Tree Story: What we can learn about climate and forest history from the rings in trees | 9am PT March 11, 2025

[Grigory Bronevetsky]

Modeling Talks

Tree Story: What we can learn about climate and forest history from the rings in trees Valerie Trouet, University of Arizona Tues, March 11, 2025 | 9am PT Meet | Youtube Stream Hi all, The presentation will be via Meet and all questions will be addressed there. If you cannot attend live, the event will be recorded and can be found afterward at https://sites.google.com/modelingtalks.org/entry/tree-story-what-we-can-learn-about-climate-and-forest-history More information on previous and future talks: https://sites.google.com/modelingtalks.org/entry/home Abstract: Dendrochronology - the study of the rings in trees - allows us to reconstruct climate variability over the past ca. 2,000 years and to put current anthropogenic climate change in a long-term context. We can use tree rings to study past mean climate, but also climate extremes - such as drought, hurricanes, and wildfires - and climate dynamical patterns, such as the jet stream. In addition to this, dendrochronology sits at the nexus of climatology, ecology, and archeology and helps us to link climate history to forest history and human history. In my talk, I will present two tree-ring based studies aimed at providing long-term records of (1) jet stream variability and (2) California wildfires. I will show how our century-long proxy records have improved our understanding of the interactions between the climate system, human systems, and ecosystems.   Bio:  Valerie Trouet is a professor in the Laboratory of Tree-Ring Research at the University of Arizona and has recently served as the founding scientific director of the Belgian Climate Centre. She received her PhD in Bioscience Engineering at the KULeuven in Belgium in 2004 and has previously worked at PennState University and at the Swiss Federal Research Institute WSL. She is a paleoclimatologist who uses the rings in trees to study climate change over the past ~2,000 years and how it has impacted human systems and ecosystems. She has published more than 100 scientific publications and is the author of Tree Story (Johns Hopkins University Press, 2020), a broad audience book about dendrochronology that has been translated in seven languages. Her research has been covered by the New York Times, The Washington Post, and NPR’s Science Friday and RadioLab, amongst others. She is a Kavli Fellow of the National Academy of Sciences, a University of Arizona Distinguished Scholar, and she received an honorary doctorate (2023) from Wageningen University in The Netherlands.

[Grigory Bronevetsky]

Video Recording: https://youtube.com/live/etVUy_tjUYw

Slides: https://drive.google.com/file/d/1FxEDs0Qd8vvTVZs4y5Isw2EQ2a9JJpoD/view?usp=sharing

Summary:

• Introduction to Tree Ring Research (Dendrochronology):

  • The annual nature of tree rings and their precise dating capabilities.

  • Advantages of tree rings over other climate archives like ice cores (broader geographical distribution, land-based data).

  • How tree ring width reflects past growing conditions (temperature, precipitation).

• Climate History and Paleo Climatology:

  • Using tree rings to reconstruct past temperature and precipitation patterns.

  • The importance of understanding past climate variability to contextualize current climate change.

  • Discussion of ice core data as a baseline for understanding long term CO2 and temperature trends.

  • The ice core data shows the unprecedented rise of CO2 in the modern era.

• Applications of Tree Ring Data:

  • Archaeology and History: Using tree rings to date historical artifacts and understand past human events.

  • Climate Reconstruction: Reconstructing past climate patterns, such as drought cycles, snowpack levels, and jet stream behavior.

  • Fire Ecology: Analyzing fire scars on trees to reconstruct past fire regimes and understand the impact of fire suppression.

  • Jet Stream Dynamics: Reconstructing the past behavior of the jet stream in Europe and its impact on regional climate.

• The Jet Stream and Historical Events:

  • The correlation between jet stream patterns, reconstructed from tree rings, and historical events like grape harvests, wildfires, and plague outbreaks.

  • This shows the strong link between climate variation, and human history.

• Issues Raised:

  • Anthropogenic Climate Change: The video highlights the unprecedented rise in atmospheric CO2 levels and the resulting temperature increases, emphasizing the need to understand past climate variability to address current challenges.

  • The Importance of Long-Term Climate Data: The video stresses the value of long-term climate records, such as tree rings and ice cores, in providing context for current climate trends.

  • The Relationship Between Climate and Human History: The discussion of the jet stream and historical events underscores the strong influence of climate on human societies.

  • The impact of modern fire supression on forest health.

• Questions Raised (Implied or Explicit):

  • Why is it important to study past climates?

  • How do tree rings provide information about past climate conditions?

  • What are the advantages of using tree rings over other climate archives?

  • How can tree ring data be used to reconstruct past climate patterns and environmental events?