I have a new friend, Dale, who is an old horticulturist like me, but who also does permaculture. He likes biochar. His property is not manicured and neat but quite variable with not only native plants but also with various fruit and nut trees & shrubs and various herbaceous food plants. Here are a few photos of his homestead. The last photo shows some berries of the Illinois Everlasting Red Mulberry.

I have to think about what food bearing trees I should grow at the top of my slope. I live in a sandy area of south Alabama and they can't get gigantic. Any advice?

You could try: Alleghany Chinkapin (Castanea pumila) a large shrub; Pawpaw, or American or Chickasaw Plums.

Maybe see what USDA zone you are in. You may want sea grapes. I live on these islands out here in the Atlantic and we have sea grapes. They can also be found in Florida, USA and in the Bahamas. Sea grapes grow on beaches and would do well in your sandy soil.