Start on left side of trench. Slopers to the right and top out near tree. Climb is at 1:22 of video:
Trench portion of Trench Boulder. Visible from main trail.
If anyone has info on any climbs in between Trench Warfare and Trenches on the Trench Boulder, please send. I think Andrew Minnick said something about a climb named Jabba the Hut, maybe?