Succession of Cherry Blossom Record-Keeping in Kyoto

For over 1,200 years, the blooming of cherry blossoms in Kyoto, Japan, has been meticulously documented by noblemen, monks, and bureaucrats. This tradition has created one of the world's most extensive climate records, particularly valuable as cherry trees, or sakura, are sensitive to temperature changes. As global temperatures rise, these trees have been blooming earlier each year, making the data increasingly relevant for climate studies.

New York Times

Yasuyuki Aono, a climate scientist, was the most recent custodian of this historical record until his death from cancer in 2025. His dedication to updating the cherry blossom bloom dates year after year was pivotal in maintaining the integrity of this long-standing tradition. Following his passing, concerns arose regarding the future of the record, as no immediate successor was available to continue his work.

Continuing the cherry blossom data alive

In the wake of Aono's death, Tuna Acisu, a data scientist at Our World in Data, initiated a search for a new keeper of the cherry blossom records. Acisu emphasized the need for someone with scientific expertise and local knowledge of Arashiyama, a district in Kyoto renowned for its cherry trees. Initial efforts to find a replacement were unsuccessful, as no researchers from Osaka Metropolitan University, where Aono had worked, stepped forward to take on the responsibility.

Continuing the cherry blossom data aliveNew York Times

As the cherry blossom season concluded, a breakthrough occurred. Genki Katata, an environmental biophysicist based in Tokyo, agreed to assume the role of custodian for the cherry blossom records. Acisu confirmed that Katata would consult the same historical sources as Aono to ensure the continuity of the data. He is expected to provide updates on the peak bloom dates in the coming days.

Continuing the cherry blossom data alive

Tuna Acisu expressed relief at finding a successor, stating, “That made me a little bit emotional,” reflecting the significance of Aono's legacy and the importance of preserving this historical data. The transition to Katata is seen as a crucial step in maintaining the integrity of the cherry blossom records, which are not only a cultural treasure but also a vital resource for climate research.

Continuing the cherry blossom data alive

While the transition has been largely welcomed, some critics have voiced concerns about the challenges of maintaining such a long-standing tradition in the face of modern pressures. The loss of Aono has raised questions about the sustainability of the record-keeping process and the potential impact of climate change on future observations.

New York Times

• “We need help from a botanist or someone local to Kyoto, Japan!” — Tuna Acisu, Data Scientist at Our World in Data

New York Times

• “You can very much see that he planned to continue,” — Tuna Acisu, Data Scientist at Our World in Data

Continuing the cherry blossom data alive

The successful appointment of Genki Katata marks a new chapter in the ongoing documentation of cherry blossoms in Kyoto, ensuring that this vital climate record continues to thrive.

New York Times