Bristlecone pines are the the world's oldest trees, living and reproducing for thousands of years. They live high up in the arid mountains of the Western United States.
In an essay for Aeon, Ross Andersen shares his struggles to understand the trees' age:
"It is hard to resist cliché when conveying the antiquity of the bristlecone pine. The oldest of the living bristlecones were just saplings when the pyramids were raised. The most ancient, called Methuselah, is estimated to be more than 4,800 years old; with luck, it will soon enter its sixth millennium as a living, reproducing organism. Because we conceive of time in terms of experience, a life spanning millennia can seem alien or even eternal to the human mind. It is hard to grasp what it would be like to see hundreds of generations flow out from under you in the stream of time, hard to imagine how rich and varied the mind might become if seasoned by five thousand years of experience and culture."