I think this is a great new forum because it has given me a chance to open up a thread on food forests. A food forest can be thought of as a mega guild of companion and nurse plants.
The difference between a food forest and a traditional garden that uses companion and nurse plants is that a food forests main backdrop consists of trees. Under the trees are shrubs and under the shrubs are flowers annual plants and ground covers.
In actuality what you have is a functioning ecosystem that feeds you and local wildlife!
I think that a good guild to start with when attempting to build a food forest is the tried and true apple guild: At the center of the guild is of course, the apple tree. At the drip line of the apple tree; daffodils are planted in a ring surrounding the tree. These will suppress grass and detur dear from eating your apples. Just outside of the daffodil circle is a broken circle of comfrey plants that will attract bees and other beneficial insects. And within this circle are one or two artichoke plants (contrary to common belief artichokes can actually be grown in most climates).
The artichokes will provide a nice soil building mulch for the apple tree and the other members of the guild.
Dotted among the above plants are yarrow, nasturtiums, dill and fennel. These will all attract beneficial insects and add to the mulch layer. And Yarrow is a nutrient accumulator that will accumulate nutrients from the soil and in it's leave and prevent them from being leached away.
Plantains, dandelions, chicory and the like will naturally grow within this guild and contribute the soil and the tree. And a thick ground cover of clvoer will harbour nitrogen fixing bacteria in nodules on it's roots.