Planting and harvesting are managed activities to protect the local ecosystem but there are permits available for both activities. You are also free to go hiking and camping within the rules (distance requirements from roads and trails, wildfire management restrictions, stay limits to prevent lasting damage, etc) across the _vast_ majority of publicly owned lands. Even building structures can be done in specific circumstances with permits or leases.

This is all such easily accessed information direct from NFS, NPS, and BLM government websites, it's impossible to not view your comment as written in bad faith. Public lands are broadly your lands to enjoy and use as they exist in their natural state, so long as you're not depriving others of the same access.

Most national lands, you can in fact go hiking or camping there without asking anyone for permission. Some are permitted but only high-traffic areas. In the national forests for the most part you can literally pull over on the side of the road anywhere and camp.

In general you can do anything on the land that doesn't impede other people's ability to also do anything on general on the land. Permanent houses or crops would impede other members of the public who also own the land.

I'm curious why you exempted national parks and not national forest when the latter allows for even more use.

Personally, I use my public lands all the time, visiting several times a week and camping frequently. There's a 30K-acre chunk of national forest nearby we sold to a private corporation over a decade ago and now that's all cut off. They're just sitting on it. Used to be hunters and foragers and mountain bikers and motorcyclists and horses... Now all off limits. And what did we get in exchange?

I'm a big fan of camping in federal lands. No permits like stupid state parks, just a 2 week limit on location. I like to 4x4 on old trails, pick a wild spot that looks good for camp, then break out the axe to find firewood.

If you are not constrained by a vault toilet and pack your own water, it is a playground.

> So if it belongs to me, can I build a house there?

It is shared ownership. You want to build private property on land that everybody owns?

> Go hiking or camping? Can I do these things whenever I please without asking anyone?

Yes, you can. I do it frequently.