The NSW Natural Resources Commission engaged independent researchers under the previous NSW Koala Strategy (2018–21) to understand how koalas respond to selective harvesting in north coast state forests.
Research program
Eminent researchers from the Australian National University, Western Sydney University and the NSW Department of Primary Industries and Regional Development’s Forest Science Unit assessed koala and habitat responses to selective harvesting.
The program investigated:
- koala movement and occupancy
- koala density
- koala diet
- nutritional quality of koala habitat
This is the most comprehensive assessment undertaken in NSW on how koalas and their habitat respond to harvesting.
Key findings
The research found that selective harvesting did not adversely impact koala density at the study sites or the nutritional quality of koala habitat. The results suggest current koala protections and broader landscape protections under the Coastal Integrated Forestry Operations Approval (Coastal IFOA) are effectively mitigating risks at these sites.
Koalas showed individual dietary preferences influenced by available food resources and local conditions. They consumed a range of tree species but preferred some species more than others.
Additional findings
- Koala density was higher than expected in the surveyed forests and was not reduced by selective harvesting.
- Koala density was similar between state forest and national park sites with comparable forest types and a mix of old growth and regrowth from historical harvesting.
- Tree species composition - not tree size - determines habitat nutritional quality and influences the density of koalas a forest can support.
- Selective harvesting at treatment sites did not significantly change canopy tree species composition and is not expected to reduce habitat nutritional quality.
- Tallowwood (Eucalyptus microcorys) and small‑fruited grey gum (E. propinqua) were confirmed as important diet species, consistent with the Coastal IFOA koala browse tree list.
- Spotted gum (Corymbia maculata) and ironbarks (E. paniculata, E. siderophloia) were browsed to a considerable extent, despite not being listed as Coastal IFOA browse species.
Recommendations
Our report identifies opportunities to improve outcomes for koalas, including:
- reviewing the koala browse tree list under the Coastal IFOA
- assessing the potential economic impacts of any proposed changes
This review drew on expert advice to verify and improve koala prescription maps and underlying models under the Evaluation of PNF koala prescription map.
The report also recommends continued long‑term monitoring to evaluate the effectiveness of Coastal IFOA rules, including koala protections. This work is underway as part of the Coastal IFOA monitoring program.
Key documents
- Research plan - Koala research program (PDF 539KB) (PDF 539KB) (September 2020)
Publication of research
Researchers engaged under the Koala Research Program will publish their findings in peer‑reviewed scientific journals.
Recent publications include:
- Regulated timber harvesting does not reduce koala density in NSW north-east forests — published in the Nature Portfolio of Journals.
- Broad‑scale acoustic monitoring of koala populations stability in the face of major disturbances — published in Ecology and Evolution.