It’s well-known that trees can last a long time. While hazels and apple trees have about the same lifespan as a human (80 years), the oak in your local park is likely to outlive you, your children and your grandchildren – with the right conditions, common oaks can endure 350 years or more.
Trees owe their longevity to several factors, not least is the fact that some species don’t experience the usual side-effects of ageing, such as ill-health and loss of vigour.
Unlike us, trees have a compartmentalised vascular system, meaning that one part of the plant can live on after the rest of it has died. They can also re-grow lost or damaged organs. Some trees even clone themselves, producing thousands of trunks all sharing one network of roots. The original trunk may be long dead, but the organism as a whole continues to thrive.
Somewhere high in the White Mountains of California is Methuselah, a bristlecone pine that began its life sometime around 2833 BCE. At almost 5,000 years old, it is considered the world’s oldest non-clonal tree (a slightly older tree, Prometheus, was felled by a scientist in 1964). Its exact location is kept secret to protect it from vandalism, but visitors can see the grove where it grows.
It is awesome to think of a single tree enduring so long, but even more impressive ages are reached by those plants that can clone themselves.
The Jurupa Oak of California is one example. It resembles a tangle of bushes, but genetic testing has revealed that it is a single organism that began life during the last ice age. Its ability to send out new, genetically identical shoots has allowed it to survive at least 13,000 years of climate change and wild-fires, making it one of the oldest living things on the planet.
Even more ancient is Pando, a quaking aspen that grows in Utah. Known as ‘The Trembling Giant’, this tree has formed a colony of over 40,000 genetically identical trunks weighing 6,000,000 kg (not only is Pando the world’s oldest known organism; it’s also the heaviest).
It is hard to know exactly how long Pando has lived. While the average age of its trunks is 130, its roots are at least 80,000 years old. Some scientists believe it may have existed a million years.
The world has changed enormously since Pando started growing. Sadly, it is now thought to be dying due to a combination of drought, insects and disease, but scientists are doing what they can to save this natural marvel.