Smaller-scale projects are also common, says Akira Mori, a professor of biodiversity and ecosystem services at the University of Tokyo, pointing to dozens of initiatives around Japan.
Since the goal of removing 20% of the plantations was announced, the country has designated approximately 980,000 hectares (2.4 million acres) of sugi plantation forests as areas for focused logging and replanting. Still, not all of this is being turned into broadleaf forests: some of it is fresh plantations, often planted with low-pollen or pollen free sugi.
Japan’s ministry of agriculture, forestry and fisheries did not respond to a request for comment on how much of this allocated area has been removed and replanted so far.
Still, these efforts may not yet be large enough to make much of a difference to the pollen.
And even if it achieves the goal, 80% of the plantation forests will remain. So Japan is also trying other ways to tackle hay fever.
Pollen data and forecasts, for example, are being used to better understand of where dispersion is likely, allowing authorities to selectively cut down the worst offending forests, and researchers are even looking at spraying trees with solutions to suppress pollen. In 2023, one forecasting company distributed thousands of pollen-detecting robots – whose eyes go different colours depending on pollen levels – across Japan.
Medicine is another prong to the attack, with the development of new treatments to better ease the symptoms of pollen exposure. One Japanese trial, for example, showed a long-acting under-the-tongue immunotherapy tablet was were still helping alleviate symptoms two years after treatment. Other scientists have even been experimenting with genetically modified rice designed to alleviate allergy symptoms. (Read more about the new wave of effective cures for seasonal allergies).
A careful transition
When the sugi and hinoki forests were first planted in the 1950s and 60s, they weren’t meant to stand forever. At the time, it was assumed they would be gradually cut down and replanted over time, as had been the case before the war. But as Japan’s economy boomed in the late 60s and 70s, major cities like Kobe and Tokyo grew rapidly, and it ended up being cheaper to import wood from other countries such as Malaysia and Indonesia.
A recently clear-cut plot at Kobe’s 180-hectare restoration project shows signs of regeneration, with pink tags showing native broadleaf trees
In 2011, though, Japan set a goal of relying less on forestry imports, and has seen its domestic wood use grow from 26% in 2010 to nearly 42% in 2020.
