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| Titel |
Key mechanisms of metabolic changes in mountain pine and larch under drought in the Swiss National Park |
| VerfasserIn |
Olga Churakova, Christof Bigler, Marina Bryukhanova, Rolf Siegwolf |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250095201
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| Publikation (Nr.) |
 EGU/EGU2014-10652.pdf |
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| Zusammenfassung |
| Forests are of great ecological, economic and social importance worldwide. In many regions
they have been recently affected by water deficits during summer droughts due to increasing
temperatures and shortage of precipitation (Allen et al. 2010). Climate models predict that
drought frequency will continue to increase during the 21st century and beyond (CH
2011).
Since the foundation of the Swiss National Park (SNP) in 1914 these forests have not been
managed any more, which allows to study natural processes in these forest ecosystems. Since
the 1990s, annual and spring temperatures increased in the SNP up to 0.5 ºC and 1.02 ºC,
respectively, and average summer temperature increased up to 0.6 ºC. Annual precipitation
decreased by 81 mm compared to the mean values (927 mm) from 1917 to 1989. Therefore,
detailed studies of drought effects on the physiological functioning of trees over the last
decades are needed.
Recently, mortality processes of mountain pines were observed in the Swiss National Park
(Bigler, Rigling 2013). It is of great interest to investigate and compare the physiological
responses of mountain pine and larch to drought and to understand the mechanisms behind
the mortality processes. The goal of our study is to investigate the key mechanisms of tree
physiological responses to drought in the SNP using state-of-the-art methods of classical
dendrochronology, tree physiology, stable isotope, and compound-specific isotope
analyses.
Long-term responses of mountain pine and larch trees from north- and south-facing sites to
drought will be inferred from tree-ring width data. Based on climatic data a drought index
will be calculated and reconstructed back in time. New chronologies for stable carbon and
oxygen isotope ratios derived from both pine and larch tree-ring cellulose will provide
retrospective insight into the long-term whole-plant physiological control of gas exchange
derived from estimates of stomatal conductance, photosynthetic rate and intrinsic water use
efficiency. Carbon isotopes ratios of specific sugar compounds such as sucrose, raffinose,
fructose, ribose and pinitol in needle and wood samples will help to evaluate the impact of
drought on the carbohydrate balance and carbon allocation. Analyzing the oxygen isotopic
compositions of soil water, sap water (water in branches) and precipitation we will
determine the role of the different water sources for tree growth under drought
conditions.
The proposed work will provide a unique opportunity to assess the survival potential of
mountain pine and larch trees exposed to drought that will help to estimate risks of modern
climatic changes and forest damage.
This project was supported by Marie Heim-Vögtlin Programme PMPDP2_145507/1 granted
to Olga Churakova (Sidorova).
References:
Allen CD et al. (2010) A global overview of drought and heat-induced tree mortality
reveals
emerging climate change risks for forests Forest Ecology and Management 259:660-684
Bigler C, Rigling A (2013) Precision and accuracy of tree-ring-based death dates of
mountain pines in the Swiss National Park. Trees - Structure and Function. 27:
1703-1712
CH 2011 Swiss Climate Change Scenarios CH2011. In. C2SM, MeteoSwiss, ETH, NCCR
Climate, and OcCC, p 88 |
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