Aside from oceans, tropical forests also store carbon emissions effectively, but a team of scientists discovered that wood vines, which are also called lianas, actually limit tropical forests' ability to act as a carbon sink. As the Earth grows warmer, the growth of lianas could also increase.
Scientists found that lianas reduce one-third of tropical forests' capability to store carbon dioxide. These lianas eventually cause the death of trees three times as quickly, especially because their presence strangles them and prevents their growth.
In a study issued in the journal Proceedings of the National Academy of Sciences, experts conducted a three-year experiment which showed the effects of lianas in tropical carbon balance.
Researchers from the Smithsonian Institute observed tree growth with intact lianas and without them. At the Nature Monument in Barro Colorado Island, Panama, researchers cut all lianas present in eight plots and then left eight more plots untouched with them.
The experiment discovered that tree growth was significantly reduced by 18 percent each year due to lianas, and that the plots with intact lianas gathered 76 per cent less biomass.
Scientists meanwhile measured the forests' amount of biomass in wood compared biomass in leaves. They discovered that lianas also contribute to a forest floor filled with less wood and more leaves. When leaves wither, they release carbon emissions into the air.
"This study has far-reaching ramifications," said Stefan Schnitzer, co-author of the study. He explained that lianas add a small part to the biomass in tropical forests, but their impact on trees significantly changes how carbon is stored and accumulated.
Researchers estimated that lianas may possibly reduce carbon storage capacity of trees by about 35 percent in the future. Reduction would increase if lianas spread more or if their presence within trees that grow quickly multiplies. Lianas currently make up over 25 percent of woody stems in tropical forests, the study said.
However, Schnitzer said that despite the fact that lianas were detrimental to trees, they were still important contributors to tropical forests' carbon balance because they provided resources for wild animals. Lianas also link trees together by providing pathways above the ground which are utilized by animals as passages around the forest, he added.
"This is the first time the effect of lianas on carbon cycling has been shown in such detail and on a large scale," added Jennifer Powers, another co-author of the study.
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