08 July 2020

We reinforced our knowledge on the water and carbon cycles

Before the lockdown began in spring, Lower Sixth Geographers, including Bailey Allmey, made the short trip into the Chiltern Hills to learn more about water and carbon cycles through practical experiments.

On our trip to Amersham, we reinforced our knowledge on the water and carbon cycles by completing a variety of practicals in the local woodland area.

For the Water Cycle, we completed a practical using three hydroslopes with different surface materials; one with concrete (to simulate an urban area), one with grass (to simulate a grassland) and one with ploughed soil (to represent farmland where crops would be grown). We did this with an aim to find out which surface created the highest peak discharge, as well as which surface had the longest lag time.

Another practical we completed included calculating the interception rates in different woodlands. We did this by calculating the percentage of canopy cover three different times in each woodland using a quadrat, while measuring the amount of water collected in the water gauges from the past month in each different woodland. We were then given a control amount of rainfall, and with this number we were able to calculate the amount (in mm) and percentage of water that was intercepted, therefore finding out which type of forest had the highest interception rate. In addition to this, we also measured the interception rate of water into the ground for extra information. We did this by randomly selecting an area of ground in each woodland, and then every 30 seconds measuring the amount of water gone into the ground from 10cm3 of water.

For the carbon cycle, we completed a practical where we collected data on trees in a recently trimmed and controlled area of woodland, and then in an area where they area allowed to grow naturally, in order to find out the amount of carbon stored in these trees. By collecting data such as the radius of the top and bottom of these trees, as well as angle to the top of these trees and taking the average for each type of data. These are only a few examples, but with data like that and through various calculations we were able to calculate the amount of carbon stored in the various woodlands.

In my opinion, my favourite and most valuable part of the trip was when we collected the data on the trees, as I simply found it intriguing how by collecting such simple data we were able to calculate something so complex as the amount of carbon that is stored in the tree. I also very much enjoyed when we were in the class, and by going through some of the ideas of each cycle helped me to reinforce my knowledge about them.