Japan is experiencing a severe rise in seasonal allergies that affect millions of people each spring. The main cause is not pollution or lifestyle, but a forestry decision made after World War Two.
During the post war recovery period, leaders replanted large areas of forest. They chose mostly cedar and cypress trees to restore damaged land and prevent soil erosion. This helped stabilize mountains that had been stripped during the war years.
However, these trees produce high levels of lightweight pollen. Over time, this turned into a national health problem.
How forests became a pollen source
Around one fifth of Japan’s land is now covered with these planted forests. Many of the trees have reached full maturity and release even more pollen.
Each spring, strong winds carry pollen into cities. This triggers widespread allergic reactions among the population. People often wear masks outdoors to reduce exposure.
Experts say the issue has grown worse because large areas contain the same type of tree. This makes pollen release more concentrated during the season.
Impact on daily life and economy
Allergic rhinitis now affects a large share of the population. Studies suggest around 43 percent of people in Japan experience symptoms ranging from mild to severe.
The condition does more than cause discomfort. It disrupts sleep, reduces focus, and can worsen other health issues like asthma.
The economic impact is also significant. During peak pollen season, losses from reduced productivity and lower spending reach billions of dollars each day.
Why the problem keeps growing
Climate change is also affecting the situation. Spring arrives earlier in Japan, which extends the allergy season.
Older forests release more pollen as they mature. With many plantations reaching this stage at the same time, pollen levels spike across regions.
Experts describe the situation as a growing public health challenge that needs long term forest management solutions.
