How forests play a vital role in the carbon cycle

Posted Jun 2, 2019 by Karen Graham
Carbon is an abundant element that is necessary for life on Earth. Carbon atoms can be found in not only plants and animals but in rocks, soil, water, and even the air we breathe. But an overabundance of carbon, in the form of carbon dioxide, is deadly.
Canada s boreal contains the world s largest supply of soil carbon  stored in its peatlands and satu...
Canada's boreal contains the world's largest supply of soil carbon, stored in its peatlands and saturated forests.
Photo credit: Chad Delaney
In an earlier article, we talked about reforestation, the planting of trees to help to remove carbon dioxide from our atmosphere. However, this journalist thinks it is important to know what happens and how the process works when a tree is planted.
Forests absorb carbon dioxide
This is not fake news, but a scientific fact. Carbon dioxide (CO2) in the atmosphere is necessary for plants and trees to grow. This is because carbon, along with nitrogen atoms are building blocks of living things and a part of biogeochemical cycles.
Carbon atoms move from the atmosphere to plants. In the atmosphere, carbon is attached to oxygen in a gas called carbon dioxide (CO2). Through the process of photosynthesis, carbon dioxide is pulled from the air to produce food made from carbon for plant growth.
The overall process of photosynthesis
The overall process of photosynthesis
At09kg : original Wattcle : vector graphics
Plants and trees then store the carbon, above and below ground - producing oxygen in the photosynthesis process. If you guessed that sunlight is involved, you are right. Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a byproduct.
Forests in the United States absorb and store about 750 million metric tons of carbon dioxide each year, an amount equivalent to 10 percent of the country’s CO2 emissions.
The Carbon Cycle
Basically, the carbon cycle is the exchange of carbon between all of the earth’s components—the atmosphere, oceans and rivers, rocks and sediments, and all living things. The processes of photosynthesis and respiration are actually the basis of the carbon cycle.
Think of the carbon cycle as a big circle of life. Carbon moves from plants to animals through the food chain. Animals that eat other animals get the carbon from their food too. Carbon also moves from plants and animals to the soil.
The Carbon Cycle
The Carbon Cycle
Earth Observatory - NASA
When plants and animals die, their bodies, wood, and leaves decay bringing the carbon into the ground. Some of the decaying materials remain buried and will become fossil fuels in millions and millions of years.
Carbon also moves from living things into the atmosphere through the process of respiration. Humans and animals have to breathe, and when we exhale, CO2 is forced into the surrounding air. Plants also need to get rid of carbon dioxide gas through the same process.
Carbon dioxide is forced into the atmosphere when fossil fuels are burned. When humans burn fossil fuels to power factories, power plants, cars and trucks, most of the carbon quickly enters the atmosphere as carbon dioxide gas. Each year, five and a half billion tons of carbon is released by burning fossil fuels. Most of it remains in the atmosphere while what's leftover is dissolved in seawater.
Deforestation worsens climate change by releasing carbon stored in trees into the atmosphere  and pr...
Deforestation worsens climate change by releasing carbon stored in trees into the atmosphere, and preventing forests, or “carbon sinks,” from absorbing greenhouse gases for decades at a time.
U.S. Forestry Service
Here are two new words to learn as part of the carbon cycle - An object or process that absorbs and stores carbon is called a sink. Objects or processes that release carbon faster than it is absorbed are called a source. For example, a healthy plant is a carbon sink because it is taking in CO2 from the air and storing it in new leaves and roots and a larger stem.
However, a plant or tree can also become a carbon source. As an example, when a plant is eaten by an animal, and the animal uses the carbon for energy. Perhaps more meaningful in today's climate - CO2 can be sent back into the atmosphere through decomposition or like the wildfires so rampant around the world.
Why is all this important?
Simply put, although the carbon cycle is a natural ongoing process, we, as humans, have a huge impact on it. Fossil fuels, including coal, oil, and natural gas, all contain large amounts of carbon that was formed during the decomposition of plants and animals over millions of years.
Carbon dioxide levels in Earth's atmosphere have hit record highs as man-made greehouse gas emi...
Carbon dioxide levels in Earth's atmosphere have hit record highs as man-made greehouse gas emissions continue to grow
In all fairness, at the start of the Industrial Revolution, weather forecasting, forestry, and science, in general, had yet to make the discoveries that have been made in the past 100 years. We have learned so much, especially about our planet, and now, we have a chance to correct some of the mistakes we have made.
Scientists throughout the world are working to determine the amounts of carbon stored in different components of the earth and the movements between them. We can now measure the amount of CO2 in the atmosphere using satellites, and the amount of carbon stored in different samples from plants, trees, soil, and other components, scaling the results up to determine CO2 levels in an area or region.
Scientists can now calculate how deforestation, through indiscriminate logging, slash-and-burn or wildfires have contributed to rising levels of CO2 emissions in the atmosphere. And even though some of that CO2 is taken in by plants and trees, there is a huge amount of this greenhouse gas choking our atmosphere.
So, this is why planting trees is actually a very good thing to do for our planet.