Agroforestry guru Martin Crawford throws out a more extreme guess around 41:30 in "A Farm for the Future." 10 people per acre (!) on an intensively managed forest garden designed for maximum yield, but I think this estimate is for food alone. I see no reason to doubt his estimate though, considering that he's one of the most knowledgeable people on the planet when it comes to forest garden design and the best plants to design with (check out his work/publications at the Agroforestry Research Trust). Still, I would like to see some hard data, and I've been looking for almost a year since I first viewed this film.
Link to video:
A Farm for the Future
Bill Mollison claims yields from aquaculture systems can be up to a couple thousand times those of terrestrial systems. 20,000 people per acre? Sounds a bit high to me.... but who knows?
I am skeptical that we can speculate on an amount of land per person (so many different climates, soils, site conditions.... too many factors to get an average), esp. since we humans are only beginning to understand how to better manipulate the natural world to get the things we need to survive. That Mollisonism saying "the yield is theoretically unlimited" could apply to caloric yield alone. Ok, maybe not.... heheh, at least not until we find a way to reshape time and space.
