Heidi Bohan, author of "The People of Cascadia" talks about the Native American agriculture in the pacific northwest hundreds of years ago.
She explains that the native american people that were here then were well beyond "hunter gatherer". They had an agriculture all their own. Much like permaculture.
I think that this Native American idea of agriculture is far beyond current agriculture practices. Even beyond organic agriculture practices. The Native Americans used polyculture techniques and focused on plants reproducing themselves. Enhancing natural systems.
Heidi mentions that the Native Americans would do burnings to help with production. Including to keep trees out of certain agrculture fields.