While humans and animals stop producing new tissues over time – which is part of the ageing process – there’s no evidence to prove that this happens in trees. Due to this regenerative aspect, scientists believe trees actually have the ability to live indefinitely. But before that can happen, several external factors such as climate variation, storms, animal or insect attack, logging. accidents such as lightning, etc. cost them dearly. Despite these, some trees have managed to live for thousands of years. Among them is the Great Basin bristlecone pine tree in California, the U.S., which has celebrated about 5,000 birthdays!
When animals senesce, or grow older, their cells may cease to divide, or the division process may grow increasingly sloppy, leading to deleterious mistakes. On the outside, this aging process shows through cognitive decline, or wrinkles in humans. One animal in particular, the hydra, actually doesn’t seem to senesce. For all intents and purposes, it is biologically immortal.
While it’s not precisely known whether or not individual trees are biologically immortal in the same fashion, they definitely don’t grow old the same way animals do. Trees grow indeterminately, meaning that with the right conditions, they can grow and grow and grow, with only the laws of physics limiting their height. (There’s a certain point where a tree cannot send enough water from the roots to the top layer of leaves, preventing adequate photosynthesis.) Amazingly, once they hit that maximum height, instead of growing taller, they grow wider! And they do so at an ever-increasing rate! That’s right, trees actually grow faster as they age. Scientists reported this amazing finding in the journal Nature earlier this year, after examining the growth of over 700,000 trees worldwide.
While it’s not yet known precisely why trees grow faster as they age, the secret to their perpetual growth has already been revealed. Most plant cells are perpetually embryonic, meaning they can change into another cell type at any time.
Credit : Real Clear Science
Picture Credit : Google
