N.J. Stat. § 54:36-3
When an instrument creates an executory devise, or an estate in expectancy of any kind or character which is contingent or defeasible, the property which is the subject of such devise or in which such contingent or defeasible interest is created shall be appraised immediately at its clear market value. The life estate or estate for a term of years shall be valued in accordance with section 54:36-2 of this title, and if taxable, the tax shall be assessed and levied thereon immediately and shall be immediately due and payable. Thereupon, the value of the estate for life or term of years shall be deducted from the appraised value of the property which is the subject of such devise or limitation and the tax on such balance of the estate shall not be levied or assessed until the person or corporation entitled thereto comes into the beneficial enjoyment, seizin or possession thereof, at which time, if taxable under the provisions of chapters 33 to 36 of this title (s. 54:33-1 et seq.), it shall be taxed.
N.J.S. § 54:36-3