Hay Fever in Japan
Japan is facing a nationwide health emergency due to hay fever—medically known as allergic rhinitis. The root cause traces back to a large-scale reforestation effort 70 years ago, when only two fast-growing tree species were planted: the Japanese cedar (sugi) and the Japanese cypress (hinoki). These were chosen to restore forests after World War II. Now, as those trees have reached 30 years of age, they release massive amounts of pollen, triggering allergies in 43% of the population. In 2023, the government declared this allergy a national social issue and launched a plan to cut pollen levels by 50% over 30 years, including replacing forest plantations.
The crisis began after WWII, when Japan, facing oil and gas shortages, cleared vast natural forests, leaving hills around Tokyo, Osaka, and Kobe bare. To prevent soil erosion, authorities planted sugi and hinoki. Today, hinoki and sugi plantations cover roughly 10 million hectares—one-fifth of Japan's total land area. During peak season, the economic toll of hay fever reaches an estimated $1.6 billion per day.
Local Initiatives and Government Measures
Local biodiversity restoration efforts are also making a difference. For instance, the town of Nishiawakura in Okayama has reduced its hinoki and sugi forests by 84%. In Kobe, since 2020, over 180 hectares of plantations have been converted to broadleaf forests over a 15-year cycle, with a goal of expanding protected areas to 30% of all land by 2030. The most ambitious effort targets 10,000 hectares of plantations in Gunma Prefecture, while the government has identified roughly 980,000 hectares of forest as zones for targeted logging and replanting.
In 2011, Japan set a goal to rely less on imported timber, and domestic wood use rose from 26% in 2010 to nearly 42% in 2020. In 2024, the government introduced a new forest environment tax of 1,000 yen (about $6) per year per resident to fund these initiatives. However, a 2023 report found that only 30–40% of recently logged land in Japan had been replanted, though the Forestry Ministry now claims the replanting rate is around 50–60%.
'Pollen allergy has become a national health issue in Japan. It needs to be addressed urgently.'
Noriko Sato, professor and forestry researcher at Kyushu University
Climate factors also play a key role in this crisis. 'Pollen dispersal is heavily influenced by weather conditions like temperature and wind,' said Mai Sato, a spokesperson for the Japan Meteorological Association. As a result of policies promoting logging, 'we are seeing an increase in the area of clear-cutting,' added Junichi Mishiba, forest project coordinator for Friends of the Earth Japan.
In summary, Japan's hay fever crisis stems from long-standing environmental and economic processes that demand urgent action. Government efforts and local reforestation initiatives could have long-term positive effects on public health and ecological stability. The success of these measures hinges on effective replanting plans and the public's ability to adapt to new environmental conditions. It is crucial that these efforts receive support from both the government and local communities.