A great forest. Living.... and restless.
The trees wake in waves, brief hours of frenzy as frantic foliage whips about. The trees and vines and grasses scramble for reasons unknown; growing, branching, uprooting, even flailing about in some mad melee which only the plants can make sense of.
The creatures and peoples of the forest take cover, or dig for shelter, or move on to stay ahead of the oncoming wave, when they feel the leaves begin to grow restless....
When the wave of activity reaches the edge, it does not stop - there, the woods spill out onto the plains or sand or rocky cliffs, new growth sprouting, breaching the surface of the earth to seek daylight; old growth moving, uprooting and clawing up the ground to claim fresh soil; all adding just a few more meters of forest to kick and grow and climb yet more when next the trees wake.