H Ryder decided to add:

How easy are these to use? Someone has lent us one but we are afraid to
touch it. We are thinking of trying to dismantle a couple of trees with
them.
Hayley

Not too hard if you follow a few simple rules...
but I would suggest that if you are afraid of it you should not even open
the box!

http://forestry.about.com/od/forestr.../byw_saw_6.htm