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tech 20 May 2026

Japan Gripped by Mass Allergies: A 1950s Project to Blame

Every spring, Japan is overwhelmed by hay fever, affecting 43% of its population. The cause? A massive reforestation project from the 1950s using only two tree species.

Article inspired by the original source
Japan is gripped by mass allergies. A 1950s project is to blame ↗ www.bbc.com

A Spring of Distress in Japan

Every year at the onset of spring, Japan faces a genuine health crisis. Millions of people don their masks and allergy medications, not due to pollution, but because of a more insidious enemy: pollen.

The Origins of the Problem

In the 1950s, Japanese leaders undertook a massive reforestation project to counteract the deforestation caused by World War II. Unfortunately, this project focused on just two specific species: the Japanese cedar (Cryptomeria japonica) and the cypress (Chamaecyparis obtusa). While these trees are effective for soil stabilization, they are also massive pollen producers.

The Hay Fever Epidemic

Today, about 43% of the Japanese population suffers from hay fever, compared to only 26% in the UK and between 12 to 18% in the US. This high rate is largely attributed to the abundance of pollen released by these artificial forests.

Economic and Health Impact

Pollen allergies are not just a matter of comfort. They lead to significant economic losses, estimated at $1.6 billion per day due to decreased productivity and lower consumer spending. Additionally, allergies increase the risk of other health issues like asthma.

What Solutions?

The Japanese government has started considering solutions, such as diversifying forests with other less allergenic species. However, these initiatives take time and require considerable investment.

Conclusion

Japan serves as a powerful example of the long-term impact of poorly planned environmental decisions. This allergy crisis highlights the importance of biodiversity and ecological planning.

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