Arrive in Seoul in late October and the city hands you two things at once. The first is beautiful. Whole avenues turn a shade of yellow that photographs refuse to capture honestly. Underneath the canopy, the light goes warm and strange. It looks as though someone installed a filter over the entire district. The second thing is the smell, and every Seoul ginkgo tree standing over that sidewalk is responsible for it.
It hits somewhere around the third block. Sour, thick, faintly organic. Most foreigners land on the same three comparisons within a week, and none of them are flattering. Vomit. Dog mess. Rancid butter left in a hot car. Meanwhile the Koreans around you keep walking, barely registering it. They step around the little beige fruits crushed into the pavement with the unhurried precision of people who have done this every autumn of their lives.
Welcome to ginkgo season. Honestly, it is one of the most confusing experiences a newcomer can have in Korea. That is because the beauty and the stench come from exactly the same source. However, the story underneath it is far stranger than a seasonal inconvenience. Seoul planted more than a hundred thousand of these trees on purpose. It made the species its official emblem. And in 2026, the city is quietly pulling hundreds of them out of the ground.
What That Smell Actually Is
Let us start with the chemistry, because it explains a lot.
Ginkgo trees are dioecious. In other words, individual trees are either male or female, and only the females produce fruit. Inside that fleshy coat sits a nut Koreans have eaten for centuries. It gets roasted, skewered, and tucked into rice porridge. The outer pulp, though, is a different matter entirely.
As it decomposes, the pulp releases butyric acid. That is the same compound behind the smell of vomit and spoiled butter. Korean sources also point to bilobol and ginkgoic acid, both of which can irritate skin on contact. According to Harvard’s Arnold Arboretum, the effect is a defense mechanism. It once attracted seed-dispersing animals that have long since gone extinct. In other words, the tree is still running software written for a vanished world.
That is not a throwaway line. Ginkgo biloba is the only surviving species of an entire plant order. Its ancestors first appeared roughly 290 million years ago. No close relatives remain today. Its family, order, and class each contain exactly one living member. As a result, it is one of the loneliest organisms on Earth, and it earned a fitting nickname: living fossil.
So when you gag on a sidewalk in October, you are reacting to a smell older than flowering plants. Somehow that does not make it better.
Why the Seoul Ginkgo Tree Became an Official City Symbol
Here is the part that surprises most visitors. Seoul did not inherit these trees. Instead, it chose them deliberately, at the exact moment the city was reinventing itself.
On April 3, 1971, the metropolitan government named the ginkgo its official city tree. The stated reasoning still appears on the Seoul Metropolitan Government website, and it is almost poetic. The ginkgo lives long and grows tall. Therefore it symbolizes the city’s unlimited development. In 1971, with the population exploding and cranes on every block, that metaphor landed perfectly.
Yet the ginkgo did not immediately dominate the streets. Korea’s urban forestry went through three distinct eras, and each one ended badly.
Through the 1970s, Seoul planted weeping willows along the Han River and Jungnangcheon. They looked graceful. Unfortunately, their seed fluff triggered respiratory complaints. Crews removed them by the end of the decade. Next came the plane tree, which ruled the 1980s on the strength of its pollution tolerance. Then shopkeepers revolted. Plane trees grow enormous canopies that block storefront signs and sunlight, so the complaints piled up fast.
Only after that did the ginkgo take over. The shift happened largely from the 1990s onward. On paper, it was the perfect candidate. Ginkgoes resist pests, disease, and air pollution with almost supernatural stubbornness. Their thick bark shrugs off fire. Each mature tree absorbs roughly 6.9 kilograms of carbon dioxide a year. Above all, they survive compacted soil and reflected heat, conditions where most species simply give up.
There was only one flaw in the plan. Nobody could tell which saplings were female.
The Seoul Ginkgo Tree by the Numbers
The scale of what Seoul built is hard to picture until you see it written down.
The city maintains roughly 303,000 street trees. Those spread across about 1,327 designated routes and 62 species. Of that total, 102,794 are ginkgoes. In short, it is comfortably the most common tree in the capital, at around a third of everything planted. Together with plane trees, just two species account for about 60 percent of Seoul’s roadside canopy. In January 2026, the city finished a digital street tree map. It assigns coordinates and a unique ID to individual trees, which finally gives planners a precise picture.
Now the uncomfortable number. Of those 102,794 ginkgoes, 25,127 are female — about 24.4 percent. Each one fruits every autumn. Moreover, a single mature female can drop tens of thousands of seeds across a season. Seoul has twenty-five thousand of them standing over its busiest sidewalks.
The distribution varies sharply by district. That is precisely why some neighborhoods smell far worse than others. Gangnam-gu, for instance, counts 7,154 ginkgoes among its 23,293 street trees. Of those, 2,329 are female, a rate near 32 percent. Seodaemun-gu has 3,100 ginkgoes with 1,341 females, an even higher share. Meanwhile the famous Garosu-gil in Sinsa-dong takes its name directly from its ginkgo-lined street. Wiryeseong-daero, similarly, packs roughly 1,320 trees into a 900-meter stretch beside Olympic Park.
The trees, in short, are not a background detail. They are infrastructure. Like all infrastructure, they come with a maintenance bill.
Autumn’s Strangest Public Job
Every September 1, something begins in Seoul with no real equivalent elsewhere. All twenty-five districts activate what officials call ginkgo nut collection task forces. For the next two months, these crews work across the capital. Their job is to shake fruit out of trees before it can hit the ground.
The logistics are more complicated than they sound. Ginkgo fruit does not ripen all at once. Consequently, crews must revisit each tree two or three times per season. Teams use aerial work platforms and safety nets stretched beneath the canopy. The real workhorse, however, is a vibrating harvester mounted on an excavator arm. It shakes the trunk roughly 800 times per minute. Before that machine arrived, clearing a district could take two full months. Afterward, according to city officials, the same work takes about two weeks.
Gangnam alone fields three teams totaling 83 workers. As the Korea Herald reported, the citywide operation targets high-traffic areas first. Officials aim to finish by the end of October. Residents can also call the 120 Dasan hotline to request removal at a specific tree, and crews are dispatched in response.
Some districts have given up on harvesting and simply wrap the worst offenders. Seodaemun-gu, for example, installed nets under 38 trees across six locations. The Korea Times documented that low-tech fix in detail. The nets are ugly. Nevertheless, they work.
This is the part foreigners rarely see. The smell you notice in October is the residue of a failed containment operation. It is not the raw problem. Without the task forces, autumn in Seoul would be considerably harder to walk through.
The DNA Fix Korea Invented
Here is where the story turns into something more interesting than municipal housekeeping.
The root of the problem is timing. A ginkgo does not reveal its sex until it reaches reproductive maturity. Historically, that meant waiting about 15 years after planting. City crews would plant a sapling and tend it for a decade and a half. Only then would they discover whether they had installed a problem. By that point the tree was mature, expensive to replace, and often beloved by the neighborhood.
In 2011, researchers at Korea’s National Institute of Forest Science solved it. They identified a DNA marker found only in male ginkgoes. As a result, a lab can now determine sex from a leaf sample taken off a one-year-old sapling. Fifteen years of uncertainty collapsed into a single growing season.
Local governments began applying the method in 2012. Korea patented the technique domestically in 2014. It then secured an international patent in China in 2015 — a small but real example of Korean forestry science exporting a solution. More than 1,100 verified male ginkgoes went into the ground as street trees in the years immediately following.
The catch, of course, is that the fix only works going forward. It does nothing about the twenty-five thousand mature females already standing. For those, Seoul faces a much blunter choice.
2026: The Year Seoul Ginkgo Tree Removals Began
In July 2026, Korean media reported the number that makes this story urgent. Across the capital, districts have scheduled at least 792 ginkgo trees for removal or replacement during the year. The true figure is likely higher, since some projects fall outside published annual plans.
The breakdown reads like a map of where the complaints are loudest.
| District | Trees scheduled | Stated reason |
|---|---|---|
| Yongsan-gu | 254 | Improving pedestrian conditions |
| Gwangjin-gu | 115 | Replacing female trees with male trees |
| Dobong-gu | 87 | Resident complaints |
| Guro-gu | 71 | Resident complaints |
| Yeongdeungpo-gu | 71 | Streetscape improvement |
Gangnam-gu has separately planned around 200 replacements of its own. Seodaemun-gu has scheduled about 40 along Chungjeong-ro.
The economics are not trivial. Swapping a mature street tree in Seoul runs an estimated 2 to 3 million won per tree. Smaller cities manage it cheaper; Incheon’s Bupyeong-gu has come closer to 1 million. Back in 2015, officials floated the idea of replacing every female ginkgo in the capital. That estimate reached 25 billion won, or about 22 million US dollars. The story traveled far enough that the BBC picked it up. In that year alone, 446 workers were assigned to nut collection.
Environmental groups have pushed back hard. Their argument is straightforward. A mature street tree delivers shade, carbon capture, and heat-island relief that a new sapling cannot match for decades. Removing a healthy forty-year-old tree because its fruit smells is, in their view, a spectacularly short-sighted trade. That is especially true for a city that keeps announcing green targets. Similar tension runs through debates over how Seoul uses public land, from the transformation of its parks to ambitious projects like the National Saemangeum Arboretum.
Then there is the symbolic problem, which nobody in city government seems eager to discuss. Seoul is removing the tree it adopted as its own emblem in 1971. Public affection has cooled, too. Gallup Korea found the ginkgo ranked second among Koreans’ favorite trees in 2004. By 2024, it had slipped to fourth.
Where All Those Nuts Actually Go
If you are wondering what happens to the harvest, the answer is genuinely charming. It is also wildly inconsistent.
Seoul sends collected nuts to the Seoul Institute of Public Health and Environment for safety screening. The institute has tested batches for 470 pesticide residues, including six neonicotinoid compounds, plus lead and cadmium. Results published by the institute showed no detection across the board. Cleared nuts then go free to senior centers and welfare organizations, where they are roasted and eaten. Busan ran a similar program and donated roughly 10,700 kilograms in 2020 alone.
Meanwhile, other districts skip the process entirely and dispose of everything. Budget and labor constraints get cited. The result is a peculiar contradiction. In one neighborhood, autumn fruit becomes a free food supply for elderly residents. Two subway stops away, the identical harvest goes into the waste stream. That inefficiency echoes Korea’s broader struggle to extract value from what it throws away, whether that is organic waste headed for biogas or electronics gathering dust in drawers.
One warning matters here, since foreigners occasionally get curious. Ginkgo nuts contain ginkgotoxin and must be cooked. Seoul’s own guidance advises adults to eat fewer than ten per day. Children should stop at two or three. Raw nuts are genuinely dangerous, and Korean hospitals see cases every year. Furthermore, do not pick fruit off the street yourself. The pulp irritates skin, and municipal harvests exist precisely so nobody has to.
Seoul Is Not Alone, but It Is the Most Committed
Cities everywhere fight this battle. New York, Washington, Tokyo, and Shanghai all planted ginkgoes for the same reasons Seoul did. All of them field autumn complaints. American coverage has been blunt about it. Slate once ran the question directly as a headline, asking why cities keep planting a tree that smells like vomit.
Most Western cities responded narrowly. They specified male-only cultivars for new plantings and left existing trees alone. Seoul went considerably further. It built a national screening technology, deployed hundreds of seasonal workers, bought specialized machinery, and now funds systematic replacement at scale. That level of intervention reflects something specific about Korean urban governance. Complaints get logged, aggregated, and acted upon with unusual speed.
There is also a deeper irony worth sitting with. Research published in Nature Communications in 2019 analyzed 545 resequenced genomes. It established that ginkgo biloba survived the last ice ages in a handful of Chinese refugia. Humans, not nature, spread it across the world afterward. The genetic trail shows the tree reaching Korea and Japan from eastern China well before it ever arrived in Europe. Buddhist monks and Confucian scholars planted it at temples and academies. That is why Korea’s oldest specimens still stand beside them today.
The species was, in effect, rescued from extinction by people. Now it is being removed from Korean streets by their descendants because it smells bad. Few urban policy debates come with a backstory quite that long.
For what it is worth, the ginkgo has survived worse. Six ginkgo trees lived through the atomic bombing of Hiroshima. One stands at Hosenbo temple, just 1,130 meters from the hypocenter. When the temple was rebuilt, architects curved the entrance stairs around the surviving trunk rather than cut it down. All six trees are still alive.
A Field Guide to Seoul Ginkgo Tree Season
If you are visiting or newly arrived, a few practical notes will make October considerably easier.
Timing. Peak yellow in central Seoul typically arrives in late October and early November. That is roughly a week or two after the mountain foliage further north. The smell peaks slightly earlier, once fruit begins dropping in mid-October, and it fades fast after the first hard frost. Anyone planning a broader autumn trip should note that color moves down the peninsula on a schedule. That rhythm drives Korea’s enormous fall foliage economy.
Where to look, and where not to step. Male trees drop leaves but no fruit. Therefore the loveliest ginkgo streets are often the ones with no smell at all. Deoksugung’s stone wall path, the Gyeongui Line Forest Park, and much of Garosu-gil deliver color without the hazard. By contrast, older residential streets in districts like Dobong and Guro tend to be the pungent ones. That is exactly why they appear on the 2026 removal lists.
Watch your shoes. The pulp does not brush off. It smears, and it clings to rubber soles with remarkable determination. Walk the center of the sidewalk rather than the tree line, and check before boarding a bus.
Try the nuts properly. Skewered roasted ginkgo nuts, or eunhaeng, appear at street stalls and in Korean pubs during autumn. Served hot with salt, they are chewy and faintly sweet. In fact, they taste nothing like the smell that produced them. That contrast is the most Korean thing about the entire situation.
Say the word. Ginkgo is eunhaeng (은행) in Korean. Amusingly, that is also the exact word for “bank.” Autumn in Seoul is therefore full of bilingual jokes about money falling from trees.
What the Seoul Ginkgo Tree War Is Really About
Strip away the smell, and this becomes a case study in something every fast-growing city eventually confronts. Decisions made decades ago at enormous scale arrive all at once, as a bill.
In 1971, planting a resilient, symbolic, pollution-proof tree everywhere was unambiguously smart policy. Nobody was weighing sidewalk odor against carbon capture. Nobody had a way to tell the saplings apart, either. Fifty-five years later, the consequences are fully grown, deeply rooted, and impossible to undo cheaply. Korea’s answer has been characteristically technical and characteristically fast. Invent the screening tool, patent it, deploy the machines, and replace what cannot be fixed.
Whether that answer is correct remains a fair question. A city that removes hundreds of mature trees each year to solve a six-week annoyance is making a real trade. Anyone who has endured a Seoul summer knows what shade is worth. Environmental groups are not wrong to call it short-sighted. Residents who walk through the mess every October are not wrong either.
For now, the compromise holds. Every September 1, the task forces roll out. Harvesters shake the trunks, nets go up, and a few hundred trees come down. Meanwhile the rest turn gold on schedule and light up the entire city for about two weeks. Most years, one Seoul ginkgo tree in full color is enough to make everyone forgive the other hundred thousand.
