See HERE. ND does not have a strong extortion law. In fact it has been combined with other "theft" statutes. And given that in the end, nothing was paid, and someone in your situation was trespassing, I doubt that the authorities would prosecute the landowner, given the mitigating circumstances.
So while this may have been extortion, I do not believe that the authorities will act on it. You are free to make a complaint about this of course. Who knows, the authorities may look into it. Especially if he's been on their radar for something else.
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