Not Even A Nuclear Blast Could Stop One 290 Million-Year-Old Tree Species

On August 6, 1945, the United States dropped "Little Boy," one of two atomic bombs it had created as a result of the Manhattan Project, on Hiroshima, Japan. Within moments, everything within the bomb's 1-mile blast radius reached temperatures of 7,000 degrees Fahrenheit — hotter than the surface of the sun, enough to melt buildings and vaporize human tissue. 80,000 people died instantly; their physical forms evaporated in the intense heat of the explosion. The majority of the city was reduced to ash.

Despite the literal hellscape that the area had become, a handful of Ginkgo biloba trees situated just on the edge of the blast radius survived. Miraculously, they began to regrow several months later, hope literally growing out of the irradiated ground. The first mayor of Hiroshima after the blast, Shinzo Hamai, would speak to the effect these trees had on the city's survivors (via University of Oxford): "Less than a year after the destruction, spring had pushed up a green shoot through the A-bomb desert — where rumour held that nothing would grow for 75 years. The powerful emotions stirred by a little sign of life would be hard for anyone [to understand] who is not a hibakusha (an A-bomb survivor) or a Hiroshima resident."

How was this possible? The trees' leaves had burned off; their branches were little more than charred husks. Their survival can be attributed to the tree's 290 million-year lineage — Ginkgo biloba trees are one of the oldest surviving species in the world. They have no close living relatives, and their ancestors were around when the dinosaurs dominated the planet. Not only are they a scientific wonder, but they have become a symbol of resilience and beauty for generations of people all over the globe.

Trees are master survivors, and they are the reason why the Earth's oldest living organism may not be what you think it is. The Ginkgo biloba tree has survived global climate shifts, mass extinctions, and extreme natural and human-made disasters, and its resilience and longevity can be traced to a unique set of biological traits. Unlike most trees, Ginkgos exhibit an uncanny ability to shirk death by aging. In a 2020 study published in the Proceedings of the National Academy of Sciences, researchers conducted a comprehensive aging study on the trees. They found that rather than slowing down as they aged, the trees' growth rates remained steady or even sped up.

By sequencing the trees' RNA and analyzing molecules that can turn specific genes on and off, scientists found that there was almost no difference between young and old Ginkgo trees, even in species members hundreds of years apart in age. They even found that gene expression connected to the tree's ability to resist pathogens did not vary in Ginkgos of differing ages, meaning their immune systems likely don't lose much or any potency with time. Cellular production of antimicrobial compounds called flavonoids and antioxidants also bolsters their stress resistance, ensuring the trees can consistently resist environmental stress and prevent decay.

Remarkably, there is no evidence of senescence — the genetic programming that leads to death in plants and mammals — in Ginkgo biloba trees. "Ginkgo biloba trees can live for thousands of years," Richard Dixon, one of the study's authors, told the University of Northern Texas. "And, when they die, it is generally the result of external stressors such as fire, flooding, poor nutrition, disease, parasites, etc. But, if those stressors are removed and perfect conditions existed, Ginkgo biloba could go on forever."

More than just a biological marvel, the Ginkgo biloba tree has become a symbol of survival, endurance, and renewal. The six trees near the epicenter of the Hiroshima bombing that survive to this day are witnesses to the region's history, and their seeds have been planted worldwide as part of peace and remembrance initiatives.

But Ginkgo trees have held deep cultural significance for centuries. In China and Japan, they are often planted at temples, symbolizing longevity and spiritual perseverance, and have long been used for their purported medicinal qualities. Ancient Chinese texts attest to its ability to prevent aging and increase blood flow to the brain, while Western traditions have viewed it as an aid to well-being in general. Beyond their cultural and spiritual relevance, Ginkgo trees represent a valuable tool in the fight against climate change. The fact that they thrive in heavily polluted urban environments, combined with their ability to produce significant amounts of oxygen with little carbon dioxide requirements, makes them an excellent choice for urban renewal initiatives. 

Inspiringly, the very qualities that give the tree its longevity make it a go-to candidate for climate-resilient greenery in an age of rapidly changing weather patterns. However, habitat destruction and over-harvesting have led to a reduction in the tree's numbers worldwide, and in 1998, it was classified as Endangered by the International Union for Conservation of Nature. Thankfully, though, Ginkgo conservation plantations in Europe and Asia have cropped up in recent years to counter this decline. If you want to learn more about how trees and forests are reacting to climate change, check out this breakdown of the alarming climate data found while studying tropical forests and seven unusual facts about California Redwoods.