EDITOR’S CHOICE IN ENVIRONMENT
Although historically overlooked, lightning may play a surprisingly large role in shaping tropical forests, accounting for as much as 40 percent of large tree mortality. But like other drivers of mortality, it likely doesn’t affect all trees equally. “Species differ in their susceptibility to drought, their tolerance of fire, and all of these other hazards that they’re exposed to,” says Jeannine Richards, a plant ecologist at the University of Wisconsin–Madison. “Certainly, there should be differences in how they respond to the electrical current of a lightning strike.”
To explore this hypothesis, Richards and her colleagues used a combination of cameras, electrical field change meters, and field surveys to pinpoint lightning strikes and assess the damage to trees at those locations. Of the 30 species the group identified, palm trees were highly likely to die if struck by lightning, while four species of broadleaf trees—a diverse group of seed-bearing, flowering trees—had comparatively little mortality following a strike. Among all the species included in the study, trees with higher wood density seemed to have greater lightning tolerance. Richards says that the mechanism underlying this finding isn’t clear and could be the basis for further study.
Nate McDowell, a forest ecologist at the Pacific Northwest National Laboratory in Washington who was not involved in the research, says that this study has important implications for the future of tropical forests under climate change, which is expected to make lightning more common. “If lightning does increase in frequency in some regions . . . as expected,” McDowell says, “we would anticipate that this will cause changes in community demography—the winners and the losers.” He adds that changes in tree communities will likely affect the carbon cycle, although exactly how this will play out remains to be seen.
J.H. Richards et al., “Tropical tree species differ in damage and mortality from lightning,” Nat Plants, 8:1007–13, 2022.