Foraging and Land Ownership
In the old days in small villages of tribal people, no one owned the land. Sure, they owned a place they lived in, one that moved around perhaps if they were nomadic and following the migratory patterns of the animals they hunted. Later, the serfs who lived on the lands of a lord, they were tenet-farmers paying back a portion of their income based upon what they could raise on the land assigned to them.
In America, land ownership was a huge deal. It meant for the first time people could own property. Through the Homestead Act, if one took care of the land, built a home upon it, fenced or improved it, then in a set amount of time the land became their property.
As the first villages formed in the 1800's, some common land area existed on the outskirts of these villages. There, people would forage in meadows and forests and locate wild edibles that they couldn't find on their own properties. These included fish and wild game, different species of herbs for medicinals, dyes, sweetener sources, greens, starches, etc.
Today, there isn't a lot of common land. What little there is under government control and has a lot of restrictions and you can't harvest plants from many of these places. Often hunting is allowed and hunters often accidentally enter onto private property that is adjacent to them. In a collapse, with few food sources, such intrusions may be considered acts of aggressive behavior.
When I was younger, I often would harvest along country roads, and to be honest, doing that isn't quite right. On some occasions I wasn't doing any harm, and a farmer would see me harvesting some weeds and stop and ask me a question. They wondered what I was up to, and I'd sincerely apologize for being on their property (only the very outskirts of it), and explain that I was practicing old pioneer skills, meant no harm, spoke to them with the utmost respect, and immediately told them I would leave. In all but one case, they said it was fine and didn't get upset whatsoever.
Now, had I been harvesting something other than dead wood or weeds, say pawpaws growing along their fenceline, well that wouldn't have been ok, you can bet on that. It's their land.
In a collapse, people will cross boundaries and....you'd better use a lot of diplomacy. These farms and woods are very large and you'd have to walk way past the boundaries to knock on their front door, and in doing so, volatile events could occur. People imagine foraging for edibles and herbs and wild game and fish, and well....that's their food and supplies, isn't it?
There are not tons of wild places left True, one might flee to the National Forests and then harvest in a collapse, and well..who's going to stop you? This means that these are just about the only places to forage and even then technically not permitted now.
Along highways there are fencelines of farmers. Just because there isn't a fenceline, doesn't mean it isn't private property. State governments place easements on property for highways and roads, but if you think you're going to just cross the property line and harvest what you need, well some owner's liable to shoot a warning shot at the minimum.
I'm not getting where all these bugging out folks are going to set up homesteads without already owning some cabin somewhere? First, most of them can't identify plants. Second, a lot of them can't hunt or fish. Third, they don't own the land to harvest those things from.