Design a Seeding Machine to Counteract Deforestation

Background Information for Teachers

Forests play a major role in Earth's ecosystem. They currently cover about 31 percent of the world's land surface. But not every area covered with trees is classified as a forest. The Food and Agriculture Organization defines a forest as "land spanning more than 0.5 hectares with trees higher than 5 meters and a canopy cover of more than 10 percent." Forests that match this definition can be found on every continent, as shown in Figure 1. Thirty-one percent of Earth's total forest area is found in Asia, followed by 21% in South America, 17% in Africa, 17% in North and Central America, 9% in Europe, and 5% in Oceania (Annual Review of Ecology, Evolution, and Systematics, 2013. 44:593-622). Depending on where the forests are located, they are classified as temperate, subtropical, tropical, or boreal forests.

Image Credit: Wikimedia, Food and Agriculture Organization of the United Nations (FAO) / CC BY-SA 3.0
Figure 1. Proportion and distribution of global forest area by climatic domain, 2020 from the Global Forest Resources Assessment, 2020. Image credit: Food and Agriculture Organization of the United Nations (FAO), CC BY-SA 3.0, via Wikimedia Commons.

The trees within a forest are essential to our existence. They produce oxygen during photosynthesis as they generate energy for themselves to grow. Most living organisms need oxygen to survive. Roughly one-third of Earth's oxygen in the atmosphere is produced by the trees in the tropical forest. This is why forests are also called the "green lung" of Earth. Another reason why trees are important is that they play a major role in climate change, as they influence the amount of carbon dioxide, a principal greenhouse gas, in our atmosphere. During photosynthesis, trees also absorb carbon dioxide, a major greenhouse gas, from Earth's atmosphere. Forests are the largest carbon sinks on Earth. Each mature tree can remove up to 48 pounds of carbon dioxide per year from the atmosphere. This means that in one year, an acre of forest can absorb twice the carbon dioxide produced by an average car's annual mileage.

Another important ecological role of forests is that they are home to 80% of the world's terrestrial biodiversity. Biodiversity is a term that describes the enormous variety and variability of life on Earth. Forest ecosystems include not only trees, but many other plant, fungi, animal, and bacteria species. Forests provide a habitat for all of these living organisms. The tropical forests—also known as the tropical rainforests—are specifically rich in biodiversity due to their hot and humid climate. More than half of the world's species of plants and animals are found in the rainforests. These include monkeys, spiders, frogs, snakes, birds, orchids, rubber trees, insects, and many more. Even today there are still new species being discovered in the depth of the rainforest.

Image Credit: Wikimedia user P. D. Mannion / CC BY 3.0
Figure 2. Distribution of living terrestrial vertebrate species. Highest concentration of diversity is shown in red, lower concentrations are shown in blue. Image credit: Mannion, P. D. 2014. Patterns in Palaeontology: The latitudinal biodiversity gradient. Palaeontology Online, Volume 4, Article 3, 1-8., CC BY-SA 3.0, via Wikimedia Commons.

Even though forests are critical for mitigating climate change and sustaining biodiversity around the globe, their existence is severely threatened. Deforestation, the clearance of forests or trees from land—either due to human activities or natural causes such as wildfires—rapidly decreases the forest areas across the world. According to the World Wide Fund for Nature (WWF) in 2019, the tropics lost close to 30 soccer fields' worth of trees every single minute! In the last 50 years, deforestation in the Amazon caused the loss of 17% of the existing forest in the Amazon! The reasons for human-caused deforestation are manifold, but the primary reason is the conversion of forest land into agriculture land, which then allows for the creation of pulp, palm, or soy plantations and pastures. Another cause is the expansion of urban areas, which leads to the construction of new settlements, roads, and other infrastructure. Many people also depend on forests for their living as they use them for goods such as timber, food, fuel, or bioproducts, which can result in illegal and unsustainable logging practices. Only half of the currently existing forests are still primary forests, which means that they are forests of native tree species and there are no clearly visible indications of human activities. The map in Figure 3 illustrates how the worldwide forest cover has been decimated over time.

Image Credit: Canadian Geographic / The Royal Canadian Geographic Society
Figure 3. Worldwide loss of primary forests. Image credit: Steven Fick and Elizabeth Shilts, Canadian Geographic. (The map was created from observations of the Dutch-Finnish OMI Instrument on NASA's EOS-Aura satellite.)

The effects of deforestation are devastating. Destroying the forests means destroying the food and shelter that many animals and plants depend on. The loss of these habitats directly leads to biodiversity loss, as animal and plant species eventually become extinct. According to the 2019 global assessment report on biodiversity and ecosystem services, around 1 million animal and plant species are threatened with extinction! Losing the forests also means less carbon dioxide absorption by trees. Even worse, clearing forests by burning trees releases significant amounts of carbon dioxide and other greenhouse gases. Forest loss and damage is the cause of around 10% of global warming. Furthermore, people who rely on forests for their living are deprived of their livelihood, and without trees, soil becomes prone to erosion and flooding events, which are becoming more frequent.

Because the consequences of deforestation are so severe, the United Nation included the conservation and restoration of terrestrial ecosystems in their 17 sustainable development goals. Goal 15 specifically states as goal to end "deforestation and restore degraded forest" as "forests are vitally important for sustaining life on Earth and play a major role in the fight against climate change."

There are many strategies to achieve these goals. Some measures that can help prevent habitat loss due to deforestation are:

• Protecting the remaining primary forests by law.
• Implementing sustainable forest-management strategies.
• Creating dedicated tree farms for commercial and domestic use.
• Letting degraded forests "rewild."
• Conducting large-scale reforestation efforts.

Reforestation efforts that intend to counteract the effects of deforestation are already ongoing across the world. Many organizations have dedicated their mission to planting trees in areas where they have been lost. However, planting trees by hand does not scale well and replacing billions of cut trees manually is an impossible task. This is why companies have developed specific planting or seeding machines that place tree seedlings or seeds into the ground. Some of these companies even employ drones to shoot seedlings into the ground from the air in areas that are not easily accessible.

In this lesson, students will first learn about the importance of the world's forests and the consequences of deforestation. Next, students will discuss reforestation as a solution to maintain biodiversity and then design and build a miniature seeding machine that is able to place seeds on a grid in a specific pattern as quickly as possible.

Additional Background Links

• The Structure, Distribution, and Biomass of the World's Forests, Ann. Rev. Ecol. Evol. Syst. 2013. 44:593-622
• Last stands: Mapping the world's shrinking forests, Canadian Geographic
• Deforestation and Forest Degradation: Overview, World Wildlife Fund (WWF)
• Take Action for the Sustainable Development Goals, United Nations
• The global assessment report on biodiversity and ecosystem services, Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services
• How Drones are Helping to Plant Trees - A Cleaner Future, Mashable, on YouTube

Prep Work (15 minutes)

1. Prepare a bundle of the materials for each group and put them in a bag or box. If that takes too much time, write the material list on a whiteboard and ask each group to pick the materials from large piles.
2. Print out the Tree Cover World Map for each student group. Alternatively, you can show the map on a screen for everyone to see.
3. Print out 4 sheets of the Seeding Grid Template for each group. The 4 sheets need to be taped together, as shown in Figure 4. You can also leave this step for the students to do.

Image Credit: Svenja Lohner, Science Buddies / Science Buddies
Figure 4. The 4 sheets of the Seeding Grid Template need to be taped together to create the final seeding grid.

Engage (30 minutes)

1. Tell students that in today's lesson they will take a closer look at Earth's forests and their role as terrestrial ecosystems. Then say, "Did you know that according to the World Wide Fund for Nature (WWF) in 2019, the tropical rainforests lost close to 30 soccer fields' worth of trees every single minute?" Briefly discuss this statement.

   How does this statement make you feel?

   Why do you think the WWF and other organizations are interested in and recording the tropical rainforest loss?

   Why do you think we should care about the rainforest?

   Collect students' reactions to the WWF statement and their thoughts about why we should care about Earth's forests.

2. Next, focus on the importance of forests. Give students 1–2 minutes to discuss in pairs what role they think forests play as part of Earth's ecosystem. Specific questions students can address in their discussion are:

   What do you think makes a forest a forest?

   Have students share their thoughts. Use their replies to point out that not just any accumulation of trees is a forest. The Food and Agriculture Organization defines a forest as "land spanning more than 0.5 hectares with trees higher than 5 meters and a canopy cover of more than 10 percent."

   Who benefits from the existence of forests?

   Why are forests important to us or other living organisms?

   Make a list of all the reasons that students came up with why forests are important to the world and have students record them on their Student Worksheet. Students probably know that trees are able to absorb carbon dioxide and make oxygen that we need to breathe. They might also mention that forests are habitats for a lot of animals and plants, which means that they are important for the maintenance of biodiversity on our planet. Briefly explain to your students that biodiversity describes the variety of species found in Earth's terrestrial and oceanic ecosystems. The completeness or integrity of an ecosystem's biodiversity is often used as a measure of its health.

3. Show students the Tree Cover World Map.

   What do you think this map illustrates?

   Let students describe what they see. Help them realize that the map shows the locations of the major forests around the world. If they don't bring it up themselves, make students aware that the two different colors show the forest coverage at two different times (about 8,000 years ago and around 2008).

   What do you notice about the distribution of the world's largest forests?

   Listen to students' replies. Elicit responses that mention how forests can be found on all continents (except the Arctic). Tell students that 31% of Earth's total forest area is found in Asia, followed by 21% in South America, 17% in Africa, 17% in North and Central America, 9% in Europe, and 5% in Oceania. The five countries with the largest forest area (more than 50% of all global forests) are Russia, Brazil, Canada, the U.S., and China.

   How has the forest coverage changed over time?

   Students will notice that the forest coverage has decreased drastically over time. Have students point out on the map where these changes are most significant.

4. Show students the following video about deforestation, the major cause of forest loss.
   

   https://www.youtube.com/watch?v=Ic-J6hcSKa8
5. Briefly review the video contents with your students.

   Optional: Why does deforestation happen?

   What impacts does deforestation have?

   Let students summarize the key points of the video. Emphasize two points: That deforestation influences the amount of carbon dioxide, a major greenhouse gas, in Earth's atmosphere. Let students explain and record on their worksheets how deforestation and climate change (global warming) are connected. If necessary, replay minutes 0:44-1:05 of the video to explain how trees absorb and release carbon dioxide. That deforestation leads to habitat loss for many living organisms in the forest (video 1:05-1:33). Guide students to conclude that the disruption of an ecosystem leads to a shift in its entire population. This means that in the worst case, some species will become extinct as their habitat is destroyed, which results in the loss of forest biodiversity.

6. Together with your class, brainstorm solutions for how to mitigate biodiversity loss due to deforestation.

   What do you think can be done to counteract the impacts of deforestation?

   Have students share their thoughts. Some strategies that are mentioned in the video are proper management of forest resources, eliminating clearcutting (for example, by protecting primary forests), and planting new trees.

7. Tell students that reforestation plays a big role in mitigating climate change and biodiversity loss as the new trees and forests can replace the habitats that have been lost. Point out that to replace all the trees that are chopped down annually, one has to plant 15.3 billion trees—that is 15,300,000,000—every year! This is about twice the world's population and means that every single person on the planet would need to plant at least two trees per year, or each person in the U.S. would need to plant 50 trees per year.

   Do you think this goal is accomplishable?

   How do you think reforestation can be done efficiently and at a large scale?

   Let students briefly discuss this question. Help them realize that it would be impossible to plant all these trees manually. Prompt them to think about technological solutions that could help plant trees at a large scale.

8. Optional: Look into some reforestation efforts together that use manual labor, planting or seeding machines on the ground, or drones in the air.
   1. Manual reforestation video
   2. Tree planting machine on ground video
   3. Drones for tree planting video
9. Explain to students that today they will work in groups to build their own miniature seeding machine.

Explore (60 minutes)

1. Divide students into groups of 3–4 and show them the materials they have available to build their seeding machine. Also, show them the Seeding Grid Template and explain that this map shows the location where the seeds need to be planted. The goal is to build a seeding machine that is able to disperse the seeds at the precise locations as quickly as possible. Show your students the Design a Seeding Machine video as an introduction to the challenge.
   

   https://www.youtube.com/watch?v=sjfjXDOExcU
2. Next, agree on the design and performing criteria for their seeding machine project as a class. You can also set these criteria yourself in advance. You will need to standardize this so you can evaluate the performance of each machine using the same criteria. Below is a set of example criteria. You might want to change these depending on the materials and time you have available.
   1. The machine and its parts can be operated by hand by only one student during the seeding process.
   2. The machine can only be refilled with seeds three times during the seeding process.
   3. The seeds cannot be touched during the seeding process, except during refill operations.
   4. The seeds have to be placed within the dashed square around the X. One seed in each square. Only 24 seeds can be planted in total. No refilling the machine after that.
   5. The machine has to touch the ground the whole time during the seeding process.
   6. The machine's performance will be measured by how many seeds are planted correctly inside the dashed square and by how long it takes for the machine to plant all 24 seeds. The total time includes loading all 24 seeds into the machine and dispersing them in the grid. If the machine gets stuck or blocked, the seeding process for that team is over.
3. Before they start, have each group set up their seeding grid as shown in Figure 4. Make sure students keep the distance between the dashed squares the same throughout (7 cm horizontally and 8 cm vertically). Have students tape the seeding grid to the ground and then cover the seeding strip with double-sided tape. This way the seeds will stick to the ground rather than rolling away.
4. Now it is time for students to start their designing and building phase. Taking the agreed-upon criteria into account, students should use the engineering design process to design their miniature seeding machine. Give the students an indication of how much time is allotted to building, testing, and improving their design.
   1. Brainstorm solutions: Each student within a group should come up with their own initial design idea for the seeding machine and draw it on their worksheet.
   2. Choose the best solution: Let students share their ideas within their groups and agree on a single design to build. This design can also be a combination of individual designs, or a completely new one inspired by other ideas. Have students draw their selected design on the worksheet.
   3. Build a prototype: Each group should try to build their seeding machine based on the design they chose.
   4. Test and redesign: To test their design, students should start their stopwatch and then load their machine with the seeds (dried beans, colored candies, or beads) and maneuver the machine through the seeding grid. Once all 24 seeds are dispersed, the stopwatch is stopped, and the number of dashed squares that have at least one seed in it are counted. The seeding process is terminated after a maximum of 5 minutes. The total time includes the time needed for loading the seeds and dispersing them on the grid. The machine is evaluated on the time it takes to seed and the number of correctly planted seeds. Students also may want to test individual parts of the machine first as they build them to make sure they are working as intended.
   5. Students should write their test results on their worksheet. An example data table is provided on the worksheet.
   6. After each prototype test, students should evaluate their prototype. Based on their results, they should discuss:

      What works well in our design?

      What does not work well in our design?

      How can our design be improved?

      How can we ensure seeds do not get stuck and the seeds are placed more precisely?

      Can we make the seeding process more efficient or faster?

   7. Tell students that most design solutions need to be modified after each test on the basis of the test results, in order to improve it. Encourage students to change or modify their designs to make them better. Emphasize that the engineering design process is iterative. Things do not always work on the first try. It is OK if they need to revise or change their design. Even if their machine "works," they should think about how to make it better. Have students log all their prototype test results and any design change on their worksheet.
   8. During testing, students should use data tables to record the performance of their design across multiple iterations. The table provided on the worksheet uses the criteria explained in step 2.f (the number of seeds that have been correctly placed, and the total time required for the whole seeding process). The format of the table might need to be adjusted to reflect on the criteria you or the class decided on. Students should use the results in their table to assess if their machine's performance improves across multiple iterations.
5. Give students 30–45 minutes to finalize their seeding machine design. Then bring all groups together for a final performance test to evaluate the different design solutions based on the agreed-upon criteria. The final testing can be done on one seeding grid sequentially, or in parallel on several seeding grids. Record each team's results in a table on a board for everyone to see. Make sure that all the agreed-upon rules are observed during the seeding process. If your class chose to evaluate on speed and accuracy, as explained in step 2.f, these would be the steps to test:
   1. Make sure students have everything they need and start a stopwatch.
   2. Have students load their seeds and maneuver their machine through the seeding grid to plant their seeds. Stop the stopwatch once they have planted all 24 seeds. If, for some reason, a machine gets stuck, the seeding process for that group is over. Stop all seeding processes after a maximum time of 5 minutes.
   3. Count each dashed square on the seeding grid that contains at least one seed.
   4. Have students write down the results on their worksheet.

Reflect (30 minutes)

1. Ask each group to show or briefly present their machine to the class and discuss the results of the seeding machine design project as a class. Remind students to support their arguments with evidence from the test data. Some question you can use to prompt discussion are:

   Which machines or methods worked best for placing the seeds most precisely?

   Which machines or methods worked best for placing the seeds the fastest?

   Have students evaluate all of the different designs based on how precise or quickly they completed the seeding process. Prompt them to think about which criteria might be more important in the real world: having a machine that places the seeds very precisely or very quickly? What are the real-world tradeoffs between these two performance criteria?

   What were some common challenges that multiple machines displayed?

   How similar or different are all the designs?

   What features did high-performing machines have in common?

2. Based on your discussion results, together as a class nominate a winner or winners of the challenge.
3. Wrap up the lesson by coming back to the deforestation problem and the WWF statement ("in 2019, the tropical rainforests lost close to 30 soccer fields' worth of trees every single minute").

   In the beginning of this class, I asked you why we should care about the forests on our planet. Based on what you have learned in today's lesson, can you tell me why reforestation is important?

   Have students reiterate how reforestation can help maintain biodiversity and mitigate climate change. Point out that automated reforestation is only one strategy to counteract deforestation. Remind students of the other measures that can help prevent habitat loss due to deforestation, such as forest management, protection of forests by law, establishing tree farms for commercial use, or letting degraded forests "rewild." Optionally, you can show students the video How To Save Our Forests and Rewild Our Planet, which mentions all of the above measures.

4. Close the lesson with a discussion about what can be done on an individual level to protect forests, including their habitats and biodiversity.

   What are things that we, as individuals, can do to protect our forests and their biodiversity?

   Have students share their ideas. Some examples are using less paper or wood products, raising awareness about deforestation in their communities or families, being more conscious about what products they buy or use, or supporting companies and organizations that are committed to reducing deforestation.

Assess

1. Ask each group to make a poster or give a short presentation to the rest of the class about their seeding machine.
2. You can also collect each student's students' worksheet and use them to assess their design process.

Make Career Connections

Discussing or reading about these careers can help students make important connections between the in-class lesson and STEM job opportunities in the real world.

Mechanical Engineer

Add Favorite Remove Favorite More Menu

• Read More

Career Profile

A mechanical engineer designs and builds all kinds of machines to solve technical problems just like you did in this lesson. They could, for example, develop surgical robots, solar panels on a spacecraft, or design new car engines. If you like researching solutions for problems, making drawings of your designs, or building and testing your prototypes, you should learn more about mechanical engineering! Read more

Sustainability Specialist

Add Favorite Remove Favorite More Menu

• Read More

Career Profile

Sustainability specialists support and implement programs that focus on improving the environment. For instance, they could organize volunteer activities, such as planting trees within a community, assisting in strategic policy planning to protect the world's remaining forests, or helping to reduce a corporation's ecological footprint. Read more

Lesson Plan Variations

• Talk about other causes of habitat or biodiversity loss besides deforestation. Can students use the design process to construct solutions that mitigate these causes?
• Have students do more research about causes of deforestation and reforestation efforts worldwide. A tool they can use to do that are the interactive maps of the global forest watch.
• Encourage students to find out about the trees or forests in their local environment. Are they healthy? How many trees are cut down/used every year? What is the wood used for? How are they managed? Can they volunteer to help keep and grow them?
• Ask students if they know organizations or stores that support reforestation. Can they make small changes to their actions to support reforestation?
• Ask students to look more into the biodiversity within a specific forest. What kind of animals or plants live in the forests or woods that are close to them, or in the rainforest?
• Design a machine that is able to plant different seeds (to prevent monocultures). Can students make a machine that alternates which seed it is planting?