Target Grade Level / Age Range:

Grades 3-5

Estimated Time:

4 sessions of 30 min depending on depth and extension activities


Engineer ways to recycle real Christmas (conifer) trees by gathering insights on the issue of Christmas trees in landfills.


  • Design Challenge Planning Packet or Booklet
  • Poster paper (optional)
  • Recycled materials or random items students could use to build with
  • Challenge Cards
    1. Tree Recycling Option 1: Erosion Control (level 1 difficulty)
      • Container to hold water
      • Sand or soil
      • Shallow tote bin (i.e., 5” deep)
      • Christmas tree branches of different sizes and types
      • Water
    2. Tree Recycling Option 2: Wood Chips (level 2 difficulty)
      • Wood chips from different types of Christmas trees
      • Hair dryer or small fan
      • Potting Soil
      • Pine needles
      • Grass seed
    3. Tree Recycling Option 3: Brush Reefs (level 3 difficulty)
      • Christmas tree branches from varying Christmas trees
      • String, rubber bands, pipe cleaners, and/or other binding materials
      • Clear container (such as a plastic shoe box or 1 gallon jar/jug)
      • Rocks, washers, or other heavy items that will not dissolve in water
      • Algae, back striders, guppies, or planaria

Essential Files (maps, charts, pictures, or documents)


  • Biodegradable: able to be broken down, decompose, by bacteria and other living things. 
  • Landfill: a location where trash or garbage is collected and often buried to reduce smell and to extend useable land.
  • Brush reef: A habitat constructed in water using tree branches, logs, or whole trees for fish, algae, and insects. 
  • Wood chip: a small piece of wood that has been created for a purpose such as gardening or covering exposed soil. 
  • Erosion: the gradual breaking down of a landform or structure over time by physical means or through wind, water, or ice. 

Background – Agricultural Connections 

When Christmas trees are the right height, they are sold to decorate for the holiday. Each year approximately 35 million Christmas trees are sold from Christmas tree farms to decorate for the holiday season. 

After the holiday season people struggle to know what to do with their real Christmas trees, and many are sent to the landfill. This causes problems in the landfill because they take up room and can cause landfill fires. Since Christmas trees are biodegradable, they can be recycled into new products such as wood chips, erosion barriers, and brush reefs (helpful source). These products help to prevent erosion and provide habitat for animals and plants. 

Interest Approach – Engagement 

Using the PowerPoint for this lesson show students the landfill image.  Ask students what they notice about the landfill (if possible, pull up Google Earth and show students their own landfill and what it looks like from satellite image. You can search this by using the county name and landfill). Potential answers: there isn’t a lot of trash, there is a lot of trash, do they burry the trash?, it’s really big.

Ask students how they might impact the landfill in their own community. Potential answers: we throw stuff away, the garbage person takes the garbage away, we can recycle.

Using the PowerPoint for this lesson show students the picture of a Christmas tree farm. Ask students what happens at this farm each year (people cut down the trees) and why the farm is important.

Ask students what they think happens to the trees after the holiday season. Potential answers: they get put outside, they go to the garbage, they get recycled.

Discuss with students this problem: The city of Des Moines (edit town name based on where students live) has had an increase of people throwing their Christmas trees after the holidays into the city’s landfill. Even though the trees can break down overtime, this is a problem. When placed in the landfill the tree’s take longer to breakdown and there is a higher chance of fires because of the dead tree’s flammability, or ability to catch fire.

The city has three ideas of what can be done with the trees. But they have asked us to investigate these options and provide them with specific designs for each.


Day 1: Introduction and Planning

  1. Break the students into groups and handout engineering problem cards. 
  2. Tell students that their group needs to decide on one engineering option card they want to focus on. Provide students time to read through the cards and decide. 
    1. As an alternative, you can assign student groups a problem card. Or you can read the cards out loud and ask each group to choose.
  3. Pass out the Engineering Design Planning Packet (1 per group).
  4. Using the PowerPoint for this lesson discuss with students the engineering design process.
  5. Allow students time to work through Part 1: Define the Problem of the packet with their groups.

Day 2: Designing and Building

  1. Review with students the engineering design framework. Ask students what part of the framework they worked on yesterday. 
  2. Using the materials provided for their engineering problem students work in their groups to complete Part 2: Plan Solutions. First, they will draw a design for their solutions. Provide each group permission by signing off on their ideas. 
    1. Helpful tip: prepare baggies or containers that have the students supplies available in them or set up stations to reduce confusion.
  3. Students work in their groups to build their solutions (Part 3: Make a Model) using the materials provided. 

Day 3: Testing 

  1. Review with students the engineering design framework. Ask students what part of the framework they worked on yesterday. Then discuss with students the focus for the day. 
  2. Students work in their groups to complete Part 4: Test the Model. In this section students work to come up with a plan to test their designs. As they create their plans ask students how they will gather data (observations, measurements, time, etc.) to know which idea worked best. 
  3. Students then use their plan to test their designs. In their packet they will collect their data.

Day 4: Sharing

  1. Review with students the engineering design framework. Ask students what part of the framework they worked on yesterday. Then discuss with students the focus for the day.
  2. Students work together with their group members to come up with a plan on how to share their findings in, Part 5: Reflect, of their packet.  
  3. Using a gallery walk format (or presentation) students share their ideas with each other and offer feedback to the designs.
  4. Discuss with students how they would like to share what they found with the city. (optional)

Did you know? (Ag facts)

  • It can take 15 years to grow a tree to retail height of 6’.
  • Each acre of a Christmas tree farm produces enough oxygen for 18 people.
  • A typical Iowa Christmas tree farm is 3-8 acres.
  • Real trees are biodegradable and are a renewable resource.

Extension Activities 

  • Students can use their first findings to make changes to their design and make their designs better.
  • Have students compare different landfills to their own counties to see the affects of population 
  • Students can observe how biodegradable Christmas trees are by burying them in a location on the school property. Have students bury a limb from a real Christmas tree and compare it with a plastic Christmas tree. Leave it there for 1 month and then dig it up.

Suggested Companion Resources 

  • Rosie Revere, Engineer, by Andrea Beaty and illustrated by David Roberts
  • Zee Grows a Tree, by Elizabeth Rusch and illustrated by Will Hillenbrand 
  • The Girl Who Thought in Pictures: The Story of Dr. Temple Grandin, by Julia Finely Mosca and David Rieley



Cathryn Carney

Organization Affiliation 

Iowa Agriculture Literacy Foundation

Agriculture Literacy Outcomes

  • T4.3-5.d. Provide examples of science being applied in farming for food, clothing, and shelter products. 

Iowa Core Standards

  • Science 
    • 3-LS4-3. Construct an argument with evidence that in a particular habitat some organisms can survive well, some survive less well, and some cannot survive at all.
    • 3-ESS3-1. Make a claim about the merit of a design solution that reduces the impacts of a weather-related hazard.
    • 4-ESS3-2. Generate and compare multiple solutions to reduce the impacts of natural Earth processes on humans.
    • 5-ESS3-1. Obtain and combine information about ways individual communities use science ideas to protect the Earth’s resources and environment.
    • 3-5-ETS1-1. Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.
    • 3-5-ETS1-2. Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.
  • 21st Century Skills
    • (21.3-5.ES.1) Communicate and work productively with others emphasizing collaboration and cultural awareness to produce quality work.
    • (21.3-5.ES.2) Adjust to various roles and responsibilities and understand the need to be flexible to change.
    • (21.3- 5.ES.3) Practice leadership skills, and demonstrate integrity, ethical behavior, and social responsibility in all activities.
  • Math
    • (3.MD.A.1) Tell and write time to the nearest minute and measure time intervals in minutes. Solve word problems involving addition and subtraction of time intervals in minutes, e.g., by representing the problem on a number line diagram.
    • (3.MD.B.4) Generate measurement data by measuring lengths using rulers marked with halves and fourths of an inch. Show the data by making a line plot, where the horizontal scale is marked off in appropriate units—whole numbers, halves, or quarters.
    • (4.MD.A.1) Know relative sizes of measurement units within one system of units including km, m, cm; kg, g; lb, oz.; l, ml; hr, min, sec. Within a single system of measurement, express measurements in a larger unit in terms of a smaller unit. Record measurement equivalents in a two-column table. For example, know that 1 ft is 12 times as long as 1 in. Express the length of a 4 ft snake as 48 in. Generate a conversion table for feet and inches listing the number pairs (1, 12), (2, 24), (3, 36), ...
    • (5.MD.A.1) Convert among different-sized standard measurement units within a given measurement system (e.g., convert 5 cm to 0.05 m), and use these conversions in solving multi-step, real world problems.
  • English Language Arts
    • (SL.3.1)
    • (SL.4.1) 
    • (SL.5.1)
    • (SL.3.4)
    • (SL.4.4)
    • (SL.5.4)