I often get the question whether something is permaculture or not. My
answer is always Permaculture is an ethics-based design science, not a not a series of rules on how to grow. My criteria for determining if a system can be used in a permaculture design is if it meets the three ethics (earth-care, people-care, the return of surplus) and it has at least three benefits. For example a hügelkultur bed meets these ethics, because among other benefits, it uses a renewal resource (wood) to provide nutrients, conserves water, and can be used to grow food or resources that can be looped back into the system. A hydroponic system as an alternative does not meet this criteria for me, because of the
energy it often requires to grow effectively makes it unable to form a sustainable loop.
So as far as a food forest goes, it meets the ethics requirements and provides way more than 3 benefits, so yay you are practicing permaculture!
To make it more complicated, you can use permaculture design itself as a tool, not necessarily a dogma. For instance, you could have a food forest and an indoor hydroponic grow room and say you are practicing permaculture, even though you also do hydroponics. But if you are only doing hydroponics, you can't say you are practicing permaculture unless you are doing it in a way that meets the three ethics, and provides three benefits. Got to love semantics!