The Assam State Forest Minister G C Langthasa today said that due to encroachment, the area under notified forests in the state has gone down to an alarming 16 per cent in terms of closed forests which is well below the norm of 33 per cent recommended by the national Forest Policy. Terming encroachment in forest areas as a major irritant in forest management as well as in maintenance of the eco-system, Lagthansa said, "It is impossible to restore the slot forests to its original form and that is why everybody should extend a helping hand to the Forest Department in greening the State through massive afforestation."