How is tree growth rate linked to root functional traits in phylogenetically related poplar hybrids?

Fine roots play a crucial role in soil nutrient and water acquisition, significantly contributing to tree growth. Fine roots with a high specific root length (SRL) and small diameter are often considered to help trees grow fast. However, inconsistencies in the literature do not provide a clear basis on the effect of root functional traits, such as SRL or root mass density (RMD), on tree growth rate in phylogenetically related trees.

On the significance of long-term trends in tree-ring N isotopes - The interplay of soil conditions and regional NOx emissions.

As anthropogenic nitrogen (N) emissions have been rising for decades, it is critical to develop natural archives that help understand how natural processes were modified in the past. Tree-ring δN values may represent such an indicator but its validity as faithful record of N cycling changes is still debated. Here we produce long-tree-ring δN series for five white spruce stands from two boreal regions submitted to moderate industrial N inputs.

Nitrogen isotopes in the soil-to-tree continuum - Tree rings express the soil biogeochemistry of boreal forests exposed to moderate airborne emissions.

Anthropogenic N emissions represent a potential threat for forest ecosystems, and environmental indicators that provide insight into the changing forest N cycle are needed. Tree ring N isotopic ratios (δN) appear as a contentious choice for this role as the exact mechanisms behind tree-ring δN changes seldom benefit from a scrutiny of the soil-to-tree N continuum. This study integrates the results from the analysis of soil chemistry, soil microbiome genomics, and δN values of soil N compounds, roots, ectomycorrhizal (EcM) fungi and recent tree rings of thirteen white spruce trees sampled in five stands, from two regions exposed to moderate anthropogenic N emissions (3.