These are the seven layers that are generally considered to make up a food forest, however they can be a bit confusing. Take for instance a sweet potato which can act as a root crop, ground cover, and vine. Also consider a banana plant which technically fits in the herb category but is large enough to work as a tree. Try not to get hung up on having seven layers, rather concentrate on planting the trees and plants that grow well in your climate and that you want to eat.