Japan trapped in a massive allergy crisis. A 1950s project is to blame

In Japan, every spring for millions of people means not only cherry blossoms, but also the beginning of the mass allergy season. According to estimates, symptoms of moderate to severe hay fever are now observed in about 43% of Japanese people. For comparison: in Belarus, according to various data, similar problems affect about 30% of the population, in the UK — about 26%, and in the USA this indicator ranges from 12—18%.

Allergies cause not only constant physical discomfort but also lead to sleep problems, reduced concentration, and increase the risk of developing asthma and other related diseases. Japan's economic losses, caused by reduced labor productivity and treatment costs, are estimated at a staggering $1.6 billion daily during the peak season.

The Roots of the Problem

The causes of the current crisis are not related to environmental air pollution or the general deterioration of the nation's health, but to government decisions made in the first decades after World War II.

During the war years, the country experienced a severe fuel shortage, which forced the authorities to actively use forest resources for the needs of the army and industry. The result was widespread deforestation, especially in the mountainous areas around major cities — Tokyo, Osaka, and Kobe. Bare mountain slopes became the cause of numerous natural disasters: the number of devastating landslides and floods sharply increased.

In the 1950s, the Japanese government launched a large-scale program for forest restoration. To stop soil erosion as quickly as possible and provide the country with cheap raw materials for construction, the focus was placed on two local species of evergreen trees: Japanese cedar (sugi) and Japanese cypress (hinoki). These species were characterized by fast growth, unpretentiousness, and were ideally suited for industrial purposes.

In the 1960s and 1970s, during rapid economic growth, the demand for timber remained high. However, the unexpected happened: due to trade liberalization, importing timber from abroad (mainly from Malaysia and Indonesia) turned out to be more profitable than developing domestic forests in hard-to-reach mountains. As a result, the man-made plantations were not utilized and remained untouched.

Павялічыць

Today, Japan is one of the most forested industrial countries in the world, where forests cover 68% of the territory. However, a third of these areas (about 10 million hectares) are monoculture allergenic plantations.

The situation became critical when these trees reached 30 years of age — it is during this period that cedars and cypresses begin to release the maximum amount of light pollen. Since they were all planted simultaneously, the trees reached maturity synchronously, creating a giant cloud of allergens over the entire country every spring.

These man-made forests differ greatly from natural ones. In them, all trees are of the same height, undergrowth is practically absent, and so little light penetrates that birds and insects hardly live there. The ground in such forests is covered with a thick layer of dry needles, creating the effect of a biological desert.

For comparison, natural Japanese forests are much richer and more diverse. They coexist with maples, larches, red pines, and hundreds of other plant species. Such ecosystems support a colossal number of living organisms. Although Japan is considered one of the global centers of biodiversity, monoculture plantations and the loss of natural habitats pose a serious threat to this unique heritage.

Searching for a Solution

In 2023, the country's government officially recognized allergies as a "national social problem." An ambitious plan was developed: to reduce pollen concentration in the air by 50% over the next 30 years. The primary task is to reduce the areas of high-pollen cedar forests by at least 20% by 2033.

To finance this work, a special forest tax was introduced in Japan from 2024 — 1000 yen (about $6) annually from each resident. Simultaneously, the state stimulates demand for its own timber: the share of domestic timber in production has already increased from 26% in 2010 to almost 42% in 2020.

However, replacing forest areas that occupy more than 2% of Japan's total landmass in just ten years is an extremely difficult task. Simple felling is not enough: new trees must be planted immediately in place of clear-cuts to prevent soil erosion and not to undermine the achievement of national climate goals for carbon absorption.

Павялічыць

In various prefectures, re-naturalization projects — returning forests to their natural state — have already begun. In Kobe, for example, coniferous plantations are gradually being transformed into mixed broadleaf forests. Selective felling and planting of native tree species are already yielding results: rare insects, amphibians, and animals are returning to the restored areas. The felled timber is used for heating, furniture production, and the creation of traditional Japanese white charcoal, which helps projects become economically self-sufficient.

Understanding that most of the plantations will remain in place anyway, Japan is also developing technological methods of combat. Today, the country operates ultra-modern forecasting systems, employs thousands of pollen detector robots, and tests new immunotherapy methods. Scientists are even working on creating genetically modified rice, the consumption of which is capable of alleviating allergic reactions.

Global warming has become an additional obstacle. Due to rising temperatures, trees start "pollinating" earlier and earlier — in 2025, Japan recorded the earliest start of the season in observation history. This creates a dual problem: allergy sufferers suffer longer, and forests become less effective as carbon sinks. Old monoculture plantations, which provide half of Japan's total carbon absorption, lose their effectiveness with age, making their renewal not only a medical but also a climatic issue.

It is significant that until the 1960s, there was no specific term for hay fever in the Japanese language. This problem was first described only in 1963 and was then considered a rare medical novelty. Now the Japanese hope that by returning to natural diversity, they will one day be able to enjoy spring again without the need to wear masks and take medication.

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