Increasing tree density accelerates stand‐level nitrogen cycling at the taiga–tundra ecotone in northeastern Siberia

As climate warms, tree density at the taiga–tundra ecotone (TTE) is expected to increase, which may intensify competition for belowground resources in this nitrogen (N)-limited environment. To determine impacts of increased on N cycling and productivity, we examined edaphic properties indicative soil availability along with aboveground tree-level traits stand characteristics related carbon (C) across a gradient monodominant larch (Larix cajanderi) TTE far northeastern Siberia. We found no consistent evidence from soil, tree, or stand-level lower greater intraspecific density. Active layer thickness declined, but resin-sorbed organic did not covary There was, however, allocation coarse fine roots density, an pattern suggestive limited resources. Foliar C (%C, δ13C, resorption) were responsive indicating importance non-nutrient resources, like light, foliar stoichiometry. individual trees had biomass pools declined tracking decreases uptake, resorption, use efficiency, slow tissues wood. At level, our findings show high turnover acquisition, short-lived relatively content reduced residence time, productivity as increased. Yet, these positive relationships curtailed highest densities. Our observations shifts biomass, allocation, loss aboveground, root could have strong should be represented models dynamics feedbacks climate.