Agashashok Treeline Snowfence White Spruce Cone Counts (2019-2025)

The Arctic is warming much faster than the rest of the globe and the warming is seasonally asymmetrical, with modest warming during the summer months and extreme warming during the winter months. In many regions of the Arctic, extreme winter warming is coupled with observed and projected increases in winter precipitation. The combination of extreme winter warming and increasing winter precipitation will lead to rapid winter soil warming, with wide ranging consequences for ecosystem function. Warmer winter soils are generally associated with greater overwinter microbial activity, enhanced breakdown of soil organic matter and a flush of nutrients that may be available for plant uptake following snowmelt. Our long-term research near the Arctic treeline in the western Brooks Range of Alaska has revealed the potential importance of deeper snowpacks and warmer winter soils for the productivity of treeline trees and their advance into the tundra. We installed a well-replicated snowfence experiment to advance understanding of the effects of asymmetric warming and increased winter precipitation on tree growth and treeline advance in the Arctic. Here, we present counts of current year's white spruce cones made in one-sided photographs of the tree canopy each year in late August- early September.北极的增温速率远高于全球其他区域，且增温呈现季节不对称特征：夏季增温幅度较为温和，冬季则出现极端增温。在北极诸多区域，极端冬季增温与观测到及预测的冬季降水增加相伴发生。极端冬季增温与冬季降水增多的共同作用，将引发冬季土壤快速升温，进而对生态系统功能产生广泛影响。冬季土壤温度升高通常伴随更强的越冬微生物活性、土壤有机质分解加剧，以及融雪后可供植物吸收的养分脉冲式释放。我们团队在阿拉斯加布鲁克斯山脉西部北极林线附近开展的长期研究显示，更深的积雪与更温暖的冬季土壤，可能对林线树木的生产力及其向苔原的扩张具有重要意义。为进一步理解不对称增温和冬季降水增加对北极树木生长及林线扩张的影响，我们设置了重复度良好的雪栅栏实验。本数据集提供了每年8月末至9月初拍摄的树木单侧冠层照片中统计的当年白云杉球果数量。