- Fallen trees are a kind of dead organism
- Removing dead organisms from an ecosystem causes available nutrients to be removed from that ecosystem
- Hence, removing fallen trees from an ecosystem causes available nutrients to be removed from that ecosystem

- A plant is a kind of organism
- A plant / living thing requires nutrients to grow
- Hence, organisms require nutrients to grow

- If a living thing requires something then that something has a positive impact on that living thing
- A living thing is an organism
- Therefore, if an organism requires something then that something has a positive impact on that organism

- Organisms require nutrients to grow
- If an organism requires something then that something has a positive impact on that organism
- So, nutrients have a positive impact on organisms

- Nutrients have a positive impact on organisms
- Organisms are a part of an environment
- Therefore, nutrients have a positive impact on the environment

- Nutrients have a positive impact on the environment
- Removing something positive has a negative impact on the things that are positively impacted by that something
- Hence, removing nutrients has a negative impact on the environment

- Removing nutrients has a negative impact on the environment
- Harming something has a negative impact on / effect on that something
- So, removing nutrients harms the environment

- Removing nutrients harms the environment
- An environment is a kind of ecosystem
- Therefore, removing nutrients harms an ecosystem

- Removing fallen trees from an ecosystem causes available nutrients to be removed from that ecosystem
- Removing nutrients harms an ecosystem
- Therefore, removing fallen trees harms an ecosystem by removing available nutrients

Therefore, removing fallen trees harms an ecosystem by removing available nutrients
Q: A windstorm knocks down many trees in a national park. Timber companies want to get rid of the fallen trees. How would this most likely harm the park ecosystem?
Context:
- A plant is a kind of organism 
- Organisms are a part of an environment 
- If a living thing requires something then that something has a positive impact on that living thing 
- Harming something has a negative impact on / effect on that something 
- An environment is a kind of ecosystem 
- A plant / living thing requires nutrients to grow 
- A living thing is an organism 
- Fallen trees are a kind of dead organism 
- Removing dead organisms from an ecosystem causes available nutrients to be removed from that ecosystem 
- Removing something positive has a negative impact on the things that are positively impacted by that something