The land in Southaven Park rests in the Town of Brookhaven, it is subject to Brookhaven zoning laws. 
For example, the land on which the shooting range is located has been zoned as "Residential" since 1937.  Since the range did not exist at its present location until the early 1950's, its presence on residentially zoned land  classified it as a "Legal Non-conforming Use".  In fact, the range's current licensee, Mark Wroobel, said as much in his legal filings (challenging Brookhaven Town's noise law_ wherein he wrote that the range is a "Preexisting legal nonconforming use".

The shooting range was closed by Suffolk County on October 1, 2001.  The Range was eventually reopened on July 15, 2006, demonstrating that it was closed for a period of 4 years and 9 months.

Brookhaven Town Code (Zoning)

§ 85-372 Nonconforming uses. 

The lawful use of any building, structure or land existing at the effective date of the zoning ordinances of the Town of Brookhaven may be continued although such use does not conform to the provisions of this chapter, provided that the following conditions are met:

(6) Discontinuance. The substantial discontinuance of any nonconforming use for a period of one year or more terminates such nonconforming use of a structure or premises and thereafter such structure or premises shall not be used, except in conformity with the provisions of the Town Code.

Since the range was closed four 4 years and 9 months, the "one -year" requirement is easily met.  However the range supporters consistently argue that "The County" always intended to reopen the facility so it cannot be considered as "abandoned".  This issue is addressed in several court cases, but the most notable decision in regard to this issue was rendered by the New York State Court of Appeals.  In their decision in a landmark case involving non-conforming use, the court unanimously ruled that:

"In New York, the inclusion of a lapse period in the zoning provision removes the requirement of intent to abandon...discontinuance of nonconforming activity for the specified period constitutes abandonment regardless of intent" - Matter of Toys “R” Us v Silva , 89 NY2d 411, 421 [1996]; (see also, Town Bd. of Town of Southampton v Credidio, 21 AD3d 547, 548 [2005]; Matter of Pica v Bennett, 164 AD2d 859, 862 [1990]; Matter of Village of Waterford v Amna Enterprises, AD3d [2006].)

Clearly, the law not only stipulates that a nonconforming use that has been discontinued for longer than a specified lapse period (in this case, one year) cannot be reestablished, but it also defines such discontinuance as "abandonment" (which satisfies the wording of the PINE BARRENS PROTECTION ACT), but also that the "intent" to reestablish a nonconforming use is irrelevant. 

THE QUESTION OF WHETHER OR NOT sUFFOLK COUNTY INTENDED TO REOPEN THE RANGE IS MOOT SINCE THE COURT OF APPEALS DECISION CLEARLY RULES THAT THE EXISTENCE OF A LAPSE PERIOD SUPERSEDES ANY ISSUE OF INTENT.