Fire Ecology Quiz 1

What are the 4 stages of combustion in order

Preheating—> Pyroysis —> Flaming combustion —> Smoldering Combustion

What are the temps of the 4 types of combustion

If you reach the 4 stages of pyrolysis, what would be left?

What is char?

This is the byproduct of heated fuel without the presence of oxygen, produced during pyrolysis.

What is pyrolysis?

Thermal decomposition of fuel without oxygen, leads to flammable gases, vapor, and char

How much oxygen is used in pyrolysis?

None, Zero, 0

Why does preheating increase the likelihood of ignition?

What are the two types of ignition?

What would happen if you redeuce the oxygen?

What is lignin?

What is cellulose

Main component in plant cell wall and largest structural component

What is hemicellulose?

What do minerals become after wood burns?

Ash

What are the two types of combustion

Flaming

• This

Smoldering

• 
  

What are extractives?

These are anything you can extract from a plant using a solvent; they can be highly volatile and highly combustible

Eample: Resin, gum

What is the fire tetrahedron?

Fuel, oxygen, head, and chemical chain reaction

Why are extractives important for fire behavior?

• They are usually very combustible

• They have a high energy density, thus increase of heat releases

• They are often volatile (release as gas), making them combustible

• These are extracted using solvents: ethanol, acetone, toluene

What are the chemical components of wood

Carbon

• 
  

Oxygen

• f

Hydrogen

Nitrogen (Least abundant)

Minerals

Cellulose

• Begins decomposing around 300°C

What are the three components of of the fire tribale

Fule

Oxygen

Heat

The fire tetrahedron adds a fourth component to the fire triangle. What is it?

Chemical Chain Reaction

Which era of fire history is associated with “fuel debt” and the rise of megafires?

Third Fire

• This fire is driven by industrialization: the increased use of fossil fuels.

• During this period, people were taught to fear fire and put it out at all costs, which increased the fuel availability denser forest,

In the Fire Behavior Triangle, which factor is described as “the physical landscape that necer changes?

Typography:

The physical landscape

Which type of fire is described as the least common and burns as smoldering, slow-moving pockets within root systems?

Ground fire

• These are fires that smolder slowly within roots and are the least common of the three fire types

What is the 10 a.m. rule, and what year did the U.S. Forest Service adopt the 10 a.m. rule?

This rule requires that all fires are to be put out by 10 a.m. the day after they are discovered.

This rule was adopted in 1933 and abandoned in 1978

Effects are still felt today

In the Mosaic vs. Monolith framwork, what characterizes a ‘Monolith’ (megafire) landscape?

Vast, contiguous fuel accumulation burning as one massive homogeneous event

What is the chemsiry of combustion?

Is an exothermic oxidation reaction

Involves fuel+ oxygen —> Carbon Dioxide + Water + Heat + Light

What do Wildland Fuels Contain?

Cellusloe

Hemicellulose

Lignin

Extractives

What plant component is described as ''gluing cellulose microfibrils together?

Lignin

• This is found in the plant cell walls and acts as a glue binding cellulose fibers together.

What happens during pyrolysis, and how much oxygen is required?

Thermal decomposition producing flammable gases, vapor, and char; requires zero oxygen

What happens during the preheating phase?

Moisture is dried out of the fuel, leading to pyrolysis

At aproximately what temperature range does pyrolysis occur?

Occurs at approximately 200–500°C, thermally decomposing fuel without oxygen into flammable gases, vapor, and char

What temperature range is associated with flaming combustion

800-1200°C

Features visible flamesm highest heat release, fast fire spread, and strong convection

What are the characteristics of flaming combustion?

Visible flame, Strong convection, and highest heat release,

What temperature range characterizes smoldering combustion, and what limits it?

The temperature range is 250-700°C and is limited by oxygen and depleted gases.

This produces heavy smokem and char oxidation

What is char oxidation?

the process by which oxygen reacts with carbon in char to release CO2 and CO

What products result from complete combustion?

CO2, water, and maximum energy (heat and light) with little smoke

What three mechanisms can heat transfer for preheating and combustion, and which is least important?

Heat transfer occurs via combustion, convection, and radiation, all happening simultaneously.

Combustion is the least important of the three

What distinguishes flaming combustion from smoldering combustion in terms of oxygen and gas availability?

Flaming has more oxygen and active gas release; smoldering has limited oxygen and depleted gases.