Ann Fitzgerald: So much to learn from root and branch look at life of an ancient oak
Everyone should watch the film, Oak Tree - Nature's Greatest Survivor, which was recently aired on BBC 4.
Part scientific documentary, part historical investigation, it tracks the dramatic life of a specific oak, in Wytham Woods near Oxford, over the course of a year.
It was first shown in 2015, which would be a long time ago if you were a Kardashian, but not for a tree that was laying down its roots when Newton discovered gravity (1687).
The presenter is an entomologist named George McGavin, who strikes just the right note of expertise and awe.
Through the use of lasers, we learn that this oak has some 700,000 leaves, while many human hours removing every crumb of soil from the roots of a young tree expose lengths of mycorrhizal fungi threads that would stretch around the world.
I was amazed at how responsive the oak is to changes its environment.
So, in autumn, chemical messengers (like the hormones associated with some of our own biggest changes, puberty and pregnancy), flow through the branches telling the oak to break down pigments in the leaves to conserve precious water and energy for winter.
Equally incredible is how the tree responds to predator attacks at its most vulnerable, in summer, when covered in soft, young leaves.