Removing a small burl from a tree is straightforward: simply cut a little below where the burl is attached. Larger burls are not so easy. It is my feeling that harvesting burls is somewhat like cutting diamonds: there is a knack to it.
Does cutting a burl off a tree kill the tree?
No you don’t. Removing burls reduces stem strength and leads to stem decay, every time. You know that without seeing the tree.
How much is a large tree burl worth?
Most burls, especially layered burls, are not particularly valuable. On the other hand, a larger eyed burl in good condition should bring $25 to $200 depending on size, species and condition. I have had burls up to 8 feet in diameter, and many in the 4-5 foot range. Those can be worth $500 or more.
An eyed burl of large size may earn you $25 to $200. The actual price would depend on the size, condition, and species of the wood. However, you can find burl wood pieces 4 to 8-feet in diameter. These burl pieces can each bring $500 or so.