for National Geographic News
Ornamental cherry trees all over the Japanese archipelago have been blossoming unseasonably this fall, according to local media reports.
A few sakura trees—as they are known in Japan—bloom in fall most years.
But with more blossoms appearing earlier this year, there is concern that climate change is affecting a much-loved national symbol of spring.
The popular Somei Yoshino variety of cherry tree produces buds in mid-summer, but a hormone in the leaves causes the buds to hibernate.
When the leaves fall from the tree in spring, the flowers blossom, creating for a few short days a brilliant cloud of white to pale pink blooms.
If the tree loses its leaves prematurely for any reason while the weather is warm, the buds may bloom early—and once they have bloomed, they won't flower again that year.
According to Hiroyuki Wada, chief researcher at the Flower Association of Japan, this year a number of factors have contributed to cherry trees' early leaf loss.
One was an unusually dry, hot summer followed by a severe typhoon that stripped many trees of their leaves.
Another was a warm, late fall that allowed leaf-eating cherry caterpillars and fall webworms to flourish.
With their leaves stripped and the temperatures balmy, many sakura trees were "tricked" into thinking fall was actually spring.
Climate Change Link
Wada believes that climate change could be the root cause of the phenomenon.
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