What are trees made of? Why are trees important for us, and what role do they play in climate
It is with these questions in mind that I began looking at the trees in school in a new light. Determined to find answers to these questions, I immersed myself into their study and strove to understand them to the best of my potential.
Forming a small team of five students from class eleven, we carried out a detailed survey of each tree on campus, collecting data and drawing conclusions by using logical estimations. Our small project yielded some though-provoking results, which are worth sharing. Aside from providing us with oxygen as a byproduct of the process of photosynthesis, trees carry out another vital function that is very often overlooked. Trees act as carbon sinks.
How exactly does this work?
Trees take in massive amounts of atmospheric carbon dioxide and store it as biomass in solid or liquid form, as wood or sap. This is a process called carbon sequestration, and is carried out by every tree to facilitate its growth. Here is where one must answer the question –
What are trees made of?
By weight, trees are around fifty percent water. Of the remaining fifty percent, about half is cellulose or lignin, and a fraction composed of nutrients and minerals. That leaves one-fourth of the original weight, which is composed of carbon. When a dead tree disintegrates, or wood is burnt, this carbon is combined with oxygen and is released back into the atmosphere as carbon dioxide. Carbon dioxide is also produced when fossil fuels are burnt, like in the running of a car, or in producing electricity.
The total carbon dioxide emissions caused by an individual or an institution is known as their carbon footprint. If an institution’s carbon footprint is equal to the quantity of carbon dioxide that their trees sequester per year, they are said to be carbon neutral. The aim of our project was to determine Vasant Valley’s carbon neutrality. Vasant Valley has two major sources of carbon dioxide emission, and these are the school buses that we run, and the electricity that we consume. For each gallon (about 3.7 liters) of petrol combusted, around 20 pounds (9 kilograms) of carbon dioxide is released. Similarly, for every kilo-watt hour of electricity consumed, around 1.4 pounds (600 grams) of carbon dioxide are released.
After doing the math, Vasant Valley produces a staggering 411453 pounds (186631 kg) of carbon dioxide a year.
How do the trees weigh up? Within the fence, Vasant Valley has a total of a hundred and fifty-three mature trees, representing forty-three distinct species. Since a mature tree has a fixed yearly growth rate, it becomes possible to calculate the carbon each tree sequesters per year. Agro-foresters use a formula for the calculating the annual sequestration, but this requires the age, height, weigh, diameter, and species of each tree as a prerequisite. So we began painstakingly measuring each tree, and using formulae from agroforestry records to calculate these for each of the 153 trees on campus. Post the math, we found the average carbon sequestration rate to be 184 pounds (83 kg) each year. Post more math, we reached the conclusion that Vasant Valley sequesters 27895 lbs. (12653 kg) annually. This is a mere fraction of the amount of carbon dioxide we release per year- a meagre 6.77%, making Vasant Valley very, very carbon positive.
Is carbon neutrality, or for that matter carbon negativity achievable?
For Vasant Valley, it looks unlikely, but on a larger scale, the answer is yes. Bhutan has 72% of its total land area under forest cover, and as a result, sequesters three times the amount of carbon dioxide it releases, making it carbon negative. What would it take for Vasant Valley to attain carbon neutrality? Firstly, an outstanding increase in land area. We would have to plant 16 times the number of trees we currently have, (that’s 2448 more trees) and wait an average of 10 years for them to mature. Still, chances are that our carbon footprint too would increase in the meantime.
While we have the numbers to put things into perspective, we must realize that if we don’t keep striving to be more aware in and of our energy consumption, the duty our trees are performing becomes more futile each year, and the statistics are bound to spiral out of hand. If we cannot increase the amount we sequester, we must work to decrease the amount we release, by turning off the light switches, or taking the bus to school. The numbers are not just figures, they make us acutely aware of the world we live in, and the steps we must take to preserve it.