Q 01/05

Roughly what share of wildfires in the United States are started by human activity?

A) Over 85%

B) About 15%

C) About 50%

D) Under 5%

Answer · why

A) Over 85%

Campfires, power-line failures and equipment sparks lead the list; arson may account for over 20% of the human-caused ones.

Q 02/05

Which of these is listed as a natural cause of wildfire ignition?

A) Migrating birds

B) Sparks from rock falls

C) Ocean spray

D) Reflected moonlight

Answer · why

B) Sparks from rock falls

Lightning, volcanic eruptions and spontaneous combustion round out the natural causes.

Q 03/05

What is a fire that burns suspended material at the treetop level called?

A) Ground

B) Crown

C) Surface

D) Ladder

Answer · why

B) Crown

Ignition of the canopy is termed crowning and depends on canopy density, height and continuity.

Q 04/05

Ground fires that smolder slowly for months are typically fed by what?

A) Wind-blown embers

B) Peat and buried roots

C) Standing dead trees

D) Dry grass and leaf litter

Answer · why

B) Peat and buried roots

Peat fires in Kalimantan and Sumatra started after a rice project drained and dried the peat.

Q 05/05

Fires that carry flames from low vegetation into the tree canopy via small trees and vines are called what?

A) Ladder

B) Bridge

C) Column

D) Stair

Answer · why

A) Ladder

Invasive climbing plants such as kudzu and Old World climbing fern encourage them.