BUSHFIRE FUEL CLASSIFICATION OVERVIEW
2|B USHFIRE FUEL CLASSIFICATION OVERVIEW
WHAT IS THE BUSHFIRE FUEL CLASSIFICATION? For millennia, fire has played an important role in shaping Australian environments with deep implications for bushfire management and prescribed burning. The rich and diverse vegetation present in Australia results in a multitude of fuel types with distinct fuel arrangements, quantities and combustion characteristics. A fuel classification aims to integrate vegetation diversity into a few differentiable fuel types that are easily communicated and quantitatively described (Keane 2015). Australian land and fire managers have recognised the need for a national-level fuel classification to provide a consistent method of characterising and categorising fuels to support a wide range of fire management activities such as assessment of fuels, assessment of bushfire risk, planning landscape fuel management, sharing fire behaviour analysts and predicting the behaviour and growth of fires. The Bushfire Fuel Classification (BFC) provides a guideline for a standard classification of fuels in the Australian landscapes, and will be supported by a range of products as shown below:
POSITION
APPROACH
BFC OVERVIEW (THIS DOCUMENT)
THE BUSHFIRE FUEL CLASSIFICATION
GLOSSARY OF TERMS
TOOLS
SPECIFICATIONS FOR THE BFC
| 3
WHAT IS THE PURPOSE OF THE BFC? The purpose of the BFC is: To facilitate effective bushfire management by providing a nationally consistent classification of bushfire fuel to improve communication, cross-border interoperability and facilitate the use and development of bushfire management support tools, especially fire behaviour predictive tools.
HOW DID THE BFC COME ABOUT?
WHAT ARE THE BENEFITS?
The BFC emerged from extensive consultation with land managers and rural fire authorities, and a review of other classification systems used throughout the world. The Australasian Fire and Emergency Service Authorities Council (AFAC) and the Forest Fire Management Group (FFMG) commissioned the Commonwealth Scientific and Industrial Research Organisation (CSIRO) to investigate the potential for a national fuel classification. In a previous report Development of a Framework for a Bushfire Fuel Classification (Hollis et al. 2014), CSIRO investigated a potential framework for a fuel classification, to meet the desired uses for a fuel classification as expressed by state government agencies and to address the requirements of fire behaviour models and fire growth simulators. The report reviewed existing international fuel classification systems and finally, proposed a framework for classifying fuels in Australia.
• Improved cross-border operations especially with regard to common understanding around fuel type descriptions, fuel dynamics, fire behaviour predictions, hazard and risk assessments and suppression difficulty; • Supporting national rollout of fire behaviour predictive services and the new national fire danger rating system; • Improved cross-border communication and interoperability in relation to fuel assessment; • Supporting utilisation of a range of fire management support tools; • Providing a nationally consistent approach for fuel classification, terminology and best practice for fuel appraisal; • Fostering the development of nationally applicable tools and research based on the BFC standard; • Providing state agencies a means to convert their vegetation data or mapping into the BFC fuel standard; • Providing nationally consistent inputs into a range of processes including local government or landscape planning and other projects attempting to build consistency or standards; • Providing improved and more consistent inputs for prescribed burn planning, risk and hazard assessments, evidence-based decision making and for evaluation, monitoring and reporting processes; and • Improved basis for public information, engagement and education.
4 | BUSHFIRE FUEL CLASSIFICATION OVERVIEW
HOW DOES THE BFC WORK?
The BFC includes two main components: Categorising fuel – a hierarchical approach to identifying fuel types. This is achieved by using a three tier coding system. CATEGORISING FUEL The BFC uses a hierarchical approach to classify fuels (by using tiers). There are three tiers plus an optional layer of fuel description: - The top tier organises the diversity of vegetation types found across Australia into a standardised set of broad fuel types based on the structural properties of the canopy (using structural categories derived from Specht 1970, which are already in wide use); - The mid tier refines these fuel types by identifying the major fuel layers, including understorey fuels, that have a large influence on combustion and fire propagation processes; - Below the mid tier, the bottom tier provides a current description of fuel accumulation as determined by time since fire and by environmental and climatic influences; and - The BFC includes an optional customised description nested within the BFC bottom tier that allows a user-defined fuel description to support situations where the user has detailed sampling data.
Describing the fuel within fuel types – This is achieved by populating a fuel catalogue that records fuel characteristics.
| 5
An illustration of the categorising tier system is provided below (with example fuel types included):
VEGETATION DESCRIPTION e.g. EVC, NVIS
Top Tier OPEN FOREST FM3
Mid Tier
OPEN FOREST WITH SPARSE COVER OF LEAF LITTER
OPEN FOREST WITH CLOSED COVER OF LOW GRASSES
FM3_l1
Bottom Tier (under development)
OPEN FOREST WITH OPEN COVER OF MEDIUM SHRUBS
FM3_gl4
OPEN FOREST WITH OPEN COVER OF MEDIUM SHRUBS, 0-3 YEARS SINCE FIRE
FM3_sm3
OPEN FOREST WITH OPEN COVER OF MEDIUM SHRUBS, 4-7 YEARS SINCE FIRE
FM3_sm3_1
Custom Fuel Complex (under development)
OPEN FOREST WITH DENSE COVER OF TALL SHRUBS
OPEN FOREST OF MEDIUM SHRUBS 5 YEARS OLD MCCORKHILL BLOCK
FM3_st4
OPEN FOREST WITH OPEN COVER OF MEDIUM SHRUBS, 8-11 YEARS SINCE FIRE
FM3_sm3_2
FM3_sm3_3
OPEN FOREST OF MEDIUM SHRUBS 7 YEARS OLD MCCORKHILL BLOCK
DESCRIBING THE FUEL WITHIN FUEL TYPES The fuel types defined within the tier system are accompanied by a description of their characteristics (such as fuel load, fuel hazard, shrub layer height etc.). There is a list of recommended fuel characteristics; however, exactly which characteristics are to be recorded is selected at the discretion of BFC users according to their needs. The top tier will include wide data ranges for each characteristic (e.g. fuel load = 4 to 8 tonnes/ha with a mean value of 6 tonnes/ha), with that data range becoming narrower at lower tiers. The mean value is provided to enable practical applications. Each tier can support a full description of fuel characteristics, however the lower the tier, the more precise and meaningful the description. The BFC acknowledges that new fuel characteristics may be required in the future as a result of a better understanding of the effect of the physical properties of fuel on fire behaviour. As such the list of fuel characteristics is expected to expand over time. Fuel characteristics can be recorded in a fuel catalogue which can support the development of a range of fire management tools such as: • Input into fire behaviour models and fire growth simulators; • The development of photographic fuel assessment field guides or apps; and • Input into future fire danger rating systems.
6 | BUSHFIRE FUEL CLASSIFICATION OVERVIEW
Table 1 The Bushfire Fuel Classification top and mid tier fuel types Version 1 (19-11-2015)
Australian Bushfire Fuel Classification – Top and Mid Tier Cover Class
1 (1-5%)
Growth Form
Top Tier - Name
2 (5-30%) Code
Mid-Tier
Trees >30m
3 (30-70%)
Top Tier - Name
Code
Mid-Tier
Top Tier - Name
Tall Woodland
WT2
st
Tall Open Forest
g Trees 10-30m
Woodland
WM2
hg
Open Forest
gt gl st sl Trees <10m
Low Woodland
WL2
gt
Low Open Forest
gl st sl hg Shrubs 2-5m
Tall Open Shrubland
ST2
hg
Tall Shrubland
g sm Shrubs <2m
Low Sparse Shrubland
SL1
hg
Low Open Shrubland
SL2
g
hg
Low Shrubland
g sm
Hummock grassland
Sparse Hummock Grassland
HG1
Hummock Grassland
HG2
Dense Hummock Grassland
Grassland
Sparse Grassland
G1
Open Grassland
G2
Grassland
A standardised naming and coding convention has been developed based on the three tier structure. It consists of: • Standardised codes; • Standardised descriptive names; and • Additional fuel type codes outside the native vegetation structural form groups (e.g. plantations, the wildland-urban interface, horticultural and activity fuels such as logging and pruning slash). The coding has 3 separate fields AA#_aa#_#. The first field (AA#) describes the top tier, the second field (aa#) describes the mid tier and the third field (#) describes the bottom tier. Extra supplementary codes identifying rainforest vegetation and bark status can be added.
| 7
4 (>70%)
OTHER
Code
Mid-Tier
Top Tier - Name
Code
FT3
st
Tall Closed Forest
FT4 (R)
Mid-Tier
Top Tier - Name
Code
Conifer Plantation
PC
Mid-Tier PRAD
fl
PSOU PPIN
FM3
lit
Closed Forest
FM4 (R)
PARA
gt
Broadleaf plantation
PB
PESR
gl
PEMR
st
Wildland Urban Interface WUI1 (< 0.1 house per ha)
sl FL3
gt
WUI2 (0.1 ≤ houses per ha ≤ 1) Low Closed Forest
FL4 (R)
WUI3 (>1 houses per ha)
gl
Wetland
st sl ST3
hg
Tall Closed Shrubland
ST4
sm SL/M3*
g
WET1 (permanent wetlands) WET2 (combustible wetlands)
Low Closed Shrubland
SL/M4*
Horticultural
HOR
Activity Fuels
AF
Other Fuel Types
TBC
Non-combustible
NB
*Mid Tier Types
SL – Short < 0.5m SM – Medium 0.5-2m
HG3
G3^
1
Closed Grassland
G4^
1
^ Mid Tier Types
1 – Eaten Out
2
2
2 – Grazed or cut
3
3
3 – Ungrazed or natural
TOP TIER CODE
MID TIER CODE
F W P S HG G
s hg g f lit
Forest Woodland Plantation Shrubland Hummock Grassland Grassland
HEIGHT CODE (TOP/MID TIER)
T/t tall (trees >30m, shrubs 2-5m, grasses >1m) M/m medium (trees 10-30m, shrubs 1-2m) L/l (trees <10m, shrubs <1m, grasses <1m) FOLIAGE COVER CODE (TOP AND MID TIER)
1 2 3 4
less than 5% (very sparse) between 5-30% (sparse) between 30-70% (open) greater than 70% (closed)
AA#_aa#_#
shrubs hummock grasses grasses ferns litter
BOTTOM TIER CODE
Yet to be defined SUPPLEMENTARY CODES (TOP TIER)
R
Rainforest
SUPPLEMENTARY CODES (MID TIER)
B Br Bf
Bark Ribbon Bark Fibrous Bark
WHERE TO FROM HERE? The BFC has been adopted in principle by the AFAC Council and a supported program to help agencies convert data to the new standard will be rolled out beginning 2016. For further information about the BFC contact AFAC on (03) 9419 2388.
REFERENCES Hollis JJ, Gould JG, Cruz MG, Doherty M (2014) Development of a framework for a Bushfire Fuel Classification (CSIRO: Canberra) and (AFAC: Melbourne) – available from the AFAC shop at www.afac.com.au Keane RE (2015) Wildlands fuels fundamentals and applications. (Springer International Publishing: Switzerland) Specht RL (1970) Vegetation. In ‘Australian Environment’ 4th edition (ed. Leeper GW). (Melbourne University Press: Melbourne) pp. 44–67 Photos in this document were provided courtesy of: CSIRO, Office of Bushfire Risk Management Western Australia, The Bushfire CRC, Parks and Wildlife Service Tasmania and David Taylor.
Level 1, 340 Albert Street, East Melbourne, Victoria, Australia, 3002 T +61 3 9419 2388 | F +61 3 9419 2389 E afac@afac.com.au www.afac.com.au
The Bushfire Fuel Classification is part of the National Burning Project (NBP). The NBP is building frameworks and national guidance relating to prescribed burning. Products are available at: www.afac.com.au/initiative/burning