Direct carbon (C) emissions from wildland fires have been difficult to quantify, especially in montane environments where sites are difficult to access. Here we examined pre-fire C partitioning and losses in a southern Canadian montane valley ecosystem, in Waterton Lakes National Park, Alberta Canada. The objectives of this study were to: (a) quantify the C loss due to combustion at a moist riparian site compared with a dry undulating upland site and (b) compare C loss observations to an active multi-spectral lidar remote sensing index.

C losses from wildfire were consistently greater at the wet riparian site compared with the dry valley site. Average soil C losses were 92.92 Mg C ha ⁻¹ (st. dev. ± 48.60 Mg C ha ⁻¹) and 58.05 Mg C ha ⁻¹ (st. dev. ± 37.19 Mg C ha ⁻¹). Average tree C losses were 114.0 Mg C ha ⁻¹ (std.dev. ± 9.9 Mg C ha ⁻¹) and 86.9 Mg C ha ⁻¹ (std.dev. ± 13.5 Mg C ha ⁻¹) respectively. C losses from trees were greater than soils, where trees lost 55% (moist riparian ecosystem) and about 60% (drier valley site) of C during combustion. Using post-fire multi-spectral airborne lidar data, we found that increased proportion of charred soils were significantly related to enhanced reflectivity in SWIR, resulted in more negative active normalised burn ratio (aNBR) results, indicating enhanced burn severity. Increased proportional cover of regenerating vegetation resulted in less negative aNBR both at the drier site, though no significant relationships between aNBR and charred vs. vegetated results were observed at the moist riparian site. No significant relationship was observed between depth of burn/soil C loss and aNBR derived from lidar data, indicating potential limitations when using burn indices for below canopy burn severity. The use of multi-spectral lidar may improve understanding of below canopy fire fuels and C losses in optical imagery, which often occludes these important components of fire ecology. The results of this research improve understanding of C losses associated with wildland fire in montane ecosystems that have undergone fire suppression and management by Euro-American colonizers for over 100 years.

来自野地火灾的直接碳 (C) 排放难以量化，尤其是在难以进入现场的山地环境中。在这里，我们研究了加拿大艾伯塔省沃特顿湖国家公园的加拿大南部山地山谷生态系统中的火灾前 C 分配和损失。本研究的目的是：(a) 与干燥起伏的高地场地相比，量化潮湿河岸场地燃烧引起的 C 损失，以及 (b) 将 C 损失观测与主动多光谱激光雷达遥感指数进行比较。

与干谷地点相比，湿河岸地点的野火造成的 C 损失始终更大。平均土壤碳损失为 92.92 Mg C ha ^-1 (st. dev. ± 48.60 Mg C ha ^-1 ) 和 58.05 Mg C ha ^-1 (st. dev. ± 37.19 Mg C ha ^-1 )。平均树木碳损失为 114.0 Mg C ha ^-1 (std.dev. ± 9.9 Mg C ha ^-1 ) 和 86.9 Mg C ha ^-1 (std.dev. ± 13.5 Mg C ha ^-1） 分别。树木的碳损失大于土壤，其中树木在燃烧过程中损失了 55%（潮湿的河岸生态系统）和约 60%（较干燥的山谷地点）的碳。使用火灾后多光谱机载激光雷达数据，我们发现烧焦土壤比例的增加与 SWIR 中反射率的增强显着相关，导致更负面的主动归一化燃烧比 (aNBR) 结果，表明烧伤严重程度增加。在较干燥的地点，再生植被的比例覆盖增加导致 aNBR 的负值较小，但在潮湿的河岸地点，aNBR 与烧焦与植被结果之间没有显着关系。未观察到燃烧深度/土壤碳损失与激光雷达数据得出的 aNBR 之间的显着关系，表明在使用烧伤指数低于冠层烧伤严重程度时的潜在限制。多光谱激光雷达的使用可以提高对光学图像中冠层下火灾燃料和 C 损失的理解，这通常会遮挡火灾生态学的这些重要组成部分。这项研究的结果提高了对与山地生态系统中野火相关的碳损失的理解，这些生态系统已经经历了 100 多年的欧美殖民者的灭火和管理。