Geology and Landform
Stage 1 of the Skyline Walkway follows a defined ridgeline known to earlier Maori as The Warangi which varies from between 300 and 350 above mean sea level. It reaches its highes point of 445 metres at the summit of Mt. Kaukau. The flanks of the ridgeline are dissected by a series of gullies.
The basement rock is greywacke sandstone, a sedimentary rock of marine origin. In places this emerges as dramatic outcrops.
Mt Kaukau is a flat peneplain remnant of the original uplifted land surface that formerly existed over much of Wellington and has since been eroded.
During the last glaciation from 30,000 to 20,000 years ago, conditions were subalpine but progressively warmed to reach a climate optimum 7000 to 4000 years ago. Then, 2,500 years ago conditions became drier and cooler.
Maori have lived in the Wellington Region for about 700 years and the local pre-European vegetation has been described as predominantly broad-leaved forest.
European pastoralism and sawmilling starting in the late 1830s totally removed the forest and introduced exotic trees, shrubs, grasses, legumes and invasive weeds. Farm access tracks were formed and fencelines built. Bell’s Track provided access from Ngaio to the farming settlement in the Ohariu Valley.
The predominant mosaic of gorse, tauhinu and rough pasture is a typical foundation for the first stage of native forest regeneration – especia|ly if an area has been fenced-off.
In the absence of grazing, the gullies support a more advanced, dense and divers range of indigenous species, with the vegetation slowly spreading and colonising the more exposed flanks of spurs. The South-facing slope above the stream paralleling Bell’s Track is an example.
The exposed ridgeline, in addition to grasses and herbs tends to support only sparse woody vegetation and even the gorse and tauhinu is stunted. Indigenous niche vegetation grows in crevices and clings to the rook outcrop
Source: Wellington Botanical Society (Information Board on site)