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Urban Forests

A Natural History of Trees and People in the American Cityscape

by Jill Jonnes

Hardcover, 394 pages, Penguin Group USA, List Price: $32 |


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Urban Forests
A Natural History of Trees and People in the American Cityscape
Jill Jonnes

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From Thomas Jefferson's day to the present, a fascinating natural history of the tree in American cities discusses the people presidents, plant explorers, visionaries, citizen activists, scientists, nurserymen and tree nerds whose arboreal passions have shaped and ornamented the nation's cities.

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Excerpt: Urban Forests

Chapter One

"So Great a Botanical Curiosity" and "The Celestial Tree": Introducing the Ginkgo and Ailanthus

On July 7, 1806, the wealthy Philadelphia plant collector William Hamilton, sixty-one, dipped his quill pen into an inkwell and began a postscript to a letter to President Thomas Jefferson, who was summering down at Monticello. "In the autumn, I intend sending you if I live," wrote Hamilton, then in the throes of searing gout pain, "three kinds of trees which I think you will deem valuable additions to your garden." Hamilton took competitive pride in possessing every possible botanical rarity. Over the course of twenty-five years, he had transformed the Woodlands, his six-hundred-acre estate overlooking the Schuylkill River, into the young nation's premier showcase for exotic plants and trees. Jefferson, himself an ardent gardener, had pronounced his friend Hamilton's country home "the only rival which I have known in America to what may be seen in England."

Nothing gave Hamilton more joy than showing off his vast greenhouse with its ten thousand plants and his landscaped "natural" pleasure grounds, whose lawns sloped down to the river, artfully "interspersed with artificial groves . . . of trees collected from all parts of the world." He relished his visitors' amazement as they stared at strange "foreign trees from China, Italy, and Turkey," fingering the unusual leaves and bark, inhaling their "balmy odours." As Massachusetts congressman Manasseh Cutler recalled of a visit to the greenhouse: "Every part was crowded with trees and plants, from the hot climates, and such as I have never seen. All the spices. The Tea plant in full perfection. In short, [Hamilton] assured us, there was not a rare plant in Europe, Asia, Africa, from China and the islands in the South Sea, of which he had any account, which he had not procured." Another botanical pilgrim to the Woodlands favored with a personal tour peered in pleasure at "the bread-fruit tree, cinnamon, allspice, pepper, mangoes, different sorts, sago, coffee from Bengal, Arabia, and the West-Indies, tea, green and bohea, mahogany, Japan rose, rose apples. . . . The curious person views it with delight, and the naturalist quits it with regret."

Hamilton, famous as a genial host and a great talker, was not, however, generous with his green prizes. Once during a dinner party, he entered his greenhouse to pick a special camellia for the table's centerpiece and came upon a young lady with said flower in her hair. Hamilton hurled a curse, exclaiming, "Madam, I had rather have given you one hundred guineas than that you should have plucked that precious blossom." Philadelphia nurseryman Bernard McMahon complained to Jefferson that while he had bestowed upon Hamilton "a great variety of plants . . . he never offered me one in return. . . . I well know his jealousy of any person's attempt to vie with him, in a collection of plants."

And so it was no small gesture for Hamilton, dismissed by a neighbor as "interested only in his house, his hothouse and his Madeira," to be offering Jefferson among his gifts one of his rarest treasures, an offspring of his "Ginkgo biloba or China Maidenhair tree . . . said by Kaempfer to produce a good eatable nut." In 1784 Hamilton had again bested his plant-collecting rivals, securing before all others in America these exotic ginkgoes with their distinctive fan-shaped leaves. He had sailed to London that year to settle various debts, and while there he had ordered his private secretary back at the Woodlands to "take time by the forelock" and begin sowing seeds in large quantities of native trees such as "white flowering Locust, the sweet or aromatic Birch, the Chestnut Oak, Horsechestnuts, Chinacapins, Judas Trees, Dogwoods, . . . Magnolias," and not to fail to "put into a nursery handsome small plants of Elm, Lime, Locust, sweet Birch, white pine, ash leaved maple, sugar maple, aspen poplar, Zantoxylon or tooth ache tree, magnolia," etc. In a subsequent letter Hamilton asked his secretary about the fate of seeds he had sent home by sea: "Did not any of the seeds vegetate of a Bushel of Horsechestnuts, a peck of Spanish chestnuts, 3 pounds of pistichia, 11 quarts of Portugal Laurel, 5 pound of silver Fir . . . or have they all gone to the Dogs too?" And as winter approached in 1785, he instructed, "Secure the tender plants from the severe weather, otherwise all my pains will have been to no purpose," mentioning specifically his ginkgo.

The first ginkgo seeds were long believed to have been brought to Europe from Japan in 1693 by Engelbert Kaempfer, a physician-botanist with the Dutch East India Company. Those seeds produced a tree at the Botanic Garden in Utrecht, Holland. By 1754 England's Kew Gardens had acquired its first ginkgo, and today we presume that it was that tree's offspring that came to grace Hamilton's grounds.

For all Hamilton's considerable botanical mastery, he could not have known, as the leaves of his growing ginkgoes turned a pure yellow each autumn, that this species had been commonplace in the temperate North American forests of the Jurassic age. An abundance of fossils record that the ginkgo tree was among the many fauna and flora of North America that were glaciated out and effectively driven into extinction on the continent by the Ice Age. When Hamilton brought the ginkgo back to one of its former habitats, he was unwittingly reintroducing an evolutionary superstar: Scientists now know that the ginkgo biloba tree or its ancestors have existed on earth for 250 million years, longer than any other tree now living. (Both the eighteenth-century Utrecht and Kew Garden ginkgoes are still alive today.)

Nor, one suspects, could Hamilton have envisioned how rampantly ginkgo would eventually recolonize the New World, though not as a part of the forests it once dominated. Instead, ginkgo's modern incarnation would be as a cultivated urban tree, an elegant urban denizen valued for its distinctive fan-shaped leaves and above all its ability to grow in the smoggiest of cities, indifferent to poor soil and polluted air, a tree that had also survived whatever pests had once afflicted it in the era when dinosaurs stomped through ginkgo forests.

Such was Hamilton's reputation as a fanatic plant collector and propagator extraordinaire that on March 22, 1807, Jefferson wrote to alert him that explorer Meriwether Lewis would soon arrive at the Woodlands with packets of some of the precious seeds-"these public treasures"-gathered on the three-year Lewis and Clark expedition. Wrote Jefferson, "I am sure I make the best possible disposition of them." During his presidency Jefferson continued to trade various plants and trees with Hamilton, dispatching to the Woodlands on March 1, 1808, eight aspen trees with "paper whiteness of the body . . . and [stem and leaves] more tremulous." In a long letter the president praised Hamilton, saying, "Your collection is really a noble one, & in making & attending to it you have deserved well of your country." Some thought the less-than-patriotic Hamilton, who had faced two trials and acquittals for treason during the Revolutionary War, was lucky to have held onto his family's estates and the five hundred acres that were the site of Lancaster, Pennsylvania. That town's ground rents, while a never-ending headache to collect, were the basis of his great wealth.

After Hamilton's death in 1813, the Woodlands declined, as subsequent owners failed to maintain the expensive grounds. Factories, oil refineries, and railroads soon overwhelmed the nearby bucolic landscape, and in 1840 the estate's last owner sold it to a cemetery. Yet the ginkgoes lived on, still such a rarity that not long after the cemetery opened, a young Hudson River nurseryman named Andrew Jackson Downing showed up to wander its new paths in search of these legendary trees. Jackson, twenty-six, soon vaulted to fame as the nation's original home and garden guru, the Martha Stewart of his day, by publishing his Treatise on the Theory and Practice of Landscape Gardening (1841). The first such book aimed at an American audience, it would eventually go through eight editions and sixteen printings.

A slight, poetic man with intense brown eyes, dark, curling locks, and a square jaw with a dimpled chin, Downing had strong opinions about tasteful architecture, the intricacies of pomology (apple raising), and the necessity of beauty in gardens and everyday life. The youngest of five children, he had grown up in Newburgh, New York, with a beautiful view of the Hudson River and the mountains. He completed school at sixteen and went to work in the family's commercial nursery, situated on the ten acres surrounding its home and offering customers hundreds of varieties of apple, pear, peach, and cherry trees. In 1838, at age twenty-four, Downing married Caroline Elizabeth DeWint, whose mother was a niece of John Quincy Adams.

During regular visits to nearby wealthy estates as part of that work, Downing came to know and admire a number of ardent gardeners, including Henry Sargent, a wealthy New York banker who was beautifying his new estate, Wodenethe, across the Hudson. Sargent and other clients became friends, opening Downing's eyes to a world of aesthetics, culture, and knowledge that he would embrace and share with other aspiring Americans through his writings and landscape design.

After locating Hamilton's fifty-six-year-old ginkgoes amid the new Woodlands Cemetery grave sites, Downing described the tallest as being fifty-five feet high and three feet, four inches in circumference. Another famous ginkgo, not as tall, could be admired in Boston, wrote Downing, "standing on the north side of that fine public square, the Boston Common. It originally grew in the grounds of Gardiner Green, Esq. of Boston; but though of fine size, it was about three years since, carefully removed to its present site, which proves its capability for bearing transplanting. Its measurement is forty feet in elevation, and nearly four in circumference." Through Henry Sargent the up-and-coming Downing would meet horticulturally inclined Boston Brahmans, including (we speculate) a very young second cousin of Henry's named Charles Sprague Sargent, who decades later would become America's most influential tree expert.

As Downing became famous, a steady stream of visitors began to appear to admire his faux-sandstone Elizabethan villa and parklike gardens on the family land in Newburgh. They described a slight, almost Spanish-looking man of "easy elegance," who with his lovely wife (they had no children) "seem to live for the beautiful and the agreeable in life amid a select circle of friends . . . and a cheerful and unembarrassed social intercourse seems to characterize the life of this circle." In contrast to William Hamilton, who was stingy with his plants and flowers, a guest of Downing's who exclaimed in pleasure over a creamy magnolia blossom would soon find one perfuming his place at the breakfast table each morning for the rest of his stay. One observant guest noticed that amid all this ease, lush gardens, and laden fruit trees, Downing, a passionate tree lover, was in his study very early working, and often returned there long after guests were asleep.

And so we like to imagine Downing toiling discreetly away before dawn some fine morning, writing in his Treatise about the ginkgo: "This fine exotic tree, which appears to be perfectly hardy in this climate, is one of the most singular in its foliage that has ever come under our observation. . . . The fruit is a drupe, about an inch in length, containing a nut. . . . They are eaten after having been roasted or boiled, and are considered excellent." Or so he had read, for when Downing wrote this, no female ginkgo in America had yet reached puberty and begun the tree's uniquely active sex life. "Abroad," he noted, the ginkgo "has fruited in the south of France, and young trees have been reared from the nuts." "The ginkgo tree," added Downing, "is so great a botanical curiosity, and is so singularly beautiful when clad with its fern-like foliage, that it is strikingly adapted to add ornament and interest to the pleasure ground." Of course, he soon installed one of these lovelies in his garden.

The ginkgo was by no means Hamilton's only big arboreal claim to fame and urban legacy. For in the same year-1784-that he sent his ginkgoes back to the Woodlands, he also secured his other great Oriental novelty: the tree of heaven (Ailanthus altissima) from northern China. There ailanthus was more than just an ornamental fast grower. Its wood was well suited to the kitchen steamers basic to all Chinese cuisine, while one treatment for mental illness called for an elixir of ground-up ailanthus root mixed with two liters of the urine of small boys and a paste of black soybean and various other medicinal herbs, left overnight, boiled, and then administered once daily. For balding men hoping to stimulate hair growth, pharmacists proposed a pulverized mixture of ailanthus, peach, and catalpa leaves, their extracted juice smeared on bald spots.

Like the ginkgo, the ailanthus had a colorful provenance. In the mideighteenth century the Chinese imperial court banned foreigners from the Celestial Kingdom, except for certain seaports. However, the emperor did accept the presence in Peking of a handful of French Jesuit priests, well schooled in science and technology. One, Father Pierre Nicolas Le Chéron d'Incarville, joined the mission in 1740 at age thirty-four. He had studied botany under Bernard de Jussieu, superintendent of the Jardin Royal des Plantes in Paris. Arriving in Macao and traveling up through South China to Peking, d'Incarville soon began sending herbarium specimens and seeds back to Jussieu as best he could. Mistaking the ailanthus for the highly valued Chinese varnish tree-their slender, pinnately compound leaves are very similar-in 1751 he sent a supply of the ailanthus's papery seeds back to Paris.

In France, Jussieu planted some and dispatched a few more across the Channel to the Royal Society. English nurseryman Philip Miller of the Chelsea Physic Garden sowed some of them and watched his little trees of heaven grow at a prodigious rate, three to five feet a year until they reached sixty feet tall, with plentiful suckers (growths from the roots) that made it easy to raise yet more trees. The tree was already popular in Europe when Hamilton dispatched one home so that he could become the proud first possessor in America of this rarity.

Also like the ginkgo, the ailanthus was destined to become an American city tree par excellence. But while the ginkgo grew at such a slow pace that it remained a precious collectible for another century, the tree of heaven would enter the nursery trade by the 1820s, heavily promoted by the Robert Prince Nursery of Flushing, New York, for its rapid growth, frothy foliage, and indifference to coal smoke and insects. Downing, in his Treatise, championed the exuberant ailanthus, enthusing that, in its first half dozen years of life, it "outstrips almost any other deciduous tree in vigour of growth, and we have measured leading stems which had grown twelve or fifteen feet in a single season. . . . There are, as yet, no specimens in this country more than 70 feet high; but the trunk shoots up in a fine column, and the head is massy and irregular." Unlike ginkgoes, ailanthus rarely live more than sixty years, and Downing made no mention of having seen any when he visited the Woodlands Cemetery. By then, Hamilton's original ailanthus specimens may have perished but certainly would have sired many hundreds, if not thousands, of offspring.