Shanghai American School is home to over 300 trees, numerous shrubs and plant life that all contribute to the carbon cycle. Although this is the case, SAS does not have enough of a carbon sink in trees on campus to sustain the amount in printing paper. A tree absorbs CO2 (photosynthesis), uses it to produce food for its own survival, storing it as biomass allowing it to grow. When a tree respires, it releases oxygen into the atmosphere. In order to measure the amount of carbon stored in the trees, we measured the circumference of the tree at breast height and then the height of the tree. Using a chart given to us, we then determined how much carbon was stored in that tree, based on the measurements we made. Most of the trees found and measured on campus had more than one trial; I calculated the average of the circumference and height for each tree. I totalled the amount of carbon stored in trees at the SAS campus and found it was 13874.59033 kg (238 trees). I found that the bigger the circumference of the tree, the taller it was, and in most cases, stored the most carbon. .
To determine how sustainable the carbon sink is, we have to know how much carbon is used in terms of printing paper (carbon footprint of printing paper). SAS's paper consumption is large; the school pays 488,914 RMB for A4 printing paper. Each piece of paper costs 0.056RMB (SAS Source). .
488,914RMB/0.056RMB = 8,730,607 pieces of A4 paper. .
There is 8.4 g of carbon stored in each sheet of paper (Upstream Solutions), therefore:.
(8.4g*8,730,607 pieces of paper)/1000 = 73337.0988 kg of carbon.
The amount of carbon in printing paper all together adds up to 73337.0988 kg. To sustain the amount of carbon used in printing paper, the carbon sink should store at least this amount of carbon. As mentioned before, the carbon sink currently stores 13874.59033 kg of carbon, which is 5.29 times less than what is needed to sustain our usage of photocopying paper.