No shame against this family, they and their gift were taken advantage of by their city and its representatives. You don't know what you don't know, "unknown unknowns."
https://theconservationfoundation.org/protect-conservation-l...
> Conservation land trusts work for private and public land. There are many options available to help landowners preserve, protect, and restore land. Two of the most popular options are fee simple and conservation easements. The fee simple option has the conservation land trust owning and managing the land that is donated or sold. A conservation easement is where landowners and a land trust enter a legal agreement to permanently limit the use of an area to protect conservation values. Landowners can either sell or donate the easement to land trusts. Landowners retain ownership of the land, can sell their land in the future, or pass it on. But the conservation restrictions remain forever.
(i work with a land conservation trust in the midwest)
Looks like they chose the trust poorly - the trust is the one who sold it to the city I think?
To be clear, I guess that a city who had ownership rights but not development rights could be stupid and ignore a conservation easement, but I guess that is not likely.