News / Americas

Vines Overwhelming Trees in Rain Forests


Zulima Palacio

Tropical rain forests in the American Hemisphere and other regions of the world are changing rapidly.  Studies conducted over recent decades indicate that increasingly, most of the trees in South and Central American rain forests must compete for light and nutrients with "lianas" or woody vines.  Studies also show that lianas are growing so abundant as a result of climate change and higher levels of carbon dioxide in the atmosphere that they are overwhelming their host trees, and in some cases, killing them.

Deep in the tropical forest of Panama, on the island known as Barro Colorado, scientists from the Smithsonian Tropical Research Institute have been studying the flora and fauna for nearly 100 years.

Stefan Schnitzer is one of those scientists. He studies "lianas" or woody vines, structural parasites that require trees for support.  He found out that vines growing on tree crowns have more than doubled over the last four decades.

"What we found is that probably about 80 percent of the trees that are around us now have some competition with vines," Schnitzer noted.  "Vines are affecting nearly all of the trees. So most of their growth rate is being reduced because of vines."

Not only growth.  Lianas compete for nutrients in the soil, deprive trees of light, and can choke and kill them.

"You can call them natural born killers," Schnitzer added.  "What's very interesting about these lianas is they climb up a tree, that tree falls, the liana falls with it, but the tree dies and the liana stays alive."  

Schnitzer estimates that some lianas are hundreds of years old, cover dozens of trees at one time and stretch for nearly a kilometer over tree tops.  

Although some lianas produce fruits and habitat for animals, they are devastating for most trees.  One liana we found had more than 10 different rooting points within a few square meters.

"This is an enormous liana and it's rooted right there next to the tree; it's competing for all sorts of resources," Schnitzer explained.  "And then, to add insult to injury, it's sending this giant stem up into the canopy where is competing for light as well."  

Schnitzer says he believes lianas are growing faster because of drought and warmer temperatures. He says these woody vines prevent trees from growing and capturing carbon dioxide.  

In another clearing we saw, there were no trees, the vines had completely taken over.

"What you get is tree gaps that never recover or take them 20-30 years to recover back to full canopy, because there are so many lianas preventing trees from growing," Schnitzer said.

Schnitzer and his team are also working on the nearby peninsula of Gigante in another protected area.  Here, hundreds of tree seedlings from 14 native species are ready to be planted.  

Schnitzer's team will plant these seedlings in 16 plots, half with lianas and half without them.

"We will measure mortality or survival every 2-3 months, and then we measure growth every 6 to 12 months. And after two or three years we'll know which tree species are going to regenerate better when lianas are present versus when lianas are absent," Schnitzer explained.

At the end of 20 years, Schnitzer says they will know how the tropical forest is changing and how to restore and conserve it.

"The forests are changing and moving in a direction that may result in more liana- dominated forest and forests dominated by trees that can tolerate lianas," Schnitzer said.

Why should we care? Because, Schnitzer says, tropical forests contain about one third of all global terrestrial carbon.  Without trees to capture that carbon dioxide, global climate change would be an even greater threat.

You May Like

Video Russia’s Syrian Escalation Tests Obama’s Crisis Response

Critics once again question whether president has been slow to act on Syrian conflict, thus creating opening for powers like Russia More

Ancient African DNA Shows Mass Migration Back Into Africa

First genetic analysis of ancient human remains in Africa suggests massive migration from north around time of Egyptian empire More

NASA: Pluto Has Blue Sky

New photos also reveal the presence of water ice More

This forum has been closed.
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Hungary Criticized for Handling of Refugeesi
Henry Ridgwell
October 08, 2015 8:02 PM
Amnesty International has accused Hungary of breaking multiple international and European human rights laws in its handling of the refugee crisis. As Henry Ridgwell reports, thousands of migrants and refugees continue to travel through the Balkans to Hungary every day.

Video Hungary Criticized for Handling of Refugees

Amnesty International has accused Hungary of breaking multiple international and European human rights laws in its handling of the refugee crisis. As Henry Ridgwell reports, thousands of migrants and refugees continue to travel through the Balkans to Hungary every day.

Video Iraqi-Kurdish Teachers Vow to Continue Protest

Sixteen people were injured when police used tear gas and rubber bullets to disperse teachers and other public employees who took to the streets in Iraq’s Kurdish north, demanding their salaries from the Kurdish Regional Government (KRG). VOA’s Dilshad Anwar, in Sulaimaniya, caught up with protesting teachers who say they have not been paid for three months. Parke Brewer narrates his report.

Video Syrian Village Community Faces Double Displacement in Lebanon

Driven by war from their village in southwestern Syria, a group of families found shelter in Lebanon, resettling en masse in a half-built university to form one of the biggest settlements of its kind in Lebanon. Three years later, however, they now face being kicked out and dispersed in a country where finding shelter as a refugee can be especially tough. John Owens has more for VOA from the city of Saida, also known as Sidon.

Video Bat Colony: Unusual Tourist Attraction in Texas

The action hero Batman might be everyone’s favorite but real bats hardly get that kind of adoration. Put more than a million of these creatures of the night together and it only evokes images of horror. Sarah Zaman visited the largest urban bat colony in North America to see just how well bat and human get along with each other.

Video Device Shows Promise of Stopping Motion Sickness

It’s a sickening feeling — the dizziness, nausea and vomiting that comes with motion sickness. But a device now being developed could stop motion sickness by suppressing certain signals in the brain. VOA’s Deborah Block reports.

Video Making a Mint

While apples, corn, and cranberries top the list of fall produce in the US, it’s also the time to harvest gum, candy, and toothpaste—or at least the oil that makes them minty fresh. Erika Celeste reports from South Bend, Indiana on the mint harvest.

Video Activists Decry Lagos Slum Demolition

Acting on a court order, authorities in Nigeria demolished a slum last month in the commercial capital, Lagos. But human rights activists say the order was illegal, and the community was razed to make way for a government housing project. Chris Stein has more from Lagos.

Video TPP Agreed, But Faces Stiff Opposition

President Barack Obama promoted the Trans-Pacific Partnership on Tuesday, one day after 12 Pacific Rim nations reached the free trade deal in Atlanta. The controversial pact that would involve about 40 percent of global trade still needs approval by lawmakers in respective countries. Zlatica Hoke reports Obama is facing strong opposition to the deal, including from members of his own party.

Video Ukranian Artist Portrays Putin in an Unusual Way

As Russian President Vladimir Putin was addressing the United Nations in New York last month, he was also being featured in an art exhibition in Washington. It’s not a flattering exhibit. It’s done by a Ukrainian artist in a unique medium. And its creator says it’s not only a work of art - it’s a political statement. VOA’s Tetiana Kharchenko has more.

Video Nano-tech Filter Cleans Dirty Water

Access to clean water is a problem for hundreds of millions of people around the world. Now, a scientist and chemical engineer in Tanzania (in East Africa) is working to change that by creating an innovative water filter that makes dirty water safe. VOA’s Deborah Block has the story.

Video Demand Rising for Organic Produce in Cambodia

In Cambodia, where rice has long been the main cash crop, farmers are being encouraged to turn to vegetables to satisfy the growing demand for locally produced organic farm products. Daniel de Carteret has more from Phnom Penh.

Video Botanists Grow Furniture, with Pruning Shears

For something a bit out of the ordinary to furnish your home, why not consider wooden chairs, crafted by nature, with a little help from some British botanists with an eye for design. VOA’s Jessica Berman reports.

VOA Blogs

More Americas News

Guatemala Landslide Death Toll Tops 220; Another 350 Missing

Loosened by heavy rains, hillside collapsed onto Santa Catarina Pinula on southeastern flank of Guatemala City October 1, burying scores of homes

Report: More Than 58,000 Violent Deaths Last Year in Brazil

Annual report on public security says number of violent deaths up nearly 5 percent last year from 2013, when country suffered a then high of 55,000 such deaths

UN Launches Review of Possible Corruption

Audit will look at interaction between world body and two organizations that US prosecutors have accused of bribing a former top UN official

US to Publish Records on Chile 1976 Assassination

Orlando Letelier was killed, along with his American co-worker Ronni Moffitt, by a car bomb in the center of Washington

US Official: Ending Cuba Embargo Will Take Time

Commerce Secretary wraps up visit to communist-ruled island saying both sides need to learn more about each other as they work to improve relations

Missing Cargo Ship’s Recorder Sought for Clues

Officials say El Faro's voyage data recorder, similar to 'black box' on aircraft, would provide a wealth of data on what befell the ship and the 33 people aboard