Technique. Lay it over, use the throttle! Thread the needle. Do the Wattsy Wiggle! I ride some stupid tight singles (just don't post a whole lot of it as its not as exciting). Technique involves setting the bike up before the tree. Move it over so the wheels run near the base of one, and tip the bike through the gap. Throttle will still skip the back end over quite easily, even down hill.
If I'm moving too slow to employee any of the above I'll try use the clutch to lift the front wheel on the spot and pivot, or lay it over tuck the front and spin the back around. Doesn't always work.
But in saying that the lesser turning circle/lock to lock of the gasser hasn't really impacted on any trail abilities. I do notice it in the shed though, sometimes having to do a 2 point turn just to get out the door.