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Forest ecosystem responses to climatic drivers

English title Forest ecosystem responses to climatic drivers
Applicant Buchmann Nina
Number 132562
Funding scheme ProDoc
Research institution Departement Umweltsystemwissenschaften ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Ecology
Start/End 01.02.2011 - 31.01.2014
Approved amount 200'000.00
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All Disciplines (2)

Discipline
Ecology
Environmental Research

Keywords (16)

vegetation responses; climate change; eddy covariance; ecophysiology; carbon balance; tree water relations; wood growth; net ecosystem productivity; gross primary production; ecosystem respiration; forest carbon dynamics; net ecosystem CO2 bdget; dendrometer; forest response; decidous forest; coniferous forest

Lay Summary (English)

Lead
Lay summary
The project Forest Ecosystem Responses to Climatic Drivers aims at understanding time lags between climatic drivers and the respective ecosystem responses in terms of net ecosystem productivity (NEP) at the two Swiss Fluxnet sites Davos and Lägeren. The project has a highly interdisciplinary character and brings together detailed knowledge from plant physiology, forest ecology and meteorology to disentangle the effects on NEP of (i) actual physical drivers, and (ii) biotic conditions determined by past and recent climatic conditions. Understanding the natural processes determining the carbon balance of forest ecosystems is of great global interest for estimating country-specific carbon budgets within the United Nations Framework Convention on Climate Change (UNFCCC). The topic is a current hotspot at which precise questions from politics meet the incomplete knowledge of various environmental science disciplines.

We hypothesize that the current year NEP is significantly driven by climatic drivers of the recent past (month to years) and not only by present conditions as typically assumed. Furthermore we hypothesize that observed time lags between climatic drivers and NEP are due to storage dynamics of carbon and water in trees.
Our specific aims are to (i) identify climatic drivers of NEP at two contrasting forest sites, (ii) to quantify the impact of the climatic drivers on observed time lags of ecosystem responses, and (iii) to assess the underlying physiological mechanisms explaining such time lags and therefore flux partitioning.

In order to address these aims, we plan:
o to measure microclimate profiles, eddy covariance net ecosystem CO2 and H2Ovapor exchange, continuous stem radius changes, and [CO2] in tree stems at two Swiss Fluxnet sites Davos and Lägeren.
o to analyse statistical patterns of historic time series which quantify the time-dependent weight of climatic drivers on ecosystem responses.
o to compare the results of two forest types from the Swiss Fluxnet sites Davos and Lägeren.
o to test the applicability of physiological concepts to explain the observed time lags and thus flux partitioning of CO2 and H2Ovapor fluxes at the ecosystem level.
Our long-term forest ecosystem research sites (Davos since 1997; Lägeren since 2005) are predestined locations to address topics that depend on temporally and spatially highly resolved field data at different integration levels with long-term records.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Name Institute

Publications

Publication
Winter respiratory C losses provide explanatory power for net ecosystem productivity
Haeni M Zweifel R Eugster W Gessler A Zielis S Carrara A Knohl A Havránková K Herbst M Ibro (2017), Winter respiratory C losses provide explanatory power for net ecosystem productivity, in Journal of Geophysical Research – Biogeosciences, 122, 243-226.
Are trees able to grow in periods with shrunken stems?
Zweifel R Haeni M Buchmann N Eugster W (2016), Are trees able to grow in periods with shrunken stems?, in New Phytologist, 211, 839-849.
NEP of a Swiss subalpine forest is significantly driven not only by current but also by previous year’s weather
Zielis S Etzold S Zweifel R Eugster W Haeni M Buchmann N (2014), NEP of a Swiss subalpine forest is significantly driven not only by current but also by previous year’s weather, in Biogeosciences , 11, 1627-1635.
Climate extremes and the carbon cycle
Reichstein M Bahn M Ciais P Frank D Mahecha MD Seneviratne SI Zscheischler J Beer C Buchmann (2013), Climate extremes and the carbon cycle, in Nature, 500, 287-295.
Contrasting response of grassland versus forest carbon and water fluxes to spring drought in Switzerland
Wolf S Eugster W Ammann C Häni M Zielis S Hiller R Stieger J Imer D Merbold L Buchmann N (2013), Contrasting response of grassland versus forest carbon and water fluxes to spring drought in Switzerland, in Environmental Research Letters , 8, 035007.
Forest NEP is significantly driven by previous year’s weather
Zielis S Etzold S Zweifel R Eugster W Haeni M Buchmann N (2013), Forest NEP is significantly driven by previous year’s weather, in Biogeosciences Discussion , 10, 15587-15611.
Long-term stem CO2 concentration measurements in Norway spruce in relation to biotic and abiotic factors
Etzold S Zweifel R Rühr N Eugster W Buchmann N (2013), Long-term stem CO2 concentration measurements in Norway spruce in relation to biotic and abiotic factors, in New Phytologist, 197, 1171-1184.
Compensation of net carbon loss after wintertime explains annual net ecosystem productivity of European forests
Haeni M Zweifel R Eugster W Gessler A Zielis S Carrara A Knohl A Havránková K Herbst M Ibro, Compensation of net carbon loss after wintertime explains annual net ecosystem productivity of European forests, in Journal of Geophysical Research – Biogeosciences.
Increasing relevance of spring temperatures for Norway spruce trees in Davos, Switzerland, after the 1950s
Churakova OV (Sidorova) Eugster W Etzold S Cherubini P Zielis S Saurer M Siegwolf R Buchmann, Increasing relevance of spring temperatures for Norway spruce trees in Davos, Switzerland, after the 1950s, in Trees, 28, 183-191.

Collaboration

Group / person Country
Types of collaboration
Prof. Timo Vesala, Helsinki Finland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
- Exchange of personnel
Dr. Sabine Augustin, BAFU Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Industry/business/other use-inspired collaboration
Sabine Braun, Institute of Applied Plant Sciences, IAP Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Industry/business/other use-inspired collaboration
Prof. Janusz Olejnik, Poznán Poland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
- Exchange of personnel
Prof. Anders Lindroth, Lund Sweden (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
- Exchange of personnel
Dr. Matthias Dobbertin, WSL (2012 verstorben) Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
- Exchange of personnel

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
AGU Talk given at a conference Compensation of winter respiration to predict annual carbon uptake in European forests 09.12.2013 San Francisco, United States of America Eugster Werner; Zweifel Roman; Buchmann Nina; Häni Matthias;
AGU Talk given at a conference Significance if previous years's weather for forest net ecosystem productivity 09.12.2013 San Francisco, United States of America Eugster Werner; Häni Matthias; Zweifel Roman; Buchmann Nina;
Batsheva de Rothschild Seminar on “Coordina-ted approaches for studying long-term ecosystem responses to global change” Talk given at a conference Lessons learned from two long-term Swiss forest sites: focusing on carbon and water dynamics 30.09.2013 Ramat Hanadiv Park , Israel Buchmann Nina;
International Conference on Climate Change and Tree Responses in Central European Forests Talk given at a conference Response of forest ecosystems to previous year’s weather as key to better NEP models 02.09.2013 Zürich, Switzerland Eugster Werner; Häni Matthias; Zweifel Roman; Buchmann Nina;
International Conference on Climate Change and Tree Responses in Central European Forests Talk given at a conference The Swiss Fluxnet: Greenhouse gas fluxes and responses of two Swiss forests to natural and anthropogenic impacts 02.09.2013 Zürich, Switzerland Buchmann Nina;
International Conference on Climate Change and Tree Responses in Central European Forests Talk given at a conference TreeNet 02.09.2013 Zürich, Switzerland Buchmann Nina; Zweifel Roman; Häni Matthias; Eugster Werner;
TreeNet workshop Talk given at a conference Net ecosystem productivity and stem radius change 12.04.2013 Bachtel, Switzerland Zweifel Roman; Eugster Werner; Buchmann Nina; Häni Matthias;
Carbo-Extreme Annual Conference Poster Time lags in forest net ecosystem productivity 02.04.2013 Seefeld, Austria Buchmann Nina; Zweifel Roman; Häni Matthias; Eugster Werner;
PhD Colloquium on Climate Change - Science, Economics, and Policy Individual talk Link between tree growth and forest carbon balance: Measuring CO2 balances instead of estimating 12.02.2013 Zürich, Switzerland Häni Matthias;
WSL series Talk given at a conference Results from the PhD 11.12.2012 Birmensdorf, Switzerland Häni Matthias; Zweifel Roman;
Plant Science and Policy PhD-Symposium Individual talk TreeNet: Presentation on ProDoc project status 09.12.2012 Zurich, Switzerland Häni Matthias;
Hawkesbury Institute of the Environment, University of Western Sydney Individual talk The C balance of mountain forests: Responses to natural & human impacts 09.05.2012 Sydney , Australia Buchmann Nina;
GHG-Europe Annual Meeting Poster Do forests care about the past? 17.04.2012 Pitesti, Romania Häni Matthias; Zweifel Roman; Buchmann Nina; Eugster Werner;
GHG-Europe Annual Meeting Poster TreeNet 17.04.2012 Pitesti, Romania Buchmann Nina; Zweifel Roman; Häni Matthias;
Seminar at CSIRO Individual talk The Swiss FluxNet: GHG fluxes & ecosystem responses to natural & anthropogenic impacts 04.04.2012 Canberra, Australia Buchmann Nina;
Swiss Global Change Day Poster Net ecosystem productivity vs. stem radius changes 04.04.2012 Bern, Switzerland Häni Matthias; Eugster Werner; Buchmann Nina; Zweifel Roman;


Communication with the public

Communication Title Media Place Year
New media (web, blogs, podcasts, news feeds etc.) TreeNet web Western Switzerland German-speaking Switzerland 2013

Associated projects

Number Title Start Funding scheme
136273 CarboCount CH: Quantifying greenhouse gas fluxes and their sensitivity to climate variations: A case study in Central Europe and Switzerland 01.01.2012 Sinergia
148992 ICOS-CH: Integrated Carbon Observation System in Switzerland 01.07.2013 Research Infrastructure
127227 PSC "Plant Sciences and Policy" 01.11.2009 ProDoc

Abstract

RelevanceThe project Forest Ecosystem Responses to Climatic Drivers aims at understanding time lags between climatic drivers and the respective ecosystem responses in terms of net ecosystem productivity (NEP) at the two Swiss Fluxnet sites Davos and Lägeren. The project has a highly interdisciplinary character and brings together detailed knowledge from plant physiology, forest ecology and meteorology to disentangle the effects on NEP of (i) actual physical drivers, and (ii) biotic conditions determined by past and recent climatic conditions. Understanding the natural processes determining the carbon balance of forest ecosystems is of great global interest for estimating country-specific carbon budgets within the United Nations Framework Convention on Climate Change (UNFCCC). The topic is a current hotspot at which precise questions from politics meet the incomplete knowledge of various environmental science disciplines. Working HypothesesWe hypothesize that the current year NEP is significantly driven by climatic drivers of the recent past (month to years) and not only by present conditions as typically assumed. Furthermore we hypothesize that observed time lags between climatic drivers and NEP are due to storage dynamics of carbon and water in trees.Specific AimsOur specific aims are to (i) identify climatic drivers of NEP at two contrasting forest sites, (ii) to quantify the impact of the climatic drivers on observed time lags of ecosystem responses, and (iii) to assess the underlying physiological mechanisms explaining such time lags and therefore flux partitioning. Experimental Design and Analysing ConceptIn order to address these aims, we plan:- to measure microclimate profiles, eddy covariance net ecosystem CO2 and H2Ovapor exchange, continuous stem radius changes, and [CO2] in tree stems at two Swiss Fluxnet sites Davos and Lägeren. - to analyse statistical patterns of historic time series which quantify the time-dependent weight of climatic drivers on ecosystem responses.- to compare the results of two forest types from the Swiss Fluxnet sites Davos and Lägeren.- to test the applicability of physiological concepts to explain the observed time lags and thus flux partitioning of CO2 and H2Ovapor fluxes at the ecosystem level.Our long-term forest ecosystem research sites (Davos since 1997; Lägeren since 2005) are predestined locations to address topics that depend on temporally and spatially highly resolved field data at different integration levels with long-term records. Expected Value of the Project ProposedOur project will contribute to fill the gaps in our knowledge of how tree physiological processes (particularly growth and tree water relations) are linked to ecosystem-level gas exchange (investigated by eddy covariance) and their respective dependencies on climatic drivers. Such mechanistic understanding is urgently needed to advance climate impact science and to decrease uncertainties in current vegetation-climate models. Since understanding the role of ecosystems in global climate change is currently a hot topic in science and for society concerned about climate change, we expect to provide relevant information to national administrations and to satisfy their demand for more precise, country-wide forest ecosystem carbon budgets.
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