Auckland wood availability forecasts for the period 2008–2040

Data

Method used to obtain forest areas
Method to develop yield tables
Large-scale owners’ harvest intentions

Method used to obtain forest areas

The areas were obtained from the NEFD as at 1 April 2007 (Ministry of Agriculture and Forestry, 2008). To reflect the regime split in the harvest intentions data provided by the large-scale owners, 1600 hectares was transferred from the old pruned croptype into the old unpruned croptype.

In addition, the small-scale owners’ estate was reduced by 15 percent. This was done because the area in this ownership category is often reported on the basis of gross area rather than net stocked area.

Method to develop yield tables

In 2007 new yield tables for the Auckland region were developed in the following manner:

large-scale owners provided yield tables for their estate;
these were averaged on an area-weighted basis to get regional yield tables for each croptype;
yield tables for old (age 18+ years, planted in 1989 and earlier) radiata pine were then calibrated to match the harvest intentions data provided by large-scale owners; that is, the assumption is that the harvest intentions data is the most accurate information available as it is based predominantly on detailed inventory;
yield tables for young radiata pine croptypes (planted in 1990 and later) were also adjusted in consultation with large-scale owners;
the yield tables developed for the large-scale owners’ estate were also applied to the small-scale owners’ estate.

Large-scale owners’ harvest intentions

Large-scale owners were asked to provide details of planned harvest volume by log grade and area from 2007 to 2015. The harvest intention values for 2007 to 2013 were then included at the beginning of the forecasts to provide the most realistic wood availability forecasts over this period. The original intentions provided for 2014 and 2015 had a significant spike in volumes. Following review of these with the companies concerned, it was decided to cap the volumes for 2014 to 2018 at the 2013 level.

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