Oak Tree: Nature's Greatest Survivor begins with the onset of autumn. McGavin discovers how the tree senses and then prepares itself for the changing of the seasons. He excavates a tree to study the highly complex root system of an oak. East Malling Research was involved in the episode.
The next chapter of the film is winter. McGavin spends a night in the tree and learns how it almost goes into a state of hibernation - while providing shelter for several species of insects and animals in winds and sub-zero temperatures.
As spring begins, he sets up two solar powered cameras to capture the trees' transformation throughout the season and discovers how pollen can be used to understand the history of the landscape over the last 12,000 years.
In the final season, summer, he looks at the vast web of life that relies on the oak.