Each spring, Japan experiences a unique phenomenon: daily pollen forecasts broadcast by television networks, often featuring red maps highlighting high-pollen areas and suggesting mask use. This practice is directly linked to the widespread planting of Japanese cedar trees, known as "sugi," which began in the years following World War II. Between 1945 and 1955, Japan planted about 4.5 million hectares of sugi and hinoki (Japanese cypress) as part of a government-led reforestation effort. This initiative aimed to rebuild the country after the war, using these fast-growing trees for their value in construction and their ability to quickly cover deforested land. However, by the 1960s, the economic situation changed as cheaper wood imports from Southeast Asia made domestic plantations less profitable. These plantations were largely abandoned, allowing the trees to grow unchecked. Now, these mature sugi trees release massive amounts of pollen in synchronized waves each spring, causing widespread allergies. According to the Japanese Ministry of the Environment, 38.8 percent of the population suffered from pollen allergies in 2019, a significant increase from 16.2 percent in 1998. This condition, known as cedar pollinosis, was almost nonexistent in Japan fifty years ago. National surveys conducted every decade by Japanese otolaryngological societies show a steady rise in the prevalence of cedar pollinosis. In 2019, medical costs related to allergic rhinitis, including pollinosis, reached about 360 billion yen in reimbursed care, highlighting the economic burden of the issue. In response, the Japanese government held a ministerial conference in 2023 to address the problem. The conference was tasked with developing a national plan that includes gradually cutting down the oldest sugi plantations and replanting them with varieties that produce little or no pollen. This reforestation strategy is expected to take several decades to implement fully.