Squished Ginkgo Berries

Ginkgo tree berries lay squished on the sidewalk outside of Andersen Hall on Tuesday, Nov. 12, 2019, in Lincoln, Nebraska.

As a part of our initiative called Curious Cornhuskers, an anonymous reader asked The Daily Nebraskan, “The fallen fruit near Anderson Hall smells really bad, why do they smell? Why were those trees planted?”

Unsuspecting students trekking through select spots around campus have likely had their nostrils assaulted by the putrid stench of a mysterious gunk. This gunk, while at first may be mistaken for the excrement of a dying animal, is the fallen fruit of the tree known as the ginkgo.

The infamous plant and subsequent rotten fruit piles can be found in front of Nebraska Hall, across the street from Andersen Hall, in front of the Bio-Fiber Development Laboratory on East Campus and more locations around the University of Nebraska-Lincoln campuses. 

While the tree is known during most of the year for its fluttering fan-shaped leaves, the ginkgo becomes a chlorophyll-based celebrity in the fall when it drops its brightly-colored fruit onto campus sidewalks. Eileen Bergt, an assistant director of Landscape Services at UNL, is no stranger to the stench of the fallen fruit.

“I have heard the fruit smell described differently — my favorite is they smell like dirty gym socks or a pungent aged cheese,” Bergt said.

Bergt said that UNL plants the trees mainly for the beauty of their leaves and their ability to thrive in urban environments.

“It is a tough, adaptable tree that has upright form and a good yellow fall color,” Bergt said.  “Ginkgos also make good street trees that have been documented to live longer than other urban trees.  They withstand air pollution, soil compaction, pests, disease, salt, wind, cold and drought.”

Justin Evertson, assistant director of the Nebraska Statewide Arboretum, explained that the ginkgo trees are unlike many other trees in the sense that they can be either male or female.

“It’s what they call dioecious, it has a male tree and a female tree. Only the female trees produce fruit,” Evertson said. 

Bergt said UNL takes steps to make sure the only trees planted on campus are male ginkgos and not the females that drop seeds, but there’s a problem — it’s remarkably difficult to tell the males from the females.

“It takes about 20 years for a ginkgo tree grown from seed to produce seeds, or if the tree is grafted, it may be five to six years. Therefore, the tree may be medium-sized before we find out that we have gotten the incorrect tree — a female tree that produces seeds.  At that point, our department may decide to remove the tree and replant or keep the tree depending on the location of the tree and its size,” Bergt said.

The ginkgos are planted because they are willing to put up with the harsh, tree-adverse environment of the concrete jungle, but the ambiguity in the tree’s sex is what often leaves female trees free to drop their stinky parcels of plant matter. 

The resulting piles of mashed up, Ping-Pong ball-sized gingko fruit release an odor that, while frightening, is the result of millions of years of hard work on the tree’s part. According to Evertson, the plant’s rank produce is actually a genius seed delivery system that evolved at the time of the dinosaurs.

“The theory is that they evolved to produce fruit that smelled real bad because they wanted to attract animals that liked carrion, or dead things,”  he said. “You know how a dog will eat poop? Some animals just are attracted to eating rancid and acrid smelling things.”

But since evolving the stinky fruit, Evertson said most of the creatures that consumed and inevitably dispersed the seeds of the ginkgo tree have gone extinct. However, the same toughness that keeps the tree alive in downtown Lincoln kept it alive for well over a million years in China, until human intervention started spreading the plant.

Evertson said he’s not aware of any creatures that still eat the tree’s fruit in present times. In a way, the tree seems to be dropping its fruit as a sort of yearning for a simpler time. A time where there were no students to gag every time they crossed the tree’s path — a time when the world was full of creatures willing to indulge in its disgusting raw fruit.

“The ginkgo is what they call an anachronism. It's out of place and out of time,” Evertson said. 

culture@dailynebraskan.com

This article was modified at 10:09 a.m. on Nov. 15 to correct the spelling of Andersen Hall.