Mortise and tenon felling cut - GIF

[Haroun]

I had no idea what he was doing until 3:20 mark. I thought he was making room for a hydraulic jack or something. No, that's pretty cool.

So is that chainsaw surgical sharp or what? There's no way I could make those cuts with any chainsaw I've ever owned.

He's likely using a chain with fewer teeth & no antikickback teeth will cut very fast. Also the saw motor is worked over to run faster & stronger. It's a good idea NOT to use a saw chain without antikickback features unless you are very skilled & willing to take the risk of getting very hurt. Tree guys I've talked to have saws that are very fast cutting but unsafe for the average person.