Redwood tree

The First Doctor compared the difference between his own lifespan and that of a human with the lifespan difference between a dragonfly and a redwood tree. (PROSE: Byzantium!) Indeed, such trees could live for centuries. Professor Jonathan Weems was able to extract a special energy from their sap which could be converted into rays projected by a special ray machine, granting a human being the same longevity as a redwood tree, at the cost of paralysing them as their metabolism began to operate at the speed of a tree's. (COMIC: Dr. Who's Time Tales)