Getting hit by lightning is not usually a good thing. But one tropical tree species seems to harness heaven’s wrath. Not only do the trees survive lightning strikes, but their height and voluminous crowns act as natural lightning rods, attracting strikes that damage foes and boost their competitive advantage in the dense jungle.
The finding, reported March 26 in New Phytologist, comes from a years-long effort at Barro Colorado Nature Monument in Panama, where scientists studied lightning’s overall impact on the forest. Using a camera array, drones and ground teams, researchers tracked lightning strikes and their effects. The team expected to find only detrimental effects on trees; however, it soon became clear that Dipteryx oleifera, also called “almendro,” benefited from the shock therapy to fend off rival trees and get rid of parasitic vines.
A particularly powerful impact on a liana-covered D. oleifera in 2019 is what cemented the idea of a link between the tree and lightning’s beneficial effects, says forest ecologist Evan Gora of the Cary Institute of Ecosystem Studies in Millbrook, N.Y. “It looked like a bomb went off.” The strike damaged 115 surrounding trees, half of which died within two years. Additionally, all the liana vines that covered the D. oleifera perished. The impacted tree, however, was practically unscathed, standing tall and healthy with its direct competitors removed.
To confirm the suspected tree-lightning relationship, Gora and his colleagues documented the fate of 93 trees struck by lightning, including nine D. oleifera specimens. After two years, all the D. oleifera trees were doing fine — thriving, Gora says — in stark contrast to a 56 percent mortality rate among the other species.
One reason for this resilience is that, apart from a few ruffled leaves, D. oleifera trees aren’t damaged by lightning. The electric shock, however, eliminates most of the parasitic lianas that grow on them. These vines are ubiquitous in the jungle, stealing light and nutrients from large trees.
Connections between the vines and branches on neighboring trees spread electrical current to those trees, damaging them as well. This frees up space, light and nutrients for the almendro trees. On average, about nine nearby trees were killed per strike.
In fact, growing next to a D. oleifera tree seems to be hazardous for neighboring trees, as the findings suggest that almendro trees actively attract lightning. They tend to grow taller and possess wider crowns than their neighbors, making them 68 percent more susceptible to strikes. One D. oleifera tree was struck twice in five years, and the researchers estimate that the typical tree is struck an average of five times over its 300-year lifespan.
The competitive advantage gained from these strikes increases the D. oleifera’s reproductive success by 14 times, the researchers found.
Connecting the dots between the strikes and the effects was not easy and required the right tools and a long-term perspective. “A lightning strike lasts a few milliseconds,” Gora says, “and then it takes months for the trees and lianas to die afterwards, so it’s not an easy-to-observe process, unless you happen to be tracking the lightning strikes.”
How D. oleifera survives the lightning strikes remains unclear. One possibility is that the tree’s wood has low electrical resistance, allowing it to safely conduct current to the ground without excessive heat buildup. Another hypothesis posits that the tree’s crown structure redirects electricity away from the trunk, channeling it toward neighboring trees.
“It’s really difficult to understand the dynamics of the interaction between trees and lightning,” says ecologist Bianca Zoletto of Wageningen University & Research in the Netherlands. She stresses the importance of collaborating with physicists to understand what happens when a tree is struck by lightning and find the coping mechanisms employed. “It would be fascinating to be able to say something more on that, but that goes a bit more in the physics side rather than the ecological side of the study.”
