Those are not trees you're looking at in the beginning of the video. Those are the clouds of dust rising into the air from a large number of artillery rounds impacting with the exact same area in a very short period of time.

The exact location of this footage is currently unknown, as is the disposition of the Russian troops in the general vicinity of this specific artillery strike. All we know for sure is that the Soldier recording this is aiming his camera in the general direction of the Russian trench lines. If the Russians are still in there, I doubt they're happy.