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Ngā Tohuwhenua Mai Te Rangi: A New Zealand Archeology in Aerial Photographs

Dune country

Dune country

The west coast of Auckland and Northland has prevailing strong south-westerly winds, difficult harbour entrances and many long exposed beaches. Transported to the shore by ocean currents, the sand on the beaches was driven inland by wind action along very extensive sections of coast, so that, where steep, hilly topography does not dominate and prevent the migration, dunes run inland for up to 15 km. Over time the raw sand became covered with forest, until it was disturbed by Māori burning or deteriorating climate and wind patterns. The Kaipara Harbour was formed over tens of thousands of years by massive deposits of sand forming peninsulas which enclosed a bay. Most of the other sheltered harbours, such as the Hokianga, were formed by somewhat smaller sand peninsulas. 14 Settlement on this coast seems to have been late in pre-European history, with widespread deforestation on the extensive dunes commencing about 400 years ago. Earlier ages for first settlement have been reported only for the far north of Ninety Mile Beach, and there is a single early (thirteenth-century) radiocarbon age for settlement at Maioro south of the Manukau Harbour. 15

Two broad zones held contrasting settlement potential: the inner harbour shores, and the active dune country of the ocean coast. The highest, inland tracts of sand towards the harbours had a kauri forest cover. The surfaces of these sands are now exposed as a brittle crust, occasionally broken into and eroded but generally stable. The soils are of poor natural fertility. These areas have relatively few pre-European sites except near the edge of the harbours and on the hill country inland from the immediate coastal strip. 16 Pā are common on the eastern harbour margins and on the central hills of this dune country.

Further towards the ocean coast, the younger, sandy soils were more prone to wind erosion, especially once their original vegetation cover was destroyed. In periods with little wind erosion, the blown sand has been stabilised first by the colonisation of manuka and kanuka, then by a light coastal forest cover. This locked up an available source of nutrients that, once released by firing, were used for Māori gardening. Gardens were also created on swamps in the dunelands. Burning not only set off a renewed bout of erosion, forming the apparent duneland 'deserts' that are seen today, but also offered a useful opportunity for Māori settlement. These were the subject of study by John Coster during the early 1980s as part of an effort to reduce the destructive effects of planting pine trees. 17 There were small whānau settlements throughout the western dune country, but not within 1 km of the sea. 18 Occasionally there are pā, especially by the dune lakes, examples of which are illustrated in chapter 15 where the primary point of interest is gum-digging. On dunes in the immediate vicinity of the coast are remarkable, more or less continuous, large middens, scattered over and eroding down the surfaces of the unstable dunes.