by Jim Atwater
Highland Park, the oldest publicly owned arboretum in the country, is now home to many of our planet’s most remarkable woody plants. Two of the most unusual, a male and female, grow on either side of the path just below the center of the reservoir. This is part of their story.
In 1988 it was estimated that there were some 4300 giant ginkgos with trunk diameters of 10 ft or more in the Japanese islands, some estimated to be over 1000 years old. Compared to bristlecone pines growing at 10,000 ft in the White Mountains of California, one determined to be 4600 years old, or the 3000-year-old Giant Sequoias of the Sierra Nevada Range, these ginkgos might still be considered young upstarts. That is until you take the longer view.
While other trees familiar to us were still only a gleam in Nature’s eye, 225 million years ago the ginkgo began evolving, assuming its present form about 65 million years ago. Leaf fossils from the tertiary period have been found that are identical to its present foliage, a butterfly-shaped leaf with no central rib. A plant now so unique that it exists as the sole member of its genus.
As might be expected, ginkgo can thrive in the most hostile of places, settings that would discourage most other plants. The species is so ancient it has either evolved before or survived all of its natural enemies.
Where it originated is also an enigma, but its natural home appears to have been southeast China where it avoided extinction during glacial periods due to the size of the Asian land mass. Almost unknown in the wild, some 250 ancient trees are growing in the Tian MuShan Nature Preserve, the oldest known collection in the world, approaching in age the great Sequoias of California. Ginkgos were introduced to Japan in the sixth century a.d. Believed to be the Bodhi tree under which Buddha found enlightenment, it quickly became sacred and was planted extensively near places of worship. A dioecious plant, the fruit (botanically a seed encased in a pericarp) from the female is prized in Asia as a delicacy and an extract from the foliage is popular as a medicinal aid for improving circulatory function and possibly even memory.
The ginkgo appeared in Europe around 1730 and in North America at Philadelphia in 1784, becoming the first ornamental Asian tree to be used for shade on these two continents. A splendid specimen growing at Kew Gardens, London since 1762 still thrives there, robustly, but none in the western world have had time to achieve the major-league status of their Asian ancestors. You would think that a tree with such a compelling resume deserves to be in everyone’s yard. Well, maybe or maybe not. Thirty-five years ago we acquired one because of its distinctive shape and foliage. That was before I learned that one should avoid the female plant, which bears the “fruit” which tends to have an unattractive aroma when decomposing in the autumnal sun. The shopper should be wary, for it will be 20 years before fruit first appears. Ours was over 25 when we first noticed something new growing near the crown. Now, its copious burden of miniature orange fruit reminds us of the approaching holiday season. However, one has to get accustomed to the fragrance. The squirrels in our yard certainly have taken a liking to them!
As might be expected of such a relict, it will thrive in the most challenging locations and has become ubiquitous in urban landscaping. No other woody plant can survive so well among the concrete and exhaust fumes of a congested major city. Fortunately a number of cultivars exist, some of them upright or columnar, which can fit into the tightest places.
The skeptical must wonder how a plant could endure essentially unchanged by the cataclysmic events that must have occurred over the last 65 million years. I don’t have the answer, but perhaps this will help. When the atomic bomb was dropped on Hiroshima in August 1945, a ginkgo estimated to be 150 years old growing next to a temple one kilometer from the explosion’s epicenter appeared to survive while all around was obliterated. In time new life emerged on the surviving trunk, which stands today on the rebuilt temple grounds, a testament to the perseverance of nature and probably the most famous tree in all of Japan.
Photos copyright Kimbery Burkard, 2009.