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Dr. Estelle Arbelay

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Dr. Estelle Arbelay

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Postdoc

Dr. Estelle Arbelay

Multi-proxy tree-ring analysis of conifer trees disturbed by insect outbreaks

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Ph.D., Earth Sciences, University of Berne, Switzerland (2012)
M.Sc., Geography, University of Fribourg, Switzerland (2008)
B.Sc., Geography, University of Fribourg, Switzerland (2006)

 

As a dendroecologist I study tree rings to understand the influence of forest disturbances on tree physiology and forest dynamics. Through historical reconstructions based on tree rings I have investigated the impacts of debris flows and snow avalanches on deciduous forests of Europe. I am currently investigating the impacts of wildfires and insect outbreaks on coniferous forests of western North America, including the highly disturbed forests of Interior BC. My research aims to assist forest management and forest conservation. Follow me on ResearchGate.

 

PostDoc Research

 

Multi-proxy tree-ring analysis of conifer trees disturbed by insect outbreaks

Insect outbreaks are a major disturbance influencing forest dynamics in many ecosystems and affecting forest productivity worldwide. Reconstruction of insect outbreak histories is fundamental to forest management. While the action of cambium feeders on trees leads to the formation of scars, that of defoliators reduces tree growth. The occurrence of past insect attacks can thus be inferred from such tree-ring signatures. However, it necessitates an accurate dating of events, with high temporal resolution, as well as their attribution to the correct disturbance agent. Insect scars and fire scars are difficult to distinguish. Furthermore, tree growth reduction following insect defoliation is manifested in ring width with a lag of one or more years. This project tackles these issues directly by using a multi-proxy approach that includes measurements of ring width, wood density, wood anatomy and wood chemistry in order to improve reconstruction of past insect outbreaks. Two conifer trees from British Columbia and their respective pests are within the scope of this project: the mountain pine beetle (Dendroctonus ponderosae), a cambium feeder that injures lodgepole pine (Pinus contorta), and the western spruce budworm (Choristoneura occidentalis), a defoliator that ravages Douglas-fir (Pseudotsuga menziesii). The next phase of this research also integrates the larch budmoth (Zeiraphera diniana), a defoliator that ravages European larch (Larix decidua) in Switzerland and Europe. It is hypothesized that insect attack on conifer trees results in significant differences between normal wood formed prior and wound wood formed after the attack. Preliminary results are promising and have shown that variations of tree-ring proxies over time might contribute to differentiating insect scars and fire scars, and increasing detection of defoliation events. In addition to guiding forest management, the upcoming results of this project will provide fundamental insights into the physiological response of conifer trees to insect attack. This information is needed to counter recent, severe outbreaks of cambium feeders and defoliators observed around the world, which threaten forest resilience to global warming.

 

 

SELECTED PUBLICATIONS

Arbellay E, Daniels LD, Mansfield SD, Chang AS. (in prep). Cambial injury in lodgepole pine (Pinus contorta): mountain pine beetle vs. fire.

Arbellay E, Daniels LD, Chavardès RD, Jarvis I. (in prep). Dating of western spruce budworm defoliation events in Pseudotsuga menziesii with latewood chronologies and blue intensity.

Arbellay E, Daniels LD, Chavardès RD, Jarvis I, Stoffel M. (in prep). Dating of larch bud moth defoliation events in Larix decidua with latewood chronologies and blue intensity.

Arbellay E. 2016. Tree rings and insect outbreaks. Branchlines 27: 19.

Arbellay E. 2013. Trees as historians of past insect outbreaks. Branchlines 24: 10–11.

 

CONFERENCE ABSTRACTS

Arbellay E, Daniels LD, Chavardès RD, Jarvis I. 2016. Toward more precise tree-ring estimates of forest defoliator outbreaks: western spruce budworm and larch bud moth. NAFIWC 2016, 6th North American Forest Insect Work Conference, Washington DC, USA.

 

Arbellay E, Daniels LD, Mansfield SD, Chang AS. 2016. Toward more precise tree-ring estimates of mountain pine beetle outbreaks. NAFIWC 2016, 6th North American Forest Insect Work Conference, Washington DC, USA.

 

Arbellay E, Daniels LD, Mansfield SD, Chang AS. 2016. Mountain pine beetle scars vs. fire scars in lodgepole pine (Pinus contorta). AmeriDendro 2016, 3rd American Conference on Dendrochronology, Mendoza, Argentina.

 

Arbellay E, Daniels LD, Mansfield SD, Chang AS. 2014. Comparing wood traits between normal and wound wood in lodgepole pine: effects of mountain pine beetle and fire scarring. FIBRE 2014, 2nd Canadian Conference on Forest Innovation by Research & Education, Vancouver, Canada.

 

Arbellay E, Daniels LD. 2014. Differentiating between mountain pine beetle scars and fire scars in lodgepole pine. WorldDendro 2014, 9th International Conference on Dendrochronology, Melbourne, Australia.