Tree ring dating lesson plan
Photo of Ponderosa Pine illustrating years of diminished growth due to Pandora Moth defoliation (white arrow and bracket). Speer, Indiana State University, provided by Henri D.Grissino-Mayer, The University of Tennessee, Knoxville, Go to the University of Arizona Laboratory of Tree Ring Research website to help complete the Tree Ring Concept Map Worksheet. More about the photograph) Lesson plans and essays for teachers and students explore North Carolina's past before European contact.Tree-ring analysis requires observation and pattern recognition.Help your little nature lover learn about tree-ring dating with this helpful guide.He'll also learn a bit about a tree's inner layers, and then he can take a quick quiz when he's done.I wish to thank Rex Adams for being an understanding and patient mentor throughout my summer of dendro-enlightenment, and Henri D.Grissino-Mayer for teaching me to be a little more computer literate.
The captions beside the pictures contain terminology used by dendrochronologists when referring to tree-ring characteristics.
Each year a tree’s growth ring has two parts; one is wide and light colored, and the other is narrow and dark. This grows during the wet spring and early summer when the tree has a lot of sap, and the cambium cells giving rise to the trunk growth are large and thin walled.
As the summer winds down and the transition to the cooler autumn occurs, the tree’s growth rate slows.
This results in the cambium cells becoming smaller and thicker-walled.
By winter, when the sap finally stops flowing, a smooth dark ring marks the end of the tree’s annual growth.