Passive crown fire
n. A type of crown fire in which the crowns of individual trees or small groups of trees burn, but solid flaming in the canopy cannot be maintained except for short periods (Scott and Reinhardt 2001).
Passive crown fire encompasses a wide range of crown fire behavior, from occasional torching of isolated trees to nearly active crown fire. Passive crown fire is also called torching or candling. An intermittent crown fire is similar to passive crown fire, but implies intermittent active crown fire rather than individual-tree torching.