TOKYO - Highly poisonous mushrooms capable of causing severe skin damage through contact and even death if eaten are appearing in large numbers on Mount Takao in western Tokyo, raising concerns for hikers and families as unusually hot summer weather and prolonged autumn rainfall have created ideal conditions for fungal growth.
The bright red mushrooms, known in Japanese as kaentake, are among Japan's most dangerous poisonous fungi. Resembling rising flames or human fingers as they grow, they contain powerful toxins that can cause severe skin irritation and blistering if touched, while ingestion can prove fatal.
Mount Takao, which attracts approximately 3 million visitors annually, is a popular destination for hikers, families and school excursions. The mountain's relatively accessible trails and cable car service make it particularly popular among children and casual visitors, increasing concerns that people unfamiliar with the mushrooms may accidentally touch them.
Warning notices have been posted around the mountain, including near the cable car station, where prominent signs display photographs of the mushrooms and warnings in both Japanese and English instructing visitors not to touch them.
Despite repeated efforts to remove the poisonous fungi, new mushrooms continue to emerge, sometimes in precisely the same locations where earlier specimens were eliminated.
An inspection of the mountain's hiking trails found numerous varieties of mushrooms growing along the paths, including several bright red specimens later identified by an expert as kaentake.
One specimen measured approximately 5 centimeters tall and protruded from the soil like a thick red finger. Smaller examples, some measuring just 1 centimeter, were growing nearby. About 50 meters farther along the trail, two additional pinkish-red mushrooms measuring approximately 3 centimeters were discovered.
Experts confirmed that the red mushrooms observed during the inspection were kaentake.
The problem is particularly noticeable around Trail No. 5, which circles the area near Mount Takao's summit. Unlike the paved Trail No. 1, this route passes through narrow, unpaved sections with exposed rocks, dense vegetation and limited sunlight.
Tall trees keep much of the trail shaded even on sunny days, creating damp conditions favorable for mushroom growth. Experts say kaentake frequently appears near dead or weakened trees, tree stumps and decaying wood.
During a subsequent inspection, two finger-shaped red mushrooms were found growing directly in front of a warning sign placed beside a large fallen tree.
A smaller specimen had also emerged beneath them overnight. The two larger mushrooms had been observed the previous day, but the additional growth was discovered during the following day's visit.
The location had previously been cleared of kaentake, and the warning sign had been installed following the original discovery.
Researchers believe the repeated appearance of mushrooms in the same locations is attributable to underground fungal networks known as mycelium, which can remain in the soil after the visible fruiting bodies have been removed.
Removing the mushrooms above ground therefore does not necessarily eliminate the fungus, allowing new specimens to develop when environmental conditions remain favorable.
Another red mushroom measuring nearly 5 centimeters was discovered beside a warning sign at a second location along Trail No. 5, where poisonous mushrooms had also previously been removed.
A regular visitor who has climbed Mount Takao approximately 800 times said kaentake typically begins appearing around summer and that he had photographed particularly large specimens in previous years.
Although he had observed the mushrooms since around September last year, he said he could not recall another autumn when so many continued emerging in October. He suggested the prolonged rainfall may have contributed to the unusual growth.
The mountain's visitor center has been strengthening warnings and removal efforts. A facility near the summit also issued a warning on social media, noting that kaentake was appearing repeatedly along hiking trails, possibly because of the recent extended period of rain.
Koichi Inoue, a university professor specializing in mushroom research, said this year's weather had created particularly favorable conditions for fungi.
The combination of intense summer heat and prolonged rainfall, especially during September, encouraged the growth of many mushroom species, he explained.
Central Tokyo recorded 37 consecutive days of rain, the longest such period on record, providing persistent moisture that helped mushrooms flourish.
Inoue warned that the danger extends well beyond mountain trails because kaentake can also grow in ordinary urban parks and other locations where suitable trees and decaying wood are present.
Children require particular attention because the mushrooms' unusual shapes and vivid colors may encourage them to touch or pick them up.
Dog owners have also expressed concern about pets investigating or eating the fungi during walks. One visitor said dogs naturally explore such areas and that owners might discover a problem only after their animals had swallowed something dangerous.
Similar warnings have been issued by local authorities in other parts of Japan.
In Tochigi City, Tochigi Prefecture, highly poisonous kaentake mushrooms were discovered at several locations near a wildflower garden in a municipal park.
The mushrooms were promptly removed, but officials warned through social media that additional specimens could emerge.
Their concerns proved justified when more kaentake subsequently appeared in the same park, requiring another round of removal.
Authorities in Fujiyoshida, Yamanashi Prefecture, have also urged residents and visitors to remain alert for the poisonous mushrooms.
The proliferation of kaentake comes as other dangerous mushrooms have been appearing in public spaces across Japan.
During September, poisonous mushrooms believed to be the large white species known as oshiroikarakatake were found at several locations along the Arakawa River embankment in Tokyo, where residents frequently walk and exercise.
The mushrooms, which can grow relatively large and have an ordinary white appearance, contain toxins capable of causing severe gastrointestinal symptoms and headaches if consumed.
The growing number of potentially dangerous mushrooms has also raised questions about whether smartphone applications and artificial intelligence can help people distinguish poisonous species from edible ones.
Inoue warned against relying exclusively on AI-based mushroom identification systems, saying their accuracy remains insufficient for decisions involving potentially fatal poisoning.
In tests using mushroom photographs, AI identification achieved an accuracy rate of only about 60% to 70%, he said.
Many poisonous mushrooms closely resemble edible varieties, making visual identification particularly difficult even when using image recognition applications.
Inoue said identifying mushrooms through AI or internet image searches alone is unreliable and could lead people to mistake dangerous species for safe ones.
The warning is particularly relevant during the autumn foliage season, when large numbers of people visit mountains, forests and parks to enjoy the changing leaves.
Experts recommend that hikers avoid handling unidentified mushrooms with bare hands and never collect wild mushrooms for consumption without reliable identification.
They also warn against giving unidentified mushrooms to other people, as an incorrect judgment could expose others to serious poisoning.
At Mount Takao, the continuing appearance of kaentake beside existing warning signs illustrates the difficulty of controlling the fungus once its underground network has become established.
With schoolchildren, families, hikers and pet owners continuing to visit the mountain throughout autumn, authorities are urging visitors to remain vigilant, particularly along shaded trails and around dead trees where the poisonous mushrooms are most likely to appear.
Source: KTV NEWS
