Do NOT in any circumstances attempt to use any ladder for tree pruning, especially if chain saws are being used.
Do Not use a chain saw for limbing/pruning unless standing on the ground or in an aerial lift designed for raising people.
Avoid using the chain saw above waist hight.
Chainsaws cut, even when turned off.
Arms, legs, hands and feet do not regenerate.
Insure that there is nothing above you that might fall, they are called widow makers for a reason.
If necessary send the kids to visit the 'grands' failing that I would suggest locking them in the house. Too much disturbance, you can't concentrate on them and the job at hand.
If using rope make sure that it is at least 3/4 inch 19 mm in diameter; wrap the rope around a secure object between you and the tree then stand between the anchor and the tree.
Rope smaller than 3/4 inch does not have the shock strength needed and if it is wrapped around your body it has the potential to cut or amputate.
The consumption of liquor
should be avoided until after the mess is cleared up and tools are safely put away.
Do Not cut the limb between you and the tree trunk, don't laugh check YOU TUBE.
Insure that there is a clear/safe area for things to fall in. This should be about twice the size you think you need.
Plan an escape route and keep it clear, drop the tool and run
Check your insurance coverage, for an "I didn't think" clause
Tree felling, removal or removal is not easy; there have been incidents where a crane has been used to hold the tree vertical lowering it so that a couple of feet could be removed from the bottom.
Silver Maples will rot, become hollow, from the centre of the limb or trunk out. I have seen as little as 3 inches, 8 cm of good wood around the edge of a 4 foot, 120 cm diameter tree. From your description of the situation it is very likely that there is some rot happening.
Been there, saw that,
John
Forestry Engineering Technician
It is your decision do to it your self or call a professional. They have the
experience, equipment and insurance for this type of work.