Parts of the Amazon rainforest degraded by human activities such as farming, timber extraction, and burning are markedly hotter, drier, and more flammable, and store less carbon than areas of intact forest, according to a new survey of more than 33,000 acres.
The study, published in the journal JGR Biogeosciences, found that degraded areas were 11.7 degrees Fahrenheit warmer on average than intact swaths of Amazon rainforest. Damaged forests also cycled 35 percent less water between plants and the atmosphere, absorbed and stored 34 percent less carbon, and were at higher risk from fire.
The findings are based on 3-dimensional scans of forest using lidar, an airborne laser scanning system, as well on-the-ground surveys to confirm tree species, Mongabay reported. Surveys were conducted near the Brazilian areas of Belterra, Paragominas, Feliz Natal, and Tanguro, as well as in Paracou, French Guiana.
The research also found that during periods of intense drought, intact Amazon forests begin behaving like degraded ones, cycling less water and storing less carbon.
“Essentially, at some point, the [whole] system runs out of water, and the climate stress is more relevant than the forest structure,” Marcos Longo, a carbon cycle and ecosystems researcher at NASA’s Jet Propulsion Laboratory and lead author of the study, told Mongabay.