Part 1: Explore the Pueblo Bonito Site

In Part 1, students go on a virtual expedition to Pueblo Bonito. They explore the site and the surrounding countryside using Google Maps.

Part 2: Use a Skeleton Plot to Discover the Age of a Pit House

In part 2, students will use a qualitative methodology and create a "skeleton plot" from a scanned image of an original tree-ring sample collected at Pueblo Bonito in the 1920s. Then they use their plot to figure out the year the tree was cut to build the site.

Part 3: Measuring Ring Width to Determine the Paleoclimate of Pueblo Bonito

In part 3, students measure the rings to produce a time-series graph of a tree-ring sample. Then they combine their measurements with those of their classmates to produce a preliminary tree-ring record.

Part 4: Megadroughts and the People of Pueblo Bonito

In Part 4, students investigate a millennial-length tree-ring reconstruction to identify the existence of droughts and megadroughts that may have affected the people of Pueblo Bonito and the surrounding region.

• Lab 3 Student Activity Sheet Activity Sheet - (PDF (Acrobat (PDF) 127kB Mar14 19))(Word (Microsoft Word 2007 (.docx) 64kB Mar14 19));
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• Part 3 Data Table - here (Text File 2kB Sep20 16)
• Part 3 Sample graph of mpb31 data here
• Sample graphs and Teacher Notes for Part 3 - PDF (Acrobat (PDF) 501kB Jun2 16)

Tree Rings and the Ancestral People of Pueblo Bonito: Uncovering the Past

General Recommendations:


• To add a hands-on component, consider purchasing a core apparatus (about $240) Forestry Suppliers. Visit The Ultimate Tree-Ring Webpages for tips, advice on cleaning kits for your core apparatus, and more information.
• Have ImageJ downloaded on all student computers or give them the link to download it themselves.
• If you would like students to learn the rudiments of ImageJ on an individual basis have them go through the ImageJ Beginner's Tutorial.
• Students need to access Excel or similar graphing software in Part 3. Or, you can assemble the individual student results and create a class graph yourself.
Facilitation Tips:

Part 1 - Explore the Pueblo Bonito Site


• Begin the lab by projecting an image of Pueblo Bonito and asking students to make observations about the structure and function of the various shaped rooms in the ruin.
• Discuss the first set of Stop and Think questions with students. Ask them to imagine how a family of four would live in a room the size of an average pit house in Pueblo Bonito.
• If you want to show more details of what a pit house interior might look like, show the diagrams shown here.
Part 2 - Use a Skeleton Plot to Discover the Age of a Pueblo Ruin


• If you would like to review a tutorial on skeleton plots, see Making Skeleton Plots.
• Go through the skeleton plot example given in the student text.
• Have students answer the Stop and Think questions and discuss them as a class.
Part 3 - Measuring Tree Ring Width to Determine the Paleoclimate of Pueblo Bonito


• If you are not familiar with measuring on images with ImageJ, review the ImageJ tutorial found here.
• Decide how you want to divide the dataset and the number of decades of tree ring data that your students will measure using ImageJ. You can have students select their own interval of rings or you can assign them an interval. Keep in mind that either the students or you will need to assemble all the parts of the data and create a graph for the class to analyze and discuss.
• Bring up the image and go through how to set scale and take a sample measurement if possible.
• See sample student table and graph in the Printable Materials section.
Part 4 - Megadroughts and the People of Pueblo Bonito


• Instead of having students read the Ed Cook article online in the first section of the activity, assign it for homework.

• Bannister, Bryant , 1993, Andrew Ellicott Douglass: A Detective in Science: Transcription of a presentation by Bryant Bannister at the 1993 Partners in Science Conference, Univ. of Arizona, unpub., p. 14–20.
• Bannister, Bryant; Hastings, Robert E. Jr.; Banisterm, Jeff, 1998, Remembering A. E. Douglass: Journal of the Southwest, Vol. 40, No. 3, p. 307-318. http://www.jstor.org/stable/40170111
• Creasman, P.P., B. Bannister, R.H. Towner, J.S. Dean, and S.W. Leavitt. 2012. Reflections on the Foundation, Persistence, and Growth of the Laboratory of Tree-Ring Research, circa 1930-1960. Tree-Ring Res. 68(2): 81–89.
• Dean, J. S., & Robinson, W. J. (1978). Expanded tree-ring chronologies for the southwestern United States. Chronology Series III. [Accessed at: http://wwwdev.ltrr.arizona.edu/sites/ltrr.arizona.edu/files/bibliodocs/Dean,%20Jeffrey%20S.,%20Robinson,%20William%20J._Expanded%20Tree%20Ring%20Chronologies%20for%20the%20Southwestern%20United%20States_1978.pdf]
• Douglass, A.E. 1929. The secret of the Southwest solved by talkative tree rings. National Geographic Magazine v. 56, no. 6, p. 736-770. [Link: http://isu.indstate.edu/jspeer/dendro/Douglass1929.pdf ]
• Fagan, Brian, 1999, Floods, famines, and empires: Basic Books, NY, 284 p
• Fritts, H. C., 1976, Tree rings and climate: The Blackburn Press, Caldwell, NJ.
• Grissino-Mayer HD, Baisan CH, Swetnam TW, 1997, A 1,373-year reconstruction of annual precipitation for the southern Rio Grande basin. Fort Bliss, TX: Unpublished Final Report to the Legacy Program, Directorate of Environment, Natural Resources Division.
• Guiterman, C. H.; Swetnam, T. W.; Dean, J. S., 2015, Eleventh-century shift in timber procurement areas for the great houses of Chaco Canyon. Proceedings of the National Academy of Sciences. [Accessed at DOI: 10.1073/pnas.1514272112 ]
• Haury, E. W., 1962, HH-39: Recollections of a Dramatic Moment in Southwestern Archaeology. Tree-Ring Bulletin 24: 3–4. [Link: http://www.treeringsociety.org/TRBTRR/TRBvol24_3-4_11-14.pdf ]
• Kuniholm, P. I., 2001, Dendrochronology and other applications of tree-ring studies on archaeology. In Handbook of Archaeological Sciences, edited by Brothwell, D. R.; Pollard, A.M., pp. 35–46, John Wiley, New York. [Link: http://dendro.cornell.edu/articles/kuniholm2001a.pdf ]
• MacDonald, G. M., et al., 2008, Climate Warming and 21st-Century Drought in Southwestern North America, Eos Trans. AGU, 89(9), 82–82, doi:10.1029/2008EO090003.
• Nash, S.E. 1999. Time, Trees, and Prehistory: Tree-Ring Dating and the Development of North American Archaeology 1914–1950. Salt Lake City: The University of Utah Press.
• Robinson, William J., 1976, Tree-ring dating and archaeology in the American southwest: Tree-ring Bulletin, v. 36, p. 9­–20. [Accessed at http://www.treeringsociety.org/TRBTRR/TRBvol36_9-20.pdf ]
• Robinson, William J., Harrill, Bruce G.; Warren, Richard L., 1974, Tree-Ring Dates from New Mexico B Chaco-Gobernador Area: (tDAR id: 323308) [Accessed on Dec. 28, 2015 at http://hdl.handle.net/10150/220714 ]
• Stahle, D.W.; Dean, 2010, North American tree rings, climatic extremes, and social disasters, IN M.K. Hughes et al. (eds.), Dendroclimatology, Developments in Paleoenvironmental 297, Research 11, DOI 10.1007/978-1-4020-5725-0_10
• Stahle, D.W.; J. R. Edmondson, J. N. Burns, D. K. Stahle, D. J. Burnette, E. Kvamme, Lequesne; Therrell, M. D., 2015, Bridging the Gap With Subfossil Douglas-Fir At Mesa Verde, Colorado: Tree-Ring Research 2015 71:2, 53­–66
• Guiterman CH, Swetnam TW, Dean JS, Eleventh-century shift in timber procurement areas for the great houses of Chaco Canyon, Proc Natl Acad Sci U S A. 2016 Feb 2; 113(5): 1186–1190. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4747737/
• Lab 2, Part 2: The specimen is a juniper cross-section from the kiva in room 162 at Chaco Canyon. It was collected by Neil Judd and A.E. Douglass in 1922. The ring at 954 AD is missing. Image provided by Dr. Pearce Paul Creasman.
• Chaco Research Archive, Tree-Ring Resources: http://www.chacoarchive.org/cra/chaco-resources/tree-ring-database/
• How Archaeologists Uncover History With Trees: https://www.sapiens.org/column/curiosities/tree-ring-dating-mesa-verde/