I'm quite experienced with chainsaws. Chainsaws are loud and fuel-thirsty, and dangerous in untrained hands. They are not ideal when all a person wants is to cut back a few branches in their garden. I also think the way they cut is inefficient, since a slot at least as wide as the chain has to be turned to swarf.
Loppers, on the other hand, cut branches efficiently and with no swarf. But they struggle with anything thicker than an inch or so.
Giant Loppers take things to the next level, and bear a strong similarity to the hydraulic scissors used by rescue teams ("Jaws of Life"). A hydraulic piston drives the giant blades very slowly and gracefully through branches up to six inches thick. Simply clamp the Giant Loppers onto the branch, unreel the hose, and sedately work the foot pump until the tree gives up.