Coto for NBC Connecticut.
The hurricanes that pounded Puerto Rico in 2017, blasting away most of its forest cover, may give scientists clues to how the world will respond to climate change and increasingly severe weather.
Researchers at El Yunque, the only tropical rain forest overseen by the U.S. Forest Service, are running controlled studies on how plants respond to higher temperatures combined — since the cataclysmic blow from Hurricane Maria — with severe weather. Not far away, another group is looking at how hurricanes affect the forest environment.
“It’s a once-in-a-century opportunity to look at these two aspects of climate change together,” said Tana Wood, a research ecologist with the Forest Service.
Wood heads a team testing how plants themselves respond to higher temperatures. The 2017 hurricane season, with Maria following a lesser blow from Hurricane Irma, has given them a chance as well to see how storms affect the recovery of ecosystems already under stress, a key concern in the Caribbean, where scientists say warmer temperatures could lead to more intense hurricanes.
On a recent trek to the site, Wood brushed aside thick branches and leaves the size of laptops as she made her way to three plots surrounded by infrared panels that heat the air and soil by 4 degrees Celsius (7 degrees Fahrenheit). The vegetation there was shorter and a bit browner compared with the three unheated control plots. The warmed plots run on 480 volts of electricity, and while the lines are isolated from the soil, the scientists use insulated boots to avoid getting electrocuted in case of an accident.
Nearby, plant physiologist Rob Tunison clamped what looked like a small compact mirror around a dark green leaf to measure photosynthesis, spending 30 minutes to an hour per leaf.
Wood said they are looking at how temperatures affect basic processes such as photosynthesis — by which plants transform sunlight into energy while absorbing carbon dioxide and releasing that gas along with oxygen into the atmosphere — as well as how soils respond.
The researchers are also studying nutrients and microbes in the artificially warmed plots of land, keeping sending frozen samples to a lab in California for analysis.
Knowledge about tropical plants and soils could eventually be plugged into models to determine how vastly broader ecosystems respond to changes.
“We are also able to look at the potential for tropical plants and soils to acclimate to consistently warmer conditions over time,” Wood said.