As one of my CAS activities with the students (all teachers are involved with CAS in UWC schools) I cut wood. If no one cut down trees around the college then we would be overrun with them so its environmentally sound. The wood is cut into logs sold to teachers and burned on their wood burning stoves so they can heat their houses with a renewable source of energy instead of electricity which in Norway is all produced from hydro hmmm.

Anyway, there is an interesting bit of physics in wood chopping. The best way to split a log is to first set the axe into it then turn it the other way round and hit the blunt end of the axe against a big log (as shown in the photo). This uses the momentum of the log to split it rather than the smaller momentum of the axe head. But according to newtons 3rd law the force on the axe should be the same as the force on the wood so how come the wood splits more easily when hit in this way?

I reckon its because when the stump is hit the way shown it is the axe that is slowing down the log so the force on the log is large. When hit the other way up the axe is slowed down by the log which requires a smaller force since the axe has a smaller mass than the log. The force on the tree stump is the same in each case.