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Sand Stabilisation Projects

New Zealand's first great ecological success story...  

Recent History

Even as recently as 1964 there were still 10,000 acres in bare sand, and a further 12,000 acres in marram (having just started the journey from sand to forest).

New Zealand has a number of sand forests, because of our long sandy coastlines and agricultural history. Forests were used to stabilise the sand dunes, when many areas faced an enormous problem of dunes overrunning areas that had been de-stabilised by human activity. In the 1870's Sheep and Cattle grazing had already begun to cause problems in many coastal areas. By 1873 James Stewart reported fully grown trees buried by dunes and in the Kaipara dunes of 90 metres tall. Just a few years damage could transform an area from bush to desert. 

The first NZ Forest Act of 1874 was largely in response to concern about the increase in coastal dune invasions. However, little was actually done. In 1880 the area of coastal drifting sands was 46,000 hectares. By 1909 it had grown to 120,000 hectares. 

In 1903 the Sand Drift Act was enacted, but it wasn't until 1913 that the Public Works Dept made its first efforts in sand stabilisation. By 1924 only 65 hectares of marram had been planted at Woodhill. 

The Great Depression

With the problem increasing each year, the great depression came to the rescue of the New Zealand coastline and lands. The Public Works Dept administered the unemployment relief fund, with 80,000 registered unemployed at their disposal they set them to work on sand stabilisation projects around the country. In 1932 planting of marram grasses began in earnest. In Woodhill there were 4 camps of 20-30 men per camp working all year around, with supplies being brought in from neighbouring farms and plants supplied from a Nursery also in what was then a barren wasteland of sand dunes. 
Photo from Enviro History

Photo From EnviroHistory NZ http://envirohistorynz.com/ 


How did they do it?

Combatting the dunes was neither a quick, nor an easy job.  The basic techniques were well known from similar problems in France and Germany.  It involved building fences, planting generations of stabilising plants (each one sheltering the next and adding nutrients to the sand) and eventually planting pine trees.

Stage 1 - Fences and Marram Grass planting.  Fences of untreated pine and other materials were placed in the dunes to provide some stabilisation. If the dunes over-ran a fence another was placed on top and so on until the foredunes (nearest the sea) were stabilised.  These fences also acted as windbreaks when marram grass planting began.  The Marram was grown in nurseries inland and then hand dug out, split up and replanted in the sand behind the foredunes.  Other sand grasses used alongside Marram were, Pingao, Silvery sand-grass (Spinifex) and Shore Spurge for sand binding, as well as specialists such as Jointed Wire Rush for wet sand areas.

Stage 2 - Only after the marram had been successful (sometimes it failed or was overrun) and grown for 2-3 years was the next plant introduced.  Tree lupins provided larger cover for the tree seedlings to come and importantly introduced nitrogen and nutrients into the barren sand.  

Stage 3 - It took four years from planting the Tree Lupins for their nitrogen and biomass (leaf litter) to reach optimal level for planting trees.  Maritime, Ponderosa and Radiata Pine, along with Macrocarpa were the favoured species.  Radiata Pine eventually became the number one species in all coastal sand forests, for its high tolerance to salt and ability to thrive in inhospitable conditions.

Information from Peter McKelvey's "Sand Forests: A historical perspective of the stabilisation and afforestation of coastal sands in New Zealand.