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Radiata pine - spatial productivity indices

Description

Spatial productivity metrics for radiata pine:

  • Site Index, a measure of height growth potential, and
  • 300 Index, a measure of volume growth potential which can be used as inputs to the 300 Index Growth Model for predicting stand volume.

The growth model is implemented in the Forecaster Calculator, available online from the NZ Farm Forestry Association and in the Forecaster, which can be licensed from Integral Ltd.

Productivity surfaces are also licensed for use within the NZFFA TreeFarmer application.

 

Date: June 2022 Version: v1

Owner: Scion

Contact: Michael Watt, Scion

 

Link to report / paper

Watt et al (2021)

 

Preview Image

 

Dataset attributes

Spatial extent National. Large lakes and a large plantation forest located in the central North Island were masked.
Spatial resolution Productivity surface developed at 25m resolution.
Temporal extent The Permanent Sample Plot data used represents stands planted from approximately 1976-2012, and growing conditions from ~1976-2020.
Temporal resolution Not applicable. (Growth models generally annual time-steps with some monthly sub-routines).
Evaluation method (Validation) Independent dataset comparison
Evaluation result (Numeric) A validation undertaken on a test dataset not used for model fitting showed the model of 300 Index has a coefficient of determination (R2) of 0.68, an RMSE of 3.45 m3/ha/yr, and a percentage RMSE of 12.6%, while the model of Site Index has a coefficient of determination (_R_2) of 0.80, an RMSE of 2.08 m, and a percentage RMSE of 6.9%.
Evaluation result (Categorical)
Uncertainty method
Uncertainty data format (Numeric)
Uncertainty data format (Categorical)

 

Methodology

Using a national dataset (n = 3,676 plots) a regression kriging model was used to predict 300 Index and Site Index from environmental surfaces.

A detailed description of the modelling methods and results is given in:
Watt, M.S., Palmer, D.J., Leonardo, E.M.C, Bombrun, M. (2021) Use of advanced modelling methods to estimate radiata pine productivity indices. Forest Ecology and Management, 479, 118557.

 

Fitness for purpose / limitations

This table indicates whether the dataset is suitable for different types of questions at different scales.

Note: Users should carefully consider their purpose as this dataset may not be suitable.

Operational Absolute Relative Screening/scoping
Block/farm No No Maybe Yes
Multi-farms(5+) No No Maybe Yes
Catchment No No Yes Yes
National/regional No Maybe Yes Yes
Caveat(s) The presented surface is intended only as a guide for afforestation and growers should take into account the impact of microsite when choosing an appropriate species. These surfaces were derived from permanent sample plot data, which typically comprise plots of well managed trees, that do not have any unstocked areas and are sited away from exposed ridges. Consequently, we recommend that presented values of 300 Index and Site Index are reduced by 15% when applied to standard forestry sites.

Data and Resources