Does atmospheric nitrogen deposition cause critical nutrient imbalances in temperate tree regeneration?

{"title":"Does atmospheric nitrogen deposition cause critical nutrient imbalances in temperate tree regeneration?","authors":"Viktoria Dietrich,&nbsp;Jörg Niederberger,&nbsp;Jana Frank,&nbsp;Markus Hauck","doi":"10.1007/s00468-025-02615-z","DOIUrl":null,"url":null,"abstract":"<div><h3>Key message</h3><p>Nitrogen deposition and precipitation analyzed along independent gradients did not cause major foliar nutrient imbalances that affected tree health in temperate tree regeneration of <i>Fagus sylvatica</i>, <i>Pseudotsuga menziesii</i> and <i>Abies alba</i>.</p><h3>Abstract</h3><p>While drought tolerance receives great attention in the scope of climate change research, the response of trees to high N deposition, which is also part of global change, has remained less studied. We investigated 45 temperate forest stands across Germany along a gradient of atmospheric N deposition of 22 kg N ha⁻¹ a⁻¹ (range 10–32 kg N ha⁻¹ a⁻¹) and analyzed foliar nutrient concentrations and ratios in saplings of European beech, Douglas fir, and silver fir. We also measured relative shoot length increment and (as a proxy for intrinsic water use efficiency, WUEi, and stomatal conductance, <i>g</i>_s) foliar δ¹³C signatures to detect potential effects of nutrient imbalances on productivity and plant water relations. Although all species responded on deposition with increased foliar N concentrations, reduced foliar nutrient concentrations were only observed for P, but not K, Ca, Mg, and Fe. The effect on foliar P concentrations was only observed at sites with low mean annual precipitation (range 565–1690 mm). Reduced growth was not observed. Low foliar P concentrations were associated with high <i>g</i>_s in Douglas fir, which poses a potential risk under dry conditions and is consistent with the literature, but lacks a mechanistic explanation. The lack of nutrient imbalance at high N supply can at least partly be explained by the relatively low absolute amounts of nutrients needed by the small-sized tree regeneration.</p></div>","PeriodicalId":805,"journal":{"name":"Trees","volume":"39 2","pages":""},"PeriodicalIF":2.1000,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00468-025-02615-z.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Trees","FirstCategoryId":"2","ListUrlMain":"https://link.springer.com/article/10.1007/s00468-025-02615-z","RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"FORESTRY","Score":null,"Total":0}