just like how to eat a elephant.. one bite at a time.........lower branches first,, and just keep going up, till want to quit, then topple it over..had a 40 inch dbh hackberry I took down.. the thing had sooo many large branches above,, that when it went over,, it stopped at 45 degrees!! much fun cutting off of the loaded branches!!!
I lost the biggest on the place a few years back from the straight line wind associated with a level 2 tornado .117 feet ,4 feet at stump level .Most of them in my little woods are right at 100 feet ,including the shag bark hickories .Some of the oaks ,red and white are 3-31/2 feet at stump . I think one big old burr oak is right at 4 feet .
I for one will not drop one just to prove I can do it .If it's not dead or a hazard it stays as it is .Those big oaks were 12 inches in diameter during the American revolution .I'd just as soon they stay after I'm gone .My great grand children might enjoy them .