I've got this silver maple sapling growing in my yard that I want to get rid
of. A number of years ago, a former neighbor who once owned a christmas
tree farm in Wisconsin told me about a common chemical compound he used to
kill unwanted trees. I've since forgotten the name of that compound. Can
anyone here jar my memory?

The procedure, he said, is to cut a gash into the trunk of the tree, smear
it with this chemical and then cover the gash by tying a rag soaked in
vegetable oil around the trunk. In a few weeks, the tree dies.

I used this method once a long while ago, and it was very effective.

Any leads are much appreciated.
Arsenio