Story: Manawatū and Horowhenua region
Page 3 – Human impact on the environment
The landscape in 1840
In 1840, when European colonisation began, forests covered the interior, and there were dunes, grassland and swamp on the coast. The most stable sand dunes were covered in mānuka, flax, toetoe, cabbage trees and bracken fern. Kahikatea and pukatea were the dominant trees on the flood plains of rivers and wet sand plains, but where the land was well-drained tōtara, tītoki, ngaio, kānuka and akeake flourished.
In low-lying, inland Kairanga, the trees were mainly podocarps – tōtara, rimu, kahikatea – and also tawa. Flax, toetoe and raupō (bulrush) grew in open swampy locations. Further towards the Ruahine Range, in the Pohangina valley, tōtara grew in the lower areas, and other podocarps and tawa higher up the valley slopes.
Māori food sources
Māori used the coast as a source of shellfish, the rivers and streams for eels, and the forests for birds, particularly kākā (parrots) and kererū (wood pigeons).
Change after 1840
Between 1870 and 1910 there was a massive forest clearance to make land available for the settlers. Indigenous trees gave way to European grasses, first on the drier bush-cleared tracts and then on the drained wetlands. Native birds and freshwater fish became scarcer as the forests were felled and waterways channelled.
The first attempts at drainage around Makerua in the 1890s triggered the growth of native flax in place of raupō, but further drainage in the 1920s opened the way for pasture.
From dunelands to pasture
On dunelands the native cover was mostly spinifex and pīngao, with ground-hugging shrubs on the landward side. Further inland were toetoe, mānuka and shrub daisies.
From the 1860s the ground cover was replaced with pasture grasses for sheep and cattle grazing. The dunes expanded but are now held in check by plantings of lupins, marram grass and California conifers – the macrocarpa (Cupressus macrocarpa) and radiata pine (Pinus radiata).
In the 20th century, swamp drainage and flood control was a major engineering task in Manawatū, culminating in the Moutoa sluice gates and floodway built between 1959 and 1962. The project is still recognised as one of New Zealand’s key flood-control structures. It includes 300 square kilometres of rural land, along with flood-prone areas of Palmerston North.
The region’s sand dunes are aligned not with the coast but with the prevailing westerly wind. The longest stretch, 18 kilometres, is inland from Hīmatangi.
Rivalling Wellington as an accessible, windy environment, the mountain ranges either side of the Manawatū Gorge have proved ideal for wind farms. In 1999, 48 turbines were installed, and 55 were added in 2004. Manawatū provides just under 160 megawatts of New Zealand’s total installed wind-farm capacity (nearly 170 megawatts). This is enough to power more than 70,000 households – three times what Palmerston North would require.