Wildfire Knowledge Graph · Fire Behaviour
Fire that advances through the canopy of trees or shrubs, independently or coupled with surface fire below.
In plain language
Crown involvement ranges from individual or grouped torching to sustained active spread through connected canopy fuels.
Why it matters
Crown fire can produce high intensity, long-range firebrands and rapid changes in suppression feasibility.
Crown fire: torching is not sustained crown spread
A crown fire involves combustion of foliage and fine fuels in the canopy. A tree or small group of trees burning in the crowns (often called torching or passive crown fire) is not automatically evidence that an active crown fire is spreading continuously from canopy to canopy.
Interpretation example: a photograph showing flames reaching crowns demonstrates crown involvement at that location, but cannot by itself establish the fraction of the perimeter in active crowning or the incident’s forward spread rate. Those require time, scale and independent observations.
Whether crown fire develops depends on surface-fire intensity, canopy base height, canopy bulk density, fuel moisture, wind and local terrain. Fuel treatments can change some of these conditions, but no single canopy-spacing prescription guarantees that a crown fire will be prevented. Any operational interpretation must use site-specific evidence.
Connect this concept to Crown Fire Transition and Fireline Intensity.