It was the best of times. It was the worst of times.
Millions of people in Japan celebrate the arrival of spring every year with their delicate cherry blossoms. But the seasonal change also brings many miserable months of incessant sneezing and nasal congestion.
Hay fever, or pollen allergy, has such an impact in Japan that Prime Minister Fumio Kishida described it in April as “a social problem” and instructed his ministers to seek an answer.
Taro Yamada, a parliamentarian from the ruling party, recently stated: “Pollen allergy is said to be the national disease.”
It is enough to compare Japan with other countries to see the dimension of the problem.
In the United States about 8% of the population suffers from hay fever. In other countries between 10 and 30%.
In Japan, on the other hand, hay fever or “kafunsho” (pollen disease in Japanese) affects 42.5% of the population, according to a study by the Japanese Ministry of the Environment in 2019.
The percentage, double that of two decades ago, is currently equivalent to more than 50 million people.
And the Japan Forestry Agency estimated that pollen allergy causes economic losses of at least $2.2 billion a year, including medical bills and decreased worker productivity.
Why does hay fever have such magnitude in the Asian country?
The answer lies largely in the Japanese forests and in a story that began more than 70 years ago…
cedars and cypresses
Allergic rhinitis or hay fever is a disease in which the nasal mucosa becomes inflamed and irritated.
The term “hay fever” comes from the 19th century, when the smell of hay was thought to have an irritating effect. But then it was discovered that the disease had nothing to do with fever or hay, but with an allergy to pollen.
Symptoms can include sneezing, itchy nose, nasal congestion, runny nose, and watery eyes, among others.
Pollen grains from many plants cause allergic reactions. But in Japan the problem originates especially in the forests of two species of trees: cedars and cypresses.
The same 2019 Ministry of the Environment study indicates that 38.8% of Japanese suffer from an allergy to Japanese cedar pollen (japonica cryptomeria), the national tree of Japan that is locally known as “sugi”.
And 25% of the population suffers from allergy to the pollen of the Japanese cypress or hinoki (Chamaecyparis obtusa).
People with these allergies may never have seen a cedar or cypress before.
Clouds of pollen released from forests are blown over long distances by the wind.
Both Japanese cedar and cypress are native trees to the country and have been a part of its landscape for hundreds of years.
That they ended up contributing to a “national disease” is due to policies adopted after World War II.
The “herculean” task of reconstruction
“During World War II, Japan’s forests were cut down and devastated,” Iwao Uehara, a professor at the Department of Forestry at the Tokyo University of Agriculture, told BBC Mundo.
“Due to the scarcity of wood after the war, large quantities of cedars and cypresses were planted, because they grow relatively fast, with a straight trunk.”
David Fedman, a historian at the University of California-Irvine, is a specialist in the environmental history of Japan and author of the book “Seeds of Control: Japan’s Forestry Empire in Colonial Korea.”
“One of the most pressing material needs immediately after the war was for materials for urban reconstruction in Japan,” Fedman told BBC Mundo.
“Here it is worth remembering the firebombing campaign that devastated Japan’s largely wooden buildings in the closing months of World War II.”
“Therefore, the occupation authorities faced a Herculean task of urban reconstruction, as well as a severe shortage of timber and forest resources as a result of Japan’s mobilization for all-out war.”
The occupation of Japan by the victorious Allies in the war lasted until 1952. Cedar plantations expanded in the following years.
In some cases, even diverse natural forests were cleared to replace cedar monocultures, explained Professor Uehara.
“In this way, cedar and cypress plantations increased throughout the country and were carried out on a large scale even in mountainous areas that were not suitable for these species.”
“Japanese cedar today makes up 45% of the planted forests in Japan, and cypress 25%,” Uehara added.
Individual actions were added to state policy.
“People also believed that planting cedars and cypresses would benefit Japan. There was even a song that encouraged people to plant cedar and cypress trees.”
unviable plantations
The vast plantations of cedar and cypress became a bad business in the following decades.
“Cultivation and maintenance of cedar plantations is a labor intensive task. In the 1950s and early 1960s, cheap labor was plentiful, so widespread cedar planting made sense,” Fedman said.
Disruptions in other industrial and agricultural sectors in the late 1960s and 1970s made cedar an increasingly less viable forest enterprise, he added.
Changes in the timber market had dire consequences for cedar.
“I explain them in detail at the conclusion of my book, ‘Seeds of Control.’ The bottom line is that the economics of domestic logging have become prohibitively expensive. Increasingly, cheap gaizai (“wood from abroad”) was imported, leaving no small number of domestic logging operations in dire straits.”
The lack of exploitation of the local wood caused the cedar forests to become denser and the trees larger, aggravating the problem of pollen clouds.
It is estimated that currently cedar forests cover 12% of the Japanese territory.
Not just the forests
The Japanese Ministry of the Environment estimated in early spring that the amount of circulating cedar pollen would be the highest in 10 years by 2023.
However, for Professor Uehara there is something we should not forget: cedar and cypress forests are not the only “culprits” of the hay fever crisis in Japan.
Other factors are aggravating the pollen allergy problem and have a global impact.
One of them is pollution in cities.
A study in Switzerland determined, for example, that some pollutants bind to pollen particles, increasing the allergic reaction.
And other polluting particles can damage the surface of the pollen causing it to break up into small fragments.
Climate change is also affecting the pollen season, which not only starts earlier, but lasts longer.
There are indications that plants produce more pollen and sooner when temperatures are higher.
A study this year in the United States found that between 1990 and 2018, the length of the pollen season in North America increased by at least 20 days and the concentration of pollen in the air by 21%. That is largely due, according to the authors, to global warming.
A lesson for the world
Prime Minister Fumio Kishida warned that Japan’s hay fever crisis “will not be resolved overnight and requires long-term efforts.”
A panel of ministers must propose concrete measures in June.
The government has already identified some actions, according to the local press: cutting down cedar forests and replacing them with varieties of that species that produce less pollen, using artificial intelligence to make alerts about pollen levels more accurate, and improving medical treatments.
For Professor Uehara, the post-war hay fever and forest crisis in Japan holds a profound and global lesson above all: destroying biodiversity can have unforeseen consequences decades later.
“The main problem is the artificial planting of a species of tree. The main measure should be to promote mixed forests of cedar and other species, ”he told BBC Mundo.
“The richness of biodiversity and the hay fever crisis are inversely proportional.”
Uehara recalled a line from a “famous seventh-century Japanese collection of poems called Manyoshu: ‘Pollen flies in spring, spring has come.’”
“So this pollen problem has been around for 1,400 years!”
“In my opinion the most basic response to the problem of hay fever is to be in harmony with nature.”
Keep reading:
* What are the symptoms of a throat allergy caused by dust
* How to know if we are allergic to antibiotics?
* Can allergies cause asthma?
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