Final answer:
Cutting down a tree releases the stored carbon dioxide back into the atmosphere, contributing to the greenhouse effect and climate change. A large tree would have absorbed a substantial amount of CO₂, which is then lost when it is cut down and not replaced.
Step-by-step explanation:
When a tree is cut down, the stored carbon dioxide (CO₂) it accumulated throughout its life is no longer sequestered. This tree, which might have been 40 m tall with a 0.5 m diameter trunk, would have contained a significant amount of carbon, since wood is approximately 50% carbon by mass.
The density of wood is roughly 800 kg/m³, and considering the volume of our hypothetical tree cylinder, we can calculate the tree’s ability to have absorbed CO₂ from the atmosphere during its growth. If the tree is burned or decomposes without being replaced by new vegetation, that CO₂ is returned to the atmosphere, contributing to the greenhouse effect and potentially to climate change. Deforestation has a two-fold impact on carbon levels: it reduces the Earth’s capacity to absorb CO₂ and often results in an immediate release of stored carbon, further exacerbating global warming.