TREES ARE THE tallest, most massive, and longest-lived creatures on earth. But oaks hold none of the records. The oak is not the tallest tree. That distinction belongs to a redwood in northern California, which tops out at about 368 feet, easily twice as tall as the tallest oak. Neither is the oak the most massive tree. That honor is held, if you wish, by the General Sherman sequoia in Kings Canyon National Park, weighing in at about two thousand tons, though if you are thinking genetically, the record may instead be held by a clonal aspen grove in Utah that covers more than 106 acres. The oak is not the oldest tree. The bristlecone pine holds that record, at something in excess of 4,867 years. The oak is not the strongest tree. Ebony, teak, and many other tropical woods have greater strength under tension, compression, and shearing forces. And the oak is far from the fastest-growing tree. There is a species of albizia in Malaysia that can grow more than an inch each day; an oak is lucky to do a foot each year. Any old maple, pine, poplar, or eucalyptus can easily outrun the oak.
So what is so special about oaks?
I asked Kevin Nixon, a paleobotanist at Cornell University, who studies the origin of oaks.
“Nothing,” he said, and paused.
“But what is impressive about them is that you can go from Massachusetts to Mexico City and find that the same genus—the oaks, that is, Quercus—is dominant, when there are very few other genera that are even common to both places.”
“Well, why is that?” I asked, trusting that oak held some world record at least.
“No reason,” he replied nonchalantly.
Quercus hindsii, California white oak (Collection of William Bryant Logan)
It was a good thing we were speaking by phone, since he did not see my cheeks puff out and redden as I tried to keep from spluttering. There was an awkward silence.
“It’s like the chambered nautilus,” he continued, at last. “The Nautilus genus was once very diverse, but then it overspecialized until it could only live in one particular niche in one particular way.”
“Go on,” I said. He had my interest.
“But the oaks never overspecialized,” he continued. “They never found a niche. They are so successful exactly because there is no reason that they are. Restricted distribution only happens when there is just one reason for a creature’s success.”
Here was an unexpected and tantalizing idea. The persistent, the common, the various, the adaptable has value in itself. The oak’s distinction is its insistence and its flexibility. The tree helps and is helped in turn. It specializes in not specializing.
And indeed, the champion trees are niche holders: The giant redwood can only survive on a cool, fogbound band of warm coast. The ancient bristlecone pine only grows on one high mountain ridge, where no pest can survive long enough to attack it. Ebony needs great heat, great water, and little variation in temperature to make its strong, flexible, durable wood. The clonal aspen thrives and expands only at altitudes and on exposures high and difficult enough to ward off competing species. None of these record trees thrives throughout the temperate zone, in the middle of the world, where the unexpected is commonplace.