Determining eligible pre-1990 land

Who has done the mapping?

Land Information New Zealand (LINZ) commissioned the Ministry of Agriculture and Forestry (MAF) in September 2010 to map all the Crown Forest Licensed (CFL) land to determine the eligible pre-1990 land which would qualify for an allocation of New Zealand Units (NZUs). The shapefiles and the schedule of legal descriptions for each area of CFL land were saved to CD and delivered to the FEUT.

How was the eligible pre-1990 land determined?

The maps were derived using the following technical documents:

  • A guide to pre-1990 forestry allocation and exemptions (December 2010)
  • A guide to mapping forest land for the Emissions Trading Scheme (March 2009)
  • Geospatial Mapping Information Standard

These documents provide guidelines for data sources for mapping pre-1990 forests, and provide illustrated examples and mapping standards to show how forest and non-stocked areas should be mapped.

Has the mapping been independently verified?

The FEUT commissioned Dr Pete Watt, Head of Forest Resource Mapping, Indufor Asia-Pacific (IAP) to review and verify the eligible pre-1990 forest land for all 47 CFLs. This process involved reviewing all the digital mapping layers prepared by MAF. MAF’s analysis was assessed to ensure compliance with MAF-published technical documents and guidelines, and against available satellite imagery and aerial photography.

For many parts of New Zealand the primary record of land cover as at 1990 comes from 30m Landsat satellite imagery. This imagery was used to confirm the presence of plantations in 1990 and to identify any non-stocked areas. Additional images of about the same spatial resolution (20-30m) from 1996, 2000 were used to monitor the forest development and confirm the stocked areas.

Post 2000, several high resolution images were available. These include 2006-08 10m SPOT 5 and 2008 2.5m SPOT Maps. The higher spatial resolution enabled further refinement of the planted area and confirmation that the area was still forested at the end of 2007. It also allowed refinement of the CFL boundary relative to the surveyed LINZ legal boundary.

An illustration of how different satellite imagery depicts eligible pre-1990 forest land is presented below.

IAP is an international forest advisory and consultancy firm with offices in Auckland and Helsinki, Finland. IAP operates a specialised resource mapping unit within its Auckland office.