best to cut tree down 1st. Low as can be. Then buy some stump killer. Its a powder that comes in a cardboard can. Follow directions and it works!!! And Hopefully.all the roots that may want to send up sprouts. If any suckers come up. Dig to root.drill holes in root. Not through root. And pour straight round up type product in holes.
Dont do this if edible plants are close by. 😬