First acquisition (AC question)

[DougShrapnel]

Assume an ACist society. Assume that property is a natural phenomenon that arises from possesion and control. At what point does land become released as property and into the public domain for a "2nd first acquisition"? For instance I aquire land that no one is using. I build a house. At a point I move from my house and neglect the land. Since I have neglected the land, I have negated my ownership of the land. I neither have possesion of the parcel of land or control of the parcel of land. Without possesion or control no ACist should be able to make the case for ownership of the land. Assume that no one wishes to purchase the land, at the price you want for it. How does an ACist handle the transfer from ownership to a natural unowned state ready for first acquisition?