The science behind a tree's long life

Being tree surgeons in Manchester means that we know a lot about trees – in fact, it is quite a fascinating subject. Did you know, for example, that some trees can live for over 5000 years – which is a long time to be standing in just one spot!

The bristlecone pine tree, which can be found in the North American desert, is one of the longest living trees in the world, having lived for many thousands of years. However, the oldest known species of tree is the King’s Holly from Tasmania, which was tested by many scientists and found to be around 43,000 years old.

But why is this? Why do trees have such long lives? To understand this, you need to understand something called ‘senescence’. Senescence is a biological term which refers to the process of deterioration of a cell with age.

Every living thing, whether it be a tree, an animal, or a human, will age and die. Trees simply take longer to do this because they respond differently to environmental stresses. For humans and animals, environmental stresses are things like cold, heat, and drought, whereas, for a tree, it is simply the passage of time. So, trees have learnt to adapt themselves to this stress by becoming more resilient.

One reason why trees are able to live longer than other biological beings is that their root cells seem to be less sensitive to DNA damage, and actually store DNA to help them to quickly replace any that is damaged. Although animals do the same, it seems that trees have developed in such a way that it enables them to use this technique to live for hundreds, if not thousands of years.

Another reason why trees tend to live so long, and one that we see every day as a tree surgeons in Manchester, is the way that the branches, leaves, and roots are formed. They are formed in a way which scientists describe as modular development. So, the branches are formed at the top of the tree, in a way which is repeated further down the tree. Each branch contains a leaf, a bud, and a stem, with new branches being formed constantly.

A final reason why trees outlive us all is their ability to go dormant. In a similar way to what animals do when they hibernate, trees can effectively shut down, limit their metabolic activity, and decrease their growth rate. It is almost like they are slowing down the rate at which they are aging, which therefore allows them to live for longer.