毕业生生态墙项目（The ECO Wall Project of Graduating Students）
Each year for three consecutive years before the senior students graduate, the students will plant several trees to express their gratitude to their Alma Mater for cultivating them and encouraging them to grow. All the trees on the Beijing Royal School Campus are already luxuriously green and full of vigor. The senior high school graduates of 2019 intend to devote more greenery and fragrance to the Alma Mater with a strong sense of gratitude.
Forests absorb carbon dioxide and release oxygen as they grow. According to research, for every 44 grams of carbon dioxide a tree absorbs, it emits 32 grams of oxygen; for every gram of glucose produced through photosynthesis, its leaves consume 2,500 liters of carbon dioxide. In theory, a forest can absorb about 850 kgs of carbon dioxide from the atmosphere for every cubic meter of wood it grows. In the peak growing season, one hectare of broad-leaved forest trees can absorb one tone of carbon dioxide a day and produce 750 kgs of oxygen. According to this research, all the green plants in the world emit more than 100 billion tons of oxygen each year. Forests not only produce oxygen, but also purify the air, reduce noise and regulate temperature and humidity. On average each hectare of forest can absorb 50 ~ 80 tons of dust (PM) per year. It is estimated that the amount of dust in the air on green (planted) streets is 56.7% lower than in areas without greenery, and the amount of dust over grasslands is only of that compared to the dust over bare land. It has been measured that the ground temperature in summer is 10-17 degrees lower in planted areas than in an open square, and 12-22 degrees lower than the temperature on an asphalt road. The average surface temperature of lawns in winter is 3-4 degrees higher than other, non-planted, surfaces.
The Eco-wall in BRS is a natural air purifier. It can be likened to an indoor forest, which can absorb harmful gases and dust particles (PM) in the air, reduce noise as well as beautify the environment. The green plants of the ecological wall increase the oxygen concentration in the air, which will in turn create a more natural environment which is conducive to clearer thinking and positive moods.
The Eco-wall project was designed and implemented by the graduating class of 2019. It was divided into the following sections:
Work on the wall started early, the main task was to select the most suitable wall bracket, flowerpots and irrigation system for the overall construction of the ecological wall. According to the precise measurements, the effective area of the Eco-wall was 356 cm * 304 cm, which was about 10.8 square meters. After measuring the space needed, the team members discussed the arrangements of the flowerpots to build the most stable wall, so as to avoid the wall collapsing and causing injury to teachers, students and other staff members. At the same time, members of the wall group took into account the problem of irrigation and purchased a complete flume set (four connected flumes) to facilitate irrigation.
In order to ensure the plants grow healthy, members of the lighting group bought the floodlights which have a moderate range of exposure in comparison to the size of the wall. The floodlights will allow the plants to get some necessary and sufficient light exposure in order to facilitate their growth, while at the same time increase the aesthetic value of the wall. The lighting used on the Eco-wall is adjustable and can slide on a track to allow for illumination of the entire wall and therefore all the plants on the wall. It is like a little, artificial, indoor sun.
The selection of plants was an integral part of the Eco-wall project. A selected group of students were responsible for selecting suitable plants, calculating the budget, planting the plants on the wall, as well as being responsible for the maintenance of the wall. The group researched dozens of plants which are drought-resistant and shade-loving, like the Green Radish, Trachelospermum Jasminoides Flame, Arrowroot, Jade Chlorophytum. After three or four revisions of the budget, the plant species and number of plants were finally confirmed. There will be 5 kinds of plants and 588 pots.
Planting on the wall was a difficult task, however, this was also the final and most important step for the Eco-wall project. All the students in the group made a concerted effort to help plant on the wall. In the process of planting on the wall, they firstly divided plants into individual ramets (in total there were more than 120 pots of plants); after which these were planted into the pots, filled with soil, compacted, irrigated and arranged on the wall. Students worked well together, and the cooperation within the group resulted in the process being completed in one session.
According to research, an adult inhales more than 20,000 times (15-20 cubic meters of air) a day, and each individual consumes about 0.75 kg of oxygen. According to this calculation, each urban resident needs the required oxygen provided by 10 square meters of woodlands which grow well. The population of Beijing city is about 20 million, the global population is about 7.5 billion. So according to the calculation, Beijing residents need 20,000 hectares and global residents need 7.5 million hectares of green space to provide oxygen. However, the effective area of the plants on the ecological wall is about 10.8 square meters. It can produce 0.81 kg of oxygen per day, which is sufficient to provide the daily oxygen demand of an adult.
The ecological wall appears to be alive and doing well, and the day we will leave BRS is drawing closer. While the efforts of The Ecological Wall team are not in vain, a green school is the final farewell gift we send to our school. We hope BRS flourishes, and our school can cultivate a number of talents and make great achievements every year!
Let the green leaves help us say good-bye!