Fire is a main disturbance structuring vegetation worldwide, but few studies have addressed differences in time since last fire and its relationship to fuel load characteristics and fire behavior in Neotropical savannas. We aimed to investigate fire behavior in a Cerrado open savanna of Central Brazil by conducting prescribed fires in areas with different fire-free intervals: one year (FI-1), two years (FI-2), and four years (FI-4). Specifically, we evaluated (1) the amount of live, dead, and total biomass (components of the fuel load); (2) fire behavior, including fire temperatures in three different heights (1 cm belowground, on the soil surface, and 50 cm aboveground), fire duration, residence time, fire intensity, rate of spread, and flame height; and (3) the relationship between soil heating, fuels, and fire by identifying the most important parameters driving soil heating. Total and dead fuel loads were greater in areas with longer fire-free intervals in comparison with areas burned the previous year, with the greatest increment to the fuel bed occurring in the first two years after fire. Greater fuel loads (consequently greater dead fuel loads) resulted in differences in belowground soil heating (-1 cm), where temperatures varied from 39 to 82°C in FI-2 plots and from 40 to 131°C in FI-4 plots; in FI-1 plots temperatures belowground varied from 29 to 68°C. Temperatures on the soil surface and 50 cm aboveground were also greater in plots with longer fire-free intervals, reaching over 400°C on the soil surface and exceeding 500°C 50 cm aboveground. Finally, amount of dead fuel was the best predictor of belowground soil heating, highlighting the importance of fuel loads, which is a key factor to be monitored in fire management plans of Cerrado open savannas.

中文翻译：

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在开阔的稀树草原上进行实验性燃烧：更大的燃料负荷会导致更热的火灾

火灾是全球植被结构的主要干扰，但很少有研究涉及自上次火灾以来的时间差异及其与新热带稀树草原的燃料负荷特征和火灾行为的关系。我们旨在通过在具有不同无火灾间隔的地区进行规定的火灾来调查巴西中部 Cerrado 开放稀树草原的火灾行为：一年 (FI-1)、两年 (FI-2) 和四年 (FI-4 ）。具体来说，我们评估了 (1) 生物质、死物质和总生物量（燃料负荷的组成部分）；（2）火灾行为，包括三个不同高度（地下1厘米、土壤表面和地上50厘米）的火灾温度、火灾持续时间、停留时间、火灾强度、蔓延速度和火焰高度；(3) 土壤加热、燃料、通过识别驱动土壤加热的最重要参数来进行火灾。与前一年燃烧的区域相比，无火间隔较长的区域的总燃料负荷和死燃料负荷更大，燃料床的最大增量发生在火灾后的前两年。更大的燃料负载（因此更大的死燃料负载）导致地下土壤加热（-1 cm）的差异，FI-2 地块的温度从 39 到 82°C 不等，FI-4 地块的温度从 40 到 131°C 不等；在 FI-1 图中，地下温度从 29 到 68°C 不等。在无火间隔较长的地块中，土壤表面和地上 50 厘米处的温度也更高，土壤表面温度达到 400°C 以上，地表以上 50 厘米处超过 500°C。最后，死燃料量是地下土壤加热的最佳预测指标，