The mighty tree is a wonder of nature. They provide shade, prevent erosion and provide us with oxygen. But did you know that trees also absorb CO2 from the atmosphere?
In this blog post, we will explore how much CO2 a tree can absorb and what it means for global warming. But before we dive in, let’s talk briefly about CO₂.
What is CO2 (and why does it matter)?
The atmosphere is a complex place. It contains gases such as nitrogen and oxygen, but also water vapor, carbon dioxide (CO₂) and many other trace gases. Gases in the Earth’s atmosphere behave like fluids: they mix well with each other and can move around easily by means of currents or temperature differences. Because CO₂ is a greenhouse gas, it becomes trapped in the atmosphere. This causes an increase of global temperatures which can lead to climate change.
Therefore, many people are concerned about CO₂ levels in our atmosphere and want to reduce carbon emissions as much as possible. Now that we know what CO₂ does in the Earth’s atmosphere, we will take a look at how trees absorb CO₂.
Why do trees absorb CO2?
CO₂ is absorbed by the leaves of trees in photosynthesis. During this process, energy from sunlight and water is used to convert carbon dioxide (carbon) into sugars such as glucose or sucrose which can be stored in their trunk and roots for later use.
A tree can absorb CO₂ through tiny pores in their leaves called stomata (plural of stoma). There are over 200 million stomata per square inch on a leaf’s surface and they open or close depending on the weather conditions, availability of water and levels of sunlight. However, when it is windy enough, a tree won’t open its stomata. This is because the wind dries out their leaves and prevents them from absorbing CO₂ effectively.
In fact, this happens to all plants that have openings in their leaves: when it’s too windy for example, they can stop performing photosynthesis altogether. In these cases, plants use oxygen from the atmosphere in a process called cellular respiration. This is similar to what humans do when they breathe, but plants use it as an alternative way of generating energy in absence of sunlight.
How much CO2 can be absorbed by trees?
The short answer is around 21 kilograms (or about 46 lbs) on average, per tree and per year. The longer answer, however, is that it depends on many factors.
Size of the tree
A large tree will usually absorb more CO₂ than a small one. This is because it has bigger leaves and multiple trunks which in turn means that there are many stomata to take in carbon dioxide.
Consequently, a sapling will only absorb tiny amounts of CO₂, while a fully matured tree will absorb average or above-average amounts.
Types of trees
Different species can absorb slightly different amounts of CO₂. For example, a eucalyptus tree will absorb more CO₂ than an oak tree.
Health of the tree
Trees that are stressed or sick due to pests, diseases and other environmental factors can absorb less CO₂. This is because they have to use their energy reserves for healing processes rather than taking up carbon dioxide;
Where a tree grows also matters. For example, if it’s located in a place with lots of water and sunlight, it will probably absorb more CO₂ than a tree in an area that is lacking these two things.
Trees don’t perform photosynthesis the whole year round. They go through different seasons where they stop growing or even die back certain times of the year. During these times, their stomata are closed which means they cannot absorb CO₂.
Why are trees such an important part of the fight against global warming?
It is clear that trees are essential to the fight against global warming.
First of all, they absorb CO₂ in large amounts which means their contribution is very significant in terms of drawing down carbon emissions into our atmosphere.
Secondly, they can help reduce other emissions such as methane and nitrous oxide because trees take in excess water from the ground which prevents it from seeping into rivers and lakes and making them too acidic to support life;
Thirdly, by absorbing CO₂ through photosynthesis, they contribute to producing oxygen that we need for survival. This makes them essential for the overall health of our planet;
Fourthly, trees provide us with shelter and habitats because they are home to animals such as birds, insects and mammals which make up around 80% of all living things on Earth. So if we continue cutting down forests instead of planting new ones, many animal species will become extinct.
Ways we can help save our planet by planting more trees
Deforestation is a massive and global problem that is affecting the planet in countless ways. However, it’s not too late to fight back by planting trees and do our part for reforestation!
Because the climate is changing and global warming is occurring at a fast rate, we need to take action before it’s too late. Planting trees can help reduce CO₂ emissions from the atmosphere while also slowing down climate change.
While most deforestation is happening in the tropical rainforest regions, and reforestation there is most important, there are no shortages of places where more trees can be planted.
The atmosphere is a global and interconnected system, so any action that is taken in one part of the world will have an impact on other parts. Just as cutting down a tree in Honduras will prevent a certain amount of CO₂ from being absorbed, planting a similar tree in Scotland will over time reduce the same amount of CO₂.
If you can, consider donating to an organization that plant trees in the areas with the highest deforestation rates, but don’t get stuck trying to decide where to plant a tree. What matters most is that a tree is planted, and since trees have essentially no downsides, the more the better.
You’ll not only be doing something to save the planet, but it will give you a sense of satisfaction too!