De-Coupled Water and Nitrogen Translocation From Subsoil to Canopy of Temperate Forest Trees.

Water translocates to the canopy faster than nitrogen in mature temperate forest trees, with a marked asynchrony observed across species and soil types.

• Why it matters: Understanding the timing and coupling of water and nitrogen transport is crucial for insights into tree physiology and nutrient cycling, yet direct field evidence has been limited.
• What they did: A paired dual-isotope (2 H, 15 N) tracer experiment was conducted in a temperate forest, involving 2 months of sampling from Douglas fir and European beech across different soil textures and rooting depths, measuring tracer appearance in xylem sap and foliage.
• The result: The study revealed that water reaches the canopy significantly faster than nitrogen, with uptake patterns influenced by species, soil texture, and depth, highlighting the complex, asynchronous nature of resource translocation in forest trees.