What is the oldest tree in the world?
Well, when you start talking about the oldest or biggest,
or almost any other superlative in nature, you're unlikely to find a cut and dry answer.
There are, in fact, 2 contenders for oldest tree and it depends on how you define the term.
The oldest known individual tree was discovered in 2012 in the White Mountains of east central California.
A Great Northern Bristlecone Pine that's 5,063 years old!
That's older than the pyramids!
Here's a photo of a similar Bristlecone Pine, now it doesn't look, exactly, alive
and that may be part of it's secret to success.
The high cold, arid climate of the White Mountains
turns out to be the perfect environment for fostering these ancient trees.
Strangely, the higher you go in those mountains, the older the trees get
and several studies have suggested that the longevity of pines there is directly related to how bad the growing conditions are.
Not only is the average rainfall in the White Mountains less than 30 centimeters per year,
but most of the trees are growing on Dolomite,
a type of limestone in highly alkaline soil with very few nutrients.
But over time, Bristlecones have adapted to this alkalinity, unlike other trees,
which has left them free to grow with much, if any, competition.
Bristlecones also don't expend a lot of energy on their growth;
in a good year the tree's girth will increase by about 0.25 millimeters.
So instead, they can make the most of their meager resources.
As a result, Bristlecones tend to have a pretty high proportion of dead to live wood
but this has it's advantages too: reducing respiration and water loss.
And it also helps that there aren't many other trees around, which makes it less likely that they'll fall victim to a forest fire over the millennium.
which makes it less likely that they'll fall victim to a forest fire over the millennium.
Researchers are able to determine these tree's precise age thanks to a process called "crossdating"
which involves taking core samples from both living and dead trees
and then matching up the patterns of their rings to come back with a timeline that goes back thousands of years.
For our 2nd contender, we're going to Fishlake National Forest in south central Utah.
Here lives a clonal colony of Quaking Aspen that may very well be the oldest living thing on Earth.
It's been named "Pando" and every tree, or stem,
as they're called in the 1/2 square kilometer colony, is genetically identical;
although no other individual tree in the colony is older than 200 years,
they're all connected by a single root system that's at least 80,000 years old
and possibly much older!
At over 6,000 metric tons, it also holds the distinction of being the heaviest known living organism on Earth.
So, how did Pando get so old?
Clonal colonies like Pando can reproduce either by flowering and producing seeds, or by producing a clone of themselves.
In this case, cloning just means "extending the enormous network of roots and forcing a new stem up through the ground.
Because the heart of Pando is so far beneath the ground, it can't be killed by a forest fire.
Recent studies have found that Pando hasn't reproduced sexually in more than 10,000 years.
That's quite a dry spell.
And not that surprising given it's age.
That just means that it's up to the root system to continue producing clones
and letting forest fires burn to keep invading conifers at bay.
So thanks for the evolutionary tips, world's oldest trees!
I'll be sure to keep them in mind when I turn 5,000 years old and want to go for another 5,000.
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