The Flight of the Iguana (12 page)

During the following century and a half Le Nôtre's design concept was converted to public uses, showing up in the street plans of London, Berlin, Washington, and again his own city of Paris. In London the early trend, beginning around 1800, was to plant trees in the large open spaces that were being set aside as civic parks. The avenue in Berlin known as Unter den Linden, graced with rows of linden trees and leading up to the Brandenburg
Gate, became (with the Champs-Élysées) another of the world's best-known beautiful streets. Paris was extensively redesigned during the mid-nineteenth century by Baron George Eugène Haussmann, a city planner who favored broad boulevards and bands of vegetation for a mixture of reasons. The tree-lined avenues, according to Haussmann, would serve to “disencumber the larger buildings, palaces, and barracks in such a way as to make them more pleasing to the eye, afford easier access on days of celebration, and a simplified defense on days of riot.” The margins of greenery, by Haussmann's cunning aristocratic calculation, would preserve public order by allowing “the circulation of air and light but also troops.” And in Washington, as early as 1791, the job of creating a planned city was given to a Frenchman named L'Enfant, who devised a webwork of radial boulevards and tree-lined vistas in much the same flavor as Le Nôtre's Versailles.

From Paris and Washington, then, the trend spread to Chicago, San Francisco, Minneapolis, St. Louis, and other U.S. cities. A law passed in 1807 decreed that Detroit, in the territory of Michigan, should have a row of trees on each side of its larger avenues. And of course the landscaping impulse came also to New York City, arriving there in both of its antipodal forms. Central Park, designed in the 1850s by Frederick Law Olmsted and his partner, became America's preeminent urban park, a great paradoxical rectangle of rolling and irregular forest, representing the romantic tradition that derived mainly from England. The legacy of Le Nôtre and Louis XIV appeared too—as humble and soldierly street trees, some in rows, some alone, standing their ground in places like West Forty-fourth between Fifth and Sixth.

•   •   •

According to Adrian Benepe, there are more than 600,000 street trees (and another two million park trees) in New York City. Each year the Department of Transportation plants about
10,000 trees, replacing other trees that have been injured or removed in the course of road construction. Mr. Benepe's own department, Parks and Recreation, plants another 10,000 trees. No tree is cut down unless it is dead, terminally ill and potentially infectious, or in the path of the Transportation Department, and yet those 20,000 annual plantings are barely enough to keep up with attrition. Some sources even say that attrition is running ahead of the replanting, and that New York is moving slowly, sadly, toward treelessness.

What drives the attrition? Most of New York's street trees suffer from too little water and too much heat. During respiration (yes, trees do breathe) they absorb sulfur dioxide, hydrogen cyanide, hydrogen fluoride, peroxyacetyl nitrates, ethylene, and other noxious gases that can inhibit photosynthesis, disrupt their enzyme activity, and damage their foliage. City dust also tends to clog leaf pores, which further reduces photosynthesis and respiration and can literally cause a tree to suffocate. Weakened by such forms of stress, a city tree is all the more vulnerable to parasitic insects or some microbial malady like anthracnose, Dutch elm disease, canker, oak wilt. Even these problems, according to Benepe, are not the worst of it. “I once saw a tree that died quickly after an exterminator poured his exterminating liquid on its roots.” And then again there's the poisonous insult of dog urine, contributed to the environment of New York's streets at the rate of roughly 22,000 gallons a day. Small wonder that the life expectancy of a tree in Manhattan is only seven years. It's not easy being green in that place.

“But trees
are
highly loved and respected by most people in New York,” Benepe told me. “I think there's a tremendous sense that trees in New York make the city livable.”

Impelled by that conviction, Benepe's department back in 1984 performed an interesting and, I think, very admirable exercise. The people of New York were asked to nominate individual trees that held special meaning, special value, in their own lives. The
nominations were culled by a panel, and in 1985 a book titled
The Great Trees of New York City
appeared. Here was well-merited recognition, at last, for a certain old ginkgo at the corner of 211th and Broadway; for a certain elm at St. Nicholas Avenue and 163rd; for another elm, five feet in diameter and maybe a century old, casting its shade over Washington Square Park.

No mention was made, though, of the westernmost of two saplings on Forty-fourth Street between Fifth and Sixth. That tree (probably either a Callery pear or a locust, Adrian Benepe told me) is still in its adolescence. With great luck, against the odds, it might live to adulthood. And if we both manage to survive another thirty or forty years, I look forward to nominating it for a later edition.

Wherein Norwegian Leo Talks Straight and True, Mostly

Norwegian Leo called recently, out of the wild blue, long-distance from San Jose this time, with a zoological stumper question. As always, it was delightful and confusing to hear from him.

“Dave, listen.” He sounded breathless and exigent, and as always the conversation began in the middle. “What's the largest mammal you've never heard of?”

I thought about that for a moment. Norwegian Leo is a mechanical engineer by profession, a precise and intelligent man of far-ranging but focused enthusiasms, a man who writes letters containing better English prose than most of what I read in magazines, who loves crisp language and German cameras and improbable living creatures, who is accustomed by disposition as well as by training to checking his facts down to the fourth decimal place. I knew he had said exactly what he intended to say. I thought passingly about several largish animals of the mammalian persuasion. And then I couldn't help thinking also about St. Anselm, an eleventh-century Italian monk with a smart-aleck streak who made a name for himself in the history of philosophy by inventing an infuriatingly clever piece of logic called the ontological argument. The ontological argument claims to be a proof
for the existence of God, a proof that relies only on pure rational deduction, and believe me it's as air-tight as a can of Spanish peanuts. I had all but forgotten about St. Anselm since the week he gave me a king-size headache during one college term back in 1968, but as I held the receiver to my ear now I dimly recalled that his ontological argument works from a premise not too unlike asking
What's the largest mammal you've never heard of?
I still didn't know the answer, but since Norwegian Leo (unlike St. Anselm and, for that matter, God) is such a down-to-earth and persuasive presence, even over the telephone, I did not doubt for an instant that an answer must exist.

“It's not a cetacean, of course,” Leo added. The cetaceans are the marine mammals, including whales. “Obviously you've heard of them.”

“Extinct?”

“Living,” said Leo. “Alive and well in the jungles of central Africa. Okay. That was your one hint.”

“Duh. I was thinking, I guess, about mastodons.”

“Don't be silly, Dave. You've
heard
of them.”

“Duh.”

“Obviously not the capybara.”

“No. I've heard of them.”

“And besides, they're too small,” said Leo.

“What's the largest mammal I've never heard of.”

“Correct,” said Leo. “A straight question. Perfectly fair.”

“I've heard of manatees.”

“Of course. Obviously therefore not a manatee.”

“I've heard of aardwolves. Civets. Those type guys.”

“Right. So forget about the aardwolf.”

“This is a hard one, Leo,” I said. “This is a good one. I know I'll hate myself.”

“The
OKAPI!
” His glee was of the gentle sort, eager to be shared, not the faintest bit smug; he announced this animal's name the way you would yodel the word
SURPRISE
from behind
a sofa to a person just turning six. “Found only in Zaire. Shy and retiring. Looks like a cross between a zebra and a moose. But actually it's a kind of giraffe.”

“You were right,” I said. “Spell it. I warn you, I'm taking notes.”

•   •   •

The okapi is still largely a zoological cipher. Isolated in its small range within the central African rainforests, it had been utterly unknown to science until the turn of this century, as it was utterly unknown to me until Leo's call. The only humans aware of it were a few Pygmy tribes in what was then the Belgian Congo (now Zaire) who had long since been hunting okapi using elaborate pitfall traps. When the explorer Henry Stanley went into the Congo interior in 1890, the Pygmies he met took one look at his horses, labeled them with the word
okhapi,
and explained that they had similar animals in their own dense forests. But Stanley himself never got a glimpse. And the Pygmies' claim was ecologically puzzling, because horses and horse-like animals such as the zebra and the quagga were known to be open-land species, adapted to life on savanna and steppe. What manner of horse could survive in this tangled Congo jungle, threaded through with only the thinnest network of narrow, tunnel-like game trails?

In 1901 a complete skeleton and two skulls reached London, evidence enough for zoologists there to conclude that this creature was no horse at all. Nor was it a relative of the donkey, the ox, or the various species of antelope. In fact, it seemed to have no family resemblance to any other living mammal. But then those scientists noticed uncanny similarities between the okapi remains and the fossils of a certain extinct beast named
Helladotherium,
a short-necked giraffe that had disappeared from Europe and Asia ten million years earlier. Further comparisons showed that the okapi was anatomically similar—aside from the drastic difference in length of neck—to the living African giraffe.

The giraffe itself, though, is also a range animal, with that tall gangly shape suited to loping across savanna and browsing leaves off the high branches of a few scattered acacias. The okapi, on the other hand, has remained closer to the original ancestral pattern and in that sense is more primitive: smaller and short-necked, shaped for feeding and quick escape in those thick forests. Its main enemies seem to be leopards and humans—but that's just a calculated guess. Even today scientists know almost nothing about the ecology and behavior of okapis in the wild.

The strange pattern of coloration, for instance, is still a mystery. In silhouette the okapi might be said to resemble a horse, but when its colors and markings are filled in it becomes a patchwork, chimerical beast—like a mule painted up for Mardi Gras. The face is mostly light, with dark shadowing down the muzzle and around the eyes. The neck and the body are a solid glossy dark hue that is variously described as deep gray, rich chocolate brown, or maroon. The forelegs from the knee down are dark on their forward surfaces and white in back, as though the animal were wearing chaps. The rear legs and hindquarters are decorated with loud dark-and-white horizontal stripes, the startling white stripes radiating outward from a midpoint below the tail. Seen from directly behind, the effect is like a fireworks explosion originating from the vicinity of the okapi's genitalia—bright spears shooting away centrifugally against a blackened sky. Viewing the okapi from in front, you see an entirely different sort of animal.

The zoologists are still wondering whether this garish starburst pattern across the hind end might serve some kind of intraspecific triggering function, perhaps helping male okapis focus their attention on the prospect of sexual activity, or telling okapi young where to direct themselves for suckling. Alternatively, it may be a form of camouflage against predators, the streaks blending with blades of sunlight that penetrate the jungle canopy, the patchwork quality serving to break the animal's outline into seemingly
disconnected parts. Whatever the evolutionary logic behind this coloring, no one yet knows where it came from or how it works.

There are other uncertainties. Should the okapi be considered a threatened species, or are the forests of Zaire still relatively full of them? Not known. In the wild, is their main cause of mortality those same intestinal parasites that kill them so remorselessly in zoos—or is it predation? Not known. And then the matter of their supposedly shy behavior. One authority describes them as “extremely wary and secretive, dashing through the forest at the least suggestion of danger.” Another offers testimony from a missionary, one of the few non-Pygmy humans ever to have seen a wild okapi, who told of “stopping to watch an okapi in the headlights of his car; the animal walked up to the front of the vehicle quite calmly and turning round kicked through the car's radiator.” The question here is the same as that posed by the visual pattern: Are we dealing with one animal or several?