Changemaker
Allyson Carroll
TL;DR
Allyson Carroll reads redwood tree rings as a historical record, dating everything from a tree’s growth to the fires and earthquakes it lived through.
Allyson Carroll is a research associate at Cal Poly Humboldt and a dendrochronologist, meaning a scientist who dates events by reading tree rings. Her university describes her crossdating 1.2 million tree rings for a study of the world’s tallest trees. In 2023 she received a grant from the United States Geological Survey to use redwood tree rings to date earthquakes on the northern San Andreas Fault, working to pin down the year of the large event that came before the 1906 earthquake, with collaborators including Stephen Sillett and Marie Antoine. Giants Rising describes her as studying redwood tree rings to determine tree age, growth patterns, and past climate and fire events.
Allyson Carroll is a dendrochronologist at Cal Poly Humboldt who reads redwood tree rings to date tree age, growth, fires and earthquakes.
Why OGSP Recommends It
Allyson Carroll pulls physical history out of wood. She works as a dendrochronologist and Research Associate in the Department of Forestry, Fire and Rangeland Management at Cal Poly Humboldt in Arcata. She reads redwood tree rings to establish tree age and track past forest fires. She also uses this exact method to locate historical earthquakes.
For one Cal Poly Humboldt study on the tallest redwoods, she crossdated 1.2 million individual tree rings.
Her current United States Geological Survey grant treats these trees as biological seismographs. She's hunting for the exact year a large earthquake struck the northern San Andreas Fault prior to 1906. Pinning down that specific date will directly improve earthquake recurrence models for the region.
She works alongside Stephen Sillett and Marie Antoine, connecting her with the other researchers featured in Giants Rising.
Related Resources
Key Takeaways
- She crossdated 1.2 million tree rings for a Cal Poly Humboldt study of the tallest trees.
- Her United States Geological Survey grant uses redwood rings to date earthquakes on the northern San Andreas Fault.
- That work aims to pin down the year of a large earthquake that happened before 1906, which would improve earthquake recurrence models for the region.
- She works with Stephen Sillett and Marie Antoine, who also appear in Giants Rising.
Frequently Asked Questions
What is dendrochronology?
It is the science of dating events by reading tree rings. Allyson Carroll is described by her own university as a dendrochronologist.
What does Allyson Carroll study?
Redwood tree rings, using them to establish tree age and growth patterns and to date past climate events, fires and earthquakes.
What is her earthquake research?
A United States Geological Survey funded project using redwood tree rings to date earthquakes on the northern San Andreas Fault, including the large event that occurred before the 1906 earthquake.
Where does Allyson Carroll work?
Cal Poly Humboldt, in the Department of Forestry, Fire and Rangeland Management, as a research associate.