Later this fall, the singular fan-shaped leaves of the ginkgo tree will turn a rich golden yellow, and in the silence of the night, the tree will offer a little arboreal tremor and drop its entire canopy in one go.
Not the drawn out, leaf-by-leaf striptease of the oak tree, but the total release of its unique and primal foliage. The phenomenon leaves a knobbly, naked tree but also a pavement of gold, at least for a few days. An old ginkgo can have as many as a million leaves.
Some people dislike the ginkgo, mostly for its smelly and messy fruit, others because it doesn’t pass muster as a native plant, but I love it. More to the point, Sir Peter Crane loves it. In his new book, “Ginkgo,” he ties together the botany, history and lore of a plant that is unique on Earth.
“Unique” is an overworked adjective, but it applies to the ginkgo. Among seed-bearing plants, botanists know five groups: the vast tribe of flowering plants, from maples to rice; the conifers; the palmlike cycads; and an obscure clan called the gnetales, whose most famous member is the ephedra. The fifth group is represented by the lone surviving species of the living fossil we know as Ginkgo biloba.
It is this unbroken connection to a world dating back tens of millions of years that gives the ginkgo a singular appeal, imparting a frisson, really, at the thought that among us today is the same plant known to the dinosaurs.
Old trees in general remind us of our own limited life span, but the ginkgo “epitomizes that in an even greater way because it’s a member of a lineage going back 200 million years,” said Crane, a paleobotanist and dean of the school of forestry at Yale University. When he served as director of the Royal Botanic Gardens at Kew, he knew as a venerable friend a ginkgo that was one of the few original Kew trees, the “Old Lions” dating to the mid-18th century. It was one of the first ginkgos brought to the West from China.
In spite of its tenacity, the ginkgo has only barely survived in the wild. Closely related species – known only as fossils – ran their course. Ginkgos once grew around the world, but the tree was erased from all but Asia by glaciers and, Crane believes, the extinction of animals that spread its seed.
“When the last great southward push of the ice had retreated, ginkgo was barely hanging on, perhaps only in protected valleys scattered across eastern and south-central China,” he writes. “By the time modern people arrived in that part of Asia, perhaps fifty thousand years ago, ginkgo was already a relic.”
So, as Crane points out, the lone surviving species of ginkgo came to rely on the lone surviving species of hominid – us – to save it. Nurtured for its sacred symbolism and the practical value of its nuts, the tree would take on a greater role in modern times.
Ginkgos grow tall but don’t spread much, flourish in tight quarters and endure pollution. These qualities make them useful in that most un-prehistoric of places – the city. This has been their salvation.
They are free of disease and pests (presumably because none co-evolved with them), and this in itself is a big deal when you consider the afflictions of elms, oaks, maples, lindens and ashes – and the effort, money and poisons expended to protect them. Ginkgos deserve a following on the simple basis that they are attractive and useful additions to our landscapes.
The fruit-wrapped nuts are messy and malodorous, if treasured in some quarters, and detract from the tree’s value along a street or next to a patio. Its sex is not revealed until it reaches fruiting age, about 25 years, so if you wish to plant a clean ginkgo, the answer is to get a male clone.
Ginkgos, thus, have a place on our tree lists, especially as street trees so that we can see out the growing season in splendor.