Heidi, my question is not so much on a technical level, nor about your knowledge really...
I would like to know how you feel about what you have touched from much nearer than me.
I have done a little ethnological studies at university, I have been reading books about American natives from early childhood, and I find humans great and the situation concerning.

Of course something is slowly marching in, life is there, and also the desire to center on the real things about the planet.
Humans are making culture, and culture is then making humans. We still have some freedom to move things and make some changes.

Saving and recovering skills is great, but how do you feel about what natives had and few of us have? Most part of the land produces food for humans who want to exclude other life forms from taking their share. Vegetarianism seems great for many, and only a solution to increase our population for others...
How can we apply those skills if we do not have enough room for something else than concentrated agriculture? I cannot have all I need on my land!

Aren't you anxious about this dead end meaning a lot more people will die than be born before we can truly live like our ancestors?
American ancestors are much closer, but I am sure that the Celts before the romans in Europe were also stewards of a land that was managed as a big garden.

While there might not be enough (land/electric/steel/etc) for ever person on the earth to own a 4,000sqft house, drive a hummer, eat imported swiss cheese, ice-cream made with liquid nitrogen.
There is enough land that get 14+inches of rain, it would however need +earthwoorks +bio-char +cultivar selection + perennials.
It would grow enough food to survive and there is enough local wind/hydro and remote solar in the desolate desert to provide our energy.
If we all went back to a more ancestral lifestyle of making pots out of earth/clay vs metals and bowls out of gourds vs plastic and using willow baskets vs what we use now.
We would require less resources and there would be enough for alot more people.
Maybe your idea of ancestral horticulture is all of us roaming the land slash and burn style, I thought that is what you have in mind.
So if we manage the land state park/forest style mentality but with permies know-how then we can all "visit" an area for 14day and then more on.
If we go and eat every day like it is thanksgiving then there will not be enough fish/birds/mammals left for us to eat.
But as it is now, if we stock the land/water with the correct cultivar selection we will have enough going forward.

No, my idea is the sort of idea that comes when you read in "tending the wild" (about Native Californians) that this area was one of the most populated... something like 1 person for a square miles of land. There must not be enough for a lot more people but for a lot more of other lives that humans'.

So I want to compare my FEELINGS after going through many things in anthropology and ethnobotanic etc and ask Heidi to share about this topic, or indeed any other powerlessness (that can exist side by side with all the wonder and beauties of this life! I am a very happy person!).

It is not only about powerlessness but also about the "theory" of our thought about permaculture or how we view through books what happened before we were even born. When you cross many ethnographic informations begin some flashes of deeper understandings, especially when it crosses real life experiences.

When I go into practical skills (like learning a technique), I feel great and very excited about all those fields that we can explore.
But with the wider view that comes with different knowledges, (and my main concern is our number), I feel awkward (not sure this is the right word either!).

So, my topic is not about "if we do... then we can..."
it is not about external solutions but about sharing the inside of us about it.

When I practice some ancestral skills, it gives me a sense of freedom for example.
I learned with thrill how to recognize and eat wild plants.
I have made people dream and say wahoo by lighting a fire with a stone and a piece of iron.
I lighted the family's fire quicker than my quechua host in Peru.
But I realized that what is a luxury to me is her every day life, and that my every day life would have been a luxury to her.

And in my little island here, if all the people living in the only 2 big towns want to back to their granny's land,
instead of eating the 80% imported food that the islanders eat here...
...there would be a big space problem.

As much as I love seeing wild deer. I actually prefer people watching more, so overall I dont feel uneasy about our huge population.
I do feel uneasy that we live in total disregards for the earth and other people in general.
I do feel sad that we dont have more people who pursue a more natural lifestyle, where we find fun in climbing a tree/cliff vs watching spongebob for 4 hours.
I have lived in the desert in a big city and witness a sand storm and also in a lush humid city on the coast with hurricane remnants knocking down trees.
Both of these give awe-inspiring feelings. Just looking at the barren desert landscape with clear night sky vs the lush always foggy sky is awesome to ponder.

So to give my views on your questions.
I think we have enough land for me to still enjoy the sights and wonder of nature with the other Xppl per sq miles.

Apart from the information I got about California...
Heidi, do you have some numbers about the Cascade people?
How much room was needed for their way of life?

I know this is a place providing food from the ocean too...
But land is needed for other animals,
and for medicine
and for trees for wood/carpentry/fire
for weaving and fibers etc.