The crowns of the pine are vulnerable to crown scorch at temperatures above how many degrees Fahrenheit?

The crowns of the pine are vulnerable to crown scorch at temperatures above how many degrees Fahrenheit?

• A. 100 F
• B. 120 F
• C. 135 F
• D. 150 F

Answer: (C)

Pine crowns are damaged by radiant heat from a fire once the heat near the canopy is high enough to exceed the needles’ tissue tolerance. The point at which crown scorch becomes likely is about 135 degrees Fahrenheit. That threshold is used in prescriptions as a conservative limit to help avoid canopy damage; staying below it reduces the risk, while heat above it increases scorch risk. The lower values (100 and 120) are not high enough to indicate scorch risk, and the higher value (150) represents more extreme heat, but 135 F is the standard guideline used to gauge danger and plan fire behavior. Remember that real-world scorch depends on how long the heat is held, fuel moisture, wind, and canopy structure, but 135 F serves as the practical tipping point.

Pine crowns are damaged by radiant heat from a fire once the heat near the canopy is high enough to exceed the needles’ tissue tolerance. The point at which crown scorch becomes likely is about 135 degrees Fahrenheit. That threshold is used in prescriptions as a conservative limit to help avoid canopy damage; staying below it reduces the risk, while heat above it increases scorch risk. The lower values (100 and 120) are not high enough to indicate scorch risk, and the higher value (150) represents more extreme heat, but 135 F is the standard guideline used to gauge danger and plan fire behavior. Remember that real-world scorch depends on how long the heat is held, fuel moisture, wind, and canopy structure, but 135 F serves as the practical tipping point.