New Guinea

The island of New Guinea is comprised of the Indonesian Province of Irian Jaya and the independent country of Papua New Guinea. Their boundary along 142° east longitude bisects the island virtually into two equal halves. However, the Central Cordillera, extending east-west over 2,500 km as the central spine, provides physiographic unity to the island. Indeed, they are the highest mountain ranges between the Himalayas and the Andes with an average tree line of from 3,750 - 3,900m. The Central Cordillera has narrow crested ridges above montane basins enriched by volcanic depositions of laharic material and ash (Brookfield and Allen 1988). The prominent peaks are the Puncak Jaya (Mt. Victory at 5,029m) in the west and Mount Wilhelm (4,697m) in the east. The former, originally called Mount Carstenz after a Dutch navigator, is high enough to support some small glaciers. The western section in Indonesia, Pegunungan Maoke, has three other peaks over 4,500m in elevation. The eastern section in Papua New Guinea extends from Thurnwald through the Bismarck to Owen Stanley Ranges in the extreme east. As a general pattern, the highlands have the steepest slopes towards the south. Along the northern coast are a chain of lower ranges that trend parallel to the main range. These are the Van Rees in the west, Torricelli in the middle, and Finisterre in the east. The main highlands are composed of Archaean schists and massive crystallines with lava effusives in the central part. These rock formations are rich in minerals—including gold.

The highland terrain is very rugged. The lower slopes are covered with dense tropical forests while grasslands prevail on the higher ranges above 3,000m. The highlands are inhabited by scattered tribes of the Papuan type, some of whom continue their primitive ways. The earliest settlers were centred around swamplands with taro and pork as basic foods. Subsequently, these `sedentarised' swamplanders expanded into adjoining dry land for swidden cultivation (Gorecki 1986). They were followed by the Melanesian people, mainly along the coast. The economy is based on subsistence horticulture ¹ and pig husbandry. The main crop is the sweet potato (Ipomea batatas) which was introduced in the 17th century. Forest land is cleared by fire and used for garden cultivation of various root crops. The upper limit of crop cultivation is about 2,500m with cultivation on slopes ranging from 30 to 40 degrees. These slopes are never terraced or irrigated (Humphreys and Brookfield 1991). Cultivation techniques based on indigenous knowledge seem well-adapted to fertility management (Sillitoe 1998). This has resulted in comparatively dense settlement at elevations between 1,500 - 2,500 m; one of the advantages of the sweet potato being its tolerance to low temperatures and the fact that its yield is two to six times higher than that of the taro (Smith 1985). Currently, timber extraction and mining are the main economic activities.

1 The use of horticulture here refers to the cultivation of fruit and vegetables on small holdings for subsistence and not to gardening in the decorative sense. [back]