National Exotic Forest Regional Yield Tables

The purpose of the National Exotic Forest Region Yield tables is to give the forest industry the underlying data used to produce wood availability forecasts New Zealand’s major forest owners and mangers provided information to construct the yield tables which are part of the National Exotic Forest Description (NEFD) database.

The yield tables are a tabular representation of forest yield in cubic meters per hectare (m3/ha). The yield table is expressed in terms of total standing volume (TSV), total recoverable volume (TRV) and volumes of three generic log types, together with any production thinning volumes by age (one to 40 years). There is a separate yield table for each crop type.

Log Types Specifications

The Radiata pine has four tending regimes:

Radiata pine tending regime R
Pruned without production thinning T
Unpruned without production thinning I
Pruned with production thinning Z
Unpruned with production thinning M

The Douglas-fir forest has two tending regimes:

Douglas-fir tending regime D
Without production thinning M
With production thinning Z

For each crop type and regime contributors were asked to provide separate yield tables based on when the stand was planted:

Age of stands
Stands planted pre 1990 O
Stands planted post 1989 Y
Stands of all ages A

The Otago region has an additional "year of planting" split:

Otago radiata pine
Stands planted pre 1982 X
Stands aged between 1982 and 1989 O
Stands planted post 1989 Y
Stands of all ages A

 

  Small end diameter
(cm)
Maximum branch
size (cm)
Sweep class*
Pruned 35 0 1
Unpruned 20 14 1
Pulp 10 NA 2

 

  Log length (m)
*Sweep class < 3.7 3.7 to 4.8 4.9 to 7.6 7.6 +
1 d/8 d/4 d/3 d/2
2 d 2d 3d 4d

Definitions

TRV is an abbreviation for Total Recoverable Volume; this is the volume of timber recovered during harvest. The TRV does not include bark.

TSV is an abbreviation for Total Standing Volume; this is the total standing volume of timber contained in all live crop stems. The TSV includes some non-recoverable volume such as stumps and the non-merchantable tops of stems, but excludes bark.

Crop Type for the purpose of the NEFD is defined as an aggregate of forest stands of the same species and tending regime within the same wood supply region.

Pruned refers to pruning carried out before age 12 so that more than 50 percent of stems in the planned final crop stocking will contain a pruned butt log of not less than four meters in length.

Species Group: New yield tables have been produced for:

  • radiata pine (Pinus radiata)
  • Douglas-fir (Pseudotsuga menziesii)

Stand is a defined area of standing trees or forest usually of one species, age and tending regime.

Production thinning refers to the extraction of thinnings for commercial use. Stands that have been production thinned produce a smaller clear felled volume than stands that have not been production thinned.

CAI: This abbreviation for Current Annual Increment represents the rate at which an area of forest is growing. In this report CAI is expressed as m3/ha/year and is the difference in total recoverable volume (TRV) between two successive ages. In the year following a production thinning the CAI is not reported. This is because the thinning has caused a decrease in TRV, so the CAI does not reflect the growth of the remaining standing trees over that year.

Yield Tables

Yield Tables have been produced for the following NEFD wood supply regions (WSR):

To receive the NEFD yield tables as csv files contact stats_info@maf.govt.nz specifying the names of the tables you would like to receive.

 

Last Updated: 09 March 2011

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