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Woody Vines Could Act as Lightning Rods in Tropical Forests

ByTim De ChantNOVA NextNOVA Next

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What would a tropical forest be without lianas, the long, woody vines that wrap around tree trunks and reach for reach the canopy? Well, if a new hypothesis pans out, they might have a lot fewer trees from lightning strikes.

Lianas are usually seen as a drag on trees. In fact, they’re technically parasites, accessing light high above ground using a trees’ woody trunks so they don’t have to build their own resource-intensive structures. But Steve Yanoviak, an ecologist at the University of Louisville, thinks lianas may have an unseen benefit for trees. They might act as lightning rods.

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Lianas stretch from a tree canopy toward the ground.

Jyoti Madhusoodanan, reporting for Nature:

Yanoviak’s preliminary experiments in oak-hickory forests near Louisville indicate that vine stems have lower resistance to electricity than tree branches. The data suggest that vines such as lianas could channel the current from a lightning strike, similar to lightning rods on buildings. To test the idea, Yanoviak and his group plan to set up devices to initiate lightning strikes on trees and lianas. The remote-controlled devices are giant balloons containing 1-metre-long metal pistons. When ground-based sensors suggest a strike is imminent, the pistons can be shot up to catch the bolt. The set-up could help the group trigger lightning strikes on specific trees, or specific lianas, so that they can observe the outcome.

If lianas do direct deadly current away from trees, they may help protect tropical forests from one of the dangers of climate change—hotter, drier weather. Today, tree lightning strikes kill individual trees, but they don’t cause many fires because tropical forests are generally too moist. Climate change, though, could lead to tinderbox conditions in which lightning striking a tree could lead to a forest fire.

Yanoviak and his team will head to Barro Colorado Island in Panama this July, where they’ll launch their two-year study to learn if lianas are, in fact, the lightning rods of the forest.