Vines choke a forest's ability to capture carbon

Terra Daily via SPX: Tropical forests are a sometimes-underappreciated asset in the battle against climate change. They cover seven percent of land surface yet hold more than 30 percent of Earth's terrestrial carbon.

As abandoned agricultural land in the tropics is taken over by forests, scientists expect these new forests to mop up industrial quantities of atmospheric carbon. New research by Smithsonian scientists shows increasingly abundant vines could hamper this potential and may even cause tropical forests to lose carbon.

In the first study to experimentally demonstrate that competition between plants can result in ecosystem-wide losses of forest carbon, scientists working in Panama showed that lianas, or woody vines, can reduce net forest biomass accumulation by nearly 20 percent. Researchers called this estimate "conservative" in findings published this month in Ecology.

"This paper represents the first experimental quantification of the effects of lianas on biomass," said lead author Stefan Schnitzer, a research associate at the Smithsonian Tropical Research Institute and professor at the University of Wisconsin-Milwaukee. "As lianas increase in tropical forests, they will lower the capacity for tropical forests to accumulate carbon."

Previous research by Schnitzer and others demonstrated that lianas are increasing in tropical forests around the globe. No one knows why. Decreased rainfall is one suspect, but lianas, which are generally more drought-tolerant than trees, are increasing in abundance even in rainforests that have not experienced apparent changes in weather patterns....

Lianas in a forest in Kerala, India, shot by Shyamal, public domain