This is derived from a comment in a recent youtube video of yours that noted the change in our society when the move from horticulture & hunt/gather to annual agriculture.
This one is a little out-there and probably the result of of connecting unrelated dots, please give it a shot and feel free to laugh at the end. Fortune favours the brave...
The basis for this began several years ago when I read about a study that presented a hypothesis that anorexia is a misfire of an old survival instinct (basically, if you run out of food you become restless, don't care for food the result of which would drive you to get up and move until you found more food)
More recently, research is indicating that lead poisoning results in violent behaviour on top off all the other issues.
Ok, so hopefully you are still intrigued/tolerating
So I am suggesting that there is precedent for diet significantly impacting behaviour as well as for malnutrition to initiate survival mechanisms.
Thinking of the great chestnut & maple forests you described, if we were to accept that annual plants were historically not a significant dietary input (or at the very least minor).
Then if we take what we know of annuals being that they are a transient feature of early succession, degraded soil/interrupted environment response and based on a bacterial networks and shallower roots. Which I would speculate results in a different nutrient uptake and therefore different nutrient availability when consumed (when compared to perennial sources based on deep soil, deep roots and a complex fungal network).
Bringing it together... I'm hypothesizing that this change in nutrition results in a change in behaviour i.e. this particular malnutrition initiates a response that drives hominids to move from where they are into other areas and seize that area. Simplistically and as an acute example, if you're starving you will do just about anything to get food.
We see that 'intact' tribes in the rainforest are certainly territorial, yet they are not (to my knowledge) violently expansionist. Then we look at our society where 'we' are certainly calorically secure, though malnourished, through processed food and possibly due to our near utter dependence on annuals we exhibit callous and expansionist behaviour.
Some quick examples that came to mind:
Aztecs (People of the corn) extremely war-like
Middle-East (cradle of civilization), the trees and soil are long gone, unrest has been a constant.
Do you have any thoughts on comments on this?
I'm confident I've gotten some or all of this wrong but I thought it was worth a shot.
Looking forward to a day where I can have you consult on a perennial nut/food forest of my own. Please keep up the good work.