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Fire and agriculture

by  Robert Peden

Raging flames, acrid smoke, blackened tree stumps … burning the forest had a dramatic impact, but it was once a common way to clear the land for crops and livestock.

Fire and Māori agriculture

Māori arrived in New Zealand around 1250–1300 CE. They found a land that was heavily forested, apart from the semi-arid regions of Central Otago and the Mackenzie Country, in the South Island. It is likely that hunters deliberately set fire to the bush to flush out game birds such as moa, and to make hunting easier. The fires caused widespread deforestation in the South Island east of the main dividing range, and also in large parts of the eastern North Island. It is almost certain that at times the fires got out of control, and some of the burnoff would have been accidental.

Burning sky

The story of the ‘fire of Tamatea’ has been interpreted as an allegory of the burning of the South Island’s east coast. Tamatea was in the South Island and needed fire. A priest sent it to him from the volcanic mountains Ruapehu and Ngāuruhoe, in the North Island. The fire rolled along the ground until it reached Cook Strait, where it rose into the air. As the flames travelled across the South Island, some fell to the ground, shaping the landscape.

Growing fern root

Burning became a traditional practice for Māori. The staple vegetable was aruhe (fern root), and the fernlands were maintained by regular burning. This suppressed the regrowth of other plants, allowing the fern to regenerate. In some parts of the North Island the fern country needed to be burnt every three to five years.

At the time of European settlement, fernlands were found in parts of Northland, Waikato, the Volcanic Plateau and many east coast areas, especially the Wairarapa, with the most extensive in Hawke’s Bay. In the South Island, cultivated fern country was less extensive, because the root that grew there was seldom edible.

Torches for fire and light

Māori made torches (rama) for hunting at night. The fuel consisted of dry, shredded tōtara bark and dried grass saturated with bird fat. This was rolled up inside a casing made of flax and long pieces of tōtara bark. These torches would burn for three to four hours. It is likely that torches similar to this were used for setting fire to vegetation for hunting, and for agricultural purposes.

Growing kūmara

In the North Island and the northern South Island, Māori also cultivated gardens to grow kūmara. Burning was part of the agricultural cycle to prepare new ground, with the minerals in the ash from burned scrub and fern providing nutrients for the crop.

South Island sheep runs: tussock and scrub

In the South Island, as European settlers arrived from the early 1840s on, burning played an important part in the establishment and expansion of large-scale sheep farming.

Opening up the country

At the time of European settlement, the open country of the South Island was in places ‘an impenetrable growth of tussocks, woody shrubs, and small trees’. 1 Faced with this tangle, exploring pastoralists (those who grazed sheep or cattle) burned it to make travel easier, and to open up the country for sheep. In March 1852 Edward Lee and Edward Jollie drove the first mob of sheep from Nelson to Canterbury. On reaching the area now known as Jollies Pass they were unable to push through the dense growth of matagouri and speargrass, so they set it alight. The fire burned for several days, forcing the men to sit tight until it died out.

Managing the land

Farmers continued to burn ‘run’ country (tracts of tussock grassland), for a number of reasons.

  • Burning stopped native and exotic woody plants invading grasslands.
  • Sheep stayed on certain parts of a run, leaving other parts to grow rank. Burning encouraged stock onto the less favoured parts, making greater use of the land.
  • Burning rank (overgrown) pasture reduced the fire risk – if a neighbour’s fire got out of control, it would not sweep over the property and kill the sheep.

The writer and explorer Samuel Butler, who farmed Mesopotamia Station from 1860 to 1864, claimed that burning off the rank vegetation made for contented and healthy sheep – but emphasised that it should be done with care.

The land ablaze

It was not uncommon for tussock fires to get out of control and burn many acres of countryside, killing livestock and destroying farm buildings. One of the biggest tussock fires in Canterbury began accidentally on Cracroft Station in 1863. It spread 35 kilometres to the coast at Coldstream and 25 kilometres inland to the Rangitātā Gorge, where it burned for six weeks.

The art of tussock burning

L. R. C. Macfarlane, of Kaiwara Station in North Canterbury, thought that burning was necessary where giant tussocks smothered the plants that sheep fed on. He described the art of burning:

The secret in burning is to select a time when the spring of the year is just appearing, and sap is rising; then make sure, very sure, that the base, the heart of the tussock, is moist enough not to burn. Then if possible burn in the afternoon, when there is every chance of a heavy dew that night. Avoid nor’west weather, but seek a breeze as fire will then run across the land and do less intensive burning. The real art is to just scorch the tops and open out the land between the individual tussocks so that the other plants can see the sun and receive the life it gives. 2
  1. John Buchanan, ‘Sketch of the botany of Otago.’ In Transactions and Proceedings of the New Zealand Institute 1 (1868), p. 181. › Back
  2. L. R. C. Macfarlane, Te raka: land of happy sunshine. Christchurch: Whitcombe & Tombs, 1954, p. 39. › Back

North Island farms: bush and fern

In the North Island, settlers burned native forests to make farmland for sheep and cattle.

Underscrubbing and felling

The work began with underscrubbing – cutting down the creepers and shrubs of the understorey. After these had been left to dry, they became fuel for the main fire.

The standing bush was then felled and also left to dry. Some settlers thought that felling all the big trees produced better results. However, in wetter districts the largest trees were left standing as they became waterlogged when felled and did not burn.

Underscrubbing and felling was a winter job, and the fallen trees were left to dry over summer.

Burning and reburning

Burning was done at the end of summer or in early autumn. A successful burn cleared off the smaller trees and shrubs, but left a landscape of blackened stumps and logs.

Grass seed was sown on the ash, which at first proved to be highly fertile as it contained nutrients mineralised by the burn. But as the initial fertility declined, fern and scrubby weeds invaded the oversown pastures. Further burning was an important way to remove the logs and stumps left after the first burn, and to clear off the regrowth of fern and weeds.

Controlling bush fires

Managing fires in bush country was hit and miss. A dry season was ideal for burning off felled trees and scrub, but nearby standing bush became tinder dry, and it was not uncommon for fires to get out of control.

Ground zero

Harry Combs, who grew up in Hawke’s Bay’s Forty Mile Bush, described a bush fire in 1885:

Tall trees, like tremendous torches, are ablaze from the ground up. The whole world is on fire. And then [after 10 days] the rain! The blessed, glorious rain … The long fight is over. Where magnificent trees once stood there are now scarred and twisted and gaunt trunks, and pile upon pile of charred remains … as far as the eye can see. 1

Houses and settlements built in the clearings were vulnerable if a fire took hold. During a widespread drought in the summer of 1885–86, houses, businesses, farms and thousands of acres of bush in southern Hawke’s Bay and Taranaki were destroyed by bush fires.

Fern crushing

Burning was essential in the effort to turn the North Island fernlands into grazing land for sheep and cattle. The process was known as fern crushing.

In the autumn the fern on a selected block of land was burned and the ground sown with grass and clover seed. A week or two later, as many sheep as possible were put on the land to trample the sprouting fern fronds. In some areas this had to be repeated every five years or so, as the fertility of the land declined and the fern again took hold.

  1. Harry Combs, Growing up in the Forty Mile Bush. Hamilton: Paul’s Book Arcade, 1951, p. 29. › Back

Burning and erosion

Criticism of burning tussock grasslands: 19th century

Criticism of burning in the South Island began during the time when sheep and cattle farming was expanding. In 1865 John Buchanan wrote that repeated burning in dry districts of the South Island caused the pastures to deteriorate, reducing the number of sheep that runs could carry.

In 1895 the term ‘indiscriminate burning’ was coined. Critics claimed that runholders burned at all times of the year, and for no apparent reason. Some thought that depleting the vegetation allowed rabbits to invade the grasslands, which in turn reduced the vegetation even more. Others held that burning and overgrazing by sheep and rabbits increased erosion, causing widespread loss of soil and the formation of the scree slopes that are a feature of the high hills of Marlborough, Canterbury and Otago.

A. D. McIntosh, in his history of Marlborough, described the loss of vegetation and degradation of the land, resulting in masses of rock and shingle where once there were metres of soil.

Reassessing: 1980s onwards

There has been a reassessment of the burning practices of 19th-century South Island pastoralists.

In the 1990s, geomorphologist Ian Whitehouse compared current photographs with those from the past, and found between the 1880s and the 1980s there had been little change in the distribution of bare, eroded areas. He argued that erosion had always been rapid in the high country and was linked more to high rainfall and steep slopes than the activities of farmers. Screes once thought to be caused by overgrazing and burning were, he claimed, now seen as older natural features. Comments in early sheep-station diaries indicate that burning tussock grasslands was often done with care.

Fire, earth and water

Burning Gisborne’s forest-clad hills for farming led to some of the worst erosion and flooding in New Zealand. In a storm on 19 February 1938, thousands of hectares slipped. Streams rose by 18 metres. One creek that normally flowed at 22 cusecs peaked at 33,900 cusecs. Twenty-one men lost their lives when a works camp near Māhia was washed away in a flash flood of the Kopuawhara River.

Burning and erosion in the North Island

When the easier and more accessible land had been taken up in the North Island in the early 20th century, farmers moved into the steeper hill country, where they continued to destroy the bush by fire and axe. Removing bush and fern from the hillsides increased runoff after heavy rainfall, resulting in more frequent and severe flooding. Pastures sown to replace deep-rooting native plants could not bind the land, and during rainstorms millions of tonnes of soil slipped down and filled up the riverbeds.

Controlling erosion

Concern over the degraded landscapes around the country led to the Soil Conservation and Rivers Control Act 1941. This provided for a network of catchment boards to control local flooding and erosion. In time, the boards placed greater limits on agricultural burning, so that by the 1960s it was strictly controlled.

Burning in modern agriculture

Today, burning is often seen as wasteful, and a sign of lax management. It is no longer a part of land management, for several reasons.

Restricting fires

From the mid-1940s catchment boards increasingly controlled the use of fire. In 1989 they were disbanded, and their role was taken over by the newly formed regional councils, which still restrict burning.

New methods of land management

Farmers now have other ways to control vegetation and manage the land. Burning is no longer needed because:

  • fertilisers make pastures more productive
  • pasture plants are improved
  • more intensive subdivision of farmland, and more intensive and controlled grazing restricts the opportunities for weed invasion and establishment.

Debate over stubble-burning

Perhaps the most controversial burning in agriculture today is used in cropping systems, where farmers burn stubble after harvesting cereal crops. Opponents of the practice claim that it is wasteful and pollutes the atmosphere. They argue that it is better for the environment to bale the cereal straw, rather than burn it, and plough in the stubble so it will break down, increasing the humus content of the soil.

However, some farmers claim that there is only a limited demand for baled straw, and that in the process of breaking down, the ploughed stubble uses up soil nitrogen needed for the next crop. They also argue that burning destroys harmful bacteria, fungal spores and insect pests, which could cause disease in future crops.

Hononga, rauemi nō waho

More suggestions and sources

How to cite this page: Robert Peden, 'Fire and agriculture', Te Ara - the Encyclopedia of New Zealand, (accessed 25 July 2024)

He kōrero nā Robert Peden, i tāngia i te 24 o Noema 2008