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Ecophysiology

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Research focus

Mechanisms of tree response to abiotic constraints due to climatic and edaphic factors from cell to the ecosystem level by means of system analysis, stress diagnosis and mechanistic modeling.

Main research questions

What are the physiological and morphological responses to environmental constraints/fluctuations at cell-, tree-, and ecosystem-level?
What is the strength/risk of different stressors for forest ecosystems?
How can we differentiate the various stressors and their effects?

Methods

We develop quantitative scenarios on global change effects by combining long-term monitoring with experimental approaches. Our interdisciplinary collaboration is mainly based on the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests ICP-Forests, the Swiss Long-Term Forest Ecosystem Research Program LWF respectively, operating under the UNECE Convention on Long-range Transboundary Air Pollution LRTAP. This network is complemented by experimental research platforms such as the wireless sensor network TreeNet and a lysimeter open-top chamber facility MODOEK, supported by our microscopy lab MICRO.

National and international position

The research group fosters close collaboration with universities and stake holders such as the Federal Office for the Environment FOEN, the Swiss National Science Foundation SNF, the Swiss Federal Institute of Technology Zürich ETHZ, Velux, University of Basel UNIBAS, University of Freiburg i.Br. Uni-Freiburg, Stockholm Environment Institute SEI at the University of York, Chinese Academy of Sciences CAS, CSIOR Marin and Atmospheric Research, ICP-Forests, LTER-Europe, IUFRO and COST (see FPS COST Action FP1202).

FURTHER INFORMATION

Projects

FORWARDS: European Observatory to assess the vulnerability of forests towards climate change

FORWARDS aims to develop, test, and implement a European Observatory that will supply timely and detailed information on European forests' vulnerability to climate change impacts, and provide knowledge to guide climate smart forestry

VPDrought: A novel approach to disentangle atmospheric and soil drought

By deciphering the single vs. combined VPD and soil moisture effects, we will be able to improve global predictions. We aim to apply a scale spanning approach to disentangle the processes affected by atmospheric (i.e., VPD) and soil droughts from the tissue to the tree and the ecosystem level.

Functional ecology of alpine meadows

The ongoing climate change has caused changes in the species composition of alpine meadows. Complementing the vegetation surveys realized in the GLORIA initiative, this project investigates the functional responses above- and belowground to abiotic drivers in alpine forb and grass species.

ICOS-2: Integrated Carbon Observation System in Switzerland, Phase 2017-2021

Die Forschungsstation Seehornwald Davos wurde in den 80er-Jahren von der WSL initiiert und ist damit eine der ältesten permanent betriebenen Wald-Vegetations-Forschungsstationen in der Schweiz.

SCC II - REACT

Species-specific reactions of temperate European forest trees to a changing environment. A project related to the Swiss Canopy Crane II (SCC II) site near Basel and the network TreeNet.

deepT - deep neural network algorithms to recognize species and their specific response patterns in stem growth data of TreeNet

deepT investigates times series of stem radius changes with deep neural network (DNN) algorithms in order to recognize tree species, growth patterns and tree water deficit-induced stem shrinkage characteristics.

TreeNet - The biological drought and growth indicator network

TreeNet ist ein internationales Beobachtungs- und Forschungsnetzwerk, in dem Punktdendrometer automatisch die täglichen Stammradiusschwankungen von Bäumen erfassen. Der kontinuierliche Fluss von Daten liefert Echtzeitinformationen über die Wasserverhältnisse im Baum und das radial Stammwachstum

Soil and tree resilience after forest wildfire in Southern Italy

Pine tree stand and forest site resilience after the severe 2017 wildfire on the slopes of Vesuvius, Italy

eLTER Switzerland

The Long-Term Ecologiocal Research in Europe (LTER-Europe) capitalizes on research infrastructures such as the in-situ network of sites and information technology. Thousands of research projects have been carried out taking advantage of this infrastructure.

Modelling forest growth using 3-PG

Testing 3-PG in uneven-aged forests, comparing predictions with an empirical model and developing a 3-PG R package.

Effects of unbalanced winter-spring warming

Saplings of an evergreen and a deciduous tree species are treated with various levels of defoliation (to change the C-resource availability) and unbalanced winter-spring warming, to study the effects of unbalanced winter-spring warming on spring phenology and its C-resource related mechanisms.

Waldlabor Zürich

Das Waldlabor Zürich ist ein erlebnisorientierter Bildungs- und Forschungsort, es ist das erste Waldlabor der Schweiz. Im Zentrum steht der vom Menschen beeinflusste Wald, der "Kulturwald" mit verschiedenen Formen der Waldpflege und -bewirtschaftung, der Leistungen der Waldeigentümer und der Bedeutu

Assessing past atmospheric composition in Northern China using novel tree-ring analyses

We aim to assess the presence of particles in trees and to correlate them through dating to known air pollution and sandstorms' episodes.

Drought 2018 - TreeNet meets Sentinel2

TreeNet permanently measures growth and tree water deficit (TWD) of about 250 tree individuals in forests all over Switzerland with so-called point dendrometers. TWD has shown to be a reasonable biological indicator for drought stress and quantifies the amount of missing water a tree needs to reach full saturation. In combination with spectral anomalies of satellite-based indices (e.g., NDWI from Sentinel2ab) between 2018 and a reference period we test whether we can find a close link between the two drought stress indicators.

FORClimateS

The project aims to aggregate and synthesize existing information on different spatial and temporal scales to provide decision-makers with relevant and robust information on short- and long-term risks for forests and forest functions and on adaptation strategies under different climate futures

Legacy effects on stem growth

Isodrought

We want to explore a stable isotope tree-ring approach for analyzing physiological drought responses of trees. The results are expected to provide a novel diagnostic tool for understanding causes of tree decline.

Drought duration effects

The present study will analyze the within-tree distribution of C, N, and P reserves in trees treated with different drought duration and frequency, to investigate the C, N and P reserves in relation to recovery ability and mortality following repeated drought events with various drought duration.

QUPFIS

Our aim is to estimate Swiss forest net ecosystem productivity (NEP) at monthly or seasonal resolution for each individual year in order to link biomass changes over time with global drivers.

Forests under stress

In this project we will assess the physiological processes by which trees adjust and interact among each other under a changing climate, determine the consequences of these processes on forest responses to climatic stresses and improve our understanding of these effects on forests functioning at a large comprehensive scale.

Host-mistletoe relationships

The project focuses on the host-mistletoe relationship in relation to changes in the growth environment of the host, and the underlying physiological mechanisms.

PRO3FILE

To improve our assessment of ozone effects on forest ecosystems, we advocate the need (i) for further experimental and long-term monitoring studies and (ii) to develop physiological and demographic modelling tools.

Junior Research: Der Waldboden lebt, Föhren sterben heimlich und Jahrringe erzählen aus der Vergangenheit

Was steckt hinter diesen Aussagen? SchülerInnen vertiefen sich in eines dieser Themen, eignen sich neues Wissen an, lernen genau hinzuschauen und haben Gelegenheit, sich zeigen zu lassen, wie in der Forschung gearbeitet wird.

The dynamic of ozone injury and responses within tree foliage

Relating the stress and detoxification responses at cell level to the phytotoxic ozone dose in foliage of trees

TEA-Electrical potentials and accoustic emissions of trees

TEA combines established methods in ecophysiology (i.e., measuring sap flow, detecting continuous stem radius changes, and recording the microclimatic conditions) with advanced methods of measuring ultrasonic acoustic emissions (UAEs) and detecting electrophysiological signals, so-called electrical potentials (EPs).

Metalink

Soil contamination with heavy metals is a widespread problem affecting natural, cultivated, urban and industrial sites throughout Europe. The main objective in this Swiss/Polish collaboration project is to characterize the links between environmental, genotypic, and phenotypic features in the metal-tolerant plant model Arabidopsis halleri.

Drought effects on reproductive phenology and the underlying physiological mechanisms in pine trees

We use a long-term precipitation manipulation experiment in mature Pinus sylvestris forests and a natural precipitation gradient from 840 mm to 290 mm/year with Pinus sylvestris var. mongolica, to study the "Drought effects on reproductive phenology and the physiological mechanisms of pine trees".

Tea bag decomposition study

Decomposition of plant litter is a key process for the transfer of carbon and nutrients in ecosystems. Carbon contained in the decaying biomass is released to the atmosphere as respired CO2, and may contribute to global warming. Litterbag studies have been used to improve our knowledge of the drivers of litter decomposition, but they lack comparability because litter quality is plant species-specific. The use of commercial tea bags as a standard substrate was suggested in order to harmonize studies, where green tea and rooibos represent more labile and more recalcitrant C compounds as surrogates of local litter.

CaNuPine/MICRO

In this project, adaptive and stress responses to drought stress and varying nutrient availability are being analyzed at tissue, cell and subcellular level in foliage of Scots pine and downy oak.

Carbon and nutrient dynamics of Scots pine

In the CaNuPine project, we study the effects of drought and nutrient availability on the carbon dynamics within Pine (Pinus sylvestris) trees. This will contribute to the controversial debate whether drought may or may not cause acute growth decline and mortality via carbon starvation.

Compartmentation of de-icing salts and structural reactions to salt accumulation in foliage of ornamental lime trees

Street greenery has recently emerged as a major research and urbanization issue. The main objectives in this project are to study the accumulation and effects of de-icing salts in foliage of lime trees (Tilia x vulgaris) and to apply this knowledge for selecting more tolerant lime species and cultivars, with a view to street plantation.

Integrated Carbon Observation System (ICOS)

Integrated Carbon Observation System (ICOS) is a European research infrastructure to quantify and understand the greenhouse gas balance of the European continent and of adjacent regions.

Net Ecosystem Productivity - NEPSRI

Point dendrometer-based SRI data are collected within the project TreeNet and used to estimate NEP. The estimation is performed in near-real-time on the TreeNet processing platform (TreeNet_Pro) and needs temporally highly resolved SRI data and a site-specific leaf area index as input.

MOUNTROOT

The project MOUNTROOT aims at comparing structure-function relationship in roots of two dominant herb species of pasture-woodlands in response to simulated climate change, and to integrate these below-ground insights with above-ground responses to a whole-plant framework.

Antimony uptake as a function of waterlogging in the rhizosphere

Antimony (Sb) is a rather rare but toxic element increasingly contaminating ecosystems. Principal objectives in this project are to investigate the role of changes in the soil conditions and root structure on the uptake of Sb. The results will provide understanding of the soil and root processes governing Sb availability and plant uptake.

trees

In our research project 'trees: Rendering Ecophysiological Processes Audible', we are working on the acoustic recording, analysis and representation of ecophysiological processes in plants and studying the acoustic and aesthetic requirements for making them perceptible.

Stillberg enzyme activities

Climate change will particularly influence species distribution and the structure and function of sensitive ecosystems at the treeline. In an interdisciplinary experiment carried out at Stillberg Davos we will investigate how soil warming and enhanced CO2 concentrations will affect the ectomycorrhizal community structure and extracellular enzyme activities in the soil and at mycorrhizal roots.

How beeches cope with drought

The BuKlim project aims to study the responses of Swiss beech provenances to drought. The results of the project help to assess the adaptational potential of this tree species to the changing climate.

Evolutionary traits

Elevated heavy metal concentrations in the soil are a frequent consequence of past or ongoing industrial activities. The principal objective in this project is to characterize mechanistic aspects of metal accumulation and tolerance and relate it to the genetic structure of populations of Biscutella laevigata. The expected results should provide innovative insights on evolutionary processes of metal tolerance.

MICRO

Microscopical changes in cells and tissues in response to various environmental stress factors are investigated in trees to develop diagnosis tools and understand the mechanistic link between stress and injury.

Foliar symptoms specific for ozone stress in rain forest trees of southern Brazil

The toxic effects of tropospheric ozone concentrations on plants have been reported primarily for ecosystems from the northern hemisphere with a mediterranean, temperate or boreal climate. In the southern hemisphere with its tropical climate, the impact of ozone on natural ecosystems is still mostly unknown.

Boron & salt allocation

With a quickly growing world population and raising demand for agricultural products, the productivity of irrigated agricultural soils is threatened as a consequence of soil salinization in many places with arid climates. Main objectives of this research project are to investigate the compartmentation-based mechanisms contributing to tolerance in foliage of poplar trees grown on soils contaminated with elevated levels of Boron and salts in the San Joaquin Valley in Central California.

Understory removal experiment Salgesch

Long-term research on the interactions between changes in land use and climate and their consequences regarding forest health and dynamic in the pine forests at low elevation of Central Alps

Querco

Querco, in the sense of "quid Quercus, quo vadis?" To study the reaction of 3 local species of oak (each species with 4 provenances) to drought, increasing air temperature and a combination of the two will be the focus of this experiment.

Lötschental

Lötschental offers an ideal setting to study the influence of global warming on tree-growth

Macro- and micro morphological reactions to low soil water availability in the foliage of Scots pine from Wallis

In this project, the structural changes in foliage of Scots pine are used as sensitive bioindications of environmental constraints to study the reactions of dry pine forests in Wallis to low soil water availability and changes in land use.

Irrigation Experiment Pfynwald

Drought-induced forest decline will gain in importance as the frequency and severity of drought events are expected to increase in the context of climate change. To understand how chronic drought affects tree growth, we study mature Scots pine in an irrigation experiment in an inner-Alpine dry valley since 2003.

Tree Response to Climate Change - Valais

In Valais, Scots pine (Pinus sylvestris) and pubescent oak (Quercus pubescent) grow at least temporally at the edge of their physiological capabilites. We investigate the (potential) adaptation of these and co-occurring tree species to climate change and search for limits they might reach with increasing temperatures and droughts.

TreeNet

TreeNet is a biological drought and growth indicator network of forest ecosystems. It provides information about drought responses of trees all over Switzerland and their effects on the carbon balance of forests. TreeNet links the research of the eddy flux super sites Davos and Lägeren to the forest next to your home.

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Staff

Ecophysiology

Dr. Marcus Schaub	Groupleader, Senior Scientist
Dr. David Jonas Basler	Postdoc
Dr. Arun Bose	Visiting scientist
Magalie Chavanne	Master student
Nicolas De Girardi	temporary employee
Dr. Sophia Etzold	Scientific staff member
Jonas Gisler	Technical staff member
Dr. Madeleine S. Goerg-Günthardt	Visiting scientist
Wen Guo	PhD student guest
Dr. Rudolf Häsler	Visiting scientist
Marie Horvath	Master student
Dominik Andrin Hummel	Technical staff member
Prof. Dr. Maihe Li	Senior Scientist
Gian-Battista Macor	Master student
Marcus Maeder	Visiting scientist
Xi Qi	PhD student guest
David Sommer	Civil service employee
Dr. Volodymyr Trotsiuk	Software engineer
Benjamin Turc	Visiting scientist
Dr. Pierre Vollenweider	Scientific staff member
Qingshui Yu	PhD student guest
Yanli Zhang	PhD student with Scholarshiop
Yi Zhu	PhD student guest
Dr. Roman Zweifel	Scientific staff member

WSL websites

waldwissen.net

Knowhow for forestry experts and all others interested in the forest

lfi.ch

Swiss National Forest Inventory NFI - a forest information service

envidat.ch

Access to environmental monitoring and research data

natural-hazards.ch

Warnings on natural hazards by Swiss federal authorities

slf.ch

WSL Institute for Snow and Avalanche Research SLF in Davos

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National and international position