Arctic tundra has experienced rapid warming, outpacing global averages, leading to significant greening whose primary drivers include widespread shrubification. Here we confirm that a fire–greening positive feedback loop is evident across the Alaskan tundra, and evidence suggests that this feedback loop is dominated by the fire–shrub interactions. We show that tundra wildfires, especially those with higher severity, play a critical role in boosting the overall greening of the tundra, often by enhancing upright deciduous shrub growth or establishment but sometimes by inducing increases in other vascular biomass. In addition, fire–greening interactions vary greatly within different tundra subregions, a likely consequence of the spatial heterogeneity in vegetation composition, climatic and geophysical conditions.

北极苔原经历了快速变暖，超过了全球平均水平，导致了严重的绿化，其主要驱动因素包括广泛的灌木化。在这里，我们证实了火-绿化正反馈循环在整个阿拉斯加苔原上是明显的，并且有证据表明这个反馈循环是由火-灌木相互作用主导的。我们表明，苔原野火，尤其是那些严重程度较高的野火，在促进苔原的整体绿化方面发挥着关键作用，通常是通过促进直立落叶灌木的生长或建立，但有时是通过诱导其他维管生物量的增加。此外，不同苔原子区域内的火-绿化相互作用差异很大，这可能是植被组成、气候和地球物理条件的空间异质性的结果。