The Natural Resources Commission commissioned the research to strengthen the evidence base for predicting and managing hollow‑bearing trees in NSW State forests under changing fire conditions. The project is referenced in the Forest health - Coastal IFOA Monitoring Program.
Project overview
The program engaged Dr Raphaël Trouvé, a forest dynamics researcher at the University of Melbourne, to examine how fire affects living hollow‑bearing trees and the development of new hollows in the Coastal IFOA region.
This work followed advice (see report in Project F7Perpetuating trees with hollows under Coastal IFOA) from Professor Philip Gibbons (Australian National University) on improving predictions of how many hollow‑bearing trees will be available in forests managed under the Coastal IFOA. Hollow‑bearing trees provide critical habitat for many species, including gliders, birds and reptiles. Ensuring these trees—and trees capable of forming hollows—are retained during forestry operations is a key focus of forest management.
The research used datasets from Forestry Corporation of NSW and Western Sydney University to analyse tree death and hollow development following moderate, high and extreme severity fires.
Publications
- Report - Accounting for fire impacts to improve the evidence base for tree-hollow modelling (PDF 5.74MB) (November 2025)
- Research note - Impact of fire on tree-hollow development (PDF 249.77KB) (November 2025)
Key findings
The study found:
- After high and extreme severity fire, the smallest and largest trees are most likely to die, while medium‑sized trees (20–100 cm diameter at breast height) have the lowest death rates. Mortality increases with fire severity and varies between species.
- Large trees that survive fire are more likely to develop hollows, often due to fire‑induced wounds.
- Small trees that survive fire do not immediately form hollows, even when damaged.
- Past fire history increases the likelihood of hollows, with both the number and severity of earlier fires influencing hollow presence.
- The project developed models that predict tree death and hollow development after fire, which can be incorporated into forest management planning tools used by Forestry Corporation of NSW.
- Using these models will improve the assessment of sustainable harvesting and support better planning for future hollow‑bearing trees under changing fire regimes.
- The study recommends further research on hollow development in dead trees and woody debris, which are also important habitat elements affected by harvesting and fire.
How the findings will be used
The results will support:
- improved hollow‑bearing tree modelling in harvested landscapes
- better planning for fauna habitat in forests with changing fire regimes
- updates to Coastal IFOA forest management tools
- stronger evidence for long‑term hollow‑resource forecasting.