Trees are beautiful things. They sit, for years quietly absorbing nutrients from the ground to create wood, edible materials and medicines whilst stabilising the earth around them and regulating the flow of water through soils as it passes from mountain to sea. They appear silent and inactive, yet are busily going through processes to survive and to support the lives of organisms around them.
Part of this process is absorption of CO2. Trees, like plants, need CO2 to convert the hydrogen in water into sugars which it stores to fuel its growth. Through the use of light-sensitive enzyme catalysts in each cell of a tree, the energy of sunlight is used to break the carbon-oxygen bond in CO2 to release the carbon and render it available for reaction with the water hydrogen. This may sound complex, but nearly all trees and plants rely on this process of photosynthesis to survive.
Trees, likes humans also “breathe out” CO2 at night as a means of using up excess oxygen in cells, and is the way in which they convert stored glucose energy into useable energy. Like eating a spoonful of sugar, this is how trees “eat” the glucose and other sugars created through photosynthesis to meet their needs for energy. Just like drinking a sports drink before a jog, trees have their very own corner shop in each cell where glucose is ready for when they need it.
Of these two reactions, it is the absorption of CO2 (the “inhale”) and emission of oxygen which is a more significant stream volume-wise than exhalation of CO2 and absorption of oxygen. Release of CO2 is continuous, and mostly at night but happens continuously throughout a tree’s life at a very low flow rate. Absorption of CO2, on the other hand, kicks into action at high volumes as soon as the sun comes out. The tree relishes in the sun’s rays and starts off a photosynthesis bonanza which churns out CO2 at a rate far faster than that of its emission of CO2 throughout the day. Therefore trees can be said to be “CO2-negative”; that is, they absorb more of it than they emit.
This net absorption of CO2 is an essential counterweight to humans, animals and fish within the planetary ecosystem. Animal species breathe out CO2 as a by-product of inhaling the oxygen used to burn the sugars and fats in our cells to drive daily activities such as moving muscles, digesting food and regenerating body cells. This same process is performed in the production of energy to fuel our homes, run our industries and manufacture our goods. Carbon, in the form of coal, gas or other natural fuel sources react with oxygen in the air to create energy with CO2 emitted as a result.
Though incredibly useful, over-use of the highly exothermic (energy-releasing) use of oxygen and release of carbon from natural fuel sources has resulted in increasingly elevated concentrations of CO2 in the atmosphere. They say you can’t have too much of a good thing, but in the case of planetary equilibriums, this mantra doesn’t hold true and an excess of virtually any substance in a given environment is likely to cause harm. In the case of CO2, this has resulted in the energy-absorbing carbon-oxygen bonds within gaseous CO2 to trap heat from the sun and warm the earth.
Whilst we have been eating up oxygen and churning out CO2 to drive our modern lives, trees have continued to fulfil their needs by doing, for the most part the complete opposite. They know no other way, and will likely to continue to do so whatever the fate of mankind and the way we have decided to fulfil our needs.
However the very different two plant and animal respirational systems evolved, there is an interesting fact that sits waiting to be used as a solution to the much-debated and as yet unresolved issue of CO2-driven climate change and global warming. The net amount of CO2 absorbed by a tree in a day is almost identical to that exhaled by each one of us human beings.
What does that mean? It means that for the gift of every new human life granted upon us each day, a tree should be planted to compensate for that human’s respiratory needs until that person has enjoyed their journey back into the ground. Trees should be planted as a counterweight to the prolific success of the human race, as markers of our evolution and of our ability to reproduce and survive. We do not need hi-tech solutions or political discourse to solve one of the greatest challenge posed to our human race. We just need to use what our planet has already given us. We just need to plant trees.