"The Fortingall Yew tree is possibly the oldest tree in Britain. Some people believe that it is 3000 years old, some people think it is 5000 years old, so I am estimating it is 4000, which is in the middle. This tree started to grow in 2000BC and is here today in 2018AD. So how do we get this estimate? Maths. To estimate the age of a tree, you measure the circumference of the trunk. Yew trees grow an average of 0.7cm per year. The older a tree, the harder it is to age. Using a formula from Forest Research, a Yew with a 4m circumference will be 500 years old. The Fortigall Yew once had a 16m circumference!"
