SPRUCE S1 Bog Fine-root Production and Standing Crop Assessed With Minirhizotrons in the Southern and Northern Ends of the S1 Bog

Fine roots contribute to ecosystem carbon, water, and nutrient fluxes through resource acquisition, respiration, exudation, and turnover, but are understudied in peatlands. This data set reports fine-root peak growth and standing crop measurements from a forested, ombrotrophic bog as determined using non-destructive minirhizotron technology. Minirhizotron images were collected throughout the growing seasons of 2011 and 2012 at the southern and northern ends of the S1 bog across gradients of tree density in paired hummock and hollow microtopography. The dominant woody species in the bog, and focus of the investigation, were trees Picea mariana and Larix laricina, and ericaceous shrubs Rhododendron groenlandicum and Chamaedaphne calyculata. The data were derived from minirhizotron images where root length and diameter were measured on ~weekly images and used to calculate: (1) Annual fine-root production and peak standing crop in 2011 and 2012; (2) Seasonal fine-root phenology throughout the growing seasons of 2011 and 2012; and (3) The distribution of newly-produced fine-root length throughout the peat profile in 2011 and 2012. The measurements were made in the S1 Bog, a Picea mariana [black spruce] - Sphagnum spp. bog forest in northern Minnesota, 40 km north of Grand Rapids, in the USDA Forest Service Marcell Experimental Forest (MEF). These minirhizotron images were collected prior to the construction of the SPRUCE experimental plots.

细根通过资源获取、呼吸作用、根系分泌物释放以及周转过程，参与生态系统的碳、水与养分通量，但泥炭地中的细根研究仍相对不足。本数据集记录了利用无损微根窗（minirhizotron）技术，对一处森林覆盖的雨养泥炭沼泽（ombrotrophic bog）开展的细根峰值生长与现存生物量测量结果。研究于2011年与2012年的整个生长季内，在S1泥炭沼泽的南北两端，针对树密度梯度下的成对丘状与凹坑微地形开展微根窗图像采集。本泥炭沼泽的优势木本植物亦是本次研究的焦点，包括黑云杉（Picea mariana）、美洲落叶松（Larix laricina）两种乔木，以及格陵兰杜鹃（Rhododendron groenlandicum）、盾叶越橘（Chamaedaphne calyculata）两种杜鹃花科灌木。本数据集的原始数据来自微根窗图像，研究人员以约每周一次的频率对图像中的细根长度与直径进行测量，并据此计算得到三项核心结果：(1) 2011年与2012年的年度细根生产量及峰值现存生物量；(2) 2011年与2012年整个生长季内的细根物候季节动态；(3) 2011年与2012年新生细根长度在泥炭剖面中的分布格局。本次测量工作开展于美国农业部（USDA）森林服务局马塞尔实验林（MEF）内的S1泥炭沼泽，该沼泽位于明尼苏达州北部格兰德拉皮兹以北40公里处，是一处以黑云杉（Picea mariana，即黑云杉）、泥炭藓属（Sphagnum spp.）为优势类群的泥炭沼森林。所有微根窗图像均采集于SPRUCE实验样地建设之前。