Breathe!
“EXPLANATION: So what we’re not easily seeing in the video is that the ocean is just a few feet away. You can actually hear it in the background if you listen closely. If you look on a map, Apple River in Nova Scotia sits right on the Bay of Fundy. And the area where this was shot sits on extensive tidal salt marshes. That means a network of subterranean rivers runs right under where he’s filming. Because of the soggy, brackish, loose subsoil, the trees in the area had to connect their roots to each other instead of deep into the earth. Otherwise, the roots would’ve just been eroded by the fast moving salt streams running underground. So sitting right under the topsoil is like a horizontal latticework of roots. When you get the perfect combination of strong winds and high tides, the earth will look like it’s breathing. What’s actually happening is that gusts of water from the rough tide are surging underground from the estuary while the wind is simultaneously moving the upper part of the trees. If you sway a bunch of trees that are all connected to a horizontal mesh of roots, they will lift up the soil, moss, and foliage of the area nearby to compensate for the unbalancing (imagine playing Twister on a waterbed)…. Or you know, it could just be the Treants getting angry! ;-)” -from Skooled Zone on Youtube