There is a legal concept called “Dead Hand Control” that refers to a person’s desire to control how their property is used after their death [e.g. “nobody is allowed to build on my vacant lot ever…”]. The practice has been widely criticized in legal circuits and most states have something that limits it such as the rule against perpetuities [the rule that transfers of interest in real property fail when the transfer fail to vest within 21 years of a life-in-being at the time the transfer occurs; such as “you or your heirs can have my property, but only after my bloodline ceases to exist…” – in theory a person’s lineage could go on for several centuries before ceasing, so you’d have a legal transfer of interest that just hangs out on the bench for an unknown and potentially forever period of time].
In more recent times, landowners have been seeking out ways to permanently limit the use of land to protect it from development or change. Oftentimes the present owner is concerned about an environmentally or ecologically important piece of land being paved over by a wastrel owner somewhere down the line. It proved very difficult to put a permanent embargo on changed usage of the land given laws that restrain dead hand control, but the tool of the modern conservationist to accomplish such control is known as the “conservation easement.” The conservation easement is an easement granted by the landowner to a land trust or to certain government agencies that will restrict the owner’s ability to develop the land in order to protect the land’s conservation value. Since the land trust is an abstract entity like a company that technically never dies, it tends to sidestep the rule against perpetuities issue. The land still belongs to the owner, and they will oftentimes be allowed to continue living on the land and managing the land in some way that is consistent with the conservation easement’s purpose. The land trust/gov’t agency is then charged with ensuring that the easement is not violated by the landowner or the subsequent heirs/owners. The conservation easement is usually meant to be a perpetual grant of rights and oftentimes the original grantor of the land will seed the grant with enough money to fund the land trust’s enforcement mechanisms for a while, however failure to maintain the easement itself can result in loss of the easement rights through forms of prescriptive easement [i.e. if a later owner builds or develops a conservation easement plot in a way that is counter to the easement’s provisions and is open, hostile, notorious, and such for a long enough period of time, they could arguably “claw back” the right to develop land through the easement equivalent of adverse possession].
Some folks establish conservation easements to ensure the land keeps being preserved, others do it for minor tax breaks [when a property is so encumbered, the value usually craters, which can reduce property value and reduce estate taxes. The land use system in Oregon tends to make the use of conservation easements less common than in other, less centrally regulated areas. In 2000, Oregon had merely 14,000 acres of conservation easements, whereas Montana had 450,000 acres locked behind easements. Nonetheless, the usage of conservation easements is growing in the state and a canny real estate agent should understand the implications. Point your client to an attorney if they wish to purchase a property or sell a property subject to a conservation easement, as it may have a dramatic impact on the expected value of the land at market.