Relative humidity predicts fire intensity in Cerrado burns

What the study found: Relative air humidity at the time of burning was a key predictor of fire behaviour in the Cerrado, a tropical humid savanna. Early dry season (EDS) fires under lower daytime humidity could produce fire intensities similar to late dry season (LDS) fires, while higher-humidity evening EDS fires were lower in intensity.
Why the authors say this matters: The authors conclude that fire management in Cerrado landscapes should take advantage of different diurnal, seasonal, and fuel-load conditions to meet specific management objectives. They also state that recognizing local conditions can enhance management cost benefits.
What the researchers tested: The researchers carried out experimental fires in the early and late dry seasons, during day and evening, and in areas with different fuel loads. They assessed the effects of relative humidity and fuel load on fire intensity and fuel consumption.
What worked and what didn't: Under lower daytime relative humidity, EDS fires yielded intensities similar to LDS fires. Under higher evening relative humidity, EDS fires showed lower intensities, and these intensities also varied with available fuels in different years.
What to keep in mind: The abstract does not describe specific numerical values, detailed site conditions, or broader limitations beyond the tested seasonal, daily, and fuel-load settings.

Key points

• Relative air humidity at burning time was a key predictor of fire behaviour in the Cerrado.
• EDS fires under lower daytime humidity could reach intensities similar to LDS fires.
• EDS fires under higher evening humidity were lower in intensity.
• Fire intensity in higher-humidity evening conditions also varied with available fuel in different years.
• The authors suggest Cerrado fire management should consider seasonal, daily, and fuel-load conditions.