Wednesday, July 6, 2011

Ginkgo Trees

Embrace your inner tree hugger and learn a little about the one-of-a-kind Ginkgo tree.

The Ginkgo biloba is a non-flowering plant species with no close living relatives, easily recognizable by uniquely fan-shaped leaves. When grown in sunny, well watered, and well-drained locations, ginkgoes can grow over 100 feet; some Chinese specimens are over 150 feet tall!

Ginkgoes are more than just large: they’re impressively long lived, with some trees suspected of being 2,500 years old. This astonishing lifespan is owed in part to natural resistance to disease and insects, as well as general toughness; six ginkgoes in Hiroshima survived the 1945 atom bomb explosion, despite being less than a mile away from ground zero.

This resilience may explain the longevity of the Ginkgo biloba as a species. Like horseshoe crabs, they’re considered living fossils, having survived about 50 million years without noticeable evolution. Despite their persistence, the ginkgo is actually an endangered species. Indeed, scientists suspect that it may have been extinct in the wild at one point, existing only in cultivated groves and gardens.

Originally from China, humans have been cultivating ginkgoes for over 1,500 years – most famously in Buddhist monasteries. Because of it’s association with Buddhism, the trees also became popular in Japan and Korea. The tree was first introduced to Holland in the 1700s, and shortly after spread to other European cities; it reached the Americas after the Revolutionary War. Today, ginkgoes are common “street trees” in urban areas, because of their resilience and ample shade.

Whereas most plants contain both male and female reproductive structures in one organism, ginkgoes are dioecious –trees are either male or female.  Males produce small, pollen-producing cones that release motile (free-swimming) sperm. Instead of cones, females form two ovules at the end of stalks; after fertilization, one or both of these ovules develop into seeds.

Ginkgo seeds have a yellowish, fleshy outer layer – they’re often mistaken for a fruit or berry. This fruit-like covering contains butyric acid, which smells similar to rancid butter or vomit. Although this fleshy, outer layer is poisonous, the pistachio-like seed itself is a traditional ingredient in Chinese and Japanese cuisines. Likewise, ginkgo leaves have long been used as a folk remedy to improve memory and blood circulation, although there is ongoing debate around ginkgoes scientific effectiveness.

Before we close the book on these fascinating trees, let’s consider its name. The original Mandarin word is yínguŏ (“silver fruit,” for its seed’s silver sheen), but they’re more commonly known as yinxìng (“silver apricot”). When the plant was introduced Japan, it was called ginnan (which also means “silver apricot”). This word can also be pronounced ginkyō, which was transliterated to English as “ginkgo” – though “ginkio” or “ginkjo” would have been closer in to the Japanese. No matter what you call this plant, it’s still the same unique tree it’s been for 50 million years. I guess the old adage proves true: a ginkgo by any other name would smell just as gross.

Source: 1, 2, 3, 4