Seems it is available here in Europe as the link to E-Bay shows. Plenty of info about it out there on the web too: look at the Solar lub site ( They're based here in Cheshire, U.K.). They also seem to do another bio chain oil called 'greenleaf' but that doesn't seem to be mentioned in the other link so maybe the two types of Arborol have replaced it. Thier site seems to indicate that there are two types of Arborol - one a straight oil and another the concentrate for mixing with H2O: wierd!
Arbtalk site had a thread back in 2008 but there were mixed reactions. I use Sthil Bio oil - only issue I've got is it seems to drain out of the saw if left with any in ( and that was on a new Sthil!)
Nice idea though - I guess it would be an emulsion and as such they can go a bit gummy as the emulsifier dries out. You might need to clean your saws more often but at least if you pressure wash them the run off wont be too nasty for the environment.
Love and Bananas,
Greyman
http://shop.ebay.co.uk/sis.html?_kw=BIODEGRADABLE+CHAIN+SAW+OIL+1Lt+BIO-DEGRADABLE+OIL
http://www.solar-lubricants.com/news/arborol%C2%AE-released-usa
http://www.solar-lubricants.com/biodegradable-lubricants