I’ve looked at property in Indiana and Ohio with the same type of lockouts - of course I specifically told the agents trying to sell exactly why I would never buy property that would not be 100% mine.
One of them got their panties in a bunch and asked why I would want to do anything...ummm because I might want to build a house on it and live there? The shocked look on her face after that was excellent.
I’m convinced a lot of this is just an attempt to drive more folks into the city where they can’t be self sufficient.
They are called Conservation Easements or Environmental Easements.