Forest health and habitat

Forest health
Forest health
Biodiversity
Biodiversity
Water quality
Water quality
Research and evaluation
Research and evaluation
Wood supply
Wood supply
Reporting
Reporting

This program area will investigate how harvesting is distributed through space and time. In addition, it will investigate how habitat features are retained across the landscape to support ongoing ecological function and habitat connectivity through a state forest.

Monitoring forest structure, health and regeneration

Key monitoring questions

Monitoring has been designed to answer the following questions:

  • Do harvesting conditions establish a mosaic of forest age classes at the landscape scale?
  • Do the conditions maintain functional connectivity for focal fauna species to move within and across the forest?
  • Are the conditions effective in ensuring regenerating forests meet benchmarks for forest structure, floristic composition, and coarse woody debris?
  • Are the conditions effectively promoting regeneration to maintain volume and quality for productive supply?

Project F2: Assessing change in forest structure on state forests



Researchers at the University of Newcastle analysed variation in forest structure on state forests using airborne light detection and ranging (LiDAR) data and other spatial and non-spatial data. The researchers assessed the influence of natural and anthropogenic activities including management (harvesting, prescribed fire, areas managed for conservation), natural disturbance such as wildfire, topographic position and forest type. Building on this work, researchers also analysed structural complexity, canopy height and canopy foliage density.

Worked examples have been provided for several areas of NSW State Forests across the Coastal IFOA region exploring remote sensing metrics. These examples examine the impacts of terrain, fire severity in 2019/20, historical harvesting and differences across NSW State Forest management zones on forest structural attributes.

The researchers contributed to a stage 1 report on developing the methods and remote sensing metrics to assess change in forest structure and a stage 2 report testing these methods in case studies and reporting the findings. We produced a research note to outline the research and key findings.

Key findings

The research demonstrated LiDAR metrics offer a means to summarise change in forest height and canopy coverage. Modelling canopy top height recovery and incorporating slope types, harvesting practices and Forest Extent and Severity Mapping (FESM) classes can describe the rate of change across these different factors.

This research found:

  • canopy top height and canopy coverage recovers after harvest events across a range of slope classes
  • comparable rates of canopy regrowth over time are observed despite variations in harvesting intensity
  • similarities are seen in canopy structure between areas managed for timber production and areas managed for conservation at the landscape scale
  • differences in canopy top heights due to different fire severities were observed via LiDAR
  • harvesting influences vertical and horizontal distribution of biomass, but this returns to pre-harvest levels within a short period in selectively harvested forests.

Explore the data

You can explore the LiDAR-derived data and reference layers for the seven case study regions across NSW in web maps on the NSW Spatial Collaboration Portal.

We are working to make the raw LiDAR data publicly available. In the meantime, please contact us to access the data through alternative arrangements.

Join our webinar

On 15 November 2024 (11am-12pm), Professor Scott Brown from the University of Newcastle will lead a webinar presenting findings and interactive webmaps from this research exploring changes in forest structure in NSW state forests.

Following the presentation there will be a Q&A session with a panel of forest monitoring experts, including Professor Brown (University of Newcastle), Professor Patrick Baker (University of Melbourne) and Dr Sam Hislop (FLINTPro).

Register here to join our webinar on the new LiDAR-based forest monitoring.


Project F1: Managing dieback on state forests

Project F1: Managing dieback on state forests


Dieback is a term used to describe gradual deterioration of tree health sometimes leading to tree death. There are many potential causes of dieback including pests, disease, drought, fire and management actions. The Coastal IFOA recognises Bell Miner Associated Dieback as one form of dieback and requires FCNSW to implement management actions to mitigate its further spread.

The program has engaged Professor Brendan Choat at Western Sydney University to develop a cost effective, scientifically robust method to assess the extent to which Coastal IFOA conditions can effectively manage the risk of new or existing areas subject to dieback.

Researchers will use remote sensing, time series analysis and field surveys to analyse areas of forest dieback, recovery and casual agents in coastal state forests. It will use this information to assess whether new or existing areas of dieback are having an impact on the performance of the Coastal IFOA multi-scale landscape protections and outcomes.

The Coastal IFOA technical working group will review a methods paper before researchers test the method in an agreed pilot area. A final report documenting the methods, the results of the pilot area and recommendations will be provided at the project’s conclusion.

This project will add insights to the wider forest dieback research program overseen by the Commission.

Project F3: Assessing change in tree composition on state forests

Project F3: Assessing change in tree composition on state forests


The program has engaged researchers at the Forest Science Unit, DPI to assess how tree composition has changed over time on coastal state forests. Timber harvesting has the potential to alter tree species composition and thus the habitat and nutritional quality available for many species that rely on them. The researchers will access extensive space and time plot-based datasets held by FCNSW to undertake the analysis. The investigation will also assess change in selected focal feed trees that are used by species such as koalas, greater gliders and yellow-bellied gliders (e.g. tallowwood, grey gum, bloodwood) and important non browse and timber species (e.g. blackbutt, spotted gum, turpentine).

Monitoring impacts and recovery in fire affected forestry sites

During the summer of 2019/20, approximately 65 percent of Coastal IFOA state forests were affected by fire. The Coastal IFOA was not designed to moderate the environmental risks associated with harvesting in landscapes that have been severely impacted by fire.

The Environment Protection Authority (EPA) has issued additional site-specific conditions to the Forestry Corporation (FCNSW) that tailor protections for the specific circumstances of these burnt forests. As required by the conditions, FCNSW must work with the Commission to monitor the long-term impacts and recovery of burnt sites subject to forestry operations.

The Commission developed a plan with the FCNSW to monitor fire affected sites as part of the broader Coastal IFOA monitoring program. This plan was subject to expert review and approved by the NSW Forest Monitoring Steering Committee.


Project F4: Post-fire forest recovery in the Coastal IFOA region

Project F4: Post-fire forest recovery in Coastal IFOA region


Professor Brendan Choat at the Hawkesbury Institute for the Environment, Western Sydney University will lead researchers to investigate the response, mechanics and rates of forest recovery since the 2019/20 wildfires in the Coastal IFOA region. Researchers will access field-based datasets collected since the fires and published literature to inform their analysis. This work will build on earlier insights delivered by researchers at the University of Wollongong on risks to achieving Coastal IFOA outcomes from changing fire regimes and inform the monitoring program’s broader five-yearly review of evidence in 2024.

Monitoring key habitat features

Key monitoring questions

Monitoring has been designed to answer the following questions:

  • To what extent do retained habitat features maintain their function?
  • Do the conditions support key habitat features to maintain fauna species within and across the forest?

Monitoring to date

Monitoring is investigating whether the Coastal IFOA conditions and protocols provide sufficient habitat features in an appropriate configuration to ensure persistence of key fauna species through time to support ongoing viability of focal species. This includes three tasks:

  • a review of hollow use by key dependent fauna
  • hollow mortality and recruitment modelling
  • occupancy analysis of key habitat-dependent species.

Project F5: Hollow use review

Project F5: Hollow use review

The Program has engaged Associate Professor Ross Goldingay, Southern Cross University to review the scientific literature on managing, monitoring and researching hollow bearing trees in NSW forests. The review aimed to identify cost-effective approaches to monitor hollows and highlight research gaps. In addition, the review summarised the current knowledge on hollow use by key fauna species in harvested landscapes.

The review found that most studies have been short-term in nature. There is no clear consensus on the number of hollow trees that different hollow-dependent fauna required to maintain persistence. However, some individual arboreal mammals use a subset of their dens at a high frequency - for example, between 0.1 to 1 primary den trees per hectare based on home range sizes. When managing harvested forests for fauna persistence, it is important that target fauna can access hollows that are suitable in size and appropriately spatially distributed. Management should also account for hollow attrition.

The review outlined best methods to monitor hollow use by key species including the strengths and weaknesses of each. A significant research gap is to understand how den trees either persist or are lost in a harvested landscape, particularly following fire.

This work will inform species occupancy monitoring and modelling under the coastal IFOA monitoring program and broader Forest Monitoring and Improvement Program. The work will also inform hollow simulation modelling undertaken by the Australian National University as part of the program.

Project F6: Impacts of fire on hollow-bearing trees on state forests

Project F6: Impacts of fire on hollow-bearing trees on state forests




The Program has engaged Dr Raphael Trouve, a research fellow at the University of Melbourne, to investigate the effects of fire events on hollow-bearing trees and tree hollow formation within the Coastal IFOA region. The work follows advice from Professor Phil Gibbons, Australian National University to improve ways to better predict the number of trees with hollows required under the Coastal IFOA.

Overall, this project aims to quantify the rate of mortality, collapse and formation of hollow-bearing trees on state forests following fires of different intensities in the Coastal IFOA region. The work will deliver a model that can be used within FCNSW’s FRAMES modelling system to predict the effects of a fire event based on other available covariates such as diameter at breast height and tree species group.

Project F7: Perpetuating tree hollows under the Coastal IFOA

Project F7: Perpetuating tree hollows under the Coastal IFOA


Researchers at the Australian National University (ANU), led by Professor Phil Gibbons have delivered research and recommendations to improve hollow simulation modelling on state forests. This model predicts the number of trees with hollows perpetuated under the current Coastal IFOA conditions.

Working with modellers at the Forestry Corporation of NSW (FCNSW), the researchers used the Forest Resource and Management Evaluation System (FRAMES) to model the persistence and recruitment of hollow-bearing trees under a range of scenarios. Prof Gibbons methods paper outlines the suitability of FRAMES to model persistence of hollows.

Overall, the researchers found:

  • based on data, less than 50 percent of hollow bearing trees are typically occupied by vertebrate hollow-dependent fauna; thus, using tree diameter and tree species alone to predict how many hollow-bearing trees occur will over-estimate the number of hollow-bearing trees suitable for vertebrate species
  • the number of hollow-bearing trees and number of trees with hollows suitable for occupancy by vertebrate fauna were able to be predicted using a combination of FRAMES outputs and hollow occupancy models
  • simulations for the Coffs Harbour Timber Zone showed the Coastal IFOA conditions perpetuate 8-10 trees per hectare with visible hollows and 2-3 trees per hectare with hollows suitable for occupancy by vertebrate fauna in the net-harvest area over a 200 year modelling period
  • in areas permanently excluded from harvesting (approximately 51 percent of the study area), trees with visible hollows were predicted to increase from a mean of 8 per hectare to 26 per ha and trees with hollows suitable for occupancy by vertebrate fauna were predicted to increase from a mean of 3 per hectare to 10 per hectare.

With minor changes, Prof Gibbons suggests FRAMES can be used to simulate outcomes of the current Coastal IFOA and any proposed changes to the rule set on the tree hollow resource. In addition, FRAMES can be further improved over time to better simulate impacts.

The NSW Forest Monitoring Steering Committee has endorsed Prof Gibbons recommendations, including projects to collect further data to improve hollow-specific models for FRAMES. We produced a research note outlining the key findings from this project.

Explanatory note – greater gliders

Prof Gibbons’ research and report perpetuating trees with hollows under the Coastal IFOA was conducted prior to the introduction of the Site-specific biodiversity condition for Greater Gliders in the Coastal IFOA region on 16 February 2024.

Future modelling of hollow-bearing tree persistence within the Coastal IFOA region will incorporate the new requirements for tree retention within forestry operation areas specified in the Site-specific biodiversity condition for Greater Gliders in the Coastal IFOA region.

Monitoring landscape-scale trends

Spatial Vision and the NSW Department of Primary Industries Forest Science Unit will lead a consortium including RMIT University, University of New England, PF Olsen, University of NSW, NSW Forestry Corporation and the Department of Planning, Industry and Environment to deliver baselines, drivers and trends for forest health across all tenures, including Coastal IFOA state forests. Stephen Farrell and Dr Christine Stone will lead a team of over twenty eminent scientists.