"Growing up using 2 stroke weedeaters and chainsaws I had no idea how polluting they are."

Terribly polluting. However, my understanding is that there is no potential for "fixing" chainsaws since a 4 stroke engine cannot run upside down - which is a requirement for a chainsaw.

Am I mistaken ?

Luckily we're starting to see a lot of battery operated chainsaws come onto the market with higher density Li-ion batteries. We're demoing a dewalt[1] chainsaw at my fire department and I have been using a Bosch reciprocating saw with a brush blade for light tree work for two years now ... but this is all light duty stuff and cannot replace large chainsaws...

[1] http://www.dewalt.com/products/power-tools/outdoor-power-equ...