Otago and Southland Wood Availability Forecasts for the Period 2007–2040

Data

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

Method used to obtain area

Forest areas were obtained from A National Exotic Forest Description as at 1 April 2005 (MAF, 2006). The area for the large-scale owners was used unadjusted. The area of the small-scale owners’ estate was reduced by 15 percent. The small-scale owners’ areas were reduced because they are generally reported on a gross area basis rather than as net stocked areas (excluding unplanted areas, areas not successfully established, streams and wetlands). Reductions were also made to the area of over-mature stands in the small-scale owner estate, as described later in the report.

Method used to develop yield tables

In 2006, new yield tables for Otago and Southland were developed in the following way:

• Large-scale forest owners provided yield tables for their forest estates.

• These were averaged on an area-weighted basis to get regional yield tables for each croptype.

• Yield tables for old radiata pine (age 16+ years, planted in 1989 and earlier) 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 forest owners’ estate.

Large-scale owners’ harvest intentions

Large-scale owners were asked to provide details of their projected harvest volumes (by log grade and area) for the 2005 to 2015 period. The fifteen largest owners all provided yearly (31 December) summary data for the project. Including the harvest intentions data was critical, as it provides realistic, company projections as to wood availability over this period.

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