Land Cover

Taranaki’s land cover profile is characterised by a predominance of exotic grassland and indigenous forest covers.  The largest concentrations of indigenous forest are confined to Egmont National Park and the eastern Taranaki hill country.  The most productive soils are in exotic grassland and are likely to stay that way in the future as they support intensive pastoral grazing.  Less productive soils in exotic grasslands are found predominantly in the steeper eastern hill country and are conducive to reversion to indigenous scrub/shrubland due to low soil fertility, temperate climate, and high rainfall.  Between 1996 and 2018, the area of indigenous scrub/shrubland and indigenous forest has decreased, whereas exotic forest has increased.  Exotic forest has generally replaced indigenous scrub/shrubland or exotic grassland on land more susceptible to soil erosion.  Some areas of land with a high production potential have also been cleared of indigenous scrub/shrubland and brought back into exotic grassland.  Overall, there has been a decrease in the area of marginal land with exotic grassland or indigenous scrub/shrubland and an increase in exotic forestry.  These vegetation changes provide better soil stability than both pasture and indigenous scrub/shrubland.  An increase in forestry has been influenced, in part, by market forces and government incentives or schemes.  New opportunities for manuka honey farming may stimulate further reversion or establishment of indigenous scrub/shrubland which is also better for soil stability than exotic grassland.

Taranaki’s land cover profile is characterised by:

  • A predominance of grassland/other herbaceous vegetation cover (more than half of land area), of which most is exotic grassland. The most productive exotic grassland is found on the Taranaki ringplain and the coastal marine terraces where the most productive soils support intensive pastoral farming. Only 10% of the natural indigenous cover remains on the ringplain and terraces as a result of historical vegetation clearance for agricultural development.  Indigenous shrubland/forest on the ringplain is present as isolated pockets amongst the intensively farmed exotic pasture, or along riparian margins.  Natural, indigenous riparian vegetation is more predominant in the upper reaches of the ringplain catchments while around 6,000 kilometres of new indigenous shrubland/forest is being established under the Taranaki Regional Council’s riparian management programme.
  • A substantial area of forest cover (about 35% of land area is indigenous forest). It is found mainly in Egmont National Park, the steeper parts of north Taranaki and the eastern hill country where climate, steepness, and fertility preclude clearance. Twenty to 30% of the natural indigenous forest remains in the eastern hill country, with a high proportion in the Department of Conservation’s estate.  In the hill country, indigenous forest gives way to exotic grasslands where the better land can be found on the valley bottoms, easier foothills, and hill country slopes less than 35 degrees.
  • Scrub/shrubland cover is predominantly comprised of indigenous scrub/shrubland and is found mainly in the eastern hill country. Reversion of pasture to indigenous scrub/shrubland takes place after around five years due to low natural fertility, the moist and warm climate, and the inability for farmers to apply enough stock pressure to control regrowth. Depressed economic returns have sometimes affected the timing of regular scrub clearance programmes.
  • Urban area and cropping/horticulture comprise relatively small proportions of the regional land area overall. However, there are large areas of land capable of supporting cropping/horticulture but these are currently supporting intensive pastoral grazing and are unlikely to change.

 

The key changes in land cover between 1996 and 2018 in the Taranaki region are:

  • Indigenous scrub/shrubland and indigenous forest have decreased in area due to clearance to pasture when farming returns have been good, or when cleared for exotic forestry establishment. Although there has been a decrease in indigenous scrub/shrubland and indigenous forest, there has been a corresponding net decrease in the area of exotic grasslands and an increase in exotic forestry. The advent of manuka honey farming since 2012, may have contributed to the observed increase in indigenous forest area and reduced rate of decline in scrub/shrubland area between 2012 and 2018.  More marginal land in the eastern hill country will revert to, or be planted in manuka, with or without the assistance of the Government's afforestation grant scheme or the Council's South Taranaki and Regional Erosion Support Scheme.  This will have a positive effect on soil stability as there is 80% less erosion under indigenous scrub/shrubland compared to exotic grassland.
  • Exotic forest has increased in area and has occurred mainly in the eastern Taranaki hill country. The likely drivers are higher, long-term average, economic returns for forestry compared to drystock farming, uptake of the Government's afforestation grant and emissions trading schemes, and participation in the Council's South Taranaki and Regional Erosion Support Scheme. The increase in the area of exotic forest largely accounts for the decrease in the area of indigenous and exotic scrub/shrubland, indigenous forest, and exotic grassland.  This means that there will be 90% less erosion under exotic or indigenous forestry compared to exotic grasslands and 10% better than if under indigenous scrub/shrubland.  This is a positive trend as the overall area of exotic grassland susceptible to accelerated erosion on marginal hill country land will be less.  Exotic forest cover provides better soil stability than both pasture and indigenous scrub/shrubland.

 

 

 

 

Select your story