Claiming burls....

[mrcaptainbob]

I often run across 'burls' while acquiring stove wood. Sometimes it's a nice knob on the side of a trunk, sometimes it's obvious a branch used to be there a few decades ago. So...what is the best way of releasing it from the tree for lathe use? Is there a distance around it to sink a chain around and then cut it at some far distance? Along it's axis? Along the tree's axis? How do I get what a wood worker can use? I want to give a few of these to a friend rather than the stove.