If Bill Nye Was a Very Old Tree, What Kind of Very Old Tree Would He Be?

It would be hard to think of anyone who's done more to spread enthusiasm for science among American kids than Bill Nye. Since his show "Bill Nye the Science Guy" first went national 21 years ago, he's become synonymous with televised scientific wonder among people in demographics just a little bit younger than mine. And for good reason: he does a great job conveying complex concepts to developing minds.

Nye's gotten a little more press than usual lately after his much-publicized debate early in February with evolution denier Ken Ham, and one of those bits of additional press came in the form of a guest shot on February 14 on the HBO talk show "Real Time with Bill Maher."

While talking with Maher about why he didn't find Biblical Creation myth plausible, Nye ventured into my usual turf: the deserts of California. That's cool, but he made an error in basic fact that I can't help but pick at. I don't care how popular he and his bow tie are: I can show no mercy.

Okay, I'm kidding. First off, Nye's error was a mild one, easily corrected, and I'm pretty sure I've made similar errors in my public speaking here and there. Besides which, science is a process by which we humans correct our own mistakes en masse. And I have a long way to go before I'll have done as much to spread the good word of science as Bill Nye has, whether through his media work or his heading up the Planetary Society, a space exploration education group based in Pasadena, California, Earth.

But as the error went uncorrected on the show, and as it provides me with an excuse to talk about some living things I admire other than Bill Nye, I'm going to have at it.

Here's a transcript of the relevant portion, with false starts and interruptions removed for clarity:

Maher: 46 percent of Americans believe the story of Genesis is true ... that the world was created in six days. Just give us the simplest answer you can, the first two or three things that come to your mind, why the world is not 6,000 years old.

Nye: Well, there are trees.

Maher: Trees? (laughs)

Nye: Within a few hours drive of here that are older than 6,800 years: the bristlecone pine.

Now like I said, that's the kind of mistake it's very easy to make when you're on the spot, not working from notes, and engaging in repartee with one of the snarkiest people on television. But it's a mistake nonetheless, and given that we're talking about arguing with argumentative Creationists here, it might well be a mistake that gets used to discredit Nye's message.

So let's correct it: Nye was off by about 2,000 years on the age of the oldest known bristlecone pine tree. The tree generally known as "Methuselah," which grows in an undisclosed location on the upper slopes of the White Mountains in Inyo County, and which was until recently thought to be the world's oldest single-trunked tree, is 4,847 years old this year. That means it germinated as the Second Dynasty was just getting under way in Egypt, which means it's not an effective argument against the world being created in 4004 BC.

In 2013, a bristlecone pine even older than Methuselah was discovered, though perhaps it's more accurate to say it was discovered in a laboratory while growing in the White Mountains. In the late 1950s, Edmund Schulman, one of the founders of the science of dendrochronology, which essentially means "tree timekeeping," took a core sample of one of Methuselah's neighbors and stored it away. In 2012 botanist Tom Harlan finally counted the rings. The tree is still alive, and is now 5,064 years of age. That puts its germination at 3050 BC, which is a long time ago. Back then Stonehenge was a circular ditch, and writing had just been invented in living memory by the Sumerians. But that's still not old enough for a slam-dunk "told ya so" to the Biblical creationists.

The new holder of the "Oldest Known Bristlecone Pine" title is, by default, also the oldest known single-trunked tree. Why single-trunked? Because there are trees (and shrubs, too) that are far older than the unnamed champion bristlecone: it's just that they grow lots of trunks from their ancient root systems, the oldest of which might be only a few centuries old.

One of those trees is actually much closer to the HBO studios than are the White Mountain bristlecones. In the Jurupa Mountains in Southern California's Riverside County, there's a clump of scrub oak, Quercus palmeri, that germinated from its acorn an estimated 13,000 years ago. It's not a great big impressive-looking single-trunked tree: it's a mass of roots that send up small shrubby trunks, which grow for a few decades or centuries and then die back, to be replaced by newer small trunks. But nonetheless, it's a plant that germinated 13,000 years ago.

A plant like the Jurupa oak, which lives for eons even though any individual part of it might not be all that old, is often called a "clonal colony." Admittedly, it's a little bit harder for some folks to think of a clonal colony as an individual plant. We ourselves resemble single-trunked trees more closely, and with very few exceptions we do not generally grow clonal shoots of ourselves that then replace us as we die of inevitable wear and tear. But plants are weird, and clonal colonies are a really common way plants have of blurring our definition of an "individual."

Take for example King Clone, the famous creosote ring an hour northeast of the Jurupa Oak in Johnson Valley. It's a ring of creosote bushes that germinated from a single seed about 11,700 years ago. Some of the clumps of creosote that make up King Clone may not be connected to the rest of the ring. Do they still share an individual identity with the rest of the ring? That depends on your definition of "individual." It also may depend on who's buying the beer for the botanists arguing the issue.

Not impressed with these scrubby oaks and scratchy creosotes? You want a real tree? Well, consider Pando. Few would dispute a quaking aspen's claim to the status of "tree," and Pando is an aspen to beat all aspens. It's a clonal clump of the picturesque tree growing in the Fishlake National Forest in Utah. It covers 106 acres. It has something like 40 thousand trunks. Its weight has been estimated at around 13 million pounds.

And though each of Pando's 40,000 trunks tend to get no more than 130 years old before they die, they're all connected by a single root system that is estimated to be 80,000 years old. One individual organism, 80,000 years in age.

That means Pando germinated almost 74,000 years before 4004 BC.

Still, there's something about counting tree rings all in succession that's much more emotionally satisfying than guessing at the age of gigantic clonal rings and roots. In that second case, we generally figure out how fast the clonal clumps grow and do the math. But that takes algebra. Just counting? Anyone can grasp counting.

Fortunately, there's a way to get us past 4004 BC with just counting tree rings. But we need more than one tree to do it.

Trees put on fat growth rings in years in which they get enough water and nutrients. They put on thinner growth rings when conditions aren't as comfortable. That means that you can tell more or less what growing conditions were like over the course of a tree's life by looking at the patterns on the growth rings. And since those conditions tend to be the same for other trees nearby, the growth ring patterns for those years will tend to be the same.

Let's say you have a 500-year-old tree you've just cut down. (Don't actually do that.) You examine the rings and you find that when the tree was a mere 150 years old, 350 years ago, it went through a 27-year-long drought with three wet seasons in years 8, 9, and 22.

Down the hill is an ancient ruin of an adobe, and a rough-hewn log beam that once held up the roof -- a "viga" -- attracts your attention. You look at the rings in the exposed cross-section. At the outside edge of the log you see a familiar pattern: 27 years of thin rings with thicker rings at 8, 9, and 22. There are 600 rings between that drought pattern and the trunk. That means the tree was 600 years old when the drought hit 350 years ago. Which means you've got a record, in your two tree trunk cross sections, of 950 years of tree trunk history.

Dendrochronologists have done a more complicated version of that tree-ring matching with bristlecone pines in the White Mountains. They have described about 8,000 years of chronology recorded in the growth rings of those bristlecones, some of which may have died before the odometer rolled over to the year 1 A.D.

That means that we have a confirmed record of bristlecone pine growth rings stretching back a full two millennia before 4004 BC. At some point in the Sixth Millennium BC, that earliest bristlecone pine in the dendrochronological record sprouted from a pine nut in a range of mountains already surrounded by a new desert. Its first root pushed down as deep as it could reach toward the mountain's heart. The seed's developing leaf, thin as a blade of grass, pushed skyward through the gravelly soil.

Before long that leaf's tip broke the surface, came out into the open. It began to capture the sunlight to help it grow. And the evening and the morning were the first day.