We had to (unfortunately) remove a 150+ year old maple tree from in front of our house - it had a large central branch come down in a wind storm last fall. At that point we discovered that the center was rotting - so it was just a matter of time - we decided to remove it pro-actively - not a happy decision.
Counter-weighting is critical - the main trunk was heavy and awkward - I kept it low to teh ground and moved very slowly!