GINKGO TREES ARE LIVING FOSSILS IN AN URBAN SETTING

by Whit Gibbons

October 18, 2015

I was recently reminded that some plants and animals can be readily identified by their smell. The tea olives in my yard, for example, smell delightful.

The ginkgo trees dropping their fruits, however, do not smell so pleasant. Fortunately they are not in my yard.

Ginkgo trees are extinct in the wild, and no one knows their origin for sure. Only one species exists, with a botanical history traced back to China.

The ginkgo has one of the longest fossil records among the higher plants, has no wild representatives and yet prospers today in China and North America.

Instead of individual trees being scattered throughout forests across the Chinese countryside, the strange tree is known historically only from temple gardens. Most in existence today have been planted.

The loss of biodiversity is globally pervasive, mostly the result of short term exploitation by humans through a lack of awareness or a failure to appreciate natural environments.

Ironically, our unwitting treatment of the ginkgo tree has resulted in its preservation. One of the most mysterious plants ever to reach North America, the ginkgo serves as a reminder that human intervention into nature's ways can sometimes end positively.

The ginkgo may have been clinging to the last thread of existence, only to be saved by human meddling.

Only a single species of ginkgo exists today, the sole surviving member in the entire family. To place the taxonomic unit known as a family in perspective, all species of oak, chestnut and beech trees comprise a single family.

The ginkgo is the lone survivor of a family of trees with a fossil record extending back more than 230 million years.

The ginkgo tree has been called a "living fossil" because the only record we have of its past in the wild is through fossils.

In terms of their relationship to modern trees, the leaves of ginkgoes are broad and flat like hardwoods. However, the ancestors of ginkgoes were more closely related to conifers.

Like any other plant, ginkgoes have their own biopersonality. The trees can reach a height of more than 80 feet, and the fan-shaped leaves turn bright yellow in autumn.

The two sexes are distinct, with a particular tree being either male or female. Male ginkgoes are nice trees to have around.

Female ginkgoes are especially attractive in the fall, and only the smell of their fruit detracts from their beauty.

A person unaware of being near a ginkgo tree with ripe fruit casts a suspicious eye for unleashed dogs and begins to step cautiously.

The smell of the ginkgo fruit has been described in more delicate terms as having the odor of "rancid butter."

Some botany books simply say the female ginkgo has an "unpleasant smell." But anyone encountering the yellowish, plumlike fruit in the fall will quickly assign a distinctiveness to the tree that no other can match.

Why did ginkgo trees disappear from the wild in China? They are wind-pollinated, so their demise was not due to extinction of some rare insect that served as pollinator.

Was the ginkgo an overused wood product of some ancient Oriental culture? Is the disappearance of the once-widespread tree the result of natural processes of competition with other tree species or a pervasive blight or attack by a specialized predator or parasite?

One noteworthy point, which further increases the mystery of why the species would disappear from the wild, is that ginkgoes are noted for their resistance to fungus, herbaceous insects and industrial pollution.

Despite the unpleasant smell of ginkgo fruit for a short time in autumn, the tree is beautiful. No one knows why ginkgoes survived in the temple grounds, certainly not because some order of monks enjoyed the smell, but presumably a religious order collected and replanted seeds.

But an even greater mystery is why they disappeared from all other areas. Whatever the case, ginkgoes are still here with us, despite their official ecological disappearance centuries ago.

If you have an environmental question or comment, email

(Back to Ecoviews)

 

 
SREL HomeUGA Home SREL Home UGA Home