I've been taking down trees around my place for 3 years. My method is to just get down flush with the ground and chainsaw through them. It dulls the heck out of the chain to get down in the dirt with them. (there's no way to cut them flush without digging up some dirt with the chainsaw)
I just sharpen the chain after every stump cutting. That little chain grinder I bought at Harbor Freight has gotten quite a workout.
