One way to learn about tree growth is to look at annual rings. Tree rings show patterns of change in the tree’s life as well as changes in the area where it grows. In this activity, students will trace environmental and historical changes using a cross section of a tree, or “tree cookie.”
This is one of 96 activities that can be found in PLT’s PreK-8 Environmental Education Activity Guide. To get the activity, attend a training either in person or online and receive PLT’s PreK-8 Guide. Below are some supporting resources for this activity.
Download the copyright free student pages that are included with this activity:
Reading Tree Cookies
French: Cernes d’arbre
French: Lecture de Biscuits d’Arbres
Spanish Student Page(s):
Leyendo Galletas de Arbol
Anillos del Arbol
Every month we carefully select new tools and resources that enhance PLT’s lessons. These include educational apps, videos, posters, interactive websites, careers information, and teacher-generated materials. Browse a chronological listing below:
Video Demonstration for Doing the PLT Activity Tree Cookie
Maine PLT created this video using a smartphone to demo PLT’s Tree Cookier activity to assist parents and teachers during the COVID-19 pandemic.
What Can Trees Tell Us About Climate Change?
Learn about the connection between trees and climate change, how tree rings can tell a story about past weather events, and the methods in which scientists are recording this data. What Can Trees Tell Us About Climate Change? is a resource offered by NASA’s Climate Kids, designed for upper-elementary students. Find images, fact sheets, activities, games, and articles on this and a variety of other topics—including the atmosphere, water, energy and weather—to help tell the story of our changing planet in ways that are accessible and engaging.
Tree Cookie Cross Section
Observe annual growth rings using this Tree Cookie Cross Section of a 102-year-old ponderosa pine from northwest Nebraska to learn about the many changes in a tree’s lifetime. Early on, the ring widths show average growth for a tree in arid northwest Nebraska but they began to narrow considerably when the tree was about 20 years old. Too many trees in this area of forest were competing for the same limited supply of resources. A timber harvest in 1927 removed some of the trees, reducing competition, and this ponderosa pine increased its growth as a result. When the drought of the 1930s struck, this once again reduced the available resources for this tree, as evidenced in the reduced ring widths.
Also check out what a delegation of Girl Scouts from Poland discovered when asked “What happened around 1917 that might have changed the way this tree grew?” when they looked at this Western Red Cedar tree cookie at the World Scout Jamboree.
Tree Rings Simulation
The science of tree rings is called dendrochronology. Tree rings help scientists learn about past climates by decoding tree ring patterns. Climate scientists use clues from ice cores, layered sediment deposits in lakes and seas, the structure of coral reefs, as well as tree ring sequences to learn about paleoclimates. The use of tree ring records to decode Earth’s climate history is called dendroclimatology. Use this interactive Tree Rings Simulation by the University Corporation for Atmospheric Research, Center for Science Education to learn what tree ring patterns can tell us about climate conditions in the past.
Places Where You Can Buy Tree Cookies
http://www.acornnaturalists.com/ (Acorn Naturalists may refer to them as “tree rounds” though)
http://www.nature-watch.com/ (Tree cookies are called tree discs)
Tree Cookies Information
Want to have some tree cookies for you own? Use this handy document that lays out the steps for creating a perfect tree cookie. You can read the article In Search of the Perfect Tree Cookie for even more information.
Inner Parts of A Tree Model
Help students visualize the inner layers of a tree trunk and better understand the function of its different parts by creating this easy-to-make visual aid – a cross-section of a tree trunk.
A Machine That Turns a Tree’s Rings into a Musical Score
Learn about a modified record player that reads growth rings from a tree like musical notes. Created by German artist, this machine uses the annual rings that you find in cross-sections of trees and converts them into piano music.