Thanks to the impact of introduced species on the environment , to really appreciate the picture that greeted first the Maori and then the European immigrants, you need to visit one of New Zealand's many scenic reserves or national parks. In the Tongariro, Whanganui, Taranaki, Nelson Lakes, Arthur's Pass and Mount Cook national parks, all highland forest areas, tawhairauriki (mountain beech) grow close to the top of the tree line, straight trees up to 20m high, with sharp dark leaves and little red flowers. Also at high altitudes, often in mixed stands, are tawhai (silver beech), whose grey trunks grow up to 30m. Slightly lower altitudes are favoured by the other members of the beech family, the black and red varieties. Often mixed in with them is the thin, straggly manuka (tea tree), which grows in both Alpine regions and on seashores.

New Zealand has five hundred species of flowering alpine plant that grow nowhere else in the world. Most famous are the large white mountain daisies, Mount Cook lilies - the largest in the world, and a white-flowered ­yellow-centred member of the buttercup family. Another interesting plant found on the high ground of the South Island is the vegetable sheep , a white hairy plant that grows low along the ground and, at a great distance, could just about be mistaken for grazing sheep.

One of the oldest of New Zealand's unique creatures inhabits caves and rock crevices above the snow line: the weta (also known as the "Mount Cook flea"), an insect that has changed little in 190 million years. There are several species, the most impressive being the giant weta, which is the heaviest insect in the world, weighing up to 71g and about the size of a small thrush. Weta aren't dangerous, despite their vicious-looking mandibles (they're said to have been the model for Ridley Scott's Alien ). Though weta also inhabit the bush, they're hard to spot and you're most likely to see them in museums and zoos.

The red-beaked, green takahe , a close relative of the more common pukeko, is one of the most famous of the country's flightless birds. Thought to have been extinct until 1948, its survival is currently in the hands of the DOC, who have set up protection programmes in a few highland regions . Another highland forest bird to watch out for is the New Zealand falcon or bush hawk, seen sometimes in the north of the North Island and more often in the high country of the Southern Alps, Fiordland and the forests of Westland. It has a heavily flecked breast, chestnut thighs and a pointed head.

New Zealand boasts the only flightless parrot in the world, the green and blue, nocturnal kakapo . Once widespread, it's now very rare and predominantly seen in the forests and highlands of Fiordland. You're much more likely to come across the kea , regarded as the only truly alpine parrot in the world , though its range encompasses both lowland and highland forests. Known for killing sheep (an alleged recently acquired habit), making off with people's possessions and then ripping them apart or eating them, the kea is green with distinctive orange patches on the underside of its wings and a crimson abdomen. Finally, of the smaller birds in the sub-alpine areas, the yellow and green rock wren and the rifleman , a tiny green and blue bird with spiralling flight, are commonly seen in the high forests of the South Island.