Japan's Post-WWII Forests Mean Massive Hay Fever

Japan's annual springtime sniffles aren't just bad—they're the legacy of a postwar forestry bet that went sideways, reports Nithin Coca for the BBC. To quickly restore mountains stripped bare during World War II, the government in the 1950s blanketed the country with two fast-growing evergreens: Japanese cedar (sugi) and cypress (hinoki). Those stands now cover about a fifth of Japan's land—and, once mature, pump out vast quantities of pollen. The result: roughly 43% of the population now endures moderate to severe hay fever, with an estimated $1.6 billion in daily economic losses at peak season. By comparison, some 26% of the UK population suffers, while in the US, the number is between 12% and 18%.

In 2023, Tokyo labeled allergies a "social problem" and set a target to cut pollen levels in half within 30 years, starting by shrinking cedar plantations 20%. That means a massive, decades-long remake of forests, as cities like Kobe experiment with converting monoculture stands into mixed, more biodiverse woodlands—while also leaning on new drugs, pollen forecasts, and even anti-allergy rice. The transition is complicated by carbon goals, landslide risks, and tight local budgets. Read the full BBC piece for how Japan is trying to undo a 70-year-old decision, tree by tree.