Researchers from the Technical University of Munich (TUM) have developed, for the first time, a global mathematical model that estimates how many trees die each year as a direct result of lightning strikes.
The conclusion is clear: the effect of electrical discharges on forest ecosystems has been underestimated.
320 million trees die each year by lightning
The study, published in the scientific journal Global Change Biology, reveals that around 320 million trees die annually due to the direct impact of lightning. This number does not include those that perish in forest fires started by electric storms.
This mortality accounts for between 2.1% and 2.9% of the annual plant biomass, which is equivalent to the release of 770 to 1,090 million tons of CO₂.
An overlooked disruptive agent in climate models
According to the lead author, Andreas Krause, the model not only allows estimating lightning-induced tree mortality, but also identifying the most affected regions and evaluating their consequences on the global carbon cycle.
“Lightning is an important disturbance factor, although it is often overlooked in studies on forest dynamics,” warns Krause.
Geographical impact: the tropics, the most affected
Currently, lightning mortality is higher in the tropical forests of Africa. Recent studies —such as those conducted in Panama— indicate that electrical discharges are one of the main causes of death of large trees.
However, climate models project an increase in lightning in mid and high latitudes, which could expand their ecological impact in the future.
Carbon emissions comparable to forest fires
CO₂ emissions caused by direct tree mortality from lightning are similar to those generated by burning live plants in forest fires (approximately 1,260 million tons annually).
Although the total emissions from fires are higher —due to the combustion of dead wood and soil organic matter, totaling around 5,850 million tons of CO₂—, lightning represents a significant source of atmospheric carbon that has been largely overlooked until now.
Towards more precise carbon cycle models
The study’s authors emphasize the need to collect more data on lightning-induced mortality in different types of forests.
Incorporating this variable into terrestrial ecosystem models would allow for better calibration of projections regarding vegetation dynamics and the carbon cycle. This is an essential process that regulates the carbon exchange between the atmosphere, oceans, and terrestrial biosphere.
