Topic analysis

Japan is gripped by mass allergies. A 1950s project is to blame

Japan’s widespread hay fever crisis, impacting 43% of its population and causing significant economic and health issues, is rooted in a 1950s post-WWII reforestation effort that planted monocultures of Japanese cedar (sugi) and cypress (hinoki) trees—species that produce massive amounts of lightweight pollen. The government has declared allergies a national social problem, aiming to reduce pollen by 50% in 30 years through initiatives like replacing sugi plantations with diverse forests, while local projects are already restoring biodiversity and exploring sustainable uses for harvested wood.