Resin-sorbed nitrate and ammonium in organic and mineral soils across a tree density gradient in northeastern Siberia, 2015-2016

As climate warms, tree density at the taiga-tundra ecotone is expected to increase, which may intensify competition for belowground resources in this nitrogen (N) limited environment. To determine the impacts of increased tree density on N cycling and productivity we examined edaphic properties indicative of soil N availability along with aboveground and belowground tree-level traits and stand characteristics related to carbon (C) and N cycling across a tree density gradient of monodominant larch (Larix cajanderi) at the taiga-tundra ecotone in far northeastern Siberia. In this dataset, we quantified nitrate (NO3-) and ammonium (NH4+) availability in organic and mineral soils in the field using mixed-bed ion exchange resins across a tree density gradient near the Northeast Science Station, Russia, 2015-2016. This data set consists of resin-sorbed NO3- and NH4+ expressed in milligram N per year (mg N yr-1).