Papua New Guinea lies just below the equator in the eastern South Pacific. It shares its main island with Indonesia. Its other nearest neighbours are the Solomon Islands, Australia and Vanuatu to the south, Micronesia to the east and Malaysia, Singapore and the Philippines to the north. It comprises more than 600 islands, covers a total area of over 474,000 square kilometres and has a population of 3.7 million.
One of the most striking features of PNG is the immense variety of landscape. Highlands, plateaux, valleys, savanna, rain forest, mangrove swamps, gardens, plantations, island archipelagoes and coral atolls provide a spectrum hardly matched anywhere else in the world. Almost a quarter of the country is over 1,000 metres above sealevel and many of its mountains are over four times that height.
There are at least one hundred volcanoes, some of them still active, and a large number of geothermal springs. South of the central cordillera on the main island stretch luxuriant lowlands, interlaced with one of the largest river systems in the world. The longest of these rivers is the Fly, some 1200 km in all, which empties into the Gulf of Papua where it deposits about 100 million tonnes of sediment a year. Some of PNG’s rivers have hydroelectric development, some are major transport routes and others provide additional irrigation for the plenteous crops of coffee, cocoa and copra and sugar cane.
Situated in the wet and humid equatorial tropics, PNG has little seasonal temperature variation. Regional variation, on the other hand, is quite substantial. Coastal temperatures range from 23° to 30° Celsius, while the highland areas are considerably cooler, very occasionally falling to zero degrees. Most of the country has more than 2,000 millimetres of rain a year and some parts are subject to an annual deluge five times greater. The wettest seasons are January to April and September to December, the first period bringing the northwesterly monsoons and the latter carrying heavy rain on the south east trades. The national capital, Port Moresby, has less rain than the rest of the country – about 1000 millimetres a year.
This rainfall gives rise to and nourishes the vast rainforests that cover 70% of the country. A further 10% is covered with other woodland. It is not just the extent of the forest but the variety of species it contains that makes it such a fascinating natural phenomenon. Besides the hundreds of different kinds of trees, there are over 10,000 other species of flora. The main reason for the great wealth and variety of vegetation in PNG is the corresponding diversity of habitat, the most common of which is lowland forest. With a canopy towering 30–40 metres high, the lowland forests are made up of palms and vines, and strewn with ferns and orchids. Where drainage is poor, the predominant vegetation is sago palm and pandanus. At a higher altitude, mountain forests comprise of oaks, laurels and conifers and ultimately give way to low dense scrub.