Open space tax
An extra property tax that voters approve to buy and care for parks and open land, preserve farmland and protect historic sites. Counties and towns can each have one, and the money must go into a dedicated trust fund.
New Jersey example
Say voters in your town approved an open space tax at a fixed rate, and it comes to $60 a year on your home. That money goes into the town's open space trust fund and can only be used for the purposes voters approved. Raising the rate later takes another public vote. A county open space tax is shared among towns like other county taxes.
Official source
This is a plain-English summary. Rules and dollar amounts change, so check the official source or a professional before you file or sign anything.