Growing Confidence in Forestry’s Future (GCFF): Enhancing productivity and sustainability

GCFF Session 1 : Maximise the benefits from the existing forest resource

Presentations:  GCFF conference 2019_Session 1

Introduction:  GCFF

Presenter:  Peter Clinton, Scion

GCFF Session 1 Facilitator Introduction

Session Chair:  Amanda Matson, Scion

The value of long-term trials

Presenter: John Moore, Scion

New Zealand forest researchers are lucky to have the legacy of numerous large-plot trials, planted by earlier researchers and now reaching harvesting age. Scion has undertaken end of rotation assessments in some 27 of these trials, and a vast amount of data has been generated as a result.

For example, work on stand density has:

  • increased understanding of the maximum carrying capacity of sites – a key to optimising productivity
  • confirmed that stand density is a major determinant of the realised value of a stand.

The trials have also been a valuable testing ground for new technologies such as laser scanning, tools for measuring internal wood properties, and UAV-mounted LiDAR.


SEGMOD – a tool to determine the costs and benefits of segregating logs at various points in the supply chain – has also been developed and is freely available to forest harvest levy payers. Case studies using SEGMOD have shown that returns to both growers and processors can be increased by up to 10% through better segregation practices.

Mid-rotation interventions

Presenter: Graham Coker, Scion

Trials to assess the cost-benefit of applying mid-rotation fertiliser to radiata pine have produced promising early results. The work is based on understanding plant nutrient balances throughout the rotation, and how these vary depending on site and the specific crop.

Projected end-of-rotation results from nine trial sites across New Zealand indicate that site-specific mid rotation fertiliser treatments will result in:

  • increased volume
  • increased allocation to larger, more valuable log grades
  • increased total standing value
  • increased Net Present Value – average of $4,642/ha.

Foliar fertiliser

Research into the potential for aerially applied liquid foliar fertiliser is also underway. Foliar fertiliser is widely used in other sectors, and has the potential to improve nutrient use efficiency and hence environmental outcomes.

Foliar application by UAV, especially in small woodlots, is believed to have very good potential.

Optimising final crop stand density

Presenter: Mike Watt, Scion

Final stand density is known to be an important determinant of crop volume and value. Scion has developed a model which predicts optimum final crop density for forests under pruned and structural (unpruned) regimes in any part of New Zealand. The model is freely available for forest levy payers.

Research has also revealed the economics of structural regimes in relation to stand desity in more detail than was known before. Growers now have the tools to fine-tune their final crop stocking.

GCFF Session 1 : Panel Discussion

Session Chair:  Amands Matson, Scion

GCFF Session 2 : Phenotype characterisation of trees and forest:  From UAV to models

Presentations:  GCFF_conference_2019_Session2

GCFF Session 2 : Facilitator Introduction

Session Chair:  John Moore, Scion

Remote sensing: forest characterisation

Presenter: Robin Hartley, Scion

Scientists continue to test a range of remote sensing technologies in the quest to optimise forest data collection.  From satellites to aircraft including UAVs, and hand-held tools, the challenge is to generate data at the required resolution in a timely way and at a cost-effective price.

Looking to the future, predictions made include:

  • Because a large percentage of New Zealand’s forest estate is inaccessible for UAV operations, LiDAR and satellite capture will continue to be essential
  • ‘Structure from Motion’ (SfM) is a technology with potential as a cheaper alternative to LiDAR
  • Technology will evolve to enable more coverage of stems and better branch characterisation – this will include machines that fly sub-canopy.

Area-based phenotyping: stand characterisation

Presenter: Maxime Bombrun, Scion

The dynamics of a forest depend on interactions between genetics, environment and silviculture.

Machine-learning tools to model these interactions are being developed, and can investigate how changing a particular variable can influence overall stand productivity.

Data from Kaingaroa Forest has been used –  some 2.78 million observations on 62 variables have been input into the ‘Catboost’ model, resulting in over 170 million values to be handled. The model has enabled a ranking of how different elements – for example seedlot, spring temperature, elevation, leaf area index – affect productivity.

Results show the potential of machine learning models to interpret phenotypic variability across a forest. Selection of specific seedlots for given areas of the forest to optimise productivity is one example of the many possible benefits for growers.

Individual tree phenotyping: understanding the drivers of growth

Presenter: David Pont, Presenter

Techniques using LiDAR outputs have been developed to correlate individual tree crown metrics with other physical metrics of the tree, such as height, total stem volume, and diameter at breast height (DBH). Large data sets have successfully been screened to select individual trees of interest.

In addition, UAV-based data is enabling point clouds of individual trees to be created which describe stem metrics as sweep, lean, taper and branchiness as well as stem diameter and height.

Ultimately scientists will be able to ‘fuse’ above and below canopy data, enabling trees to be measured and described by remote sensing technologies. The benefit to forest managers will come in various ways, not least in potential savings in forest inventory costs.

Virtual trees: phenotype modelling

Presenter: Damien Sellier, Scion

By combining multiple computer models describing different aspects of tree growth, a virtual tree model has been created, which can ‘grow’ radiata pine internally up to age of 7-8 years.

The model produces high-resolution 3-D maps of internal wood properties, and simulates key internal transport processes such as the movement of water and carbon dioxide.

Ultimately the aim is to produce a tool that will enable growers to make the link between the quality of their product and the growing environment. The hope is that they will then be able to adapt management factors to improve timber quality.

GCFF Session 2 Panel Discussion

Session Chair:  John Moore, Scion

GCFF Session 3 : Enhancing future forests: stacking productivity gains

Presentations:  GCFF conference 2019_Sesssion 3

GCFF Session 3 Facilitator Introduction

Session Chair:  Amanda Matson, Scion

The Accelerator Trials

Presenter: Simeon Smaill, Scion

A new series of long-term, large-plot trials, the ‘Accelerator Trials’ have been established at six sites between 2015 and 2018. The trials provide a facility for testing new science, and are already being used to trial some novel establishment and early intervention practices.

The aim is to ‘stack’ productivity gains from a range of different domains and occur at different times during the rotation.

Understanding the site

Presenter: Loretta Garrett, Scion

The Accelerator trials will be part of research to understand soil properties and their interaction with tree nutrient balances. Key to this work is the NuBalM model developed by Scion and which has various applications – for example:

  • predicting the nutrient requirements of a site for future rotations
  • predicting trees’ nutrient demand through time
  • guiding mid-rotation fertiliser interventions.

Optimising silviculture

Presenter: John Moore, Scion

Stand density, carrying capacity and stand uniformity are all known to affect overall productivity. The Accelerator trials will enable research into optimising stand productivity through manipulation of these factors for many years to come.

For example, early research into the effect of two different ground preparation techniques on growth of trees in different families has already yielded some interesting and significant results.

Stimulating soil microbes

Presenter: Sarah Addison, Scion

Trees don’t grow in isolation and microbial activity in soil plays a huge role in helping tree productivity. Microbes can increase stress tolerance, produce hormones that alter growth and keep resources such as nitrogen available for the trees to use.

Research has shown, for example, that the microbe ACC deaminase can improve drought tolerance, but importantly there is an interaction with tree genotype as well, so different families will respond to differing degrees to the presence of the microbe.

The whole area of soil microbes within forests is very new, with many unanswered questions. We are already moving from measuring microbes to actively managing their activity, however.

Research with the biostimulant ‘biuret’

Presenter: Simeon Smaill, Scion

The rate at which soil microbes and soil animals release mineral nutrients from organic matter is a key limitation to nutrient availability for trees. Research has shown that a compound called biuret can be applied to young radiata pine and increase nutrient uptake and hence growth.  The indication is that biuret helps soil microbes deliver more nutrients to plants.

In addition to better growth, biuret has been shown to increase resistance to dothistroma in one Accelerator trial in South Kaingaroa Forest.

Scion is now supporting efforts to make biuret commercially available In New Zealand.

In summary – the Accelerator Trials are considered a key legacy of the GCFF programme.

GCFF Session 3 Panel Discussion

Session Chair:  Amanda Matson, Scion

GCFF Session 4 : Ensure the future intensification is sustainable and understanding the full value of forests

Presentations:  GCFF conference 2019_Session 4

GCFF Session 4 Facilitator Introduction

Session Chair:  Simeon Smaill, Scion

Reducing harvesting impacts on steeplands

Presenter: Loretta Garrett, Scion

Work continues to reduce the risk of soil erosion and debris flows on steeplands following harvest. Research includes:

  • GIS-based mapping of erosion surfaces
  • Comparing the root reinforcement potential of different species  and species mixes
  • Revising good practice guides for managers.

Water quantity and quality in radiata pine forests

Presenter 1: Amanda Matson, Scion

Research continues into water dynamics under radiata pine; also the movement and uptake of fertiliser and how this can vary according to site management. Results indicate that some genotypes are better at utilising water than others.

Also, having additional organic matter on a new planting site, such as windrows, will reduce nitrogen loss through leaching. This suggests that there are management interventions to consider in areas where the risk of nutrient leaching is a concern.

Presenter 2: Brenda Baillie, Scion

One project monitored water quality following mid-rotation fertiliser application, and compared the relative impacts of foliar fertiliser and granular fertiliser. Results showed that any impacts on water quality were short-term, and mainly confined to the day of application.

Foliar fertiliser showed minimal impacts on water quality, again emphasising that there are ways managers can minimise the environmental risks associated with their activities.

End of rotation impacts and multi-rotation modelling

Presenter 1: Loretta Garrett, Scion

Scion is part of a global network investigating the impact of harvest residue removal and fertiliser amendment on long-term sustainability.

Conclusions of the research to date include:

  • Sites do differ in terms of the nutrient stocks they hold after harvest
  • Removal of harvest residues impacts sites with low nutrient stocks the most.
  • Adding fertiliser can increase nutrient stocks, but may not replace losses, including organic matter losses, that result from harvest residue removal.

Presenter 2: Sarah Addison, Scion

In terms of impacts of organic matter removal on soil microbial communities, bacterial communities show high resilience, but fungal communities are much more seriously affected.

In terms of impacts of fertiliser addition on soil microbial communities, the conclusion reached is that adding fertiliser reduces microbial diversity over the whole rotation, especially on sites with low soil fertility.

Presenter 3:  Loretta Garrett, Scion

Broader values of forests

Presenter: Richard Yao, Scion

The Forest Investment Framework (FIF) is a tool that combines spatial, productivity, economic and environmental data, and can assist in quantifying non-timber values of forests to assist with decision making.

Applications of the FIF in New Zealand to date include:

  • Afforestation feasibility studies
  • Regional economic development
  • Ecosystem service assessment, including to support forest certification renewal

Benefits of valuing ecosystem services

  • Independently quantifies broader value to support forest certification (e.g. FSC)
  • Informs government agencies, landowners, local communities and forest companies of the value of ecosystem services
  • Assists with long-term strategies on sustainable land use management
  • NZ banks are developing financial products for conservation of natural resources.

GCFF Session 4 Close

Presenter:  Simeon Smaill, Scion

GCFF Session 4 Panel Discussion

Session Chair: Simeon Smaill, Scion

The GCFF Research Programme:

A Systems Framework for the Sustained Delivery of Ecosystem Services in the Face of Change

Brian D Strahm, Department of Forest Resources and Environmental Conservation, Virginia Tech