A National Exotic Forest Description (2007) – NEFD
4 Database description
Area database
The base unit for collecting and recording area data is the crop type. Up to ten crop types are recognised for each territorial authority, made up of four tending regimes for radiata pine, two tending regimes for Douglas-fir, and one each for cypress species, eucalyptus species, other softwoods and other hardwoods. For definitions of crop type and tending regime see Appendix 1.
The area data in this database are organised as a net stocked area for each age by crop type and are labelled with a crop type code and a yield table code.
The area data are rounded to the nearest hectare and are recorded for ages one to 80 years.
The crop type code defines the territorial authority, the species group and the tending regime. The crop type is referenced to a specific table in the yield table database through the yield table code. This cross reference is used to prepare composite databases to calculate estimates of standing volumes and for providing input data for national and regional wood availability forecasts.
Yield table database
The yield table database contains yield aggregates of the same species group and tending regime which are located in the same wood supply region. The yield tables contain the total standing volume, total recoverable volume and three log type volumes (pruned logs, unpruned logs and pulp logs), together with any thinning volumes, by annual age class. Each yield table is labelled with a code that defines the wood supply region, species group and tending regime.
Planting and harvesting data
Data have been collected on the area of restocking, new planting and land cover before the establishment of forests. In addition the NEFD survey collected data on harvesting, including the area clearfelled, the volume yielded and the volume from production thinning for each year ended 31 March (see Table 2.1). The survey also collected data on the volume of clearfelled radiata pine by generalised log grade (pruned logs, unpruned logs and pulp/chip logs).
Other attributes
The NEFD database includes information on forest ownership, classified as:
- registered public company;
- privately owned;
- State-owned enterprise;
- local government body;
- central government;
- other forms of ownership.
The NEFD survey does not, however, attempt to collect information on forest land ownership.
Each year, the NEFD Steering Committee considers the inclusion of any other relevant attributes before requesting data from forest owners.
Land cover database
The location of New Zealand’s planted forests as identified in New Zealand Land Cover Database version 2, 2003 (NZLCDB2) are shown in Figures 8.1 and 8.2 in this report. NZLCDB2 is based on Landsat 7 ETM satellite imagery acquired in the summer of 2000/01. Further details about the NZLCDB2 are available on: www.mfe.govt.nz/issues/land/land-cover-dbase/ and www.terralink.co.nz/products_services/satellite/land_cover_database_of_new_zealand/
The full NZLCDB2 is available from the data custodians, Terralink International Ltd, as a digital theme ready to import into a geographical information system. The Ministry for the Environment is the steward of the NZLCDB2.
Contact for Enquiries
MAF Information Services
Pastoral House
25 The Terrace
PO Box 2526
Wellington, NEW ZEALAND
Fax: +64 4 894 0721
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