Bushfire risk profile, Barwon Otway Bushfire Risk Landscape, 1980–2021
Bushfire risk in Barwon Otway
The Barwon Otway BRL risk profile for the period 1980–2018, and projected changes in bushfire risk until 2021. It shows that:
- In 2017–18, bushfire risk in the landscape was 59%.
- Bushfire risk fell sharply in 1983 after the Ash Wednesday bushfires, which caused devastating losses along the Surf Coast and in the eastern Otways.
- Bushfire risk steadily increased after the Ash Wednesday fires as fuel re-accumulated across the landscape, reaching a peak of 82% in 2003.
- Since 2008, bushfire risk has fallen by 20–25% delivering a strategic, risk-based approach to fuel management.
- Fuel management activities on the FOP will reduce risk to a projected 44%, but without any fuel management, we project bushfire risk will increase to 71% by 2021.
Valuing our environment
Tolerable fire interval across Barwon Otway
The figure below shows the tolerable fire interval (TFI) status of vegetation on public land in the Barwon Otway BRL for the period 2007–18.
The figure shows that about 25% of the vegetation is below minimum TFI, and that the area of vegetation below minimum TFI has steadily increased since 2007. In 2017–18, a small 314 ha area was burnt by planned burning while below minimum TFI, and 2 ha area was burnt by bushfires while below minimum TFI. This shows that our fire management strategies are carefully considering and planning our burns to reduce our impacts on vegetation below minimum TFI.
TFI status of public land vegetation, Barwon Otway BRL, 2007–18
Growth stage structure across Barwon Otway
The figure below shows the growth stage structure (GSS) status of vegetation on public land in the Barwon Otway BRL for the period 2007–18.
The figure shows about 18% of the landscape was in the juvenile and adolescent growth stages in 2018 with a 2% increase in adolescent growth stage from the year prior. This is the result of increased levels of planned burning in recent years. As the proportion of the vegetation in the younger growth stages has risen over the past six years, the proportion of the vegetation in the older (mature and old) growth stages has fallen, from about 48% in 2009–10 to about 44% in 2017–18.
The current area below TFI and the proportion of the landscape in the younger and older growth stages is within the acceptable range set out in the Barwon Otway’s fuel management strategy.
We project that the area burnt while below minimum TFI and the amount of vegetation in the juvenile and adolescent growth stages will increase over the next decade because of planned burning in higher-risk areas. An increase in the area of younger (juvenile and adolescent) growth stages affects animals by reducing the abundance of important habitat (such as vegetation cover, logs and hollow-bearing trees), although plant diversity may increase in many vegetation types after fire disturbs them.
GSS status of public land vegetation, Barwon Otway BRL, 2007–18
A large proportion of this landscape has no recorded fire history. Nothing can be inferred about the TFI and GSS of public land with no recorded fire history.