Why Do Ginkgo Tree Berries Stink?

Distinctive bi-lobed leaves make ginkgo trees easy to identify.

Ginkgo trees are large, deciduous trees found in temperate climates. Hardy trees well-adapted to withstanding harsh urban conditions, they are able to thrive despite poor soil, pollution and packed soil. Female ginkgo trees produce large amounts of seeds covered in a seed coat. Ginkgo tree berries stink because the seed coat contains butyric acid, a chemical found in vomit, which is released if the fruit is allowed to rot.

Fruit

The seeds of a female ginkgo tree are wrapped in a 1- to 3-inch fleshy coat. The seed coat, called a sarcotesta, naturally contains butyric acid and hexanoic acids. The combination of these foul-smelling compounds produces a noxious odor that is released into the air as the seed coat rots. The smell worsens over time as the fruit is further crushed by vehicle or foot traffic.

Seed Dispersal

For years, scientists have researched the possible connection between the smell of fruit and seed dispersal. Was the smell designed to entice an animal to eat the fruit and disperse the seeds? Theoretically, given then the prehistoric evolution of ginkgo trees, the smell could have evolved to attract some type ancient bird or scavenger, aiding the spread and survival of the species over the ages. While this hypothesis seems reasonable, it is still just speculation.

Cultivar Selection

Ginkgo trees are gender-specific plants. Only female trees produce stinky berries. Avoid the foul smell problem altogether by planting a male tree. The following cultivars consist entirely of male gingko trees: Autumn Gold, Lakeview, Princeton Sentry and Fastigiata. Alternatively, grafting portions of confirmed male with a seedling rootstock will prevent future odoriferous fruit production.

Odor Management

Clean and dispose of any fallen ginkgo fruit as soon as possible; do not allow it to remain on the ground. Ginkgo fruit will not smell unless it is given the opportunity to rot. However, as this type of vigilant maintenance is not possible in all circumstances, some cities have resorted to removing ginkgo street trees.

References

• University of California Museum of Palentology; Introduction to the Ginkgoales; Julie Jalalpour et al.; 1997
• University of Florida IFAS Extension; Ginkgo biloba: Maidenhair Tree; Edward F. Gilman and Dennis G. Watson; November 1993
• "Landscape Plants for Subtropical Climates;" Bijan Dehgan; 1998
• Harvard College; Wake Up and Smell the Ginkgos; Peter Del Tredici; 2007