Chapter 4

Question 1

List parts of a fire

Answer 1

Front, back, flanks, finger, bay/pocket, island, perimeter

Question 2

List parts of a flame

Answer 2

Flame length, height, angle, and depth

Question 3

Define fuel load

Answer 3

The dry weight of combustible materials per unit area. Recommended SI units are kilograms per square metre (kg/m2) and tonnes per hectare (t/ha) (1.0 kg/m2 is equivalent to 10 t/ha).

Question 4

Fuel bulk density

Answer 4

The dry weight of fuel available to burn per unit volume. Numerically, it is equal tofuel load divided by the depth of the particular fuel layer (e.g. duff, tree crown foliage). Recommended SI units are grams per cubic centimetre (g/cm3) and kilograms per cubic metre (kg/m3) (0.1 g/cm3 is equivalent to 100 kg/m3).

Question 5

CSI

Answer 5

Critical Surface Fire Intensity - Surface fire intensity required for the onset of crowning. Influenced by canopy base height and foliar moisture content.

Question 6

Crown/canopy base height

Answer 6

Height of live canopy aboveground. Taller canopy requires a higher intensity surface fire.

Question 7

List parts of an elliptical fire

Answer 7

Head, flank, and back fire spread distance (also length to breadth ratio which describes shape)

Question 8

List the 4 methods of estimating ROS?

Answer 8

1) Direct observation
2) In-stand measurements
3) Photo/video/infrared
4) Estimate from empirical data/stat relationships (ie. Van Wagner eqn)

Question 9

List the different types of fine surface fuels that would be consumed by the passage of the fire front

Answer 9

1) Understory conifer/shrubs
2) Low veg ie grass/herbs
3) Woody material <1 cm
4) Litter

Question 10

List two emerging technologies for measuring crown/canopy fuels

Answer 10

Lidar and hemispherical photography

Question 11

Describe the limitations of estimating fire intensity from flame length

Answer 11

Exists in the eye of the beholder. Is a poor quantity to use in the scientific sense due to subjectivity.

Question 12

Describe the photoload method of fuel measurement

Answer 12

The technique involves visually comparing fuel conditions in the field with downward looking photoload sequences to estimate fuel loadings.

Question 13

Describe how surface fuel consumption is measured in the field.

Answer 13

Estimate fuel loads prior to fire, mark ground with pigtail. Use matched pairs of burned and unburned areas.

Question 14

Describe key limitations of surface fuel consumption field measurements

Answer 14

Cannot separate fuel load consumed during
flaming and smouldering phases of combustion