TOKYO, Sept. 27 (Xinhua) -- A Japanese research team conducted an aerial experiment dispersing a pollen-inhibiting agent in forests of the eastern Japanese prefecture of Tochigi to assess its effectiveness in alleviating cedar pollen allergies that afflict millions of Japanese citizens annually.
The team led by Professor Kaihei Koshio from Tokyo University of Agriculture used helicopters to disperse agents with varying concentrations over approximately 6 hectares of cedar forest in the town of Shioya on Wednesday, multiple local media outlets reported.
The primary component of these agents was sorbitan trioleate, a common food emulsifier and cosmetic humectant known for its minimal ecological impact.
As per Japan's environment ministry, sorbitan trioleate acts as a plant growth regulator, functioning by reducing the production of ethylene, a hormone associated with stamen development and pollen generation in plants. This mechanism effectively induces stamen necrosis, inhibiting pollen production in cedar trees.
Koshio said their future research will involve regular monitoring of stamen conditions and pollen dispersion patterns to validate the effectiveness of the approach.
Cedar pollen allergies, referred to as "kafunsho" in Japan, have been a long-standing seasonal concern. Cedar trees, primarily Cryptomeria japonica, release copious amounts of pollen during the spring months, leading to allergic reactions and respiratory issues in many people.
Japan's cedar forests encompass approximately 4.4 million hectares, roughly 12 percent of the country's land area. The prevalence of cedar trees corresponds to a high incidence of cedar pollen allergies.
Statistics from 2019 revealed a staggering 38.8 percent prevalence rate for cedar pollen allergies in Japan, meaning that approximately one in three individuals suffered from this condition. The direct and indirect medical costs associated with cedar pollen allergies in the country amounted to nearly 2 billion U.S. dollars annually.
The Japanese Ministry of Agriculture, Forestry, and Fisheries is actively promoting the gradual replacement of current cedar species with low-pollen-producing cedar varieties and other tree species.
However, based on ministry data, a complete transition from existing cedar forests to low-pollen cedar trees would take more than 1,100 years at the current pace. ■
