BD Seminar 2025/06/11: Compositional and Functional Responses to Experimental Understory Removal

#WSLBiodiversitySeminar
This seminar was co-organized by the WSL Biodiversity Center and SwissForestLab.
Compositional and Functional Responses to Experimental Understory Removal in the Soil and Ground Vegetation of Former Wooded Pastures Nowadays Abandoned, After Millennia of Overuse
Speaker: Pierre Vollenweider, WSL
Moderator: Arthur Gessler, SwissForestLab and WSL
Date: 11 June 2025

Abstract
As in many places in the Central Alps, the forests close to the village of Salgesch/VS were heavily exploited as wooded pastures and for other intensive land use over millennia, which may have caused the severe nutrient deficiencies observed in foliage of dominant trees nowadays. In the Salgesch experiment, forest recovery consecutive to abandonment in the 1960s has been interrupted by the experimental removal of woody understory, thereby partially recreating the former wooded pasture management. This treatment has resulted in a stable increase in both the soil temperature and moisture availability within cleared plots. After 10 years, the thickness of litter layer has been decreased and significant changes were observed in the topsoil properties. The soil mesofauna diversity and soil biological activity have been reduced and the availability of several macro- and micro-nutrients decreased. The ground vegetation has become more xerophilous and thermophilous and its foliage more xeromorphic. All these changes appear then suggestive of reversed ecosystem recovery underway in the former wooded pastures reclaimed by mixed woody species, despite current climate change.

About the Understory removal experiment Salgesch
In the low elevation forests within alpine central valleys, such as the Valais, pines have shown unprecedented signs of decline since the end of 20th century, mostly attributed to repeated droughts. However, these forests have also experienced drastic changes in land use, which specific effects and interactions with the climatic drivers are still unclear. Since 2010, the Salgesch understory removal experiment has been completing investigations performed at the nearby Pfynwald research site, focusing on the consequences of recent understory development on the ecosystem processes and dominant pine growth and ecophysiology.
https://www.wsl.ch/de/projekte/experi...

BD-Seminars
The Biodiversity Seminar Series (BD-Seminars) are organized by the WSL Biodiversity Center. Every two weeks, we aim to host a seminar speaker that presents research or outreach on topics relevant to the biodiversity community at WSL. The seminars are public and are usually broadcasted online.
This seminar was co-organized by the WSL Biodiversity Center and SwissForestLab

Find out more about the WSL Biodiversity Center and a complete list of events here: https://biodiversitycenter.wsl.ch/en/
SwissForestLab: https://swissforestlab.wsl.ch/en/