(defendant (dairy farm) sold ag preservation easement to State of Maryland on behalf of Maryland Agricultural Land Preservation Foundation (MALPF), an entity of the Maryland Department of Agriculture; MALPF then approved defendant's proposal to construct and operate creamery, processing facility, farm store and parking lot on premises; adjoining owners and plaintiff (conservation organization) alleged that such development violated terms of easement and sought writ of mandamus to compel MALPF to enforce easement; trial court determined that plaintiff and adjoining owner lacked standing to sue; on appeal, court determined that standing existed on theory of special harm, but not theory of constructive trust or third party beneficiary; easement did not create charitable trust enforceable by third parties; easement is creature of property law and made no mention of "trust" or "trustee" and provided for modification or termination by agreement of the parties; easement also not perpetual, so charitable trust doctrine inapplicable; no charitable purpose reflected in easement - MALPF paid $796,500 for easement; third party beneficiary doctrine also inapplicable because easement is type of contract between contracting parties and easement not intended for direct benefit of third parties; standing exists on basis of special harm because MALPF approval defendant's proposal was a land use decision; case remanded to trial court and burden of rebutting allegation of specific harm to adjoining owner shifts to MALPF).