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Tree growth-rings as early indicators of volcanic activity on Mt. Etna

English title Tree growth-rings as early indicators of volcanic activity on Mt. Etna
Applicant Cherubini Paolo
Number 143479
Funding scheme Project funding (Div. I-III)
Research institution Swiss Federal Research Inst. WSL Direktion
Institution of higher education Swiss Federal Institute for Forest, Snow and Landscape Research - WSL
Main discipline Other disciplines of Environmental Sciences
Start/End 01.04.2013 - 30.09.2016
Approved amount 254'039.00
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All Disciplines (3)

Discipline
Other disciplines of Environmental Sciences
Geochronology
Geophysics

Keywords (5)

Jahrringe / Baumringe; Radiokarbon; Vulkanausbrüche; Stabile Isotope; Ökophysiologie

Lay Summary (German)

Lead
Jahrringe als frühe Anzeichen von Eruptionen am Ätna.
Lay summary

Vulkane bedrohen das Leben von Millionen von Menschen. Frühe Anzeichen von Eruptionen könnten dazu beitragen, einen besseren Umgang mit der Gefahr zu finden. Bislang bleiben Vulkanausbrüche aber weitgehend unverhersehbar.

Neue Indikatoren für Ausbrüche werden dringend benötigt. Zudem wäre es bei vielen Vulkanen interessant, vergangene Aktivitäten zu rekonstruieren.

Vor kurzem konnten anhand von Satellitenbildern, sowohl am Mt. Ätna (Italien), als auch am Mt. Nyiragono (Kongo) erhöhte Photosynteseraten an genau den Stellen beobachtet werden, an welchen drei bis vier Jahre später Flankeneruptionen auftraten.

Die Zusammenhänge zwischen erhöhter Photosynthese und künftigen Eruptionen sind zur Zeit noch unklar; eine Hypothese ist, dass über das Magma Gase im Untergrund in die Böden gelangen, welche das Pflanzenwachstum fördern.

Erste Baumringanalysen vom Mt. Ätna zeigen, dass Bäume durch vulkanische Aktivität vor dem Ausbruch beeinflusst werden und daher 1) als frühe Indikatoren für Eruptionen, und 2) zur Rekonstruktion vergangener Ausbrüche verwendet werden könnten.

 

Unsere wichtigsten Forschungsfragen sind daher:

-        Können Bäume als Indikatoren für vergangene- und bevorstehende Vulkanausbrüche verwendet werden?

 

-        Welche natürlichen Faktoren beeinflussen das Baumringwachstum in vulkanischen Gebieten in welchem Ausmass?

 

-        Wie stark veränderten sich diese Faktoren während der letzten 100 bis 150 Jahre, und welchen Einfluss hatten diese Veränderungen auf das Wachstum der Jahrringe der Bäume?

Erste Resultate einer Pilotstudie am Mt. Ätna (Sizilien, Italien) haben ergeben, dass Bäume (nicht alle Bäume und nicht an allen Standorten) einige Jahre vor Vulkanausbrüchen ein erhöhtes Wachstum aufweisen.

Diese Studie lieferte erste Resultate über das Jahrring-Wachstum, ∂13C, ∂18O und 14C in den Bäumen; und erste Versuche, diese Resultate mit den Zeitreihen der Vulkanausbrüche und den Daten von drei gebietsnahen Wetterstationen zu korrelieren, wurden unternommen.

In unserem Forschungsdesign sind Beprobungen entlang von 6-12 Höhentranssekten in der Nähe jüngerer Eruptionsstellen geplant (Vegetation: pinus nigra). Zusätzlich sollen nahegelegene Standorte ohne vulkanische Aktivität (Monte Nebrodi) als Kontrollstandorte dienen.

Die Untersuchungen zielen auf die verschiedenen Faktoren ab, welche das erhöhte Baumwachstum verursachen könnten: a) Wasserverfügbarkeit, b) Nährstoffe, c) Ausgasen von Kohlendioxid (CO2) oder Ammonium (NH4) und d) das Klima (Temperatur und Niederschlag).

Jeder dieser Faktoren hat einen anderen Einfluss auf die physiologischen Prozesse und die Photosynthese der Bäume. Erste Resultate haben bereits gezeigt, dass unter mediterranen Bedingungen um den Ätna zwischen Klima und Baumwachstum nur eine schwache Korrelation besteht, und dass andere Faktoren (Grundwasser, Nährstoffe etc.) von grösserer Bedeutung sein müssen. Aus diesem Grund werden die folgenden Untersuchungen an den Standorten Ätna und Monti Nebrodi durchgeführt: i) Jahrringanalyse (Mächtigkeit der Ringe) mit jährlicher Auflösung, ii)  14N/15N und 12C/13C Isotopenanalyse und REE (rare earth elements) der Jahrringe, iii) 14C Analyse der Jahrringe (falls Bäume CO2 aus vulkanischem Gas aufnehmen, sollte dies in den Jahrringen über die 14C-Resultate (14C tot) ersichtlich sein), iv) ∂18O Analysen der Jahrringe, um unterschiedliche Wasserquellen (Niederschlagswasser oder Grundwasser, und Wasser von ausgasendem Magma) festzustellen.  ∂13C und ∂18O können Einflüsse im Zusammenhang mit Wasser von anderen Umwelteinflüssen separieren; da ∂18O von im Wasserkreislauf ablaufenden Prozessen stärker beeinflusst wird als unter biochemischen Veränderungen., v) Korrelationen von Klimadaten (Lufttemperatur und Niederschlag) mit Jahrring-Wachstum, vi) Bodentemperatur, und vii) ∂13C und pMC  von organischen Bodenfraktionen (, um kurzzeitliche Einflüsse von Umweltveränderungen festzustellen, nämlich die Aufnahme von organischem Material unter veränderten ∂13C- und 14C Bedingungen) und REE –Gehalt in den Böden.

 

Die Resultate sollen dazu beitragen, den Vulkanausbrüchen vorausgehende Prozesse besser zu verstehen, und die Reaktion des Ökosystems auf diese Prozesse darzulegen.

Sollte es tatsächlich möglich sein zu zeigen, dass Bäume als Indikatoren für  Vulkanausbrüche verwendet werden können, hätte diese Entdeckung eine grosse Bedeutung für die Gefahrenbeurteilung und das Gefahrenmanagement.

Direct link to Lay Summary Last update: 10.04.2013

Lay Summary (English)

Lead
Tree growth-rings as early indicators of volcanic activity on Mt. Etna
Lay summary

Volcanoes threaten the lives of millions of people. Early indicators of volcanic explosions could help in risk management, but eruptions remain largely unpredictable. New indicators of eruptions are urgently needed. Moreover, it would be of great interest to reconstruct past volcanic activity at many volcanoes. Recently, remote sensing techniques have revealed increased photosynthetic rates in trees growing along future eruptive fractures on Mt. Etna, Italy, and on Mt. Nyiragongo, Congo; flank eruptions occurred 3-4 years later along these same fractures. The mechanisms linking photosynthetic activity to future eruptions are currently unclear; one hypothesis is that movement of magma in the deep conduits of the volcanic system leads to degassing of substances that promote plant growth. Preliminary tree ring data from Mt. Etna suggest that trees are influenced by volcanic activity before the magma erupts, and therefore might be used 1) as early indicators of eruptions, and 2) to reconstruct past volcanic eruptions.

Our main research questions are therefore:

-        Can trees be used as indicators of past and future eruptions?

-        Which natural factors control tree-ring growth to which extent on a volcanic area?

-        How did these factors vary over the last 100 to 150 years and how did they influence tree ring growth?

Preliminary results from a pilot study on Mt. Etna (Sicily, Italy) show that trees (but not all trees and not at all locations) are growing faster several years before eruptions. The pilot study created preliminary data on tree-ring growth as well as ∂13C, ∂18O and 14C in tree rings, and first attempts could be made to correlate these parameters to time series of volcanic eruptions and climate data from three nearby weather stations. The planned experimental design foresees 6-12 elevation transects (within the black pine, Pinus nigra, vegetation belt) in the vicinity of recent eruptions. In addition, nearby area without any (direct) volcanic activities (Monti Nebrodi) will serve as a control site. We aim at investigating the several factors that may contribute to increased growth rates: a) availability of water, b) nutrients and trace elements in the wood and in the soil, c) degassing of carbon dioxide (CO2) or ammonia (NH4), and d) climate (temperature and precipitation). Each of these factors has a different impact on tree physiological processes and photosynthesis. First results show that climate is poorly correlated with tree growth in the Mediterranean climate of Mt. Etna, and that other factors are likely to be more important (such as groundwater, nutrients etc.). Therefore, the following analyses will be carried out (Both at Monti Nebrodi mountains and Mt. Etna): i) tree-ring analyses (ringwidth) with annual resolution, ii) 14N/15N and 12C/13C isotope analyses and REE (rare earth elements) of the tree rings, iii) 14C analyses of the tree rings (if trees take up CO2 from the volcanic gas, this CO2 will be 14C dead and incorporated in the tree), iv) ∂18O analyses of the tree rings, to detect different water sources (rain water or groundwater vs water from degassing magma; combining ∂13C with ∂18O will help to separate water-related from other environmental influences as ∂18O is more influenced by processes in the water-cycle than by biochemical changes), v) correlation of climatic data (air temperature and precipitation) with tree ring width, vi) soil temperature, and vii) ∂13C and pMC of soil organic matter fractions (to detect short-term impacts of environmental changes; i.e. incorporation of organic material with a changed ∂13C and 14C content) and REE contents in soils.

Our results will help in understanding precursory processes behind volcanic eruptions and ecosystem responses to them.  Furthermore, if one can demonstrate that trees are early indicators of volcanic eruptions, this discovery will have a tremendous impact in risk assessment and management.

Direct link to Lay Summary Last update: 10.04.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Insensitivity of tree-ring growth to temperature and precipitation sharpens the puzzle of enhanced pre-eruption NDVI on Mt. Etna (Italy).
Seiler R Kirchner JW Krusic PJ Tognetti R Houlié N Andronico D Cullotta S Egli M et al. (2017), Insensitivity of tree-ring growth to temperature and precipitation sharpens the puzzle of enhanced pre-eruption NDVI on Mt. Etna (Italy)., in PLoS ONE, 12(1), 1-27.

Collaboration

Group / person Country
Types of collaboration
Università del Molise Italy (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel
WSL Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
Università di Palermo Italy (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
INGV Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania Italy (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Lamont-Doherty Earth Observatory, Columbia University United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Abstract

Volcanoes threaten the lives of millions of people. Early indicators of volcanic explosions could help in risk management, but eruptions remain largely unpredictable. New indicators of eruptions are urgently needed. Moreover, it would be of great interest to reconstruct past volcanic activity at many volcanoes. Recently, remote sensing techniques have revealed increased photosynthetic rates in trees growing along future eruptive fractures on Mt. Etna, Italy, and on Mt. Nyiragongo, Congo; flank eruptions occurred 3-4 years later along these same fractures. The mechanisms linking photosynthetic activity to future eruptions are currently unclear; one hypothesis is that movement of magma in the deep conduits of the volcanic system leads to degassing of substances that promote plant growth. Preliminary tree ring data from Mt. Etna suggest that trees are influenced by volcanic activity before the magma erupts, and therefore might be used 1) as early indicators of eruptions, and 2) to reconstruct past volcanic eruptions.Our main research questions are therefore: -Can trees be used as indicators of past and future eruptions? -Which natural factors control tree-ring growth to which extent on a volcanic area? -How did these factors vary over the last 100 to 150 years and how did they influence tree ring growth?Preliminary results from a pilot study on Mt. Etna (Sicily, Italy) show that trees (but not all trees and not at all locations) are growing faster several years before eruptions. The pilot study created preliminary data on tree-ring growth as well as ?13C, ?18O and 14C in tree rings, and first attempts could be made to correlate these parameters to time series of volcanic eruptions and climate data from three nearby weather stations. The planned experimental design foresees 6-12 elevation transects (within the black pine, Pinus nigra, vegetation belt) in the vicinity of recent eruptions. In addition, nearby area without any (direct) volcanic activities (Monti Nebrodi) will serve as a control site. We aim at investigating the several factors that may contribute to increased growth rates: a) availability of water, b) nutrients and trace elements in the wood and in the soil, c) degassing of carbon dioxide (CO2) or ammonia (NH4), and d) climate (temperature and precipitation). Each of these factors has a different impact on tree physiological processes and photosynthesis. First results show that climate is poorly correlated with tree growth in the Mediterranean climate of Mt. Etna, and that other factors are likely to be more important (such as groundwater, nutrients etc.). Therefore, the following analyses will be carried out (Both at Monti Nebrodi mountains and Mt. Etna): i) tree-ring analyses (ringwidth) with annual resolution, ii) 14N/15N and 12C/13C isotope analyses and REE (rare earth elements) of the tree rings, iii) 14C analyses of the tree rings (if trees take up CO2 from the volcanic gas, this CO2 will be 14C dead and incorporated in the tree), iv) ?18O analyses of the tree rings, to detect different water sources (rain water or groundwater vs water from degassing magma; combining ?13C with ?18O will help to separate water-related from other environmental influences as ?18O is more influenced by processes in the water-cycle than by biochemical changes), v) correlation of climatic data (air temperature and precipitation) with tree ring width, vi) soil temperature, and vii) ?13C and pMC of soil organic matter fractions (to detect short-term impacts of environmental changes; i.e. incorporation of organic material with a changed ?13C and 14C content) and REE contents in soils.Our results will help in understanding precursory processes behind volcanic eruptions and ecosystem responses to them. Furthermore, if one can demonstrate that trees are early indicators of volcanic eruptions, this discovery will have a tremendous impact in risk assessment and management.
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