Hundreds of acres of reserved forest in Rangamati’s Sajek is being burned down in fire made for traditional jhum (slash-and-burn) cultivation.   Jhum farming, practised in Chattogram hill tracts, requires clearing of the forest areas to sow seeds after the first considerable rainfall during April-May.   The age-old system damages biodiversity of the forest, including rare species of flora and fauna in the hill area. As a result, nature loses its balance while wild animals, birds and insects become threatened.   During a recent visit, the UNB correspondent found that the fire has spread over hundreds of acres of reserved forest and surrounding local residential areas. This is threatening biodiversity of the hill area.     Due to destruction of forest areas, the water level has gone down and there is an acute shortage of water in the hills and wells, resulting in increasing water borne diseases.