| Explore | Oxygen is a necessity in order for life to exist. Through the process of photosynthesis, plants release oxygen into the atmosphere, giving us fresh air to breath. Without plants, humans and animals would have less fresh air to breath. Abiotic and biotic factors are two of the essential factors responsible for shaping our ecosystem. Biotic factors refer to living beings present in the ecosystem, while abiotic factors refer to non-living things or conditions (Eg- temperature, pH, humidity, sunlight, etc). While researching different trees, we realized biotic factors affect the composition of an ecosystem. These include interactions between animals and humans, or fungi and bacteria, and such interactions are important for the reproduction for species and for fundamental requirements like food. Similarly, we realized abiotic factors have similar impacts on the survival and reproduction of species in an ecosystem. For example, without sunlight, autotrophic organisms will not be able to produce food, and will die, depleting the food chain for primary consumers. This will lead to an imbalance in the ecosystem. We are interested in learning about how removing certain abiotic or biotic factors may change the ecosystem, and would love to experiment something along those lines. However, we are always open to other ideas! |
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| Research Question | Which types of trees should be planted in multiple family residents based on their absorption of CO2 per year? |
| Predictions | We hypothesize that trees with a larger weight will likely absorb more CO2, and as a result, should be planted near multi-family residential areas. |
| Experimental Design | Independent Variable: Weight of Tree Dependent Variable: Amount of carbon dioxide absorbed by tree Control Group: No control group because we are not changing anything in the experiment 1. Choose 6-10 of the most common trees in your neighborhood 2. Determine the average diameter (in inches), the average height of each tree, and the average lifespan of each tree (years) using the following source: - https://www.feis-crs.org/feis/ - https://selectree.calpoly.edu/tree-detail/searsia-lancea 3. Find the average weight using the following formula (Note- Formulas are based on algorithm calculated based on tree species in Southeast USA): - For trees with diameter < 11 in. → Weight = 0.25D^2H - For trees with diameter ≥ 11 in. → Weight = 0.15D^2H Then multiply the average weight by 120% to find the average green weight, since root systems weight 20% as much as the above-ground weight of the tree 4. Find the average dry weight of the tree by multiplying the weight of the tree by 72.5%. Based on research by the University of Nebraska, the average tree is 72.5% dry matter and 27.5% moisture 5. Determine the weight of carbon in the tree by multiplying the dry weight of the tree by 50%. Average carbon content in trees is generally 50% of the trees total weight 6. Determine the average weight of CO2 absorbed by multiplying the weight of carbon in the tree by 3.6663. 3.6663 is the ratio of CO2 to C calculated by finding the atomic weight of CO2 (43.999915 amu) and then C (12.001115 amu), and then dividing (43.999915 amu/12.001115 amu = 3.6663) 7. Determine the weight of CO2 absorbed per year by dividing the weight of carbon dioxide by the average lifespan of the tree |
| Investigation Theme | TREE |
| Grade Level | High School Students (Grades 9,10,11,12) |
| Teacher Name | Crystal Davis |
| School Name | California Academy of Mathematics and Science |
| Session | Spring 2021 |