Japan’s postwar cedar plantations are stripping an estimated 232 billion yen — around US$1.5 billion — from the economy on each peak-season day, as a warming climate lengthens the pollen season and a crisis rooted in 1950s forestry policy tightens its grip. That is according to a Panasonic Corporation survey of private firms, cited this year by the World Economic Forum, which measured lost worker productivity at the height of the pollen season.
The problem traces directly to policy decisions made in the first decade after the Second World War, when authorities responding to severe wartime deforestation planted vast monocultural stands of Japanese cedar (sugi) and Japanese cypress (hinoki) across steep terrain surrounding Tokyo, Osaka and Kobe, according to BBC reporting. Both species were selected for rapid growth and construction suitability, but the emergence of cheaper imported timber from Malaysia and Indonesia during the 1960s left the plantations largely unharvested and standing.
Those trees have since reached the mature window at which sugi and hinoki release maximum pollen, and because the stands were planted within the same postwar push they now mature and shed in unison, sending a single allergen surge over the country each spring. Sugi alone covers about 4.4 million hectares, around 12 per cent of Japan’s land, and the Ministry of the Environment counts 38.8 per cent of the population affected by cedar pollinosis as of 2019, up from 16.2 per cent in 1998 — a condition so rare before the 1960s that the Japanese had no word for it.
Ecological losses compound the public health toll because Japan’s monocultures function as biological deserts compared with the mixed broadleaf forests they replaced. Natural Japanese forests support dense populations of birds, insects and amphibians beneath maples, larches and red pines, whilst the plantations — where little sunlight reaches the dry, needle-covered ground — support almost none.
Having committed to halving pollen concentrations, Tokyo set a primary target of cutting the high-pollen cedar area by at least 20 per cent by 2033, following then-prime minister Fumio Kishida’s designation of pollinosis as a national social problem in 2023. A forest tax introduced in 2024, set at 1,000 yen — roughly A$10 — per resident annually, funds the programme, whilst a concurrent effort to rebuild domestic timber demand pushed the domestic log share of production from 26 per cent in 2010 to 42 per cent in 2020.
Re-naturalisation work is already returning fauna to treated areas, with projects underway across several prefectures and results now visible in Kobe, where selective felling and native broadleaf planting have drawn rare insects, amphibians and animals back into formerly monocultural stands. Felled cedar and cypress are being directed to heating, furniture, and the manufacture of traditional white charcoal — income that the government intends will cover each project’s costs without ongoing public subsidy.
Global warming is compressing the programme’s timeline as rising temperatures push the season earlier and stretch it longer, with cedar pollen reaching the air in parts of Japan as early as January in 2025 and Osaka going on to record its highest concentration in a decade, according to Japan Weather Association observations. The ageing plantations are also weakening as carbon sinks as they mature, eroding the sequestration Japan counts on to meet its climate targets at the very moment it is leaning on them.
Japan’s 2024 forest tax of 1,000 yen per resident funds cedar felling, now running at 70,000 hectares annually — up from 50,000 before the crisis programme began — as Tokyo pursues a 50 per cent pollen reduction target it has set itself, aiming to achieve it in 30 years.
