The Spectacular World of Iowa’s Coniferous Trees
Target Grade Level / Age Range:
45 minutes (or two 45-minute class periods depending on depth and extension activities)
To help students gain an understanding of the types of conifer (Christmas) trees grown in Iowa, and how geographical and cultural influences can affect the survival of the trees and tree industry.
- Tree Cards
- Tree cuttings (optional)
- Paper for students to write on
Essential Files (maps, charts, pictures, or documents)
- White pine: the largest pine tree in the U.S. which has soft and flexible needles that provide it a great tree for many animals. This tree is often grown on Christmas tree farms and is a number one seller for families with children because of its soft needles.
- Blue Spruce: this tree is native to the Rocky Mountain states and has a blue hue to its needles. They are often grown as Christmas trees and provide habitat for wildlife.
- Scotch Pine: a pine tree that originated in Europe and the UK but was brought to the United States and can grow in all 50 states due to its hardiness. It is often used for habitat construction, erosion prevention, and Christmas trees.
- Douglas Fir: an evergreen conifer, it provides a habitat for wildlife and is often grown as a Christmas tree. Though it can be grown as a Christmas tree, many farms grow it on a rotation of every 4-7 years as it is hard to grow outside its native area of the western United States.
- Fraser Fir: native to the Appalachian range, this tree is popular because it often holds onto its needles even after cutting.
- Balsam Fir: native to the U.S. this is a symmetrical spiral shaped conifer tree with dark green needles. It is popular as a Christmas tree and is normally grown in NE Iowa. Many animals such as birds, squirrels, mice, voles, moose, and white-tail deer are known to use this tree for food and shelter.
- Canaan Fir: a coniferous tree that is like the Balsam Fir and is often mistaken for the Balsam Fir. This tree grows in a traditional evergreen shape and needs minimal trimming. It is often used for windbreaks and as decoration during Christmas time.
- Concolor Fir: a coniferous tree that does not require pruning and has the iconic evergreen shape. It needles are a blue green with silver hues, and when crushed smells of citrus, this makes it a good addition to teas.
- Conifer (coniferous): a tree that bears cones and needle-like or scale-like leaves that are typically green all year round. These trees are an important form of soft wood and are often grown on logging tree farms and Christmas tree farms.
- Hardiness Zone: an area where a plant can survive and reproduce based on the climatic conditions such as average low temperatures. The U.S. is broken up into hardiness zones that range from 1-11 and are sometimes placed in subcategories (1a, 1b, 2a, 2b, etc.).
- Shear: the process of shaping a tree by cutting the outer edges of branches on a tree so they are relatively the same length and create the wanted shape.
Background – Agricultural Connections
Iowa’s landscape is speckled with natural ecosystems and agroecosystems. Natural ecosystems are those that have not been disturbed by humans or have been restored by humans. These areas include woodland, water ways, and prairie grass areas. The purpose of these ecosystems is to provide habitat for wildlife and recreation for humans. In contrast, agroecosystems are human made and provide a commodity for people. Corn fields are the number one agroecosystem in Iowa. Though they provide some habitat for animals, and corn mazes provide recreation for people, their main purpose is to provide food for livestock and people. Another agroecosystem in Iowa are Christmas tree farms. These farms also offer habitat for some wildlife, but their main purpose is to provide decoration for humans during the winter holiday season.
Iowa Christmas tree farms, or coniferous farms, may only be open from late October to December, but the work that goes into them is year-round. In the off-season farmers plant trees, water and fertilize trees, and shear their trees. Shearing is the process of evening out a whole tree by trimming the outer edges of branches. In contrast, pruning is the cutting and removing of selective branches. Christmas tree farmers shear their trees to shape them without hindering the growth of their tree.
Farmers also order tree plugs (seedling) and seeds during their off-season. Because Iowa has a wide range of temperatures and soil types, farmers must be specific to what trees they order. There are six main types of trees that Iowa Christmas tree farmers grow: White Pine, Concolor, Scotch Pine, Blue Spruce, Canaan Fir, and Fraser Fir. These trees can be grown in Iowa because they can withstand the extreme cold and hot temperatures that Iowa often has. These trees are also more tolerant to the varying soil types of Iowa and can be grown in acidic soils (pH 4-6.9). Though the trees just mentioned are commonly grown in Iowa, some trees are imported from other states. Douglas Fir and Balsam Fir are examples of trees that are imported because people like the look, feel, and smell of them.
When people buy trees to decorate for the holiday season, they have specific features they are seeking. These features help to determine what trees will live, and what trees will die. People prefer tall trees with the iconic triangular Christmas tree shape, and they prefer a tree that looks full and does not show thinning. These preferences affect the farmer. To meet the iconic triangular shape and fullness the farmer must shear the tree and prevent pest damage. Shearing reshapes the tree and causes the trees to bud on the shaft of a branch rather than the tip. This increases the fullness of the tree. However, not every tree can be sheared. Some trees can be damaged from pests or by winter burn. These trees become misshaped to the point that cannot be fixed. Since these trees will not sell, farmers find new ways to use these trees by cutting them for greenery and wreaths.
Interest Approach – Engagement
- Show students the image of an Iowa forest and an Iowa Conifer (Christmas) tree farm (Forest vs. Conifer tree farm document). Ask students to take individual think time and make a list of what is similar and different about the two ecosystems. (A Venn Diagram could be a useful tool to help students organize their thoughts)
- Have students’ pair-share or small group share their ideas with each other.
- Bring the class back together as a whole group. Create a Venn Diagram together with the class using the students’ ideas on the board. Some potential answers: one forest has trees everywhere and a lot of trees, the other one only has one type of tree, one has lots of different colors while the other one only has green, animals live in that one but not the other.
- Remind students that both images were taken in Iowa. Ask students if they think both images represent a forest, or if one is more forest like than the other. Guide students towards the conclusion that one is a farm and the other is a forest.
- Ask students what types of trees grow on a tree farm that look like the picture. Some potential answers: Christmas trees, spikey, green, pine, evergreens.
- Tell students these trees are called coniferous trees and that coniferous trees include trees such as pine, spruce, and firs. Discuss the differences of the trees by showing students the Pictures of Coniferous Trees PowerPoint.
- Let students know that today they are going to investigate the different types of coniferous trees that are farmed in Iowa. Write the focus questions on the board:
- What affects the chance of survival and reproduction of a coniferous (Christmas) tree?
- How do our choices affect farmers?
- Split students into groups. Ask students what it would mean for a tree to survive, what predators does a tree have? Potential answers: It doesn’t lose leaves, bugs don’t live in it, people don’t cut it down, it lives and can produce seeds.
- Remind students they are trying to answer the focus questions:
- What affects the chance of survival and reproduction of a Christmas (coniferous) tree?
- How do our choices affect farmers?
- Hand out printed copies of the tree cards (1-2 per group). Ask students to work in their groups and come up with a list of what affects each trees survival. Have students write their ideas on a sheet of paper (extra challenge: students use technology (PowerPoint, TikTok, SnapChat, music video) to share their ideas).
- Once students are finished have students do a gallery walk to each group. One group “expert” should stay and explain what they discovered about their tree(s).
- Potential answers: soil type, hardiness zone, pests, disease, where it lives (geography), the way the tree looks (people cut the trees down).
- To save time you can have each group share what they discovered and keep track of students’ answers on the board.
- Once students are back in their starting groups, have them share what they learned from other groups. Encourage students to think about patterns between the trees that helped them live and reproduce.
- Bring the class back together as a whole group and discuss what students discovered from their gallery walks and small group discussion.
- Tell students to look at the front side of their tree cards. Remind students that the front side has the same tree, but different ways the tree can look. Ask students to talk in their groups which tree they would prefer and why. Have students share their ideas with the class.
- Discuss with students that people are also predators of plants, and that humans will often choose which trees live and which ones will die based on their own preference of look, disease resistance, or market needs.
- Remind students that all these trees can be found on farms called, Christmas tree farms. Have students brainstorm in their groups how their decision of which tree they like could affect the farmer who grows the trees (extra challenge: pose to students how their choice could affect the culture of the Christmas tree industry). Then work as a class to come up with a list of affects. Potential answers: The farmer may not plant that seed if the tree won’t look the way their customers would want it. The farmer might choose a different type of tree to plant. The farmer may treat their tree or make it look better by trimming it.
- Bring the class back up as a whole group and pose the focus questions to the class. Use these questions to evaluate student learning, have students answer the focus question in their own words by making a claim backed with evidence.
Did you know? (Ag facts)
- For each tree harvested, two to three seeds are planted in its place.
- 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 operation is three to eight acres.
- Real trees are biodegradable and are a renewable resource.
- Help students make math connections by measuring the height of the different trees.
- Students can run an investigation where they collect data from their school peers seeing which tree would be most popular in an imaginary farm.
- Have students observe samples of Christmas tree cuttings using the Christmas tree Riker Frame Mounts from the IALF Lending Library. Let students observe the differences between the types of trees. Then, using their gained knowledge, have students design their own Christmas (conifer) tree farm based on an area in Iowa or the U.S. Then have them provide evidence of why they chose that area using historical and geographical reasons.
- Students can investigate other types of tree farms and create diagrams of how they differ from conifer tree farms.
- Students can investigate trees from other parts of the world and how they influence celebration and culture such as:
- Dawa dawa tree (Africa): This tree is an indicator of the changing seasons and is naturally growing in Africa. Many families would (and some still do) migrate to this tree to gather its seed pods. The seed pods would be collected and provided food for families. The food made from the seeds would be used in celebrations, medicine, and many cultural dishes to add spice and flavor.
- Mango trees (India): Providing the national fruit of India, these trees grow in the southern regions, and their fruit is often collected as a sweet treat or dessert. The tree is imbedded into the culture of India through folklore and religion (Hinduism). You will often see colors that represent the tree in clothing and depictions of the tree in households.
- Bonsai tree (Japan): Bonsai is a generic name for a tree or shrub that has been cultivated in a way to cause it to be miniature. Though they are often associated with Japan, these types of trees occurred first in the wild forest of China. Through war and travel these trees made their way to Japan. It is a common symbol of patience, meditation, and harmony which is why it is often used as a symbol of Zen Buddhism.
Suggested Companion Resources
- Zee Grows a Tree, by Elizabeth Rusch and illustrated by Will Hillenbrand
- This publication or project was supported by the U.S. Department of Agriculture’s (USDA) Agricultural Marketing Service through grant 21SCBPIA1013 Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the USDA.
- Identification of Conifer Trees in Iowa (iowadnr.gov)
Iowa Agriculture Literacy Foundation
Agriculture Literacy Outcomes
- T1.3-5 Describe similarities and differences between managed and natural systems (e.g., wild forest and tree plantation; natural lake/ocean and fish farm)
Iowa Core Standards
- 3-LS4-2. Use evidence to construct an explanation for how the variations in characteristics among individuals of the same species may provide advantages in surviving, finding mates, and reproducing.
- 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.
- Social Studies
- SS.3.21. Use map evidence to explain how human settlements and movements relate to the locations and use of various regional landforms and natural resources.
- SS.4.18. Describe how environmental and cultural characteristics influence population distribution in specific places or regions.
- 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.4: Demonstrate initiative, creativity, self-direction, and entrepreneurial thinking to produce successful outcomes.
- English Language Arts
- 3rd Grade
- RI.3.1 – Ask and answer questions to demonstrate understanding of a text, referring explicitly to the text as the basis for the answers
- RI.3.4 – Determine the meaning of general academic and domain-specific words and phrases in a text relevant to a grade 3 topic or subject area.
- RI.3.7 – Use information gained from illustrations (e.g., maps, photographs) and the words in a text to demonstrate understanding of the text (e.g., where, when, why, and how key events occur).
- 4th Grade
- RL.4.1 – Refer to details and examples in a text when explaining what the text says explicitly and when drawing inferences from the text.
- RI.4.4 – Determine the meaning of general academic and domain-specific words or phrases in a text relevant to a grade 4 topic or subject area.
- RI.4.7 – Interpret information presented visually, orally, or quantitatively (e.g., in charts, graphs, diagrams, timelines, animations, or interactive elements on Web pages) and explain how the information contributes to an understanding of the text in which it appears.
- 5th Grade
- RL.5.1 – Quote accurately from a text when explaining what the text says explicitly and when drawing inferences from the text.
- RI.5.4 – Determine the meaning of general academic and domain-specific words and phrases in a text relevant to a grade 5 topic or subject area.
- RI.5.7 – Draw on information from multiple print or digital sources, demonstrating the ability to locate an answer to a question quickly or to solve a problem efficiently.
- 3rd Grade