This is the white mulberry

Pakistan

Yes, it will take years, but that's not a bad thing. Slow-release fertilizer.

The big thing is going to be to prevent those trunks from suckering. I'd cover them in a big pile of manure topped with yard waste and a thick layer of wood chips.

I agree about the suckering. Cal Pepper trees are survivors. I know a guy who has been cutting his flush the ground for 3 years and it keeps popping back up. He is now trying to poison it somehow...

That's a bummer... I do have a lot of mulch left after clearing the trees. I think I will take the suggestion to put a layer of manure down with some mulch a d see if it prevents the suckering. Otherwise, I wil need to mechanically remove them, which could take years by my lonesome.

To prevent suckering, you need to put down something strong, not just wood chips. You can start with the strongest cardboard you can find, covered in chips. Once it pushes through, cut the shoot and reapply cardboard, raking temporarily the chips aside. This will not eliminate but reduce suckering, and weaken the tree faster. I have some stumps cut in 2009, many injected with fungi to accelerate decay and get something edible, and they are still suckering now.

If you want to minimize work, put down wood planks. Those should be enough to prevent suckering for 3 years, probably resulting in death of the stump.