Science Serving Maryland's Coasts

Tree Ring Exploration

Instructional Level: Middle School - Earth Science

Lesson Plan Standards: 

NGSS: MS-LS1-5, MS-LS2-1
CCSS: 6.SF.B.4, WHST.6-8.9
MD E-Lit: 1A, 3A, 3B

Lesson Plan: 

Dendroclimatology

Driving Question(s):

How can the subject of dendroclimatology be used to reveal historical changes in a climate?

Exploration

Dendrochronology is the study of tree rings and dating trees and/or other samples of wood. Students will practice their dendrochronology skills by analyzing a tree cross-section image and the types of wood produced by trees that compose the growth rings.  Connections between seasonal conditions and types of wood will be reinforced and applied by students in this activity. This activity requires students to work at a computer station.

Ponderosa Pine Illustrating Pandora Moth Defoliation

 

 

 

 

 

 

 

 

 

Photo of Ponderosa Pine illustrating years of diminished growth due to Pandora Moth defoliation (white arrow and bracket).  Photo Credit: Photo © James H. Speer, Indiana State University, provided by Henri D. Grissino-Mayer, The University of Tennessee, Knoxville, http://web.utk.edu/~grissino/index.htm.

Objectives: 

Students will:

  1. Be able to date a tree using a cross-section image to practice counting rings.
  2. Describe which type of cells become the “wood” of a tree and which type of cells become the bark of the tree.
  3. Describe the types of wood produced by trees depending upon seasonal conditions.

Lesson Materials: 

Computers or computer workstations

Tree Ring Concept Map Worksheet

Procedures: 

Explore:

  1. Have students practice counting tree rings using the image below (click image to download file).

Photo credit:  Cherry tree cross section.  Shelby Sawyers,  Northwest Middle School, Carroll County Public Schools.

 

This tree fell in February of 2014. Count the rings until you find the ring that corresponds to the year you were born. Make a note of any other important events in your life and the year.

       2. Hand out the Tree Ring Concept Map Worksheet.

       3. Go to the University of Arizona Laboratory of Tree Ring Research website to help complete the Tree Ring Concept Map Worksheet.

Explain:

Discuss student responses and give students the opportunity to explain in their own words how environmental conditions and tree rings are related.

Example:

Warm Temperatures + Plenty of Rainfall = ____ Rings.

Warm Temperatures + Plenty of Rainfall = Wide Rings.

The combination of warm temperatures and plenty of rainfall gives trees the opportunity to produce more wood.

Evaluate:

The explanation activity above also serves as a formative assessment that illustrates how students are connecting ideas on the concept map and the impact on the tree.

References: 

Tree Ring Background, University of Arizona, http://ltrr.arizona.edu/about/treerings

Tree Ring Website, University of Tennessee, http://web.utk.edu/~grissino/index.htm

A New Generation of American Chestnut Trees May Redefine America's Forest by F. Jabr.  Scientific American Vol. 310, Issue 3, Web Exclusives.

 

Next Generation Science Standards (NGSS): 

MS-LS1-5

Standards: MS. Growth, Development, and Reproduction of Organisms

Performance Expectations: Construct a scientific explanation based on evidence for how environmental and genetic factors influence the growth of organisms.

Dimension

Name and NGSS code/citation

Specific Connections to Classroom Activity

Science & Engineering Practices

Planning and carrying out investigations

Obtaining, Evaluating and communicating information

Accessing web site, examining the width of tree rings

Crosscutting Concepts

Patterns, Cause & Effect, Stability and Change

Scale, Proportion and Quantity

Examining variation in the width of tree rings

Disciplinary Core Ideas

MS-LS1.B Growth and Development of Organisms

MS-LS1.B Genetic factors as well as local conditions affect the growth of the adult plant

Students correlate growth to favorable environmental conditions

Common Core State Standards (CCSS): 

WHST.6-8.9

Draw evidence from informational texts to support analysis, reflection, and research.

6.SF.B.4

Summarize numerical data sets in relation to their context.

Environmental Literacy Goals (E-Lit): 

3A

Analyze and explain the movement of matter and energy through interactions of earth systems.

3B

Analyze and explain the influence of this movement on...the distribution of life.