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Re-Measurement of Farm Tōtara Project

Project Status: Current

Michael Bergin measuring in a Permanent Sample Plot (PSP).

Michael Bergin measuring in a Permanent Sample Plot (PSP).

Anna Manning remeasuring a tōtara tree in a sample plot.Anna Manning remeasuring a tōtara tree in a sample plot.This Tāne’s Tree Trust project is co-funded by Te Uru Rakau. The project involves the remeasurement of the tōtara silviculture trial plots established by the Northland Tōtara Working Group since 2007. Data from 60 Permanent Sample Plots (PSPs) will yield valuable information on growth rates, carbon sequestration, and management prescriptions for timber production and indigenous biodiversity management, associated with native forestry and native trees on farms.

Project term

It is a two-year project with a target completion date of 30 June 2022.

Background

This information is needed to complement and support other initiatives endeavouring to start a new regional industry based on the sustainable management of tōtara forests on private and Maori land.

It will also assist the Ministry of Primary Industries in their administration of the sustainable management requirements of the Forests Act, by providing updated information for growth and carbon modelling. Growth and biodiversity information is directly relevant to plantation tōtara forests and the aims of the One Billion Trees programme, as tōtara is the most common high native tree species planted nationwide.

Three areas of innovation are involved. These are:

  • The inclusion of bio-diversity surveying and assessment of ground-cover to sub-canopy development changes including regeneration. This will enable a comparison of values between managed (thinned) and non-managed stands (N.B. – only on limited selection of PSPs unless funding component can be increased).
  • The remeasurement of stands will be applied to stands where the Stand Density Index (SDI) model (based on northern hemisphere thinning forestry models) was first used in New Zealand to prescribe the level of thinning- as executed in 2012 as part of the SFF12-099 project. Updated growth data from remeasurement of these tōtara PSPs will validate/refine the use of the SDI thinning model for use in management of regenerating native forest
  • Improving the accuracy of a Northland regional growth model for tōtara

In addition, the PSPs include thinned and pruned plots that will indicate the potential of future planted and managed plantations, in comparison to unmanaged natural stands. This will enable extremely useful predictions to be made concerning the performance of new planted tōtara forests. This is critical information to the business case for establishment and management of native forestry.

A thinned Permanent Sample Plot (PSP) within a natural stand. Note the shaded conditions in the unthinned area above this thinned plot. Growth response of the residual totara trees after thinning will be measured and also the response of understorey vegetation development to the increased light conditions.A thinned Permanent Sample Plot (PSP) within a natural stand. Note the shaded conditions in the unthinned area above this thinned plot. Growth response of the residual totara trees after thinning will be measured and also the response of understorey vegetation development to the increased light conditions.

This information will assist Te Uru Rākau in administering the sustainability requirements of the Forests Act and it will help landowners and forest managers better plan and manage planted tōtara forests, including accounting for carbon sequestration, and refining silvicultural best practice (such as thinning regimes).

Progress to date

All PSPs have now been remeasured and the data entered – awaiting analysis.

Outputs

Will be made available upon completion.

Contacts for this project

  • Project Manager, Paul Quinlan: Enable JavaScript to view protected content.
  • TTT Executive Officer: Enable JavaScript to view protected content.