Here’s what you’ll learn when you read this story:

• Following the 1945 bombing of Hiroshima and Nagasaki, Japan, some experts estimated that plant life wouldn’t recover for several decades—yet sprouts regrew within a couple months.
• A new study analyzes the surprising resilience of the flora in these two cities, including the famous hibakujumoku, or A-bombed trees.
• The review article hypothesizes that, unlike in radiation zones like Chernobyl and Fukushima, “constitutive resilience”—pre-existing strategies for survival—determined what plants ultimately survived and thrived following the atomic attacks.

In the city center of Hiroshima are trees known as hibakujumoku. Derived from hibaku, meaning “A-bombed” and jumoku, meaning trees or shrubs, these “A-bombed trees” are a symbol of resilience and regrowth in a city that faced the most devastating bombing in human history. At 8:15 a.m. local time, on August 6, 1945, the United States military delivered a nuclear bomb with a yield of 15 kilotons of TNT. Within the first seconds of detonation, the heat emitted some three kilometers from the hypocenter would’ve reached upwards of 3,000 to 4,000 degrees Celsius and the bomb released 240 grays (Gy) of radiation—by comparison a lethal human dose can be as low as five Gy. Yet, despite these immensely inhospitable and acute conditions, the hibakujumoku survived.

Now, a new review article published in the journal Progress in Biophysics and Molecular Biology is taking a closer look at the flora of Hiroshima and Nagasaki to determine how these incredible plants defied expectations and regreened an area left nearly denuded of plant life following the devastating impacts of Fat Man and Little Boy.

“The atomic bombings of Hiroshima and Nagasaki in 1945 created a unique environment of acute, high-dose ionizing radiation,” the authors write. “This stands in stark contrast to the chronic, low-dose rate contamination that defines the Chernobyl and Fukushima Exclusion Zones.”

A well-known saying in politics is “never let a good crisis go to waste,” and scientists seem to have a similar philosophy when it comes to nuclear disasters. It’s why dozens of papers have reported on the 40-year-old radiation experiment known as Chernobyl, but very few studies have analyzed plant life in Hiroshima and Nagasaki. Instead of prolonged, low-level radiation, as seen in the Chernobyl Exclusion Zone (CEZ), the atom bombs delivered a devastating blow with rapidly declining radiation levels in the aftermath, meaning the question essentially shifts to how trees survive chronic stress to survival in an acute radiation event. It’s why studying trees like the hibakujumoku is so scientifically relevant.

“These trees are not merely historical relics; they are biological archives holding potential information on extreme radio-tolerance,” the authors write. “They represent an extremely small fraction of the pre-existing population that, by a combination of fortunate location, genetic predisposition, or protective microenvironment, withstood the cataclysm.”

In the aftermath of the bombings, some experts believed plant life wouldn’t recover in the area for 75 years, but sprouts started to return within just a few months. This included trees like the Ginkgo biloba—the world’s oldest living tree species—along with weeping willow and Japanese hackberry that resprouted from protected seeds. Grass species like Japanese silver grass also recovered due to rhizomes protected by the soil. The review article hypothesizes that this recovery was largely driven by “constitutive resilience,” meaning that survivor trees relied on pre-existing strategies—robust DNA repair, antioxidant capacity, and other protective morphology—rather than the generational adaptations seen in places like Chernobyl or Fukushima. Future studies, the authors argue, should look even closer at these trees, even down to their genome, to uncover molecular data about how plants survive such harsh conditions.

“We can move from plausible hypothesis to mechanistic understanding, uncovering the genetic and epigenetic foundations of extreme stress tolerance,” the authors write. “In an era of increasing anthropogenic pressure, integrating this pivotal historical case into the broader framework of environmental science provides…critical insights for predicting and fostering resilience in the future.”