Key message

We used clustering to construct fuel classes from fuel inventory data based on three stand attributes relevant to crown fire behaviour: surface fuel load (SFL), canopy base height (CBH) and canopy bulk density (CBD). Resulting fuel classes explained more of the stand-to-stand variability in predicted crown fire behaviour than fuel types of the Canadian Forest Fire Behaviour Prediction (FBP) System.

Context

Wildfire behaviour is partly determined by stand structure and composition. Fuel characterization is essential for predicting fire behaviour and managing vegetation. Currently, categorical fuel types based on associations with major forested or open vegetated landcovers are used nationally in Canada for fire research and management applications.

Aim

To provide an alternative description of selected forest fuels in Alberta, Canada, using direct classification in which fuel categories are constructed from data using analytical methods.

Methods

Fuel inventory data for 476 stands were used to construct fuel classes with clustering. Potential crown fire behaviour was modelled for resulting fuel class clusters (FCCs) and FCCs were compared with assigned FBP System fuel types. Tree-based modelling was used to identify stand characteristics most influential on FCC membership. Fuel treatment effects on FCC and modelled crown fire behaviour were explored for the FCC most susceptible to crown fire.

Results

Four FCCs were identified: Red (low SFL, low CBH, low CBD); Green (high SFL, low-moderate CBH, low CBD); Blue (low SFL, high CBH, low-moderate CBD); and Black (low SFL, moderate CBH, high CBD). Stand density of live conifers and FBP System fuel type were the most important variables influencing FCC membership; however, FCCs did not align directly with assigned FBP System fuel types. Fuel reduction treatments in the Black FCC were effective at shifting the stand to a less flammable FCC.

Conclusion

FCCs explained more of the stand-to-stand variability in predicted crown fire behaviour than assigned FBP System fuel types, which suggests FCCs could be used to improve fire behaviour predictions and aid fire managers in prioritizing areas for fuel treatments. Future technological and remote sensing advances could enable mapping FCCs across large regions. 

中文翻译：

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加拿大艾伯塔省选定易火灾生态系统中森林燃料的分类——对冠火行为预测和燃料管理的影响

关键信息

我们使用聚类来根据与树冠火灾行为相关的三个林分属性从燃料库存数据构建燃料类别：地表燃料负荷 (SFL)、树冠底部高度 (CBH) 和树冠体积密度 (CBD)。与加拿大森林火灾行为预测 (FBP) 系统的燃料类型相比，由此产生的燃料类别更多地解释了预测的树冠火灾行为中的立地变化。

语境

野火行为部分取决于林分结构和组成。燃料特性对于预测火灾行为和管理植被至关重要。目前，在加拿大全国范围内，基于与主要森林或开放植被土地覆盖物关联的分类燃料类型用于火灾研究和管理应用。

目标

提供加拿大艾伯塔省选定森林燃料的替代描述，使用直接分类，其中燃料类别是使用分析方法从数据构建的。

方法

476 个展位的燃料库存数据用于构建具有聚类的燃料类别。对产生的燃料类簇 (FCC) 对潜在的冠火行为进行了建模，并将 FCC 与指定的 FBP 系统燃料类型进行了比较。基于树的建模用于识别对 FCC 成员影响最大的林分特征。燃料处理对 FCC 的影响以及对最易受冠火影响的 FCC 的模拟冠火行为进行了探索。

结果

确定了四个 FCC：红色（低 SFL、低 CBH、低 CBD）；绿色（高 SFL、中低 CBH、低 CBD）；蓝色（低 SFL、高 CBH、中低 CBD）；和黑色（低 SFL，中等 CBH，高 CBD）。活针叶树的林分密度和 FBP 系统燃料类型是影响 FCC 成员资格的最重要变量；但是，FCC 并未直接与指定的 FBP 系统燃料类型保持一致。Black FCC 中的燃料减少处理可有效地将支架转移到不易燃的 FCC。

结论

与指定的 FBP 系统燃料类型相比，FCC 更多地解释了预测的冠火行为的立对立变异性，这表明 FCC 可用于改进火灾行为预测并帮助消防管理人员确定燃料处理区域的优先级。未来的技术和遥感进步可以在大区域内绘制 FCC。