maybe i'm putting two things together that i shouldn't but from what i've gathered i think i should be able to brace brush piles against existing stands of hackberry on a fairly steep slope and later when moving dirt out for a foundation push it down the hill into these brush traps. this would be followed by a planting of fibrous rooted plants to hold the whole thing together. the end result being a good use of brush and excess soil as well as an easier walk down the hill?
thats definitely one way of making terraces, ive read about somewhere in south america that did it this way. they would plant rows on contour of this plant they used( cant remember ), then would put some sort of cross beams with what they had, throw there scraps and waste downhill there along with soil, it would build up like your saying, the plants they planted would take root into the debris/new hillside stabilizing the terrace. when the terraces got to a level point they would simply stop and start planting.
The ultimate goal of farming is not the growing of crops, but the cultivation and perfection of human beings. - Masanobu Fukuoka