Section 31. Lands acquired under section thirty or thirty-three shall be known as state forests, and shall be under the control and management of the forester. Lands acquired by purchase for experiment and illustration in forest management and for reforestation under the provisions of chapter four hundred and seventy-eight of the acts of nineteen hundred and eight and amendments thereof, or of the corresponding provisions of later laws, as to which the period limited for repurchase by their original owners, or their heirs or assigns, in accordance with said provisions shall have expired without such repurchase, shall also be known as state forests and shall be under the control and management of the forester to the same extent as if acquired under section thirty. He shall reforest and develop such lands, and may, subject to the approval of the commissioner, make all reasonable regulations which in his opinion will tend to increase the public enjoyment and benefit therefrom and to protect and conserve the water supplies of the commonwealth.