ORNL FACE Nitrogen Concentrations (Leaves, Litter, Fine Roots, Wood)

This report documents the file, Nconc.dat, which contains the nitrogen concentration data for leaves, litter, fine roots, and wood for 1998-2006. These data were collected for rings 1 and 2 which are exposed to elevated CO2 and rings 3-5 which have ambient CO2. The 2005 and 2006 nitrogen concentrations for fine roots will be included when they become available. The N concentration in leaves could not be measured in ring 5 in 2006; an estimated value based on N concentration in litter and an average resorption efficiency is 1.073%. Additional information describing this dataset can be found in Norby, R.J. and C.M. Iversen (2006). Nitrogen uptake, distribution, turnover, and efficiency of use in a CO2-enriched sweetgum forest. Ecology 87:5-14.本报告对Nconc.dat文件进行说明，该文件包含1998—2006年期间叶片、枯落物、细根及木质组织的氮浓度数据。上述数据采集自暴露于升高CO₂浓度环境的1号、2号样环，以及处于环境CO₂浓度水平的3号至5号样环。 2005年与2006年的细根氮浓度数据将在获取后补充至本数据集。2006年5号样环的叶片氮浓度未能完成实测，现有基于枯落物氮浓度与平均养分回收效率估算得到的数值为1.073%。 有关本数据集的更多详细信息可参阅Norby,R.J.与Iversen,C.M.于2006年发表的研究论文：《CO₂富集北美枫香林的氮吸收、分配、周转与利用效率》，刊载于《生态学（Ecology）》第87卷，第5—14页。