They don’t call them “widow-makers” for nothing
I was almost killed in a similar manner in 1974. Tree work is dangerous.
10 lb/ft limbs -- 70 feet up! Yikes!
Pine beetles killed off at least a dozen big pines on my place last Summer, and now, (including a couple actually in my yard) they are starting to drop big limbs. I won't even drive my tractor under one of them -- much less attempt to cut any of them down.
Some one could get rich by coming up with a remotely-operated method of dropping those beasts in a controlled fashion.
Too bad Detcord is not commercially available. (Dang terrorists screw up all sorts of good things...)