How do you exterminate a cypressknee?

Answer 1

Why do you want to kill a cypress knee? You can take a long saw and swim down to the base and saw it away from the root. You might however cause problems. A cypress tree produces cypress knees to provide its underwater roots with air. You could grow a cypress tree on land and it would not produce knees. It only needs a way to get oxygen to its roots underwater. If you remove all its knees, you will kill the tree. If you want to kill the tree, that will be a good way to do it.