Final answer:
Trees absorb carbon dioxide through their leaves, utilizing the process of photosynthesis to convert it into organic matter throughout the tree. Tree rings represent annual growth cycles but are not the exclusive pathway for CO2 absorption. Trees significantly contribute to carbon sequestration and climate change mitigation.
Step-by-step explanation:
A tree does not absorb carbon dioxide only by its outer growth ring. Trees absorb carbon dioxide through their leaves, using stomata to exchange gases with the atmosphere. Through the process of photosynthesis, trees fix carbon dioxide into sugars and other organic compounds, which contributes to the growth of the entire tree, not just the outer ring. Tree rings are indicative of a tree's annual growth, with the light-colored earlywood representing rapid growth during the wetter parts of the year and the dark-colored latewood forming during slower growth.
Trees play a significant role in the carbon cycle by sequestering carbon in their biomass. The mass of a large tree, such as one that is 40 meters tall and has a diameter of 0.5 meters, can be substantial. Assuming the wood has a density of 800 kg/m³ and the tree's carbon content is approximately 50%, we can calculate the amount of carbon dioxide that has been fixed by the tree over its lifetime. This is a direct illustration of how trees reduce atmospheric carbon dioxide and contribute to climate change mitigation.
Ginkgo trees, being C3 plants, acquire carbon dioxide through their leaves and are a part of a broader group of plants that remove CO2 from the atmosphere and reduce the impact on climate change by sequestering carbon within their structures. Thus, while the outer growth ring marks annual growth, it is not the sole pathway for CO2 absorption.