The Secrets in Tree Rings

WHAT THEY REVEAL ABOUT OUR PAST...AND TELL US ABOUT OUR FUTURE

- Charles C. Hofer

The high desert of northwest New Mexico is a windswept and endless landscape of rolling red hills and dramatic rock formations. These are ancient lands, home to some of the oldest civilizations in North America. For millennia, the Puebloan people thrived in this desert environment. They constructed massive settlements, built from mud and stone and supported by wood gathered from the surrounding mountain forests.

In Chaco Canyon stands the ruins of one of these settlements. Pueblo Bonito was a sprawling building that stood five stories tall and contained more than 600 rooms. At its peak around 1080 CE, Pueblo Bonito may have housed up to 1,000 people in a kind of ancient apartment complex.

For hundreds of years, Pueblo Bonito marked the cultural epicenter of the Desert Southwest. Then, the Puebloans disappeared. By the 14th century, Pueblo Bonito was abandoned. To this day, nobody knows why.

But the Puebloans left clues behind. They are in the wooden beams of Pueblo Bonito. They're locked away in wooden ladders and old fire wood. The answers to why Puebloans left are hidden in tree rings.

The Art of Tree Rings

Cut a cross section of a tree and you'll see lines and lines circling each other. These patterns capture the history of the tree. Tree rings tell stories of life and death. They tell stories of wet years when there was plenty of food to eat. They tell stories of dry years when water was scarce. Tree rings tell the stories of when civilizations flourished and when they collapsed.

Dendrochronology is the science of dating things-events, climate, artifacts-by examining the annual growth patterns found in tree rings. Dendrochronologists study the tree rings of certain species of trees to piece together the history of the environment.