Bushfire risk

Port Phillip’s long-term bushfire risk regional planning target is 85%.

The figure below shows the Port Phillip region’s bushfire risk profile for the period 1980–2020 and projected changes in bushfire risk until 2023. It shows bushfire risk in the Port Phillip region:

  • is 85% in 2019–20, an increase of five percentage points from 80% at the end of 2018–19
  • is projected to fall to 82% if the entire Joint Fuel Management Program is implemented but would continue to increase to a projected 90% by 2023 without any fuel management or bushfires. This action will keep bushfire risk levels below the long-term Port Phillip region planning target of 85%.

Priority areas for planned burning include to the north of the Dandenong ranges, the forests to Melbourne’s east as well as burns to protect Melbourne’s water catchments. In addition, other key activities include the construction and maintenance of strategic fuel break networks through Melbourne’s water catchments as well a significant mechanical fuel treatment program across the forest interface to the east of Melbourne.

Bushfire risk profile, Port Phillip Region, 1980–2023

Ecosystem resilience

The figure below shows the tolerable fire interval (TFI) status of vegetation on public land in the Port Phillip region since 1980. It shows that in 2019–20:

  • about 49% of the vegetation was below minimum TFI, 16 percentage points less than in the previous reporting period
  • the proportion of vegetation within TFI was about 38%, 16 percentage points more than in the previous reporting period
  • the proportion of vegetation above maximum TFI remained stable at 1%.

In 2019–20, less than 1% of the vegetation was burnt by bushfires or planned burning while below minimum TFI. This shows that our bushfire management strategies are carefully considering and planning burns to reduce impacts on vegetation below minimum TFI.

TFI status of vegetation on public land, Port Phillip region, 1980–2020

The figure below shows the growth stage structure (GSS) status of vegetation on public land in the Port Phillip region since 1980. It shows that in 2019–20:

  • about 22% of the vegetation was in the juvenile growth stage, a decline of two percentage points from the previous reporting period
  • the proportion of vegetation in the adolescent growth stage was about 20%, no significant change from the previous reporting period
  • the proportion of vegetation in the mature growth stage was about 44%, one percentage point more than in the previous reporting period
  • there was no significant change in the proportions in the old growth stage (which remained low, at 2%) and with no fire history (which remained at 12%).

Threatened species (such as Leadbeater’s possum and Smoky mouse) rely on the habitat (such as hollow-bearing trees and coarse, woody debris) that vegetation in the mature and old growth stages provides. It will take many years before the proportion of vegetation in older growth stages recovers to the proportion before the 2009 Black Saturday fires: some vegetation communities can take up to 50 years or more to reach maturity.

GSS status of vegetation on public land, Port Phillip region, 1980–2020

Fuel management delivery

While the region achieved much of our planned burning program, we were limited by weather conditions and the need to provide support resources for early-season fires in Gippsland. Table 1 summarises the region’s fuel management activities in 2019–20.

Table 1: Fuel management activities, Port Phillip region, 2019–20

Fuel reduction

No. of treatments

Hectares

Area treated by planned burning:

  • ecological burns: 209 ha (3 burns)
  • fuel reduction burns: 2,425 ha (9 burns)
  • other burns: 122 ha (18 burns)
30

2,755

Area treated by non-burn fuel treatments:

  • mechanical mulching: 35 ha (1 treatment)
  • mechanical slashing or mowing: 954 ha (24 treatments)
  • other methods: 0 ha (0 treatments)
25

989

Total area treated to reduce bushfire risk

55

3,744

In 2019–20, we completed fuel reduction burns in the Upper Yarra Valley to protect Reefton, McMahons Creek and the Upper Yarra Reservoir. We completed burns on Mount Dandenong and around Olinda and Kalorama. We also delivered part of a larger burn around the Silvan Reservoir to protect critical water treatment infrastructure. Traditional Owners undertook two cultural burns at Greensborough and St Andrews.

In spring, burning opportunities were limited by drier-than-average conditions across the region and a need to provide support resources for early-season fires in Gippsland. This support continued through until early autumn. The region also had above-average rainfall from January to May, which limited burning opportunities to a few small windows.

Page last updated: 27/10/20