trees and carbon sequestration in the f -...

Trees and Carbon sequesTraTion in The Field 1 Parks as Classrooms GreaT smoky mounTains naTional Park

Trees and Carbon sequesTraTion in The Field

Grade Level: High School

Subject Area: Science

Activity time: 75 minutes

Setting: Schoolyard or Woods near school with pre-selected trees and Classroom with computer access

Skills: Analyzing, Applying, Calculating, Comparing, Hy-pothesizing, Inferring, Prob-lem solving, Summarizing

Vocabulary: •Carbon dioxide: A colorless, odorless, non-combustible gas. It is produced when any substance containing carbon is burned. It is also a product of respiration and fermentation. Plants absorb carbon dioxide through photosynthesis.

•Carbon sequestration: The removal and storage of carbon from the atmosphere in carbon sinks (such as oceans, forests or soils) through physical or biological processes, such as photosynthesis. For trees carbon is sequestered in its cel-lulose (plant cells).

•Carbon stock (“reservior”, “source”): A reservior or com-ponent of the carbon cycle that releases more carbon than it absorbs.

•Carbon sink: A “pool” that stores and traps carbon.

Materials:•A pre-established plot in mixed forest near your school•Clipboard•Pen or pencil for recording data•Carbon sequestration worksheets (pages 4-8)•Teacher guide for tree growth factor and carbon calculator (page 3)•Teacher answer key (pages 9-12)•Tape measure per group•Calculator per group•Local tree field guide per group•Computer with downloaded CO2 calculation Excel table at http://www.fs.fed.us/ccrc/topics/urban-forests/ctcc/ (there may be trees in the pre-established plot that cannot be found in the calculation table and one will have to substitute similar species in to get total number of pounds of carbon sequestered).

Objectives: 1) understand how to calculate the DBH of a tree2) identify tree species2) understand how trees sequester CO23) understand how much CO2 an average tree sequesters in a year4) practice math skills

Background: Teacher can discuss with students 1) connections between respiration, photosynthesis, and tree carbon sequestration, 2) how trees sequester CO2, 3) the normal balance and the current imbalance between amount of CO2 absorbed and released, and 4) “old” sources of carbon versus “new” sources of carbon

During photosynthesis trees take CO2 out of the atmosphere, and combine it with water and light

to produce food. They release oxygen as a by-product. During respiration trees use oxygen (O2) to convert food to energy, releasing CO2. Overall, trees absorb more CO2 than they release. They store it as wood growth.

Respiration equation: C6H12O6 (carbohydrates) + O2 (oxygen) H2O (water)+ CO2 (carbon dioxide) + Energy

Photosynthesis equation: H2O (water)+ CO2 (carbon diox-ide) + Energy C6H12O6 (carbo-hydrates) + O2 (oxygen)

Normally, there is a balance be-tween the amount of carbon diox-ide produced as plants and animals breathe, and as living things (whose cells are carbon based) die. These are called “young” sources of carbon, because they are constantly produced and are used again by the system. Additionally, carbon is stored in trees, grasses, and soils.

Plants use carbon to grow; just as you use food to grow taller, plants use energy stored during photo-synthesis to grow cellulose (plant cells). When we cut down whole forests of old growth trees, or clear land and pave it over for develop-ment (especially if there’s burning to clear land involved), we release the carbon that’s been stored in these living things for decades or even sometimes centuries.

Additionally, we’re concerned on a global scale about “old” sources of carbon being released—the car-bon-based oil, coal, and other fossil fuels that we extract from their stable form deep within the ground and release into the atmosphere as


carbon dioxide gases.

Globally, humans are releasing more carbon dioxide than living things—forests, grasses, oceans, and soils—can absorb. The excess gases sit in the atmosphere above the earth’s surface and absorb heat energy from the sun, warming the earth’s average temperature overall. This doesn’t mean that everywhere on earth feels warmer—in fact, warming the atmosphere near the earth’s surface creates often violent wind patterns that change day to day weather, bringing storms, high levels of rain and snow, and hot and cold air currents at sometimes unexpected times. So it makes more sense, even though overall the global average temperature has warmed over the past century, to call what’s happening global climate change, which better explains the variations and unexpected events that we’re recording across the world.

There are many people thinking about how we can fix this imbalance between the amount of carbon released into the atmosphere and the amount absorbed. One way is to look to trees and find out how much carbon dioxide they can absorb and store in their trunks. During the activity we will be viewing data of trees’ species and diameter at Diameter at Breast Height (DBH) and using the pre-calculated total number of pounds of CO2 sequestered —or absorb to grow—in a year.

Procedure: Discuss the vocabulary terms listed on page 1 and the background of carbon sequestration on pages 1 and 2. Go out into the schoolyard or woods nearby for the field portion of the activity. Students will complete Step 1 on their worksheet. Students should be split into small groups (2-4 people). Each group can be responsible for a section of the plot or for a certain tree species. Each group should identify each flagged tree (teacher should have these trees preflagged with a number associated with each tree), record the common name, scientific name, and the circumference of the tree (completing Table 1 in Step 2 of worksheet). The tree circumference should be measured at standard “breast height” (DBH) which is 4 1/2 feet (1.5 meters) from the ground. When all of the trees in the plot are measured, the groups will come back together as a big group and talk about the dif-ferent trees you found (types, DBH, etc) and discuss their thoughts on their hypotheses. Move inside to the computer(s) for analyses. Remember the “Hints! Page” on page 7 is for their use. The answer key is a helpful guide for teachers facilitating the activity (answer key found on pages 8-12). Use the downloaded CO2 calcula-tion Excel table at http://www.fs.fed.us/ccrc/topics/urban-forests/ctcc/ to convert the DBH and tree species to total number of pounds of CO2 sequestered. Refer to page 3 for Teacher Guide for determining tree growth factor and using the USFS carbon calculator. Have one student volunteer to write Table 1 on the board so that all of the students can see the calculated numbers. Each group should be placing their data into their own Table 1 after calling out their tree species and DBH and receiving the total number of pounds of carbon sequestered. After each group has finished their own data in Table 1 then students can use the collective total on the board of Table 1 to combine all of the data for use in Table 2.

References: • http://www.clker.com/clipart-map-symbols-automobile-car-white.html• http://www.clker.com/clipart-truck-car.html• http://www.insights.co.nz/dynimages/Insights%20carbon%20tree.JPG• http://www.epa.state.oh.us/dapc/climatechange/carbon_sequestration.aspx• http://www.slate.com/id/2181499/• http://www.epa.gov/climateforaction/learn/glossary.htm• http://www.learner.org/jnorth/tm/leaf/HowOld.html* http://www.fueleconomy.gov/feg/maintain.shtml


Growth Factor of Common Trees Ash, Green = 4.0 Aspen = 2.0Birch, River = 3.5Birch, White = 5.0 Cherry, Black = 5.0Cottonwood = 2.0 Dogwood = 7.0Elm, American = 4.0Hickory, Shagbark = 7.5Ironwood = 7.0

How to use the growth factor to calculate the approximate age of a tree: DBH (inches) X Growth Factor

*** You will have other trees in your plot besides the ones listed above. Use the Internet to determine which of the above species are closest in growth rate to the trees in your plot,

There may be trees in the pre-established plot that cannot be found in the Carbon Calculator calcula-tion table and you will have to subsitute similar tree species in to get total number of pounds of carbon sequestered. Below are some common tree substitutions:

•Carpinis caroliniana = American hornbean, Instead use Carpinus betulus (Common hornbeam) Pacific NW, CABE_F •Liriodendron tulipifera = Tulip poplar, North and Central Coast, LITU •Acer saccharum = Sugar maple, Midwest, ACSA2•Liquidambar styraciflua = American sweetgum, South, LIST•Quercus alba = White oak, South, QUAL•Acer rubrum = Red maple, Midwest, ACRU•Cornus florida = Flowering dogwood, South, COFL•Oxydendren arboreum = Sourwood , Instead use Robinia pseudoacacia (Black Locust) North and Central Coast, ROPS•Ulmus alata = Winged elm, South, ULAL•Betula lenta = Sweet birch, Instead use Betula nigra (River birch) South, BENI•Acer pensylvanicum = Striped maple, Instead use Acer sacsharinum (Silver maple), Midwest, ACSA1•Aesculus flora = Yellow buckeye, Instead use Liriodendron tulipifera (Tulip poplar), North and Cen-tral Coast, LITU

TeaCher Guide For deTermininG Tree GrowTh FaCTor

Linden or Basswood= 3.0 Maple, Red = 4.5 Maple, Silver = 3.0 Maple, Sugar = 5.0 Oak, Pin = 3.0Oak, Red = 4.0 Oak, White = 5.0 Redbud = 7.0 Spruce, Colorado = 4.5Walnut, Black = 4.5

TeaCher Guide For usinG The usFs Carbon CalCulaTor


Name___________________________

TreesaNdCarboNsequesTraTioN

STEP 1: a. Location:

b. Collectors:

c. Date:

d. Create a hypothesis out of the following question: Do you think young, small trees or old, large trees will sequester more carbon dioxide? Why do you think that this is so? #1. Hypothesis:

STEP 2: Directions: In your study area, your group will collect species and size information about trees. Use the identi-fication tag on the tree to determine the common name for the tree species to identify each tree. Have your re-corder write its common and scientific names in the table below (use the attached sheet for the scientific name). Help your measurer measure the tree’s circumference at DBH (diameter at breast height, 4.5 feet (1.5 meters) from the ground). The fifth through seventh columns will be completed after you return to the classroom with the computer and calculator.

Table1(TreesiNsChoolyardorWoodsNearThesChool):2.

Tree ID

Tree species (Common name)

Tree species (Scientific name)

Cir-cumfer-ence (inches)

DBH (circum-ference divided by 3.14)

Total number of pounds of CO2 seques-tered per year (calculated by computer)

Growth Factor

Approxi-mate Age of Tree(DBHx-Growth Factor)

* When you see (Hint!) = Use hint page if you need help with figuring out the equation!* Diameter x Growth Factor = Approximate age of tree in years* Total number of pounds of CO2 sequestered this year are calculated from a US Forest Service carbon calculator.

4.5 ft (1.4 m)DBH = Diameter at Breast Height.DBH is measured at 4.5 feet (1.4 meters) from the ground.


STEP 3: 3. Complete the following chart:

A. Tree Species (Common name)

Tree Species (Scientific name)

B. Total number of pounds of CO2 sequestered

C. Number of individual trees of the same species (for all groups)

D. Average CO2 sequestered by an average, single tree of that species (B column divided by C column)

1.

2.

3.

4.

5.

6.

7.

Total of B column: __________

Total of C column: __________

4. Create a bar graph with Tree species (common name) to Number of individual tree species

5. What tree species has the most individuals? (column C and above bar graph)? _____________________

6. What tree species has the highest average CO2 sequestration (column D)? ____________________

Table2(summaryofTreesfromTable1)(Hint!) = Use hint page if you need help with figuring out the equation!

Num

ber

of In

divi

dual

Tre

e Sp

ecie

s

Tree Species (Common Name)


7. Why would a tree sequester zero pounds of CO2?

8. What is the average number of pounds of CO2 sequestered for a tree in the plot? (Hint!) ___________ average number of pounds of CO2 sequestered for a tree in the plot

9. Carbon dioxide emissions are the transportation sector’s main contribution to climate change. Carbon dioxide emissions are directly proportional to fuel economy. Name three ways a person can increase their ve-hicle’s efficiency (meaning the less gas it uses to go the same distance) producing less carbon dioxide and improving their fuel economy? a. b.

c.

10. How much CO2 does the plot of trees sequester in terms of cars’ emissions over the year? (Hint!) ___________ cars’ worth CO2 sequestered by trees in our plot

11. But not everyone drives a car. Many people travel in pickup trucks, vans, or RVs. Howmuch CO2 does the plot of trees sequesters in terms of trucks’ emissions over the year?(Hint!) __________ trucks’ worth CO2 sequestered by trees in the plot.

12. In 2009, 4,026,815 cars visited the Great Smoky Mountains National Park. How many cars, on average, traveled through the park each day? (Hint!) _________ cars per day

13. How many pounds of CO2 does each car, on average, emit in a single day? (Hint!) __________ lbs CO2 emitted per day by an average car

14. How many pounds of CO2 are emitted by visitor car use in the park each day? (Hint!) _________ lbs CO2 emitted per day by all visitor cars

15. How many pounds of CO2 are sequestered by an average tree each day? (Hint!) ________ lbs CO2 sequestered by an average tree each day

(Hint!) = Use hint page if you need help with figuring out the equation!


(Hint!) = Use hint page if you need help with figuring out the equation!

16. How many trees like the average one in the plot would it take to sequester the carbon from visitors, staff, and scientists driving for a single day in the Smokies? (Hint!) ________ trees

17. List four ways YOU can reduce the total CO2 in the atmosphere. a.

b.

c.

d.

18. Knowing what you know now, go back to Question #1 and determine if your hypothesis was supported or rejected?


HINT! Page For Useful Equations

8. Hint: Total of B column (ALL of the species’ totals for pounds of carbon dioxide) Total of C column (ALL of the individual number of trees)

10. Hint: Total of Number 3, B column of total lbs CO2 the plot of trees sequester (0.916 lbs CO2 emitted/mile by an average car) x (12,000 miles each yr)

11. Hint: Divide the pounds of CO2 sequestered by the pounds of CO2 emitted for each truck. Total lbs CO2 our trees sequester (1.15 lbs CO2 emitted/mile by an average truck) x (12,000 miles driven each yr)

12. Hint: 4, 026,815 cars in Smokies each year 365 days in year

13. Hint: (0.916 lbs CO2 emitted/mile) x (12,000 miles driven each year) 365 days in a year

14. Hint: Number of cars per day (Number 12 answer) x lbs CO2 emitted by visitor car use per day (Number 13 answer)

15. Hint: lbs CO2 sequestered by an average tree each day (Number 8 answer) 365 days in a year

16. Hint: lbs CO2 emitted in the park by visitor cars each day (Number 14 answer) lbs CO2 sequestered each day by an average tree in our plot (Number 15 answer)


1. Create a hypothesis out of following question: Do you think young, small trees or old, large trees will sequester more carbon dioxide? Why do you think that this is so? Students hypotheses will vary

2. ID Tree species

(Common name)Tree species (Scientific name)

Total number of pounds of CO2 sequestered dur-ing this year

DBH (inches)

Growth Factor

Approximate Age of Tree (DBHxGrowth Factor)

A1 Yellow birch Betula alleghaniensis 0 19 4 76

A2 Northern red oak Quercus rubra 308.7 16 4 64

A3 Northern red oak Quercus rubra 31.4 3 4 12

A4 Smooth shadbush Amelanchier laevis 267.2 9 4 36

A5 White basswood Tilia americana 33.4 4 3 12

A6 Black cherry Prunus serotina 267.2 9 5 45

A7 Red maple Acer rubrum 17.8 2 4.5 9

A8 Red maple Acer rubrum 306.6 15 4.5 67.5

A9 Yellow buckeye Aesculus flava 31.4 5 4.5 22.5

A10 Yellow buckeye Aesculus flava 138 12 4.5 54

A11 Black cherry Prunus serotina 327.8 10 5 50

A12 Smooth shadbush Amelanchier laevis 32.5 3 4 12


A14 Yellow buckeye Aesculus flava 55 7 4.5 31.5

A15 Yellow buckeye Aesculus flava 100.7 10 4.5 45


A17 Yellow buckeye Aesculus flava 31.4 4 4.5 18




3. A. Tree Species (common name)

Tree Species (scientific name)

B. Total number of pounds of CO2 sequestered (for all groups)

C. Number of individ-ual trees of the same species (for all groups)

D. Average CO2 sequestered by an average, single tree of that species (B column divided by C column)

1. Yellow birch Betula alleghaniensis 0 1 0

2. Northern red oak Quercus rubra 340.1 2 170.05

3. Serviceberry Amelanchier laevis 299.7 2 149.85

4. White basswood Tilia americana 33.4 1 33.4

5. Black cherry Prunus serotina 595 2 297.5

6. Red maple Acer rubrum 322 2 161

7. Yellow buckeye Aesculus flava 1006.5 10 100.65

Total of B column: 2596.7

Total of C column: 20

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4.

5. What tree species has the most individuals? (column C)? ___Yellow Buckeye_____

6. What tree species has the highest average CO2 sequestration (column D)? ___Black Cherry_____

7. Why would a tree sequester zero pounds of CO2?The tree has reached its maximum growth and it sequesters no (or very close to no) CO2 once the tree is basically mature. A mature tree still respires but it isn’t putting on new wood and locking in carbon as it does so. Additionally, different species mature at different rates. See Yellow birch example(A1) versus Yellow buckeye example(A16), same DBH (19) but different results of sequestration, yellow birch is mature and little to no sequestering is occuring while yellow buckeye is still growing and sequestering carbon.

8. What is the average number of pounds of CO2 sequestered for a tree in the plot? (Hint!) ___129.8__ average number of pounds of CO2 sequestered for a tree in the plot

9. Carbon dioxide emissions aren’t regulated, as other emissions (sulfates, nitrates, etc) are. But, it’s the trans-portation sector’s main contribution to climate change. Carbon dioxide emissions are directly proportional to fuel economy. Name three ways a person can increase their vehicle’s efficiency (meaning the less gas it uses to go the same distance) producing less carbon dioxide and improving their fuel economy? * Observe speed limit: While each vehicle reaches its optimal fuel economy at a different speed (or range of speeds), gas mileage usually decreases rapidly at speeds above 60 mph.* Drive sensibly: Aggressive driving (speeding, rapid acceleration and braking) wastes gas. It can lower your gas mileage by 33 percent at highway speeds and by 5 percent around town.* Remove excess weight: Avoid keeping unnecessary items in your vehicle, especially heavy ones. An extra 100 pounds in your vehicle could reduce your MPG by up to 2 percent.* Avoid excessive idling: Idling gets 0 miles per gallon. Cars with larger engines typically waste more gas at idle than do cars with smaller engines* Use cruise control: Using cruise control on the highway helps you maintain a constant speed and, in most cases, will save gas.* Use overdrive gears: When you use overdrive gearing, your car’s engine speed goes down. This saves gas and re-

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White bassw

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Serviceberry

Black cherry

Yellow buckeye

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duces engine wear. * Keep your engine properly tuned: Fixing a car that is noticeably out of tune or has failed an emissions test can improve its gas mileage by an average of 4 percent, though results vary based on the kind of repair and how well it is done* Keep tires properly inflated: You can improve your gas mileage by up to 3.3 percent by keeping your tires inflated to the proper pressure.* Use the recommended grade of oil: You can improve your gas mileage by 1–2 percent by using the manufacturer’s recommended grade of motor oil.* Commuting: Avoid peak rush hours. Drive your most fuel-efficient vehicle. Take advantage of carpools and ride-share programs. * Traveling: A roof rack or carrier provides additional cargo space and may allow you to meet your needs with a smaller car. However, a loaded roof rack can decrease your fuel economy by 5 percent.

10. How much CO2 does the plot of trees sequester in terms of cars’ emissions over the year? __0.24__ cars’ worth CO2 sequestered by trees in our plot

11. But not everyone drives a car. Many people travel in pickup trucks, vans, or RVs. How much CO2 does the plot of trees sequester in terms of trucks’ emissions over the year? ___0.19___ trucks’ worth CO2 sequestered by trees in the plot.

12. In 2009, 4,026,815 cars visited the Great Smoky Mountains National Park. How many cars, on average, traveled through the park each day? __11,032__ cars per day 13. How much CO2 does each car, on average, emits in a single day? ___30.1___ lbs CO2 emitted per day

14. How many pounds of CO2 is emitted by visitor vehicle use in the park each day? __332,063.2__ lbs CO2 emitted in the park each day

15. How many pounds of CO2 are sequestered by an average tree each day? _0.36__ lbs CO2 each day 16. How many trees like the average one in the plot would it take to sequester the carbon from visitors, staff, and scientists driving for a single day in the Smokies? __922,397__ trees

Teacher can discuss with students reasons why the number of trees in the Smokies is probably not adequate to seques-ter all of the carbon that enters the park through ALL human activity (not just via vehicle emissions). Reasons why we cannot estimate the number of trees in the park and reasons why CO2 car emissions are not the only CO2 sources, etc.

17. List four ways YOU can reduce total CO2 in the atmosphere. Some examples of ways in which we can reduce total CO2 in the atmosphere includes:1. Produce less CO2 as we burn carbon-based fuels for energy & products (hybrids, alternative sources of energy, recycling)2. Improve farming practices. Stop releasing “old” sources of carbon in land use: don’t clear cut and/or burn old growth forests3. Use fewer things that require carbon-based fuels! Bike, walk, use a push mower, etc

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4. Add more living things that sequester carbon—plant trees and plants5. What kind of car you drive, how you drive, and how much you drive all make a difference. 6. Promote energy efficiency in the home to use less electricity and gas. 7. Insulate your hot water tank and pipes.8. Insulate your house. 9. Reduce the temperature on your thermostat by 1°C. 10. Wash full loads in the washing machine, and dry clothes outside where possible.

18. Knowing what you know now, go back to Question #1 and determine if your hypothesis was supported or rejected? Students’ answers will vary

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