What's the oldest tree in Austin?
There are trees in the mountains along the border of California and Nevada that are thousands of years old. They have lived since the time of hieroglyphs in Egypt and the building of Stonehenge. They are impossibly old.
Austin does not have any of those trees.
But that doesn’t mean we don’t have old trees whose longevity can inspire awe.
Lindsey Taucher stands under the canopy of a huge live oak tree on the campus of St. Edward's University in South Austin. The tree, known as the Sorin Oak, has been a part of her life since the 1990s.
“I went to undergrad here at Saint Edward's University, and during that time the Treaty Oak was poisoned,” Taucher said. (You can read all about that incident here.) “So I think I've always been curious about trees and how they live or die — at nature’s, or other, hands.”
That led her to ask ATXplained: What’s the oldest tree in Austin?
This seems like a simple question, despite there being hundreds of thousands of trees here. Most of them are relatively young, perhaps a few decades or so, and a really old tree would certainly be known to Austin’s many tree enthusiasts.
Your immediate guess might be the obvious one.
This giant tree at Fifth Street and Baylor — near the downtown Whole Foods — is definitely a contender. I stood under the tree with Emily King, the City of Austin’s urban forester.
So how old is it?
“We can hazard some decent guesses about how old this tree is,” she said. “It's easily several hundred years old.”
It turns out finding the age of a tree is not as easy as I thought. There are a couple ways to do it. First, you can just know when it was planted. Maybe you were there or maybe there are old photographs of it as a sapling.
But when you’re talking about trees that are hundreds of years old, that’s not a thing.
With older trees, maybe there's a record. Maybe someone wrote down, “I planted this tree on such and such a date.” Or maybe a story was passed down orally from generation to generation.
Another option is to count the rings inside the tree — one ring for every year. But that’s not so easy, either.
“Usually the easier time to count those rings is when you have a slab of trunk,” King said. “And that's obviously not something that you can do while the tree is still standing.”
As in, while it’s alive.
You can take a core sample, but that means drilling into the tree, which can damage it — potentially shortening its life.
Another way is to just measure how big around the tree is. But again, that’s going to give you only an approximation of the age, because there are so many factors involved in tree growth. How much water is around? How good is the soil? What species of tree is this? Some trees grow faster than others.
“There are kinda two strategies of growth for a tree,” Karl Flocke, a woodland ecologist with the Texas A&M Forest Service, said. “You could either put a lot of energy into having really hard, durable wood that withstands rot and decay. Or you can be a tree that lives fast and dies young — that puts all your energy into growing quickly, but isn’t as well protected.”
Live oaks — like Treaty Oak — are the slow and steady kind. They’ve got one of the longest lifespans for trees in this area.
So just for fun, we measured the tree. There’s actually an official way to measure girth, taking the measurement 4 and a half feet up from the ground.
Treaty Oak, we found, is 15 feet, 3.5 inches around.
So what can that tell us?
Back in 1976, the city did a tree census where they measured a bunch of trees in Austin, including the Treaty Oak. At the time, the tree had a girth of 14 feet, 6 inches. That means in almost 50 years, it’s put on about 9 or 10 inches. But this tree was poisoned back in 1989. Maybe it would be even bigger if that hadn’t happened.
In this case, there’s a helpful sign that says the tree was 100 years old when Christopher Columbus arrived in North America. That would make it somewhere around 600 years old. That might be true. It might not be.
“I have no idea," King said.
So is Treaty Oak the oldest tree in Austin? Maybe.
I decided to go find some other big trees.
Along a trial at McKinney Falls State Park, there’s a huge bald cypress named appropriately: Old Baldy.
Legend has it this tree stood here more than 300 years ago when Spanish missionaries came through. A sign nearby claims it's 500 years old. It’s bigger than Treaty Oak, coming in at 17 feet around. But here’s the thing: Bald cypresses grow pretty fast.
For instance, there are two bald cypresses on the Hike and Bike Trail that are more than 20 feet around — probably the biggest trees in the city! But they have a constant water source from the lake, so they have an advantage that would allow any tree to grow faster. So we’re going to disqualify those for “oldest.”
So what’s next?
Tucked away on a little street in East Austin, there’s another giant tree. It has three trunks growing from its base — though one of them appears to have broken off at some point. Its canopy is massive. Its gnarled branches reach across the street.
This was the fourth-biggest tree in the 1976 tree census, just behind two cypresses and a cottonwood that was noted to be in bad shape at the time and seems to have been removed sometime since.
I’m here with Michael Embesi, an arborist with Bartlett Tree Service. We don’t measure this one, because it’s on private property. But I ask him how old he thinks this tree is.
“I really don't know,” he said. “It's kind of fun as well to have a little bit of mystique or mystery to a tree when you look at it, and you're like, ‘That tree’s been here a very long time.’”
I’d heard about a technique called resistograph where you can count the rings without cutting the tree down. Basically, you drill a big needle into the tree and it measures slight changes in the density of the wood, which can identify how many rings you’re drilling through.
“I don't like to do it unless it's required because it does make a small hole,” Embesi said.
But over at the Sorin Oak at St. Ed’s, they did use a resistograph about three years ago.
“The best we can actually date it now is about 250 years old,” said Roy Johnson, the university's arborist. “It's certainly among the oldest” in Austin.
But there's one more problem: Live oaks are hard to age with a resistograph or even when you cut them down.
“[Live oaks] could put on several growth rings in a year, which makes it virtually impossible to accurately know the age of a tree,” Flocke said.
There was one more tree I wanted to check out, in a parking lot on the Northeast corner of Braker and I-35. This really old tree is in a little mulched island next to a tool store. It’s surrounded by a chain-link fence, presumably to protect it from the road construction happening about 20 feet away.
It was measured in that 1976 tree census, but it wasn’t officially included in the list because it wasn’t in the city limits back then. Now it is.
The tree is big, but not as big as some of the others we’ve visited. The trunk is held together by a huge metal bolt. The canopy is a spiderweb of cables suspending the branches like a marionette.
A sign here claims the tree “may be 700 years old." That it started growing around the time the Crusades were ending in the Middle Ages, that it was 200 years old when Columbus arrived in North America, that it existed under all six flags that ruled Texas and that it observed the growth of Austin from frontier town to modern city.
Is any of that true? If it is, then there’s little doubt this would be the oldest known tree in Austin.
But of course, we can’t really know.
An investment of time
“My short answer to 'What is the oldest tree in Austin?' is: Nobody knows," Flocke said. "And if someone tells you they know, they’re just guessing."
Why does this even matter? Who cares how old the trees are?
In a practical sense, they represent an investment of time. We cannot replace the oldest trees in our lifetimes or even two or three lifetimes.
The oldest among them live on a scale we cannot comprehend. The ancient bristlecone pines in the Sierra are thousands of years old. They have been present for more history than we can understand. But even our live oaks with only a few hundred years on them have witnessed the transformation of this place — for better or worse. From indigenous people to conquering settlers, from a wild landscape to one hemmed in by asphalt. And maybe we cannot hear them telling us what they’ve seen, but it’s nice to imagine it.
One more thing I think I need to mention here: It might literally be impossible to find out what tree is the oldest in Austin because, depending on how you define “tree," you could have trees with much, much longer lifespans than we will ever know.
We think of the tree as just the part we can see above the ground. But there is so much of it that lives beneath the ground, too. What if the old roots sprout new trunks?
“It's very common for the willow tree to maybe die off, but the roots are still intact and we get sprouts,” Embesi said. “So that tree remains over generational times and so in many ways, that tree could be one of the oldest trees in Austin.”