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.