N.Y. Est. Powers & Trusts Law § 10-10.2

§ 10-10.2 Power to lease in tenant for life; scope\n A power may be conferred upon a tenant for life to make leases of real\nproperty for a term of not more than twenty-one years to commence in\npossession during his lifetime. If the power authorizes, or the life\ntenant makes, a lease for a term in excess of twenty-one years, such\npower or lease is valid for twenty-one years, but is void as to the\nexcess.\n