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Cambridge University Herbarium


The Polar Past

Researchers: Ciara Greaves & Clive Oppenheimer (Department of Geography), Magdalena Opała-Owczarek (University of Silesia) & Alma Piermattei (University of Torino)

As plants grow they are constantly adapting to their environment, so their features (e.g. tissue layers, growth shape, flowering time) can provide a reliable readout for historical environmental conditions. This means we can use herbarium specimens to reconstruct historic climates and track the effects of contemporary climate change on our flora.

Ciara's Greaves' PhD research (funded by a C-CLEAR NERC DTP studentship) focuses on the effects of extreme weather events that have followed large volcanic eruptions. As a proxy for climate conditions, Ciara used ‘blue rings’ - features of tree ring anatomy that form under cooling conditions. The material used in the research includes precisely dated herbarium specimens of Salix and Dryas species collected over the last 200 years as well as modern collections of the same taxa. The research aims to improve our understanding of how extreme weather events have affected global climate, as well as their impacts on human societies.

Greaves, C., Crivellaro, A., Piermattei, A., Krusic, P.J., Oppenheimer, C., Potapov, A., Hordo, M., Metslaid, S., Kask R., Kangur, A., Büntgen, U. (2022). Remarkably high blue ring occurrence in Estonian Scots pines in 1976 reveals wood anatomical evidence of extreme autumnal cooling. Trees.