Regeneration in European beech forests after drought: The effects of microclimate, deadwood, and browsing

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Dominik Thom - , Technical University of Munich, University of Vermont (First author)
  • Christian Ammer - , University of Göttingen (Author)
  • Peter Annighöfer - , Technical University of Munich (Author)
  • Réka Aszalós - , Centre for Ecological Research (Author)
  • Sebastian Dittrich - , Institute of General Ecology and Environmental Protection (Author)
  • Jonas Hagge - , Nordwestdeutsche Forstliche Versuchsanstalt, University of Göttingen (Author)
  • William S. Keeton - , University of Vermont (Author)
  • Bence Kovacs - , Centre for Ecological Research (Author)
  • Ole Krautkrämer - , University of Marburg (Author)
  • Jörg Müller - , University of Würzburg (Author)
  • Goddert von Oheimb - , Institute of General Ecology and Environmental Protection (Author)
  • Rupert Seidl - , Technical University of Munich (Last author)

Abstract

With progressing climate change, increasing weather extremes will endanger tree regeneration. Canopy openings provide light for tree establishment, but also reduce the microclimatic buffering effect of forests. Thus, disturbances can have both positive and negative impacts on tree regeneration. In 2015, three years before an extreme drought episode hit Central Europe, we established a manipulation experiment with a factorial block design in European beech (Fagus sylvatica L.)-dominated forests. At five sites located in southeastern Germany, we conducted three censuses of tree regeneration after implementing two different canopy disturbances (aggregated and distributed canopy openings), and four deadwood treatments (retaining downed, standing, downed + standing deadwood and removing all deadwood), as well as in one untreated control plot. In addition, we measured understory light levels and recorded local air temperature and humidity over five years. We (i) tested the effects of experimental disturbance and deadwood treatments on regeneration and (ii) identified the drivers of regeneration density as well as seedling species and structural diversity. Regeneration density increased over time. Aggregated canopy openings supported species and structural diversity, but reduced regeneration density. Tree regeneration was positively associated with understory light levels, while maximum vapor pressure deficit influenced tree regeneration negatively. Deadwood and browsing impacts on regeneration varied and were inconclusive. Our study indicates that despite the drought episode regeneration in beech-dominated forests persisted under moderately disturbed canopies. However, the positive effect of increased light availability on tree regeneration might have been offset by harsher microclimate after canopies have been disturbed.

Details

Original languageEnglish
Pages (from-to)259–273
Number of pages15
JournalEuropean Journal of Forest Research
Volume142
Issue number2
Publication statusPublished - Apr 2023
Peer-reviewedYes

External IDs

Scopus 85143593605
ORCID /0000-0001-7408-425X/work/145222859

Keywords

Keywords

  • Seedlings, species diversity, structural diversity, tree establishment, understory