CORDED:
The reason a chain saw can't use a power cord is that it would need to
be
hundreds upon hundreds of feet long and would be impossible to drag
through
the chaparral without catching on scores of bushes, rocks, and trees.

CY: Even with a portable generator, still not really convenient.

BATTERY:
The reason a chain saw can't use a battery is that it would die after
felling only a few trees and cutting up the limbs. We'd spend more
time
waiting for it to charge than cutting.

CY: Need the new Nuclear Power Batteries. They are sold out of North
Korea, on Ebay. Don't want the Iranian Nuclear Power Batteries, they
sometimes explode.

FOUR STROKE:
The reason most chain saws aren't four strokes, as far as I can tell,
is
that four strokes without oil pumps can't be placed in all the
positions
that a chain saw needs to be without spilling oil into the cylinder.

CY: And they are heavier. The used to be made, for felling trees. When
one knows the saw operation is always going to be in the same
position. They were operated by two men.

TWO STROKE:
The reason most chain saws are two strokes, I presume, is that is less
expensive than a oil-pump driven four stroke and the two stroke works
in
any position.

CY: Also, the two stroke fires on every piston stroke, so the HP to
weight ratio is much higher.

BTW, if there are good four-stroke chain saws on the market, let me
know
which you prefer.

CY: I havn't looked, but they are likely out of the home owner price
range.