Japan's sakura trees bloom earlier due to climate change

Japan’s sakura trees bloom earlier due to climate change


Sakura trees are beautiful when they bloom, arousing fascination in many people. A recent study, however, suggests that this same flowering is increasingly earlier and would coincide with the increase in temperatures in Japan. However, this can have consequences on the surrounding fauna.

Ever earlier flowering

The term “sakura” refers to the ornamental cherry trees of Japan, as well as their flowers. There are more than 600 varieties, differing in particular by the number of petals or the color of the flowers (and leaves). In Kyoto, the peak bloom in 2021 occurred on March 26, the earliest full bloom date in about 1,200 years. In 2022, this same peak (also called “hanami”) occurred on April 1.

A team of researchers from the Met Office (UK) and Osaka Metropolitan University (Japan) published a study on the subject in the journal Environmental Research Letters on May 16, 2022. According to scientists, climate change as well urban warming have advanced the date of the hanami by eleven days.

Causes and consequences

The British and Japanese researchers say this earlier flowering peak coincides with rising temperatures in Japan. In Kyoto, average March temperatures are now several degrees higher than what we had in pre-industrial times. According to scientists, climate change is the main factor in the earliness of hanami. However, urban warming also plays an important role. Indeed, buildings and asphalt absorb much more heat from the sun than rural landscapes. This is a well-known phenomenon. This is called an urban heat island (UHI).

Scientists also believe that earlier cherry blossoms could have a significant impact on Japan’s economy. Indeed, hanami is a cultural event in the country. The inhabitants as well as the tourists have the habit of picnicking under the trees and consuming special products. However, this party lasts a week and many people go ahead to plan everything.

The study didn’t just look at cherry trees. Indeed, scientists point out that many other plant species bloom earlier each year, again due to climate change. However, plants, insects and other animals maintain an interdependence, at the level of their development, their food as well as their reproduction. Unfortunately, earlier flowering of plants can therefore cause a desynchronization of their life cycle in relation to insects and other animals and jeopardize the integrity of ecosystems.