Food forests are a farming system based on natural principles. So, we want easy-to-crack and big nuts, sweet tasting apples, and thus cultivars (specifically bred or cultivated species that offer guaranteed shape and taste) that guarantee these harvests. At the same time, we want resilient systems that can take a beating, so people who want to work with seedlings to develop new cultivars are very welcome, but then the outcome is not guaranteed, because each seedling will be different from its parents and from its sibling.
The exotic species discussion runs right through this. Which is actually about invasive exotics, species that can develop as pests. Not every plant that does not originally belong here is invasive. In fact, if you look around you, whether in gardens, forests or in agriculture, most of what you see is an exotic species, which fortunately is not invasive at all.
Food forest owners must abide by the law and be aware of the Red List of invasive species and not plant them. Read more about this on the website of the Greendealvoedselbossen.nl