These Deadly Vines Threaten to Strangle Rainforest Trees
The Effects Could Be Disastrous For Our Carbon Cycle
by Sabrina Stangler, age 15
There is a type of vine that is relentlessly strangling the Forests of Central and South America. They are known as lianas. Some scientists call them tree-hugging villains.
Lianas creep up the trees, winding around their trunks, and eventually choke them out, outcompeting the trees for nutrients, water, and light. Once a liana has rooted itself and successfully scaled the tree, it grows at a faster rate than the tree itself. The tree can become covered with the vines; it will eventually fall and die under their weight.
The carbon cycle, the natural biochemical process cycling carbon through our ecosystems, is important to the health and functioning of the environment, wildlife, and humankind. With almost one third of the Earth’s carbon stored in trees, they play a major role in this critical process. Lianas do not store nearly as much carbon.
The reduction of trees in our planet’s forests decreases the carbon storage capacity available on Earth. This causes the amount of carbon dioxide in the Earth’s atmosphere to rise, contributing to its warming.
Another effect of lianas is an imbalance in forest diversity. Some trees can grow faster and often manage to escape the threats of lianas. This causes other trees that cannot escape the strangulation of lianas to die more often in comparison. This results in an abundance of trees that are better able to survive. These trees tend to be less dense, and store less carbon. Supplanting trees with lianas or eliminating trees with higher carbon storage capacity causes the forest’s net carbon storage capacity to shrink.
Despite the troubles that lianas bring to tropical ecosystems, they are a native species that provide a few benefits to animals. Lianas function as a source of food during the dry season because the plant tends to flower and fruit during that time of year. Also, lianas climb their way up to the treetops and form a network of pathways for small animals to travel throughout the forest canopy.
Dr. Stefan Schnitzer, a biologist at UW-Milwaukee and an associate of the Smithsonian Tropical Research Institute, is performing several experiments to gain more knowledge about lianas. His experiments test hypotheses such as water absorption ability and the vines’ efficiency in using carbon dioxide.
One experiment set up by Schnitzer involves sixteen 260-by-260-foot forest plots in the Panama region. His team is cutting down all of the lianas from half of the plots and observing and comparing them over several decades.
Dr. Oliver Phillips, a researcher at the University of Leeds in England, has another approach to liana research. He is observing liana dominance across a forest that becomes progressively drier from one side to another.
Scientists are unsure how lianas are going to develop and what their effect will be on tropical forests, but they are working hard to figure out what to do about their increasing presence.
[Sources: The New York Times; sciencedaily.com]