Amended Bushfire Risk Assessment and Risk Management Plan

                                Ecological Natural Area Management

The reasons that the two fuel loads are specified instead of allowing the consultant to input any fuel
loads based on an assessment of the extent vegetation is to ensure that the fuel loads used reflect
the maximum potential fuel accumulation and to allow for a worst case scenario. An assessment of
the fuel loads in the extant vegetation could potentially be less than the maximum fuel accumulation
if the assessment is conducted after vegetation management works such as prescribed burning.
Figure 15 below shows fuel accumulation curves for open forests in eastern Australia which indicate
that none exceeds 20 t/ha maximum fuel accumulation.
                   30
Fuel load (t/ha)




                   20


                   10


                   0
                   30
Fuel load (t/ha)




                   20


                   10


                   0
                        0   5     10          15        20      30    0         5         10         15         20       30
                                Time since fire (years)                                 Time since fire (years)

Figure 13: Fuel accumulation curves for open forests in eastern Australia
State Planning Policy Natural Hazards, Risk and Resilience Technical Manual: A ‘fit for purpose’
approach in undertaking natural hazard studies and risk assessments (Queensland Department of
Infrastructure, Local Government and Planning, 2016) also specify potential maximum fuel
accumulation for vegetation communities in Queensland. The vegetation community in the
technical manual that is specific for the subject vegetation is shown on Table 6 below.
Table 7: Excerpt from State Planning Policy Natural Hazards, Risk and Resilience Technical
Manual of potential maximum fuel accumulation for the subject vegetation communities.
 Vegetation Hazard Class                                                   Potential Fuel Load
 22.2 Melaleuca woodlands on lowland coastal swamps                     19.7 t/ha
(Queensland Department of Infrastructure, Local Government and Planning, 2016, page 21)
From Table 6 above, the vegetation community described in the technical manual has a potential
maximum fuel accumulation no greater than 25 t/ha.
Methods that can be used for for the assessing fuel loads include:
    • Vegetation sampling and oven drying to derive weight of dry fuel and
    • Estimating fuel load using the Overall Fuel Hazard Guide (McCarthy et. al., 1999).
The actual fuel loads of the impacting vegetation were not assessed, however, based on the above
published potential fuel accumulations from the published literature shown above, this report will
use the next highest acceptable fuel load from AS3959 which is the “Woodland” fuel loads which
are 15 t/ha surface fuel load and 25 t/ha total fuel.


Bushfire Risk Assessment and Management Plan for a small rural subdivision at 15 Jirrama Cr, Cooroibah               March 2022

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