In addition to any other remedy available under existing law, upon failure of any private owner of forest land which is subject to a cooperative agreement entered into pursuant to this subchapter to comply with the terms of such agreement, or upon failure of any purchaser of timber or other forest products from such land to comply with the terms and conditions required by such agreement to be included in the contract of sale, the Attorney General, at the request of the Secretary concerned, is authorized to institute against such owner or such purchaser a proceeding in equity in the proper district court of the United States, to require compliance with the terms and conditions of said cooperative agreement; and jurisdiction is conferred upon said district courts to hear and determine such proceedings, to order compliance with the terms and conditions of cooperative agreements entered into pursuant to this subchapter, and to make such temporary and final orders as shall be deemed just in the premises. As used in this section the term "owner" shall include the heirs, successors, and assigns of the landowner entering into the cooperative agreements.