Initial Publication Date: October 23, 2017 | Reviewed: March 13, 2019

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Educator Guide: Lab 3 - Tree Rings and the Ancestral People of Pueblo Bonito: Uncovering the Past

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Summary and Learning Objectives

In Lab 3, students take a journey to the desert in the U.S. Southwest and examine and interpret data to tell the story of the ancestral peope at Pueblo Bonito: When did they live in the region? What were the environmental conditions like in the region in the past? Why did they leave their homes in the 13th century?

They learn about how scientists work in the field and search for clues to determine what the climate was like in this region in the past. Then, students evaluate the ring patterns of a sample of wood collected from the site to determine the exact date the tree was cut to construct the pueblo. Then students explore how tree rings can be used to determine periods of drought in the past. To complete the lab, they investigate a long-term data set produced by tree-ring records as a proxy to identify the existence of drought and megadroughts that may have affected the people of Pueblo Bonito.

Note: Please download the Student Activity Sheet (pdf or Word version) found in the Printable Materials section of this document if you wish to have students respond to Stop and Think questions as they go through the lab.

Learning Objectives

After completing this lab, students will be able to:

  • explain how scientists assign exact calendar dates to tree-ring samples and to a historic archeological structure such as Pueblo Bonito.
  • Construct a "skeleton plot" and measure and graph tree-ring data.
  • describe how "proxy" data such as measurements of annual growth rings in trees reveal the nature, scale, and duration of extreme and extended droughts.
  • explain the history behind the origin of the science of dendrochronology.



  • Activity Overview and Teaching Materials

    Detailed overview of what students will do in each part of the lab and how long it will take.

    Printable Materials

    Downloadable and printable files needed for each part of the lab, including student handouts and answer keys.

    Teaching Notes and Tips

    What you need to prepare ahead of time, and general recommendations for classroom implementation.

    References and Additional Resources