Target Grade Level / Age Range:

Grades 6-8

Estimated Time:

45 minutes, plus additional presentation time


Students will learn about plant growth and problem solve using their parameters with decorative Christmas tree production as the lens.


  • White board
  • Dry erase markers
  • Pens/pencils
  • Optional: rulers, colored pencils

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


  • Bough: a main branch of a tree
  • Deciduous: a tree or shrub that sheds its leaves annually
  • Evergreen: a plant that retains its leaves throughout the year
  • Conifer: a tree that bears cone and needle-like or scale-like leaves that are typically evergreen
  • Pruning: trim (a tree, shrub, or bush) by cutting away dead or overgrown branches or stems, especially to increase fruitfulness and growth
  • Pests: a destructive insect or other animal that attacks crops, food, livestock, etc.
  • Pesticide: a substance used for controlling insects, weeds, fungus, disease, or other threats to cultivated plants
  • Leader: The vertical step at the top of the tree trunk
  • Fertilizer: a substance added to soil or land to increase its fertility

Background – Agricultural Connections

According to the Iowa State University Extension, there are about 200 Christmas tree producers in Iowa. There are a number of Christmas tree species grown across the country and world, but the Extension suggests three main pine trees (Scotch, White, and Red) in their publication.

 Different evergreen trees have different characteristics that folks may prefer or not prefer for their Christmas tree needs. Things like strength of bough, how full the branches grow, the shape and color of the needles, and even the smell of the tree can be factors. However, some of these factors, particularly color and shape of the tree, can be impacted by the grower simply meeting the needs of the tree.

 In Iowa, our soils are very fertile, and trees likely will not have the same fertilizer requirement of other crops. However, since trees take more than one year to mature, extra care will need to be taken to make sure pest pressures like disease and insects don’t damage the integrity of the tree over its long lifespan. These pests and diseases may need to be addressed with cultural, physical, or chemical control methods to keep the trees safe.

 Trees also must be shorn or pruned regularly to promote proper shaping and branch development. This will set apart a tree grown in a ditch from a tree grown on a Christmas tree farm. When shearing trees, farmers take extra caution with the topmost branch, where the star or angel will be placed. This branch is called the leader. Sometimes the leader may want to split into two, or it may get bent from birds landing on it. These types of physical characteristics are important to pay attention to when raising these end products.

 On Christmas tree farms, new trees are planted each year. Trees are spaced at least 5 feet apart on each side to allow for growing space between trees, easy access for maintenance, etc. Trees can be planted by hand or with tools and heavier equipment. Larger tree farms may have larger equipment to handle these tasks more efficiently.

Between rows of trees, lanes are also planned. These lanes may allow for larger vehicles, machinery, and allow for “fire breaks” that can prevent the entire tree crop from burning in case of emergency. The handout for this lesson goes more in depth on planning lanes and tree spacing.

Interest Approach – Engagement

 Start class with a bell-ringer question written on the whiteboard for students to think and take notes about quietly on their own: “What do plants need to thrive? What factors can threaten or injure plants?”

After about 5 minutes, allow for large group sharing and take notes of students’ ideas. The list should include but not be limited to sunlight, adequate rain, good soil, nutrients, drainage, etc.


  1. Tell students that they will be delving into what Christmas trees need, and how Christmas tree producers meet those needs.
  2. Revisit list of what plants need to thrive. Point out good ideas they might have, like adequate sunlight, adequate rain, etc.
    1. Ask students what might happen if these needs are not met.
    2. What are some bad things that could happen to a tree that is not cared for? Possible answers: Rot, uneven growth, poor coloring, potentially death
  3. What are some of the factors that could injure a plant?
    1. Climate not suited to the plant, extreme weather events, weed pressures, insects, disease, etc.
    2. Are all of these things avoidable?
      1. No, not all – but some are. Plant plants in areas with the correct climate, monitor for pest and disease damage and treat as necessary, etc. But, if a tornado comes, this is unavoidable.
  4. Poll the class. By show of hands, how many have had a living Christmas tree in their home? How many have visited a Christmas tree farm before?
  5. What types of factors might decorative tree producers, like Christmas tree farmers, need to pay attention to, to care for their trees? Is this similar to the list they made at the start of the class?
  6. Next, hand out information to students on Christmas tree care. Read the first two pages together as a class.
    1. The Christmas Trees in Iowa document includes two pages on Christmas tree information in general; three pages specific to Scotch Pine, White Pine, and Red Pine; and one student worksheet. The first five pages are condensed and edited excerpts from the four Extension links linked in the Essential Files section. If more digital research is needed for the students, only the last page of the handout may be necessary and they can use the above links to learn more.
    2. Allow the students about 10 minutes to skim the additional information on the individual tree species. Encourage them to take notes, highlight important details, etc. as necessary.
  7. After reading the information, bring the whole group back together and discuss what they learned about tree management.
    1. What factors do tree farmers need to think about?
      1. Planting new trees – what equipment to use, how far apart to plant trees, planning tree spacing and planning lanes
        1. Christmas tree farms sell trees every year. This means they need to replace those trees each spring and care for them for several years until they are ready to be harvested. Trees can be planted with hand tools or with larger equipment or machinery. What tree spacings were recommended in the reading?
      2. Tree maintenance – pruning or shearing trees to maintain shape, controlling weeds and other pests
        1. When trees grow in the wild, they do not look like Christmas trees. Christmas trees look uniform, dense, and manicured because of pruning. Tree farmers have equipment like electric shears to help trim longer branches away from the tree and correct the leader. When trees are pruned, it encourages more dense growth instead of sparse, scraggly growth. Tree farmers need to prune their trees regularly – at least once a year – to raise a beautiful, symmetrical, balanced tree.
        2. Pruning and shaping trees is an important piece of care. A lot of pruning is done with handheld knives like seen in this video: Or in this video: Some pruning can be done with gas powered cutters and a long cutter bar like seen here: Or here: Some pruning can be done with an electric pruner rotary knife like here: Or here: Ask students to evaluate the competing design solutions using a systematic process to determine how well they work to prune trees, how much effort is involved, and which the students would prefer.
      3. Farm maintenance – Mowing around the trees can help ensure that other plants don’t interfere with the trees’ growth.
    2. What are some challenges to growing Christmas trees? Possible answers: Disease, insects, extreme weather events, rodents, birds, deer, fire, etc.
  8. Next, tell students that they will be designing a tree management plan as if they are a Christmas tree farmer.
    1. Direct them to the Design your Christmas tree farm worksheet. This page gives some basic information about a generic tree farm in Iowa. If this was their farm, how would they design it? Where would they place buildings? What species of tree would they plant? How far apart should the trees be planted? Instruct them to include a wide lane where a vehicle could get through the trees? Where will visitors to the farm park?
    2. Instruct students that they will need to map the layout of the farm, including tree variety and tree spacing.
    3. Once their map is completed (with labels), they will need to fill in the blanks explaining why they chose the layout, spacing, and tree varieties they did. They should also fill in the blanks explaining other tree care steps they might have to take to handle challenges during the growing season (think weather, abnormal tree growth, insects, other pests, weed pressure, etc.).
    4. Answer questions as needed and allow students some time to work on their map. Monitor their work and answer questions during the process.
    5. If some students are working faster than others, encourage them to go a step further and consider other various factors of tree farming. Where would they put their shop or machinery shed? What types of trees are the prettiest to them? Would they also make wreaths? How would they market their trees?
  9. Finally, plan time to share out these projects. This can be during the next class if necessary. Allow each student or student group to share their plan for their farm and defend their choices. As a whole group, analyze if they met the needs of the trees given the constraints (climate zone, pest pressures, etc.).

Did you know? (Ag facts)

  • There are about 200 Christmas tree producers in Iowa
  • There are more than 15,000 Christmas tree farms in the U.S.
  • About 100,000 people are employed by the live Christmas tree industry in the U.S.
  • In 2012, 24.5 million live Christmas trees were purchased in the U.S.
  • The average purchase price of a Christmas tree was $41.30 in 2012

Extension Activities

  • Use tree planting populations as prompts for math questions as a warm-up for math class.
    1. If 1740 trees can be planted on one acre using 5’ x 5’ spacing, how many trees can be planted on 7 acres with 5’ x 5’ spacing? Answer: 12,180 trees
    2. One Christmas tree farmer uses 5’ x 6’ spacing (1450 trees per acre) and has six acres. Another farmer uses 6’ x 7’ spacing (1037 trees per acre) and has nine acres. How many Christmas trees total are planted on these two farms? Answer: 18,033 trees
    3. Farmer Ida has 128 White Pine trees that she will sell for $198 each. She also has 307 Scotch Pine trees that she will sell for $214 each. If she sells all of her trees, how much money will she have? Answer: $91,042
    4. Now, Farmer Ida has to pay for staffing, property tax, and other bills. Total, she needs to pay $58,032. How much will she have made in profit? Answer: $33,010



Chrissy Rhodes

Organization Affiliation

Iowa Agriculture Literacy Foundation

Agriculture Literacy Outcomes

  •  Science, Technology, Engineering, and Math:
    1. Explain the harmful and beneficial impacts of various organisms related to agricultural production and processing (e.g., harmful bacteria/beneficial bacteria, harmful/beneficial insects) and the technology developed to influence these organisms
    2. Identify science careers related to both producers and consumers of agricultural products

Iowa Core Standards

  • Science
    1. MS-LS1-5 Construct a scientific explanation based on evidence for how environmental and genetic factors influence the growth of organisms.
    2. MS-ETS1-2. Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.