The Rivanna Rambler

November 20, 2008

One of the oldest living plants on earth, Ginkgo biloba, owes its longevity to its ability to tolerate a wide range of climatic condition.

 

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This show originally aired on November 20, 2007 on “The Rivanna Rambler,” a weekly public affairs show airing every Thursday at 11:55 a.m. on WTJU 91.1 FM or wtju.net

Occasionally, I get a call from someone – usually my husband – to report a sighting that is noteworthy of investigating for this show.  So last week, when my husband called, asking for the Rivanna Rambler in a whiny, pinched voice, I knew another tip was on its way.

“I want to report a tree,” the voice said.

I pretended it was a crank call.  “What kind of tree?  Who Is this?”

“A tree with leaves falling off of it.”

“What kind of tree?”  Hey, leaves were falling everywhere around town as the cold air and shorter days were finally forcing autumn’s leafy splendor to the ground.

“Gink-go.” The voice said.
Before I could say, “So what?” my husband, in normal voice now, told me that the gingko trees along Monticello Avenue that had just shed their leaves.  He had come upon them, empty and bare, a perfect circle of fan-shaped yellow leaves at the base of each tree.

Now, I know of ginkgo biloba, used for thousands of years medicinally in the Far East, as a popular herbal supplement that is said to improve circulation and treat memory loss – and researchers at Johns Hopkins say it shows promise of minimizing brain damage from stroke.  I had not paid it much attention, though, during tree courses, because it was only a specimen tree – requiring propagation because it is not native to this area.

But I was startled to learn that the gingko does, in fact, tend to drop its leaves all at one time, as though in response to a signal spread simultaneously through the organism along pathways we have yet to discover.  A signal, that it is time.  Time to let go and pass into the quiet dormancy of winter.

I thought I’d better investigate for myself, so I drove over to UVA and found a large specimen on the curve of Alderman as it joins Ivy Road, just opposite the Chapel.  Its dark trunk and branches were not completely bare, but I could see the distinctive spur shoots on its branches.  Along that side of the road, five other ginkgos had been planted, young ones, only twenty feet tall, and here I saw at the base of each the telltale circle of yellow.  Later, I learned that the oldest local specimen stands by the Rotunda –- the Pratt Ginkgo, named for William Pratt, the first Superintendent of Buildings and Grounds, who planted it from seed in 1860.  Blandy Experimental Farm has a grove 340 specimens, one of the largest collections outside of China.

By the age of the dinosaurs 200 million years ago, several species of ginkgos had been widespread in North America and Europe for many millions of years.  But the tree seemed to decline after the age of the dinosaurs, and was gone from both North America Europe two million years ago.  When it was rediscovered 1691 in Japan, botanists realized that the tree had actually survived in China where Buddhist monks cultivated the tree and spread it by seed to Japan and Korea.  Records show that individual trees have lived 3000, maybe even 4000 years – and the species perhaps owes its survival to its longevity.

The gingko tree is now ubiquitous – as an ornamental in gardens all over the world, as street trees, as specimens in botanical gardens everywhere. In the Far East it is still planted near monasteries and shrines because it is thought that the bark and leaves secrete a sap that is fire-retardant.  It survives well in urban settings around the world due to its natural resistance to diseases, insects, air pollution and even radioactive radiation.

Not surprisingly, once noticed, I started to see the ginkgo tree everywhere.  Around town, on side-streets to the Downtown Mall, in people’s yards.  Last week, when I traveled to New York, it was everywhere, in parks, planted on shaded cross-town streets whose brownstones towered over them, their yellow leaves were a comforting reminder.  There are, in this world, only a few visible biological examples of such endurance – we know, even though we may not accept, that the flesh is mortal and that each species, each plant, each organism has its own time of dying.  The ginkgo tree that relinquishes its leaves in a sudden flush will forever be my autumn reminder that, to every thing, there is a season.