Tuesday, November 17, 2009
Today in IGSS - C02 Sequestered in a Tree
Students participated in a science lesson which focused on the CO2 sequestered in a tree.
They learned that trees will sequester atmospheric carbon dioxide at an average of 50 pounds of carbon dioxide per tree per year. The rate of carbon sequestration depends on the growth characteristics of the tree species, the condiition for growth where the tree is planted and the density of the tree's wood. I learned that is greatest in the younger stages of tree growth between 20- 50 years.
Students learned how to roughly estimate the amount of CO2 sequestered in a given tree. When they divide by the tree's age they can calculate a yearly sequestration rate.
Students spent about 15 minutes outside finding trees to measure using a string and ruler to measure the circumference of a tree at chest height, and paced off a convenient distance from the tree ( ~50feet) to calculate the height of the tree using this height calculation:
Height = tangent of angle of elevation x base distance
Using formulas and calculators inside the classroom, students determined the total weight of the tree, the dry weight of the tree and the weight of carbon in the tree.
Then they were able to figure out the lbs. of carbon dioxide sequestered in the tree.
Concluding activity: Compare the C02 produced by a family to the C02 sequestered in a tree.
Students calculated that 100 trees were being used per month just for New Trier students C02 footprint on their commute to school!
Using a carbon calculator it is calculated that an averge of C02 emitted each year per person is 7.5 tons. See carbon calculator.
To explore this topic further see the work of the Center for Urban Forest Research Tree Carbon Calculator. Their program allows users to realize that trees don't just look nice; people now have an incentive to plant trees or maintain those already standing.
Readings this Week:
Emerson: Chapter 2 and 1st 1/2 of Chapter 3 - due Monday
US and Environment Part II readings due Tuesday; read pp. 6-18 (a good oak) in Leopold's Sand County Almanac. A Sand County Almanac is a combination of natural history, scene painting with words, and philosophy.
Leopold defines his land ethic: "A thing is right when it tends to preserve the integrity, stability,
and beauty of the biotic community. It is wrong when it tends otherwise."
Emerson: Finish Chapter 3 and Auto-dialectic journal #2. due Wednesday;
US and Environment Reading Packet III assigned