Sedentism, food storage, climate, human evolution, & half-baked theories

I don't have anything informative to write tonight, as I just blew all my energy researching a question to which I still have no good answers or even new pointers: what, if any, relationship do coldish (or temperate?) climates have to food storage, sedentism, warfare, and hierarchy in human cultures? I'll write more about hierarchy in future posts, as the current question came up for me because I want to understand why, when, and how hierarchy and other traits I perceive as negative arise in cultures. But for now I'll write a bit about my non-answers to the more specific question of climate's influence.

I read in Matson & Coupland's The Prehistory of the Northwest Coast that humans didn't migrate north of about 40 degrees latitude until about 40,000 years ago when they learned to make custom-fit clothes allowing them to brave colder environments. The authors made this statement as an aside, so didn't really go into much detail. After reading this, I wondered whether modern and ancestral human confinement to tropical and subtropical areas, where they could hunt and gather food pretty reliably all year long, resulted in evolution for not just hunting & gathering, but specifically fully nomadic hunting & gathering?

I say "fully nomadic" to distinguish from the semi-sedentary pattern seen both on the Pacific Northwest coast, and inland among the Kalapuya and, I think, of other inland people in northern California. The concentrated rainy season here would give a lot of incentive to adopt a lifestyle in which you actively gather resources during the dry and warm part of the year, and hunker down and relax under shelter during the wet and cold part. I assume tribes in other areas (of the US or of the world) also had semi-sedentary lives, but I don't know enough to find other examples yet. As I explore that more, I'll pay attention to the difference between horticultural tribes (cultivating certain patches of soil best suited to staple calorie production, thus setting up somewhat permanent residence around that resource) vs hunter-gatherers, relying more completely on nature's provision, with less intensive management techniques such as burning.

People in the Pacific Northwest had permanent houses in winter villages, which they used year after year. Some people, along the coast where they had water access to move things by canoe & raft, even had multiple house frames in different spots, and moved the planks of their houses from site to site through the year. Others migrated from the spring to the fall to different temporary, seasonal camps, but returned to their permanent houses for the winter. I imagine some people may have left their villages totally empty during the migratory part of the year, but others may have had people (maybe elderly?) in residence throughout the year, or tag-teams of coming and departing groups on resource-gathering expeditions.

I think that sedentism (semi- or full-) depends on food storage, since otherwise your group would seriously deplete the local environment as natural resources become scarcest through those winter months. FBy contrast, fully nomadic groups might travel in larger bands during the plentiful months, when ample game and plants could support a relatively high population density in a given spot. But for winter, they would break up into smaller groups, each group dispersing to take advantage of resources inadequate for the full, large group. The archaeological evidence suggests that for the first few thousand years after migrating into the region, pacific northwest people lived fully nomadic lives, leaving behind no evidence of permanent houses. Eventually they entered the pattern of semi-sedentism which continued until European contact.

People in tropical and subtropical areas don't have to deal with major seasonal shifts in food availability, so they wouldn't have much incentive to stay in one spot beyond its temporal carrying capacity. Why go to the trouble of preserving, storing, and safeguarding food when you know that you can always go out and find what you need, no matter what day of the year?

So, if we evolved as fully nomadic hunter-gatherers, with cultures which encouraged resource distribution amongst the tribe rather than stocking food away for lean times, what effect did storing food and settling down for the winter have? Could that explain the development of those traits I associate with civilization and with horticulturalists: hierarchy, slavery, and warfare?

Now that I've explained my question, I'll leave it at that for tonight. But I'll follow up soon with my feeble explorations of the answer!