East Coast wood availability forecasts for the period 2007–2040

Data

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

Method used to obtain forest areas

Area figures were obtained from the National Exotic Forest Description (NEFD) as at 1 April 2005. To reflect the regime split in the harvest intentions data, 1200 hectares in the large-scale owners’ estate was transferred from the old pruned croptype into the old unpruned croptype. Area in age-classes 1 to 4 years in the large-scale owners’ estate was reduced by 10 percent to allow for the expected reduction following remapping prior to silviculture.

In addition, the areas of the small-scale owners’ estate, apart from the investment syndicates managed by Roger Dickie New Zealand and Forest Enterprises, were reduced by 15 percent because the area in this ownership category is often reported on a gross area rather than net stocked area basis (which excludes unplanted areas, areas not successfully established, streams, wetlands, etc.). In addition, reductions were made to the area of over-mature stands in the small-scale owner estate (as described later in the report).

Method to develop yield tables

In 2007 new yield tables for East Coast 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 16+ years, planted in 1989 and earlier) radiata pine and Douglas-fir were then calibrated to match the harvest intentions data provided by large-scale owners; the assumption is that the harvest intentions data provides 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 2005 to 2015. These harvest intention values were then included to provide the most realistic wood availability forecasts over this period.

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