Tree-Ring Research

Southwest Fire:

Fire-Scarred Trees
scar close up

Close up of fire scars recorded in tree growth. Photo by Tom Swetnam

fire-scarred trees

Ponderosa pine showing many fire-scars in a large catface. Photo by Henri Grissino-Mayer.

  • These fire scars are dated to the exact years of the fires that made them by a process called crossdating:
    • Matching patterns of wide versus narrow rings across many tree samples
    • Often done by skeleton plotting the ring growth onto graph paper
cross-section with dated scars

Cross section showing many fire-scars (white arrows). Photo by Chris Baisan.

example crossdating

Example crossdating of sample graph (top) with master graph (bottom). Image by Paul Sheppard.

Bandelier site

Example fire graph for Bandelier National Monument, New Mexico. Image by Tom Swetnam.

Laboratory of Tree-Ring Research, University of Arizona
Tucson, Arizona 85721 USA
Main Office: (520) 621-1608, Fax: (520) 621-8229
Comments to Paul Sheppard: sheppard @