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Redwood - spatial productivity indices

Description

Spatial productivity metrics for redwood (Sequoia sempervirens):

  • Site Index, a measure of height growth potential, and
  • 300 Index, a measure of volume growth potential.

These metrics are used as inputs to a redwood growth model which is available in 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 were masked.
Spatial resolution Productivity surface developed at 25m resolution.
Temporal extent The displayed projection of 300 Index assumes a planting date of 2000 AD. Stands established after this date are likely to have higher productivity.
Temporal resolution Not applicable. (Growth models that use the prodiuctivity surfaces generally have annual time-steps with some monthly sub-routines).
Evaluation method (Validation) One-at-a-time validation.
Evaluation result (Numeric) The multiple regression model that was developed to predict 300 Index from environmental and stand variables fitted the data well (R2 = 0.66, RMSD = 6.80 m3 ha−1 yr−1).
Evaluation result (Categorical)
Uncertainty method
Uncertainty data format (Numeric)
Uncertainty data format (Categorical)

 

Methodology

Using a national dataset (n = 130 observations) a multiple regression model was used to predict 300 Index and Site Index from environmental surfaces.

A detailed description of the modelling methods is given in: Watt, M.S., Kimberley, M.O., Rapley, S., Webster, R. (2021) Comparing volume productivity of redwood and radiata pine plantations in New Zealand. Forest Ecology and Management 500, 119628.

 

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