There is a tax loophole where you buy a lot of land and donate 90% of it to the government to be "public parkland". However, in actuality, you're the only person who has convenient access to this land and nobody else can build there, so you get nearly all the benefits of this land while claiming a big tax deduction.
It doesn't sound like what is happening here, but I don't think you should be able to block development on land you donated indefinitely.
It doesn't sound like what is happening here, but I don't think you should be able to block development on land you donated indefinitely.