Tree rings are like snapshots from the life of a tree. These circular rings show many things, from a record of the earth’s previous climate conditions to the age of the tree. 

The light and dark rings of a tree offer evidence of the tree’s age, the weather conditions it’s experienced, and its growth patterns. The light rings indicate wood growth in spring and early summer. The dark rings reflect growth during late summer and autumn.

Tree rings can indicate climate changes with precise accuracy. The first-year growth is the center of the circle. Rainy seasons often look like wider bands of light-colored growth. Dry seasons produce thinner, darker rings. Forest fires produce scar-like features. The lines of the ring will appear thicker, much like a scar on human skin.

The study of past climates is a scientific field called paleoclimatology, and scientists who study climate change often examine tree rings to verify information about weather changes. As our climate evolves, this field has become increasingly important. Today, scientists use valuable natural records to create models of climate change. In addition to tree rings, scientists study sediment from lakes and oceans, as well as cores drilled from ice in the Antarctic.

Understanding the Past … Predicting the Future

By understanding the past, scientists can create models of the future.

One example of this is the International Tree-Ring Data Bank (ITRDB), a collection of records of tree-ring data from around the world. The records are housed in the NOAA National Centers for Environmental Information (NCEI) and used to estimate past temperatures, droughts, and precipitations.

You can search tree ring data by study, text, interactive map, and google earth map. There are 4,250 data sets from 66 countries on 6 continents. If you’re seeking information about the earth’s past, this is a useful resource to explore.

Using these statistics, scientists can reconstruct temperature fluctuations, precipitation levels, and droughts over the last 2,000 years. 

Does It Work in Your Backyard?

The study of past climate conditions, tree rings, and current climate changes poses some interesting questions.

Here are a few:

How Old Is the Stump in Your Backyard?

Just like scientists count tree rings, you can too. If you have a stump in your backyard, start counting from the middle. Each dark ring reflects late summer/fall growth—which should give you an indication of how old the tree was before it was cut.

When Was the Last Big Drought, Fire, or Rainstorm?

You can use graphs of tree rings to evaluate when the stump in your yard encountered the last big precipitation, drought, or fire. You can tell by the color and thickness of the rings.

In addition to evaluating the stump, you can also compare them to local records of weather conditions and climate changes in your region.

Does Older Data Compare With Current Tree Rings?

According to climate.gov, a larger tree’s ring data is an accessible record reflecting long-term variations in temperature or precipitation. 

Much of the value in using tree ring data is to have a longer time frame to analyze and to generate more reliable and statistically relevant data. Human error is always an issue with any long-term scientific data, but tree rings don’t lie.

Do You Have to Cut Down a Tree to Study the Rings?

The short answer is no, you don’t have to cut down a tree to analyze its rings. There’s an instrument called an “increment borer” that can get a thin strip of wood from a living tree. This strip goes from the outside of the tree to the center of the core.

Using this instrument, you can study tree health and history while keeping the tree healthy and happy. Experts suggest getting help from a tree expert, science teacher, arborist, or botanist before you try this in your backyard.

What Do Very Old Trees Tell Us?

Very old trees can provide insights into weather conditions during periods before weather records were kept. For example, one of the oldest living trees in the world is the Methuselah Tree. This is a bristlecone pine tree that is believed to be nearly 5,000 years old. This tree is located in the Inyo National Forest in California, and you can see it on the Methuselah Trail.

Most weather records only go back 100 to 150 years, so old trees offer a glimpse into conditions long before these records were kept.

Taking Care of Trees

In addition to reading tree rings to learn about weather history, trees tell us a lot about their health. The color of leaves, the moisture of branches, and spots on tree trunks can indicate that a tree needs attention.

Trees tell us a lot about their health without using words. If you are noticing changes in your trees, please speak with an arborist right away. Many conditions can be treated fairly easily when you know what they are and what to do.

The experts at Mr. Tree in Oregon can help you understand your trees, take care of them, and keep them healthy. While the Pacific Northwest climate is continuing to change, we know that not everyone is familiar with what it takes to care for the health and happiness of the trees that are growing near their homes. You may have questions about tree care, and we are happy to help with that too.

We love trees and can help you keep the tree rings growing for years to come. If you have questions about tree trimming, tree removal, tree shaping, tree pruning, or stump grinding, please do not hesitate to contact the arborists at Mr. Tree.