Carbon cycle perturbations in high-latitude ecosystems associated with rapid warming can have implications for the global climate. Belowground biomass is an important component of the carbon cycle in these ecosystems, with, on average, significantly more vegetation biomass belowground than aboveground. Large quantities of dead root biomass are also in these ecosystems owing to slow decomposition rates. Current understanding of how live and dead root biomass carbon pools vary across high-latitude ecosystems and the environmental conditions associated with this variation is limited due to the labor- and time-intensive nature of data collection. To that end, we examined patterns and factors (abiotic and biotic) associated with the variation in live and dead fine root biomass (FRB) and FRB carbon (C), nitrogen (N) and phosphorus concentrations for 23 sites across a latitudinal gradient in Alaska, spanning both boreal forest and tundra biomes. We found no difference in the live or dead FRB variables between these biomes, despite large differences in predominant vegetation types, except for significantly higher live FRB C:N ratios in boreal sites. Soil C:N ratio, moisture, and temperature, along with moss cover, explained a substantial portion of the dead:live FRB ratio variability across sites. We find all these factors have negative relationships with dead FRB, while having positive or no relationship with live FRB. This work demonstrates that FRB does not necessarily correlate with aboveground vegetation characteristics, and it highlights the need for finer-scale measurements of abiotic and biotic factors to understand FRB landscape variability now and into the future.

与快速变暖相关的高纬度生态系统中的碳循环扰动可能对全球气候产生影响。在这些生态系统中，地下生物量是碳循环的重要组成部分，地下的植被生物量平均比地下的生物量要多得多。由于分解速度慢，这些生态系统中也有大量死根生物量。当前对高纬度生态系统中生根和死根生物量碳库如何变化的理解，由于数据收集的劳动和时间密集性，与这种变化相关的环境条件受到限制。为此，我们研究了与活根和死根细根生物量（FRB）和FRB碳（C）的变化有关的模式和因素（非生物和生物），横跨北方森林和冻原生物群落的阿拉斯加横向梯度上23个地点的氮（N）和磷浓度。尽管主要植被类型差异很大，但我们发现这些生物群落之间的活或死FRB变量没有差异，除了在寒带地区活FRB的C：N比明显更高。土壤C：N比，水分和温度以及苔藓覆盖率解释了整个地点的死：活FRB比变化的很大一部分。我们发现所有这些因素与死FRB呈负相关，而与活FRB呈正或无关系。这项工作表明FRB不一定与地上植被特征相关，