RE: Clearing 1 acre for plot
clover is a good choice for a plot like this.
Use round up - 2x if you need to - then disturb soil & broadcast clover. It will grow around the stumps fine - Hopefully most stumps will Die backcompletely - but if not - treat them over the next year or two - or cut them closer.
It will probably be 2years before you can plow - KEEP IT MOWED and you will have success with clover.
FH