OVERALL FUEL HAZARD GUIDEassessment already established in the Victorian Overall Fuel Hazard Guide (McCarthy . et al. 1998) and includes several outcomes from Project Vesta research

2Kangaroo Island National Parks

OVERALL FUEL HAZARD GUIDEfor South Australia

Second Edition February 2011

www.environment.sa.gov.au

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Table of ContentsAbout this guide ... 1 Fuel Layers 2 Discontinuous Fuels 5 Using this Guide 5

Assessing Surface Fine Fuel Hazard 6 Low Surface Fine Fuel Hazard 6 Moderate Surface Fine Fuel Hazard 6 High Surface Fine Fuel Hazard 7 Very High Surface Fine Fuel Hazard 7 Extreme Surface Fine Fuel Hazard 7

Assessing Near-Surface Fuels 8 Low Near-Surface Fuel Hazard 9 Moderate Near-Surface Fuel Hazard 9 High Near-Surface Fuel Hazard 10 Very High Near-Surface Fuel Hazard 11 Extreme Near-Surface Fuel Hazard 12

Adjusted Surface Fuel Hazard 13

Assessing Elevated Fuel Hazard 14 Low Elevated Fuel Hazard 15 Moderate Elevated Fuel Hazard 15 High Elevated Fuel Hazard 16 Very High Elevated Fuel Hazard 18 Extreme Elevated Fuel Hazard 20

Assessing Bark Hazard 22 Low Bark Hazard 23 Moderate Bark Hazard 24 High Bark Hazard 25 Very High Bark Hazard 26 Extreme Bark Hazard 27

Overall Fuel Hazard 28 Equivalent Fuel Loads (t/ha) for given Hazard ratings 29

Interpreting Overall Fuel Hazard 30Determining Project Vesta Fuel Hazard Scores 31References 32Acknowledgements 32Fuel Hazard Assessment Data Sheet 33

About this guideThe purpose of this guide is to assist firefighters and fire planners, to assess the hazard posed by Bark Fuel, Elevated Fuel, and Surface Fine Fuel in forest, woodland and shrubland fuels. It builds on the principles of fuel hazard assessment already established in the Victorian Overall Fuel Hazard Guide (McCarthy et al. 1998) and includes several outcomes from Project Vesta research (Gould & Sullivan 2004). This Second Edition has been updated to align with more the recent Overall Fuel Hazard Assessment Guide, 4th edition (Hines et al. 2010). This guide specifically uses Fuel Hazard images and data from South Australian fuel types.

This guide aims to assist with: • defining and identifying the different components of Fuel Hazard, • assessing Fuel Hazard levels for Surface, Near-Surface,

Elevated and Bark Fuel, and• integrating Fuel Hazard compenents to assess

Overall Fuel Hazard.

This guide should be used to: • identify Fuel Hazards during fire management planning, • identify Fuel Hazards before and after prescribed burning operations, and • identify Fuel Hazards during fire suppression operations.

Overall Fuel Hazard Guide for South Australia 1

Fuel LayersFuel in forests, woodlands and shrublands can be divided into four layers based on its postion in the vegetation profile:

Canopy Fuel The crowns (leaves and fine twigs) of the tallest layer of trees in a forest or woodland. Not measured as part of Overall Fuel Hazard.

Bark Fuel The flammable bark on tree trunks and upper branches.

Elevated Fuel Shrubs and juvenile understorey plants up to 2-3m height. Canopy of <4m height can be included in the elevated fuel when there is no identifiable separation between the lower shrubs. The individual fuel components generally have an upright orientation. Elevated Fuel is highly variable in ground coverage.

Near-Surface Fuel Grasses, low shrubs and heath, sometimes containing suspended components of leaves, bark and twigs. This layer can vary from a few centimetres to up to 0.6 m in height. Near-Surface Fuel components include a mixture of orientations from horizontal to vertical. This layer may be continuous or have large gaps in ground coverage.

Surface Fuel Leaf, twigs and bark on the forest floor. Surface Fuel (or litter) components are generally horizontally layered. This usually contributes the greatest to fuel quantity. Includes the partly decomposed fuel (duff) on the

soil surface.

Overall Fuel Hazard Guide for South Australia2


Canopy

Bark

SurfaceNear Surface

Elevated

Fig 1 Fuel layers (after Gould & sullivan 2004)


Canopy Crown Fire

Bark Embers/Firebands Spot Fires

Elevated Fuel (shrubs up to 2 m high)

Near-Surface Fuel Surface Fire Flame (suspended litter, low shrubs) Height

Surface Fuels Smouldering Flame (leaves, bark, twigs, grassy Fuels) Residual effects Depth

Fig 2 Fuel layers and their effect on fire behaviour (from Gould and Sullivan 2004)

Photos: (from top to bottom left to right) 1 Measuring Surface Fine Fuel

1

Overall Fuel Hazard is defined as follows:

Overall Fuel Hazard = (the sum of the influences of) Bark Hazard + Elevated Fuel Hazard + Surface Fine Fuel Hazard

Suface Fine Fuel Hazard = Litter Fuel Hazard adjusted to account for the presence of Near-Surface Fuel

Each Fuel layer contributes to different effects of fire behaviour: flame depth and height, surface fire, rate of spread, spotting and crown fire (Fig 2).

Discontinuous FuelsWhere fuels are discontinuous (that is have significant 'gaps' between 'clumps' or 'patches' of fuel), such as in Mallee or other semi-arid shrubland fuels, the fuel arrangement (overall ground coverage and size of 'gaps' in realtion to 'patches') becomes a significant factor in fire spread (and hence Fuel Hazard). Outcomes from Project Vesta (Gould & Sullivan 2004) suggest that the use of fuel cover should be used in addition to a rating of Fuel Hazard.

In this guide, estimates of the thresholds of Elevated Fuel continuity required to sustain fire spread under the reference first attack conditions have been made and incorporated into the descriptions. These estimates still need to be further tested.

Using this GuideWhen using this Guide, the characterising descriptions (in italics and quotation marks at the beginning of each category description) should not be used on their own, but read in conjunction with the rest of the category description. The images used are examples of the particular Fuel Hazard level - they do not represent all possible presentations of that Fuel Hazard level. Fuel Hazard assessments should be based on the descriptions, using the images as examples only.



The structure of Surface Fine Fuel has been found to be better related to fire behaviour than the Surface Fine Fuel load (McCarthy et al. 1998). Surface Fine Fuel Hazard can be assessed by measuring litter-bed depth. Litter-bed depth should be measured in millimetres using a simple depth gauge. Five measurements of litter-bed height should be made at each sampling site (an area of approximately 10 m in radius). Separate assessments should be made at different locations (suggested at 200 m to 1000 m apart) around a area so that the range of variation in a fuel type is sampled. The litter-bed depth is the distance (in mm) from the soil surface (point where mineral soil is exposed) to the top of the litter-bed (the top of the leaves, twigs and bark lying on the soil surface, including duff).

A simple depth gauge can be constructed from a ruler and a circular piece of hard plastic, masonite or plywood as shown on page 7. To use this gauge, a small gap is made in the litter-bed down to mineral soil and the end of the ruler is placed resting on the mineral soil surface. The disc is pushed down with a very light pressure, and the ruler is read off level with the top of the disc. Note that the end of the ruler beyond the scale has been adjusted to match the thickness of the disc.

Assessing Surface Fine Fuel Hazard

Photos: (from top to bottom left to right) 1 Low Surface Fine Fuel Hazard, 2 Moderate Surface Fine Fuel Hazard,

3 High Surface Fine Fuel Hazard, 4 Very High Surface Fine Fuel Hazard, 5 Extreme Suface Fine Fuel Hazard

2 3

1

The following table can be used to convert litter-bed height to Surface Fine Fuel Hazard:


Surface Fine Fuel Hazard rating system based on Litter-bed height

Surface Fine Fuel Low Moderate High Very Extreme Hazard Rating High

Litter-bed height <15 15 <25 25 <35 35 <50 >50 (incl. duff) (mm) Equivalent litter load (t/ha) <4 4-8 8-12 12-20 20+ Litter Cover (%) <60 60-80 80-90 90-90 >95%

4 5


Near-Surface Fuels are live and dead fine fuels which lie just above the ground surface, but not on it. Typical Near-Surface Fuels include grass tussocks, dead bracken, low shrubs or low wiregrass and are generally less than 30 cm above the ground, but may be up to 60 cm high. Near-Surface Fuels interact with the surface litter to increase fire behaviour, and therefore need to be considered when assessing Surface Fine Fuel Hazard (Gould & Sullivan 2004). Like Elevated Fuels, the moisture content of suspended dead material will vary in Near-Surface Fuels depending on weather conditions. However, Near Surface Fuels will always burn in any ground fire (regardless of intensity) - unlike Elevated Fuels. If there is little Surface Fine Fuel (or it is wet), fire can spread in the Near-Surface Fuel alone.

Near-Surface Fuels are assessed visually over an area of approximately 10 m in radius. Separate assessments should be made at different locations (suggested at 200 m to 1000 m apart) around an area so that the range of variation in a Fuel type is sampled.

Near-Surface Fuel levels are assessed and if significant are used to adjust the Surface Fuel Hazard score.

Assessment of surface litter cover can be assisted by using the following visual chart. Each quarter of anyone square has the same area of black.

Assessing Near-Surface Fuels

Photos: (from top to bottom left to right) 1 Low Near-Surface Fuel Hazard, 2 Low Near-Surface Fuel Hazard,

3 Moderate Near-Surface Fuel Hazard, 4 Moderate Near-Surface Fuel Hazard

1 2

A P P E N D I X 3 C

LITHOLOGY CODES

S U R F A C E S T R E W C O V E R C H A R T

25

G U I D E T O A N A T I V E V E G E T A T I O N S U R V E Y

Section 3

CODE DESCRIPTION

100 Sedimentary (not for field use)

110 Calcareous material

111 Limestone

120 Sandstone

130 Siltstone

140 Shale

150 Conglomerate

160 Laterite (Ironstone)

170 Silcrete

200 Metamorphic (not for field use)

210 Slate

220 Quartzite

CODE DESCRIPTION

230 Gneiss

240 Schist

250 Marble

260 Haematite

300 Igneous (not for field use)

310 Quartz

320 Basalt

330 Granite

400 Miscellaneous (not for field use)

410 Outwash Material

777 Not identified

2% 10% 20% 50% 90%

Chart for estimating Each quarter of any one square has the same area of blackabundance of coarse fragments

Source: McDonald et al. (1990) Australian Soil and Land Survey Field Handbook,

Second Edition, Inkata Press.

tk Vegetation Guide 3 3/6/98 1:41 PM Page 25

Source: McDonald et al. 1990.

Low Near-Surface Fuel HazardNear-Surface Fuel absent or virtually absent (< 10% ground cover). Near-Surface Fuel plays no role in fire behaviour.


43

Tussock Grasses Low Sedges/ Hummock Grasses Low Shrubs Rushes

10-20% cover 10-20 % cover 10-20% cover 10-20 % cover little or no little or no suspended bark, suspended bark & leaves leaves or twigs

Moderate Near-Surface Fuel Hazard

Enough Near-Surface Fuel to give occasional boost to flame height. In marginal burning conditions, may assist in keeping surface (ground) fire spreading.

Very large gaps between fuel patches.

<20% dead material

High Near-Surface Fuel HazardPatches of Near-Surface Fuel that boost flame height. Under marginal burning conditions, only these patches will burn, but they are not well enough connected to permit fire to spread continuously without stronger wind.

Gaps between fuel patches > fuel patches.


Photos: (from top to bottom left to right) 1 High Near-Surface Fuel Hazard, 2 High Near-Surface Fuel Hazard,

3 Very High Near-Surface Fuel Hazard, 4 Very High Near-Surface Fuel Hazard

1

2


20-40% cover with 20-40% cover 20-35% cover 20-40% cover >20% dead with >20% dead may have suspended bark leaves or twigs

may have suspended bark and leaf material


3 4

Very High Near-Surface Fuel HazardAlmost continuous Near Surface Fuel and contributes significantly to fire spread and flame height. A fire burning under marginal conditions will still spread readily (given wind or slope).


30-60% cover with 30-60% cover 40-60% cover 40-60% cover >30% dead grass with >30% dead or other leaf or other leaf and bark litter and bark litter

Fuel patches > gaps between fuel patches.

Extreme Near-Surface Fuel HazardContinuous Near Surface Fuel continuous and contributes significantly to fire spread. Burning under marginal conditions will spread readily in this layer without having to consume the surface layer.

Very small gaps between fuel patches.


Photos: (from top to bottom left to right) 1 2 3 4 Extreme Near-Surface Fuel Hazard

21


>60% cover with >60% cover with >60% cover >60% cover >50% dead grass >50% dead grass or other leaf and or other leaf and bark litter bark litter


4

3

Surface Fuel Hazard Adjusted for Near-Surface Fuel

Surface Hazard Near-Surface Hazard Rating

Surface Hazard Rating

Litter Depth (mm)

L M H VH E

L <15 L L M H VH

M 15- <25 M M H VH E

H 25- <35 H VH VH VH E

VH 35- <50 VH VH E E E

E >50 E E E E E

3

Adjusted Surface Fuel HazardThe Near Surface Fuel rating is used to adjust the Surface Fuel Hazard Rating.

To determine the effect of Near-Surface Fuel Hazard:

1. Select the Surface Fuel Hazard Rating

2. Select the Near-Surface Fuel Hazard Rating

3. Identify where these two columns intersect to provide an adjusted Surface Fuel Hazard Rating.

Assessing Elevated Fuel HazardElevated Fuel comprises shrub, heath, and suspended material. The level of hazard depends on the fuel continuity (horizontal and vertical), height, amount (weight), proportion of dead material, thickness of the foliage and twigs, and flammability of the live foliage.

The flammability of the Elevated Fuel is highest when: the foliage, twigs and other fuel particles are very fine (e.g. maximum thickness 1-2 mm); the proportion of dead material is high; the fuels are arranged with a high level of density and horizontal and vertical continuity that promotes the spread of flames; and the live foliage has low live fuel moisture contents.

The vegetation type and the time since last fire substantially determine the level of Elevated Fuel Hazard.

Elevated Fuels are assessed visually over an area of approximately 10 m in radius. Separate assessments should be made at different locations (suggested at 200 m to 1000 m apart) around an area so that the range of variation in a fuel type is sampled. The characterising descriptions, in italics and quotation marks at the beginning of each category description, should not be used on their own, but read in conjunction with the rest of the category description.


1 2

3

Photos: (from top to bottom left to right) 1 2 Low Elevated Fuel Hazard, 3 4 5 Moderate Elevated Fuel Hazard

Low Elevated Fuel Hazard"Easy to walk through in any direction."

Elevated Fuel virtually absent or low flamability species (such as chenopods).

Moderate Elevated Fuel Hazard"Easy to walk through, but vegetation does brush against legs occasionally."

Elevated Fuels add very little to the flame height or rate of spread of a fire except at Extreme levels of fire danger.

The Overall Fuel Hazard of the site depends almost entirely on the bark and Surface Fine Fuels, except at Extreme levels of fire danger.

This category is characterised by: • sparse understorey vegetation; • bracken, heath or shrubs that are re-establishing after a fire. • Mallee re-establishing after a recent fire.

The Elevated Fuels generally have the following characteristics: • elevated material is sparse/dispersed or arranged so that it does

not sustain flames readily;• dead material is virtually absent (<20%); • 20-30% Elevated Fuel cover or

no fine fuel within 1m of the ground.


4 5

High Elevated Fuel Hazard "Moderately easy to walk through, but brush against or step over vegetation most of the time."

Elevated Fuels cause some patchy increases in the flame height and/or rate of spread of a fire.

This category is characterised by vegetation such as:

• Bracken which has moderate density and age;• shrubs with moderate density and moderate flammability of live foliage

(eg Pultenea spp., Hibbertia spp.);• tall shrubs (e.g. at least 5 m high) with not much fine fuel for the first

few metres above the ground (e.g. Acacia spp., Allocasuarina spp.);• Broombrush (Melaleuca uncinata);• Mallee with a sparse shrub understory (more 'gaps' than fuel)


2

Photos: (from top to bottom left to right) 1 2 3 4 5 6 High Elevated Hazard

3 4

1

2

The Elevated Fuels generally have the following characteristics:

• moderately dense;• the proportion of dead material is 0-20% by dry weight

(including suspended leaves, bark and twigs);• if tall (e.g. at least 5 m), then there is not much fine fuel

for at least the first 2-4 m above the ground;• 30 - 50 % Elevated Fuel cover or

little fine fuel within 0.5m of the ground (most fine fuel above this height).


5

6

Very High Elevated Fuel Hazard"Difficult to walk through. Need to carefully select path and step high."

Elevated Fuels mostly dictate the flame height and rate of spread of a fire.

Elevated Fuels are a dominant part of the Overall Fuel Hazard of the site. Surface Fuels are less important; fires may even spread when the Surface Fuels are wet. The additional presence of taller shrubs (e.g. Banksias, Hakeas, Wattles) may further enhance the hazard. This category is characterised by vegetation such as:

• heath which contains 20-30% dead material; bracken which contains 20-30% dead material and which is dense enough to suspend other material such as eucalypt bark;

• wiregrass of which a substantial proportion is 0.5-1 m high and which is dense enough to suspend eucalypt leaves and other fine fuel above the ground;

• shrub understoreys that are dense, contain 20-30% dead material, and which are at least 1 m high;

• grasses and annuals that are dense, greater than 1 m high and which are or will be at least 80% cured;

• Mallee with a dense shrub understory (more fuel than 'gaps');

• Broom or gorse which are at least 1m high and contain 20-30% dead material.


Photos: (from top to bottom left to right) 1 2 3 4 5 Very High Elevated Fuel Hazard

31

2


• the density and continuity (vertical and horizontal) are high;• the proportion of dead material is 20 - 30% dry weight

(including suspended leaves, bark and twigs);• the general height of the vegetation is at least 0.5 m and usually

at least 1 m (ignoring small amounts protruding from the general shrub layer);

• the fuel particles are mostly less than 1 - 2 mm thick;• 50 - 80% Elevated Fuel cover or fine fuel at least 0.5m

and usually at least 1m above the ground.


4

5

Extreme Elevated Fuel Hazard"Very difficult to see where you are going. Need to use arms to push through vegetation."

Elevated Fuels almost entirely determine the flame height and rate of spread of a fire.

The Overall Fuel Hazard of the site is Extreme irrespective of the Bark and Surface Fuels.

This category is characterised by vegetation such as:

• Tea tree, Melaleuca or heath that is at least 2-3 m high and where fine fuels are present from top to bottom of the vegetation;

• Wiregrass that is dense and at least 2-3 m high;• Mallee with a very dense shrub understorey and little

elevated-canopy separation; • Broom or gorse that is dense and at least 2 m tall.


Photos: (from top to bottom left to right) 61 2 3 4 5 Extreme Elevated hazard

1 3

42


• vegetation is tall (at least 2-3 m), dense and continuous from top to bottom;

• large amounts of leaves, twigs and other fuel particles with maximum thickness less than 2 mm are distributed from ground level to the top of the vegetation;

• proportion of dead material is >30% by dry weight (including suspended leaves, bark and twigs);

• the flammability of live foliage is high;• the weight of living and dead elevated fine fuel is high

(greater than about 10 t/ha);• >70% Elevated Fuel cover and fine fuel at least 1m

(and usually at least 2m) above the ground.


65


Assessing Bark HazardBark Hazard can reduce the likelihood of first attack success in wildfires and increase risk of control problems at prescribed burns at low to moderate FFDIs (Forest Fire Danger Indices, McArthur 1973) by producing short range spotting. At High to Extreme FFDIs Bark Hazard can produce short and long distance spotting, and act as a link between Ground and Canopy Fuels increasing the likelihood of crown fires.

The important considerations when looking at Bark Fuel hazard are:

• amount of loose fibrous bark - particularly “stringybark”;• amount of bark burnt off in any previous wildfire or prescribed burn,

both at the base of the tree and up the bole;• amount of long loose “ribbony” bark. Bark Fuels are assessed visually over an area of approximately 10 m in radius. Separate assessments should be made at different locations (suggested at 200 m to 1000 m apart) around an area so that the range of variation in a fuel type is sampled.

Photos: (from top to bottom left to right) 1 2 Extreme Bark Hazard, 3 4 5 Low Bark Hazard

1 2

Low Bark HazardNo bark present that could contribute to fire behaviour.


Stringybarks Platy and Subfibrous Smooth or Gum barks barks

Recently burnt Recently burnt Entirely smooth bark 100% of bole charred >90% of bole charred e.g. Red Gum, e.g. Messmate, e.g. Grey Box, Black Box SA Blue Gum, Brown Stringybark, Mallee Box, Sheoaks White Gum, Red Stringybark Acacia retinoides Manna Gum or Desert Stringybark

3

45

Moderate Bark HazardVery little bark is available to allow spotting to occur. Fires with a flame height of 0.5 m to 1.0 m will not "climb" these trees, and so spotting generally does not cause a problem. Moderate Bark Hazard is characterised by:

• in Stringybarks, the bark is black for a substantial distance (3-4 m) up the bole of most trees;

• in other bark types, where the fibrous/subfibrous bark is fine textured and held very tightly to the bole of the tree, e.g. Box, Sheoak.



Bark tightly held Very tight bark No long ribbons of bark >90% of bole charred e.g. Grey Box, Black Box e.g. Red Gum, e.g. Messmate, Mallee Box, Sheoaks SA Blue Gum, Brown Stringybark, Acacia retinoides Swamp Gum, Red Stringybark Manna Gum or Desert Stringybark

Photos: (from top to bottom left to right) 1 2 3 4 Moderate Bark Hazard, 5 6 7 8 High Bark Hazard

1

3

2 4



Few pieces of bark losely Tight bark, long unburnt Long ribbons of bark, held 50% to 90% of bole e.g. Grey Box, Black Box but smooth trunk charred below 2 m Mallee Box, Sheoaks e.g. Red Gum, e.g. Messate, Acacia retinoides SA Blue Gum, Brown Stringybark, Swamp Gum, Red Stringybark Manna Gum or Desert Stringybark

High Bark HazardA limited amount of bark is available to cause spotting. Fires with a flame height of 0.5 m to 1.0 m will "climb" some of these trees and cause sporadic spotting. High Bark Hazard is characterised by:

•in Stringybarks, most of the lower bark (i.e. below 2 m) is black, but there may be substantial portions of unburnt bark further up the bole and into the head of the tree;

•in other fibrous or subfibrous bark types (e.g. Box, Peppermint, Mallee) the bark is held tightly to the trunk and some of the lower portions may have been removed in a prescribed burn or wildfire;

•< 10% of Stringybark trees per hectare in a mixed species stand, but having a Bark Hazard up to Very High.

6

5 7 8


Very High Bark HazardSignificant amounts of bark are available to cause spotting. Fires with a flame height of 0.5 m to 1.0 m will "climb" most of these trees and cause significant spotting. Very High Bark Hazard is characterised by:

•In stringybarks where most of the bole above 1 m is unburnt and substantial quantities of bark are loosely held;

•In box eucalypts where trees are large and have loose fibrous bark, particularly in the upper branches;

•In mallee eucalypts where strips of bark are suspended above the ground;•In Swamp Gum, Manna Gum (or similar species) with loose fibrous bark around

the base and long ribbons of bark in the upper branches.


Significant amounts of Loose bark Long ribbons of bark bark losely held 10% to 50% e.g. Black Box to ground level of bole charred. Little or Peppermint Box e.g. Red Gum, no charing above 1 m SA Blue Gum, e.g. Messmate, Swamp Gum, Brown Stringybark Manna Gum Red Stringybark Mallee species or Desert Stringybark

Photos: (from top to bottom left to right) 1 2 3 4 Very High Bark Hazard, 5 6 Extreme Bark Hazard

1 32

4


Extreme Bark Hazard Huge amounts of bark are available to cause spotting. Fires with a flame height of 0.5 m to 1.0 m will "climb" virtually all these trees, and the bark sustains the flames easily, even when there is little heating from below. Strong updrafts during almost any fire are likely to dislodge numerous "firebrands". Extreme Bark Hazard is characterised by:

•Messmate and other Stringybarks where large amounts of loosely held bark

are present from the bole to the upper branches (i.e. generally long unburnt);


Outer bark weakly Does not occur Does not occur attached, bark easily dislodged <10% of bole chared e.g. Messmate, Brown Stringybark Red Stringybark or Desert Stringybark

5 6

Overall Fuel HazardThe following tables are used to combine the assessed levels of Bark, Elevated and Surface Fine Fuel Hazard (after adjustment for Near-Surface Fuel Hazard) to give an Overall Fuel Hazard rating for a site. The starting point for these tables is Bark Hazard, so this should be used to choose the appropriate table. Then look-up the square which corresponds to the assessed level of Elevated and Adjusted Surface Fuel Hazard to determine the Overall Fuel Hazard rating.

Bark Hazard: Low/Moderate

Bark Hazard: High

Bark Hazard: Very High/Extreme


Surface Fuel Hazard*

L M H VH E Elevated L L M M H H Fuel Hazard M L M M H H H L M H VH VH VH VH VH VH VH VH E E E E E E


L M H VH E Elevated L L M H H H Fuel Hazard M L M H H H H L H H VH VH VH VH VH VH VH E E E E E E E


L M H VH E Elevated L L VH VH VH E Fuel Hazard M M VH VH E E H M VH E E E VH E E E E E E E E E E E

*Adjusted for Near-Surface Fuel.

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Fuel Low Moderate High V High Extreme

Bark 0 0 2 5 7

Surface* 2 5 10 16 20

Elevated 0 0 2 6 10


Equivalent Fuel Loads (t/ha) for given Hazard ratingsThe following table gives average equivalent Fuel loads for the various Hazard levels for each Fuel component. The components can be added to give an estimate of Fine Fuel load (i.e. in tonne per hectare).

* Adjusted for Near-Surface Fuel

e.g. High Bark High Surface Very High Elevated

2 + 10 + 6 = 18

Thus use Overall Fuel Hazard of 18 t/ha

The total can then be applied into the McArthur Meter Mk. V (1973) for predictions of forward rate of spread and flame height.

Be aware of the limitations of this meter.

Interpreting Overall Fuel HazardThis Guide describes five categories of Overall Fuel Hazard. These categories are based on the ability of suppression forces to control a fire in these Fuels. The five levels of Fuel Hazard are based on a Reference First Attack, which in Victoria (Wilson 1993) is defined as being:

• direct attack with a 50kW bulldozer (D3/4 class) and a small 1-4 type fire unit (400 l capacity) and crew,

• a single fire • within 30 minutes of detection/ignition • burning on level terrain with good access • when the McArthur FFDI Drought Factor is 10 and • the wind speed is 20 km/h (at 10m in the open).

First attack resources vary in South Australia (typically, less use of bulldozers are made in first attack), the 'Reference First Attack' still provides a useful reference benchmark (particulalrly as it provides a link to fire behaviour) and is the basis for Fuel Hazard assessment in this Guide.

The relationship between Overall Fuel Hazard levels and fire suppression have been investigated by McCarthy and Tolhurst (1998). The following table summarises the range of FDI within which the reference First Attack will Succeed.

The overall fire threat is affected by Overall Fuel Hazard, the risk of fire ignition, the type of assets at the site, slope and weather.


Overall Forest Fire Danger Index Fuel Low Moderate High V High Extreme Hazard 0-4 5-12 13-24 25-49 50-100

Low 100% 100% 100% 100% 100-99%

Moderate 100% 100% 100% 100% 100-96%

High 100% 100% 100% 100-96% 96-64%

Very High 98-96% 96-94% 94-92% 92-70% 70-10%

Extreme 78-74% 74-65% 65-48% 48-18% 18-1%

Determining Vesta Fuel Hazard ScoresFuel Hazard ratings for each fuel layer can be converted into Project Vesta Fuel Hazard Scores by the following table. The converted Hazard Scores can then be used with fire behaviour prediction tables in publications such as Cruz et al. (2010) and Gould et al. (2007).

To determine the Vesta Fuel Hazard Score:

1. Select the Fuel Hazard Rating

2. Select the Fuel Layer from Vesta Fuel Hazard Score

3. Identify where these two columns intersect to provide a corresponding Vesta Fuel Hazard Score.

Vesta fuel hazard score

Fuel Hazard Rating

Surface Near-surface Elevated Bark

Low 1 1 1 0

Moderate 2 2 2 1

High 3 3 3 2

Very High 3.5 3.5 3.5 3

Extreme 4 4 4 4

Notes:

• Surface and Near Surface Hazard Score and Near-Surface height (cm) is required for fire spread prediction.

• Rate of spread and Elevated fuel height (m) is required for flame height prediction.

• Rate of spread, surface and Bark Fuel Hazard Scores are required for prediction of spotting distance.


ReferencesCruz, MG Matthews, S Gould, J Ellis, P Henderson, M Knight, I and Watters, J (2010) Fire Dynamics in Mallee Heath: Fuel, Weather and Fire Behaviour Prediction in South Australian Semi-arid Shrublands. CSIRO Sustainable Ecosystems, Canberra, ACT; Department of Environment and Heritage, Adelaide, South Australia.

Gould, J and Sullivan, A (2004) Fuel Hazard Development. Client Report for Fire Management Unit, Dept. Urban Services, ACT. CSIRO Forestry & Forest Products, Canberra.

Hines, F Tolhurst, KG Wilson, AAG and McCarthy, GJ (2010) Overall Fuel Hazard Assessment Guide, 4th edition. Report 82, Fire Management Branch, Department of Sustainability and Environment, Melbourne, Victoria.

McArthur, AG (1973) Forest Fire Danger Meter Mk V. Forest Research Institute, Forestry and Timber Bureau, Canberra.

McCarthy, GJ Chatto, K and Tolhurst, K (1998) Overall Fuel Hazard Guide. Research Report No. 47. Fire Management Branch, Dept. of Natural Resources and Environment, Victoria.

McDonald, RC Isbell, RF Speight, JG Walker, J and Hopkins, MS (1990) Australian Soil and Land Survey - Field Handbook, 2nd edition, Inkata Press, Melbourne, Victoria.

Wilson, AAG (1993) Elevated Fuel Guide. Research Report No. 35. Fire Management Branch, Department of Conservation and Natural Resources, Victoria.

AcknowledgementsThis work is based largely on the work of the Victorian Overall Fuel Hazard Guide (McCarthy et al. 1998) and the preliminary results of CSIRO's Project Vesta research (Gould & Sullivan 2004). Thanks to Peter Ellis and Jim Gould (CSIRO), Greg McCarthy (Dept. Sustainability & Environment, Vic.), Kevin Tolhurst (University of Melbourne) for advice & discussion in revising the Victorian and Vesta guides for South Australian conditions.



Fuel Hazard Assessment Data SheetDate: Collector: Reserve Name:

Site Information Site no. 1 Site no. 2 Site no. 3

Location Description:

Road/ Track Name:

Year of last known fire

Slope º

Aspect

ID No.

Vegetation Association (dominant overstorey species)

Vegetation Association (dominant understorey species)

Photo reference

Zone

Easting (GDA94 MGA UTM)

Northing (GDA94 MGA UTM)

Surface fuel layer (Assess over a 10m radius)

Litter bed depth measurements (mm)

Average Litter Depth (mm) mm mm mm

Surface Litter % Cover % % %

Surface Fuel Hazard L M H VH E L M H VH E L M H VH E

Near-surface fuel layer (Assess over a 10m radius)

Near-surface % Cover % % %

Near-surface % Dead % % %

NS Average Height(cm) cm cm cm

Near-Surface Fuel Hazard: L M H VH E L M H VH E L M H VH E

Adjusted Surface and Near-surface Fuel Hazard (Refer to table in the Overall Fuel Hazard Guide)

Adjusted Surface Hazard L M H VH E L M H VH E L M H VH E

Elevated fuel layer (Assess over a 10m radius)

Elevated % Cover % % %

Elevated % Dead % % %

Elevated Fuel Ave Height (m) m m m

Elevated Fuel Hazard: L M H VH E L M H VH E L M H VH E

Bark fuel (Assess over a 10m radius)

Stringybark Fuel Hazard L M H VH E L M H VH E L M H VH E

Gum Bark Fuel Hazard L M H VH L M H VH L M H VH

Platy/ Subfibrous Bark Fuel Hazard

L M H VH L M H VH L M H VH

Bark Fuel Hazard: L M H VH E L M H VH E L M H VH E

( Only use the Stringybark hazard rating if more than 10% of the trees are Stringybark AND it has the highest rating. Otherwise use the bark with next highest rating.)

Overall Fuel Hazard calculation (Refer to table in the Overall Fuel Hazard Guide)

Overall Fuel Hazard L M H VH E L M H VH E L M H VH E

Comments? Are the plots representative of the average fuels across the sampling location? Yes No

© Department of Environment and Natural Resources

Images and fuel data come from a variety of sources,

including the Victorian Department of Sustainability and

Environment, SA Department of Environment and Natural

Resources staff (Hafwen Pearce, Kay Richardson, Mandy

Slipper, Brett Stephens, Ian Tanner and Joe Tilley, the former

SA Department for Transport, Urban Planning and Arts

(Geographic Analysis and Research Unit) and SA Country

Fire Service.

ISBN 1 921018 88 7

March 2011 FIS: 90985

For further information contact: Fire Manangement Branch Regional Conservation Department of Environment and Natural ResourcesGPO Box 1047, Adelaide SA 5001

OVERALL FUEL HAZARD GUIDEassessment already established in the Victorian Overall Fuel Hazard Guide (McCarthy . et al. 1998) and includes several outcomes from Project Vesta research

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