Tonka Bean Trees in Panama Can Survive Lightning Strikes And Then Use that Charge to Take Down ‘Clingy Partners’

All ecosystems envelop within themselves peculiar strategies that make them stand apart. Recently, a team of researchers found a unique facet in a forest ecosystem of Panama, stated Live Science. The facet was associated with a particular tree. Findings regarding this facet were published in the journal New Phytologist.

The study's subject was the tonka bean tree (Dipteryx oleifera) growing in the lowland rainforests of Panama. Researchers noted that, unlike other giant trees, this species did not get destroyed by lightning. Furthermore, the trees utilize this lightning to get rid of their competitors. 

The team has been monitoring Panama’s Barro Colorado Nature Monument for a decade, and all the giant tree species in the region showed damage when struck by lightning, except the tonka bean trees. "We started doing this work 10 years ago, and it became really apparent that lightning kills a lot of trees, especially a lot of very big trees," study lead author Evan Gora, a forest ecologist at the Cary Institute of Ecosystem Studies, shared. "But Dipteryx oleifera consistently showed no damage," Gora added.

For the study, the team installed several electric field sensors and cameras in the region. In total, they recorded 100 lightning events through this setup. To pinpoint the exact positions in the area where the lightning struck, a high-resolution detection system was laid out. An antenna array was affixed throughout Central Panama, whose function was primarily to spot the incoming radio waves from lightning strikes. The energy patterns received by each sensor allowed researchers to determine how strong or weak the lightning strike was in that particular area. The involvement of on-the-ground surveys and drone imagery, further helps them in determining which spot was impacted by lightning.

The team would then observe the condition of the trees in the area affected by lightning. Researchers found that tonka bean trees suffered no harm in the impacted places. After analyzing the tree plot records going back decades, experts further found out that after lightning, it was the neighbors of the tonka bean tree that were damaged. "Over those 40 years, there's a quantifiable, detectable hazard of living next to Dipteryx oleifera. [As a tree], you are substantially more likely to die than live next to any other big old large tree in that forest," Gora said.

The study claims that the tree's resistance against lightning is a result of its internal structure. The structure provides the species with high internal conductivity, which allows the current to flow through the trees without building up heat. The team also found that after each strike, 2.4 tons (2 metric tons) of nearby tree biomass disappeared. Researchers speculated that this phenomenon could be the result of parasitic vines associated with tonka bean trees, stated SciTech Daily. Experts think that lightning travels through adjoining vines between tonka bean trees and neighboring trees. The tonka bean tree remains unscathed because of its structure, however, the neighbor would perish from the lightning. 

The tonka bean trees appear to get rejuvenated after each strike, stated Live Science. Experts estimated that there could be a 14-fold increase in lifetime seed production for these trees after lightning. This was possibly because the current destroyed parasitic veins and allowed the trees to acquire more nutrients, stated SciTech Daily.