Teacher Appreciation Week 2024

Teacher Appreciation Week 2024

Teacher Appreciation Week 2024 Blog

Discover Tree Ring Dating and How People Adapted to Climate Change

“The Moquitch haven’t gone anywhere, they have just changed. A drought came and the  water stopped running. They had to move out of this area…They changed.” 
- Rena Pikyavit, Southern Paiute Tribal Member

Rena Pikyavit Fremont Indian State Park

Rena Pikyavit, Southern Paiute tribal member, providing interpretation at Fremont Indian State Park.

The Moquitch (Fremont people) grew corn, beans, and squash. They hunted wild animals and ate wild plants to complete their diet. Corn was the most important of these food sources because the seeds could be dried and stored for three or more years. Corn needs warm soil, warm weather, and water and requires a three-month frost-free growing season.  If it is too cold in the spring, corn seeds will not start growing.  Too much heat can dry out the soil. Too much water can flood corn fields and wash away the plants.  Too little water means the plants won’t produce much food.

Weather is the combination of temperature, rain or snow, wind, and other conditions we experience daily. Climate is the combination of many years of weather that might be hot or cold, dry or wet. During Fremont times the climate was warm and wet enough to allow farming of corn, beans, and squash. Weather varied from year to year, and from region to region within the lands occupied by the Fremont. Because they could store corn seeds for years, they could still have food for two or three bad years.

Landscape At Fremont Indian State Park

Landscape at Fremont Indian State Park in Utah. Photo by Courtney Agenten.

Teachers Observing Rock Art At Fremont Indian State Park

Teachers observe rock art (writing) at Fremont Indian State Park in Utah. Photo by Courtney Agenten.

Teacher Climbing Into A Fremont Pithouse Replica At Fremont Indian State Park
Teacher climbing into a Fremont pithouse replica at Fremont Indian State Park in Utah. Photo by Courtney Agenten.

The Fremont people could not change the climate, but they could change how they lived in response to it. A hot dry climate or a cold climate reduced corn production, so they might have needed to find more food for their families. A warm wet climate meant that they might have had more food than they needed and could have traded with others. Sometimes the weather within the Fremont homeland in any given year was hot and dry in one area and warm and wet in another.

Archaeologists think that Fremont people responded to changes in climate in two general ways. The first is where and how they lived. They could choose to move to another area within the Fremont homeland or they could move higher in elevation where the weather was cooler. They could choose to live in large villages where they could work together to irrigate fields and grow more food, or they could live in family groups and farm over a wider area to take advantage of small, scattered water sources.

Archaeologists have identified evidence that the Fremont people responded to climate change by changing the way they interacted with each other. In larger villages people who wanted to trade food or other items could have more choice. The Fremont may have chosen leaders who directed how food was shared or traded. Perhaps, they built public buildings and developed practices to help each other, much like churches or towns organize to help each other today.

Tree Ring Dating and Climate Change

A Tree Cookie
Tree Cookie. Photo by Courtney Agenten.

Archaeologists work with other scientists to reconstruct the climate that past people like the Fremont experienced by studying tree rings. Trees add two rings of growth each year, which you can see in a cross-section of a tree called a tree cookie. A light-colored ring grows during the spring and early summer. In a warm and wet year, a tree grows a lot and creates a wide ring. A dark-colored ring grows in the late summer and early fall when growth slows. Many wide rings together, show that the climate was good for all plants in that area for several years. Narrow light-colored rings show that the climate was unfavorable for all plants, including corn.

But how do we know when the climate was either good or bad for plants? Another very useful thing about tree rings is that they can be used to determine when a tree lived. The first ring inside the bark records the last year of growth. We can create a master sequence of wide and narrow rings by overlapping tree cookies, starting with a tree cut down this year. We can then find older and older trees from the area, like we see in the Master Sequence illustration (free sample lesson plan). All trees in the same region will grow wide or narrow light-colored rings in response to the same weather conditions, which makes it possible to compare specific growth years across time.

Tree's Life At A Glance Int
A Tree’s Life at a Glance Interpretive Sign, Quarry Hill Nature Center in Rochester, Minnesota. Photo by Courtney Agenten.

Archaeologists create a master sequence of tree rings in an area like the Fremont homeland by drawing vertical lines on a piece of paper at the end of each tree ring. We know the age of each of these lines because we start with a line representing a tree that was cut down this year. We then count backwards, with each dark ring representing one year of growth.

Kids With Tree Stumps
Homeschool students make music with tree stumps. Can you see the rings in the tree stump? You can count backwards from the year 2022 when the tree was cut down to determine the age of the tree. Photo by Courtney Agenten.

Both archaeology and the oral histories of descendant Native Americans have much to tell us about climate change and the adaptations people have made to these changes including remarkable local adaptations. For example, when farming was feasible in the region that is now Utah, the Fremont people lived primarily on a diet of corn and other cultivated plants supplemented by wild foods gathered from the surrounding landscape. When farming was no longer tenable, the Fremont and their descendants shifted back to a more nomadic foraging lifestyle. Both adaptations were well-suited to the climate.

You can teach a positive, hopeful message about climate change to students with a FREE Project Archaeology lesson, Fremont Indians Adapt to Climate Change.

Be A DendrochronologistPreview of Lesson Plan components:

Enduring Understanding

Using the tools of tree-ring dating, archaeologists study past climate and how past people adapted to changes in climate.

Essential Question

How did Fremont people change their culture (way of living) in response to changes in climate?

What Students Will Learn

• Archaeologists reconstruct past climates using tree rings, which helps them to identify times when the climate was favorable for farming and when it was not.
• Climate reconstruction helps archaeologists identify changes in past people’s culture that occurred during times when the climate was favorable and unfavorable for farming.
• Cultural changes show how past peoples changed their way of life to adapt to climate change.

What Students Will Do

• Date tree rings to identify when the climate was good or more difficult for farming.
• Compare ways that the Fremont might have changed their culture in response to times when the climate made farming either easier or more difficult.


Students will show their grasp of the enduring understanding by completing a chart that identifies at least three ways that Fremont people might have changed their way of life in response to changes in climate.