Tree sapling responses to 10 years of experimental manipulation of temperature, nutrient availability, and Shrub cover at the Pyrenean treeline

Maria A. Angulo, Josep M. Ninot, Josep Peñuelas, Johannes H.C. Cornelissen, Oriol Grau*

*Corresponding author for this work

    Research output: Contribution to JournalArticleAcademicpeer-review


    Treelines are sensitive to environmental changes, but few studies provide a mechanistic approach to understand treeline dynamics based on field experiments. The aim of this study was to determine how changes in the abiotic and/or biotic conditions associated with global change affect the performance of tree seedlings (later saplings) at the treeline in a 10-year experiment. A fully factorial experiment in the Central Pyrenees was initiated in autumn 2006; 192 Pinus uncinata seedlings were transplanted into microplots with contrasting environmental conditions of (1) increased vs. ambient temperature, (2) increased nutrient availability vs. no increase, and (3) presence vs. absence of the dominant shrub Rhododendron ferrugineum. We assessed the performance of young pines on several occasions over 10 years. The pines were removed at the end of the experiment in autumn 2016 to characterize their morphology and to conduct chemical and isotopic analyses on their needles. Both the warming and the fertilization treatments increased seedling growth soon after the start of the experiment. R. ferrugineum facilitated the survival and development of pine seedlings during the early years and affected the chemical composition of the needles. Toward the end of the experiment, the transplanted P. uncinata individuals, by then saplings, competed with R. ferrugineum for light and nutrients; the presence of the shrub probably altered the strategy of P. uncinata for acquiring nutrients and buffered the effects of warming and fertilization. The pines were highly sensitive to all factors and their interactions throughout the entire experimental period. These findings indicated that the interactive effects of several key abiotic and biotic drivers associated with global change should be investigated simultaneously for understanding the contribution of young trees to treeline dynamics.

    Original languageEnglish
    Article number1871
    Pages (from-to)1-13
    Number of pages13
    JournalFrontiers in Plant Science
    Publication statusPublished - 8 Jan 2019


    This research was partly funded by the Comissionat per a Universitats i Recerca of the Generalitat de Catalunya, the European Social Fund, and the Synergy grant ERC-SyG-610028 IMBALANCE-P.

    FundersFunder number
    Comissionat per a Universitats i Recerca
    Seventh Framework Programme610028
    European Research Council
    Generalitat de Catalunya
    European Social Fund


      • Chemical composition
      • Competition
      • Facilitation
      • Fertilization
      • Open-top chamber
      • Pinus uncinata seedlings
      • Pyrenees
      • Rhododendron ferrugineum


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