In this episode of The Children’s Hour, we explore how scientists study tree rings to uncover the secrets of the past. The Kids Crew talks with Dr. Peter M. Brown, a dendrochronologist, about how trees record history in their rings—from floods and droughts to wildfires and climate change. We also learn about the oldest living trees, petrified forests, and how tree science helps archaeologists date ancient ruins. This episode includes a free learning guide to keep the discoveries going.

This episode comes with a free Learning Guide.

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Dr. Brown explains how trees grow a new ring every year. Wide rings mean the tree had plenty of water and sunshine, while narrow rings show times of stress, such as drought. The Kids Crew learns how scientists use an instrument called an increment borer to take small samples of trees without cutting them down. This lets researchers gather tree histories that go back hundreds or even thousands of years.

Some trees are older than others, yet do not look as old as they really are. Bristlecone pines are the oldest trees on record, dating back more than 5000 years. But in another episode of The Children’s Hour called Forests, we learn that some seemingly small creasote “bushes” are actually more than 10,000 year old trees. 

We find out how tree rings can be matched, or “cross-dated,” to figure out the exact year an old beam in an ancient building was cut down. This process has helped archaeologists date villages and ruins across the Southwest and around the world. Tree rings also reveal the impacts of climate change today, showing how warmer summers and changing rainfall patterns are affecting forests everywhere.

The show takes us on a journey to meet some of the oldest trees on Earth. Methuselah, a bristlecone pine in California’s White Mountains, is nearly 5,000 years old. Dr. Brown tells us about giant sequoias, which grow wider than a classroom, and how they can live for thousands of years. We also hear about petrified wood—ancient trees turned to stone—that still keep their tree rings after millions of years. Even fossil wood can show evidence of forest fires and climate conditions long before people existed.

The show takes us on a journey to meet some of the oldest trees on Earth. Methuselah, a bristlecone pine in California’s White Mountains, is nearly 5,000 years old. Dr. Brown tells us about giant sequoias, which grow wider than a classroom, and how they can live for thousands of years.

We also hear about petrified wood—ancient trees turned to stone—that still keep their tree rings after millions of years. Even fossil wood can show evidence of forest fires and climate conditions long before people existed.

We also learn about aspen groves, which grow from one mother root system. Some scientists think these living tree communities could be as old as 80,000 years, making them some of the oldest and largest living organisms on Earth. While their exact ages are debated, their ability to keep spreading and regenerating shows the resilience of trees and forests.

The Kids Crew asks big questions: Can trees live forever? Why do some trees live much longer than others? How do forests change after fires or thinning? Dr. Brown helps us understand that trees are “modular organisms,” always growing new leaves, bark, and roots. Trees often die because of outside forces like insects, drought, or people cutting them down. But their rings remain as a diary of their lives and the environments they lived in.

The Children’s Hour is produced by The Children’s Hour Incorporated, a New Mexico nonprofit organization. This episode was written and produced by Katie Stone, with production help from Christina Stella, Sarah Gabrielli, and Thaniel Lentz. Amber Shiel writes our learning guides.

The Children’s Hour is distributed by Native Voice One, the Native American Radio Network.

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