Is Fire Living or Non-Living?

Is fire living or non-living? Explore the depths of this question with expert guidance from the team at the Western Fire Chiefs Association (WFCA).

In discussions about fires, fire officials often refer to the “behavior” of the fire, giving it a life-like element to this natural disaster. A fire necessitates oxygen and fuel to sustain itself, similar to the basic requirements of living organisms. Despite these similarities, a fire is not classified as living.

Why is Fire Considered Non-Living?

Fire is considered non-living because it lacks the key characteristics of life defined by biologists. For something to be considered living, it must exhibit all eight characteristics of a living thing:

Order:

What is it?

This refers to the building block of life, otherwise known as cells. Living things are organized structures composed of one or more cells that work together to form tissues and vital organs essential for survival.

Does fire have this characteristic?

No, a fire is made up of a mixture of high-temperature gases with cells or order.⁴ It is no coincidence that wildfires are often described as “unpredictable”.

Sensitivity or Response to Stimuli:

What is it?

Living things react to different signals they receive, such as plants leaning toward light sources, growing along fences, or reacting when touched. Even small bacteria can move towards or away from chemicals (chemotaxis) or light (phototaxis).

Does fire have this characteristic?

Debated, but by a biological definition, no.If a fire were able to respond to stimuli then it should be able to avoid firefighting foam seeing as how it poses a threat to the sustainability of the flame.⁵ This is often mistaken as a characteristic of fires because of the sparks that come up when the fire is stoked. 

Reproduction:

What is it?

Single-celled organisms reproduce by copying their DNA and then splitting the cell into two new ones. Multicellular organisms usually produce special reproductive cells that create new members of the species. Throughout the reproduction process, genes with DNA are passed to the offspring, ensuring the continuity of the species with shared similar traits such as size and shape.

Does fire have this characteristic?

Debated, but by a biological definition, no.Spot fires are not considered a reproduction of a fire because fires cannot copy their DNA, this means the fires will not share the same traits.³ For example, an oil fire is not the same as a house fire even if they are both lit by the same source of fire.²

Growth and Development:

What is it?

Organisms grow and develop based on their genetic code. Genes contain directions that control how cells grow and develop, making sure that offspring will have similar traits to their parents when they grow up.

Does fire have this characteristic?

Debated, but by a biological definition, no. Although fires do grow, it is a result of how much oxygen and fuel is around them rather than a result of their gene coding.

Regulation:

What is it?

This refers to the mechanisms enabling living things to regulate their responses to environmental and other pressures. For instance, the human body’s circulatory system delivers oxygen where needed and removes waste materials from the body.

Does fire have this characteristic?

Debated, but by a biological definition, no. Although fires do not have systems that require regulation, this is thought to be a characteristic due to the chemical bonds acting as regulation on what is burned for fuel and how it burns.²

Homeostasis:

What is it?

This is the ability of an organism to maintain steady internal conditions, such as the human body maintaining a constant internal temperature.

Does fire have this characteristic?

No. Similar to the previous characteristic, fires do not have internal conditions to be maintained. The temperature of the fire will depend on the environment’s condition.³

Energy Processing:

What is it?

All living things need a source of energy to function. Some get energy from the sun through photosynthesis, while others get it from the food they eat through cellular respiration.¹ This is the characteristic that fire has most in common with living things.

Does fire have this characteristic?

Yes, like living things, a fire can consume fuel to sustain itself self. A fire’s source of energy comes from any fuel within its reach, allowing the fire to grow and spread.

Why is This a Common Question?

Whether or not fire is living is a common question because a fire seemingly possesses almost all eight characteristics of a living thing. As described above, an argument can be made on behalf of fires for almost all these characteristics, although the biological definition debunks most of these arguments.

Other Interesting Facts About Fire

Having discussed whether fire can be classified as alive, it’s worth exploring some intriguing facts about this fascinating phenomenon:

• Humans cause 89% of annual wildfires.⁶ Most wildfires are caused by humans and can result from many kinds of activities. For example, a stray ember from a campfire can spark a blaze, or a spark from a car engine can ignite dry grass. Not all human-caused fires are accidental. Starting a fire on purpose, to hurt the environment, buildings, or people, is called arson. Arson is against the law and can have extreme consequences.

Sometimes, firefighters will very carefully light fires on purpose, referred to as a prescribed fire, to clear overgrown plants and help nature thrive.⁷ However, these burns are handled by professionals in controlled conditions. Wildfire, on the other hand, is unplanned and extremely dangerous. Even if fires start small, it is difficult to predict if they will become large, destructive wildfires that threaten human lives and communities.

• Three things are needed for a fire to start: heat, oxygen, and a fuel source. This combination is commonly referred to as the fire triangle by firefighters. These three things combined can create ignition and start a fire.⁸ Sources of heat can be cigarettes, a spark from a campfire or a gas-powered tool like a chainsaw, or even the sun. Fuel can be the dry wood you use to make a campfire, or it can be plants and grass. Dry weather, especially droughts, and windy days make wildfires more likely and more dangerous.
• Wildfires move at an average of 14 miles per hour. The speed of a wildfire varies depending on the terrain, the type of fuel available, and weather conditions.⁹ Rising smoke and heat can dry out fuel further up the slope of a hill, so fire burns more quickly uphill. Wildfires can also quickly get out of control when flames move from the ground to the tops of trees.
• Lightning hits the Earth more than 8 million times every day.¹⁰ Surprisingly, about 10-20% of these lightning strikes can start fires. When lightning occurs, it releases a significant amount of energy. If the conditions are right and the surroundings are dry, the lightning strike has the potential to ignite fires.¹¹
  
• Wildfires start from the accumulation of deceased organic matter, including fallen leaves, twigs, and trees. In certain situations, the build-up of this dead material reaches a point where it generates sufficient internal heat, potentially leading to spontaneous combustion. The heightened temperatures produced through this process can then act as a catalyst, igniting the surrounding environment.¹²
  
• A large wildfire, commonly known as a conflagration, possesses a remarkable capability to exert a profound influence on local weather conditions, effectively giving rise to its own atmospheric phenomena. Termed “fire weather,” this dynamic interaction involves the intense heat generated by the wildfire, initiating powerful updrafts and the formation of towering pyrocumulus or pyrocumulonimbus clouds. These fire-induced clouds, resembling conventional storm clouds, significantly impact temperature, humidity levels, and precipitation patterns in the immediate vicinity. The accompanying updrafts influence local wind patterns, potentially intensifying the fire’s spread in a self-perpetuating cycle.¹³