Agashashok Treeline Snowfence White Spruce Needle Length (2017-2024)

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 measurements of white spruce needle length made using WinSeedle software on scanned images of oven dried needles collected in late August- early September of each year.

北极的增温速率远快于全球其他区域，且增温具有季节不对称性：夏季增温幅度较为温和，冬季则出现极端增温。在北极多数区域，极端冬季增温与观测到及预测的冬季降水增加现象相伴出现。极端冬季增温与冬季降水增加的共同作用，将引发冬季土壤快速升温，进而对生态系统功能产生广泛深远的影响。冬季土壤温度偏高通常与更强的越冬微生物活动、土壤有机质分解加速以及养分大量释放相关，这些养分可在融雪后被植物吸收利用。我们在阿拉斯加西部布鲁克斯山脉的北极林线（treeline）附近开展的长期研究表明，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（tundra）的扩张具有重要意义。为加深对不对称增温和冬季降水增加如何影响北极地区树木生长及林线扩张的理解，我们设置了重复性良好的雪栅栏实验（snowfence experiment）。本数据集呈现了通过WinSeedle软件，对每年8月末至9月初采集的烘干针叶扫描图像进行测量得到的白云杉（white spruce）针叶长度数据。