Fires in nature：練習題

• a.

  Ladder fire

• b.

  Surface fire

• c.

  Crown fire

• d.

  Ground fire

• a.

  Large logs ignite faster than dry grass because they contain more stored energy.

• b.

  High ratios slow down the spread of fire because of increased oxygen consumption.

• c.

  Fuel moisture content is irrelevant if the ratio is higher than 2:1.

• d.

  Finer fuels with high ratios dry out faster and ignite more easily than heavy fuels.

• a.Upslope fires pre-heat uphill fuels through radiation and convection, increasing the rate of spread.
• b.South-facing slopes in the Northern Hemisphere have higher fuel moisture, slowing fire spread.
• c.Deep canyons typically decrease fire intensity by sheltering the fuel from oxygen flow.
• d.Fires burning downslope move faster due to the effects of gravitational sliding on embers.

• a.

  Large, compact logs with low surface area

• b.

  High moisture content in living vegetation

• c.

  High surface-area-to-volume ratio of fine, dry fuels

• d.

  High mineral content within the organic matter

• a.

  Immediate loss of timber and wildlife habitats during the blaze.

• b.

  The release of carbon dioxide into the atmosphere during combustion.

• c.

  Increased surface runoff and flood risk due to the creation of hydrophobic soils.

• d.

  Death of fire-fighting personnel during the suppression phase.

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