Japan is facing a widespread allergy problem linked to a post-World War Two reforestation policy that reshaped much of the country’s landscape, the BBC reported.
During the war, large areas of forest around major cities were cleared, as the country relied on wood for energy and construction materials. To quickly restore woodland and cope with the increased risk of landslides and soil erosion, Japan decided after the war to plant mainly two fast-growing tree species — Japanese cedar (sugi) and Japanese cypress (hinoki). Today, these plantations cover around a fifth of Japan’s land area.
Containing almost no wildlife, these artificial forests are more than just spooky as they release large amounts of lightweight pollen, which, over the years, has become a national health issue, contributing to severe seasonal allergies across the country.
Hay fever now affects an estimated 43% of Japan’s population, creating health and economic challenges for many working adults. Researchers say the issue has intensified as the trees have matured and begun producing more pollen. Even animals like macaques are affected by pollen.
In response, the Japanese government announced plans to reduce pollen levels by half over the next 30 years, including cutting back sugi plantations. Some local governments and organizations have already started replacing monoculture forests with more diverse ecosystems.
