What are other things you can do to minimize your carbon footprint?

LAB – Carbon Sequestration                                                                       Name: ______________________

 

Introduction:

 

Humans are contributing to global climate change by emitting large quantities of greenhouses gases into the atmosphere. Carbon dioxide is a key greenhouse gas because of the large amounts of it that humans emit and because of its long residence time in the atmosphere. Carbon dioxide, however, also plays an important role in many natural processes such as photosynthesis and respiration. It is when we release too much carbon dioxide that it causes environmental problems.

 

Carbon sequestration is the process of capturing and storing carbon. Carbon can be stored in trees, soil, and in the ocean. Carbon sequestration can happen naturally like when carbon is stored in trees as part of photosynthesis, but engineers can also create opportunities for carbon sequestration by purposefully planting trees in certain areas or researching and creating manmade ways of storing carbon such as pumping carbon into the ground.

 

Carbon sequestration can help to offset the excess carbon we emit into the atmosphere.  The amount of carbon you emit is known as your carbon footprint.  You emit carbon when you drive your car, heat your home, eat food, buy clothing, use electronics, etc.  You are directly emitting carbon when you travel by car, bus, train, or airplane.  But most of the carbon you emit is emitted indirectly.  For example, fossil fuels that emit carbon when burned are used on a farm to grow your food and then to package and transport it. Or the clothes you wear and the goods you buy are created using energy, most of which results in carbon emissions.

 

Trees are a promising ways of sequestering carbon to help mitigate climate change. Plants can use energy from the sun to convert carbon dioxide and water into sugar (C₆H₁₂O₆).  Plants then use some of the sugar for their metabolism and store some of it in their tissues.  The amount of carbon stored by a plant depends on its mass and on each species’ ability to store carbon.

 

Photosynthesis: 6CO₂ + 12H₂O + solar energy è C₆H₁₂O₆ + 6O₂ + 6H₂O

 

Globally, we are removing forests at the rate of 13 million hectares per year.  Removing forests by burning them, which is a common method, not only removes carbon sinks, but also adds more greenhouse gasses to the atmosphere. In this activity, you will investigate a forest’s ability to store carbon and make conclusions about using trees to sequester carbon.

 

Please read materials and methods.  This is what you would have done to collect the data.  Since we are not meeting in person you will need to use the data sheet labeled “carbon sequestration” you can find in the labs module on Canvas to do your calculations and answer the questions.  Ensure you complete the data sheet that is part of this lab with the data provided. YOU MUST COMPLETE AND SUBMIT THE DATA SHEET IN ORDER TO GET CREDIT FOR THIS LAB!!!

Materials and Methods:

You will need:

• flexible measuring tape
• tree ID guide
• flagging tape or colored string
• >20m measuring tape
• chalk (to mark trees measured)
• pen/pencil
• data sheet
• calculator

 

In the field:

1. Create a square plot in the forest that is 20mx20m using measuring tape.
   1. Getting the corners to be right angles is the most difficult part. Do your best!
2. Tie flagging tape or string on trees or shrubs in the four corners of the plot, and then tie tape/string on trees/shrubs along the edges of the transect to mark it.
3. For each tree with a circumference of ≥ 10cm, record the species and its circumference (in cm).
4. Mark measured trees with chalk so you do not measure them twice.

Back in the lab:

Do the following calculations to finish filling in Table 2.

 

Calculate the diameter at breast height (DBH, in cm)

Diameter = circumference / π

 

Calculate the biomass of your tree or shrub (in kg)

The formula for this is M=aD^b

M= biomass

a= species coefficient a (see Table 1)

D= DBH

b= species coefficient b (see Table 1)

 

Is this species hardwood or softwood?

Hardwood trees are angiosperms, plants that produce flowers.

Softwood trees are gymnosperms, plants that produce seeds, but not flowers (think pine trees).

 

Calculate the amount of carbon in your tree (in kg).

To do this:

Multiply biomass by 0.521 for hardwood trees.

Multiply biomass by 0.498 for softwood trees.

 

Sum the total amount of carbon in your 20m x 20m (400m²) plot.

 

To find how much carbon is stored in a one-hectare (ha) plot of NVCC forest, simply divide the total kg of carbon by 0.04 ha.  (0.04 ha = 400 m²)

 

 

 

Table 1. Species-Dependent Coefficient and Exponent Values for Biomass Equation

 

Tree Species	a	b
Beech	.0842	2.5715
Black gum	.0792	2.6349
Hackberry	.0792	2.6349
Hemlock	.0622	2.4500
Hickory, mockernut	.0792	2.6349
Hickory, pignut	.0792	2.6349
Hop hornbeam	.0792	2.6349
Hornbeam	.0792	2.6349
Maple, Red	.0910	2.5080
Maple, Sugar	.2064	2.5300
Oak, black	.0904	2.5143
Oak, chestnut	.0554	2.7276
Oak, scarlet	.1130	2.4572
Oak, white	.0579	2.6887
Pine, white	.1617	2.1420

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 2. Data sheet

 

Tree Species	Circumference (cm)	DBH (cm)	Biomass (kg)	Hardwood or softwood?	Amount of carbon in tree (kg)
				TOTAL carbon in plot:
				TOTAL carbon in 1 ha:

 

Discussion Questions:

 

1. The average American emits 19,840 kg carbon per year. How many hectares of NVCC forest would you need to plant to offset each American’s carbon?

 

 

 

 

 

 

 

 

 

2. There are 316 million Americans. How many hectares of NVCC forest would you need to plant every year to offset all of America’s carbon emissions?

 

 

 

 

 

 

 

3. The United States is 983 million hectares, much of it unsuitable for forest growth. Is planting trees to offset this country’s carbon emissions a sufficient solution for climate mitigation?

 

1. Why or why not?

 

 

 

 

 

 

4. Would planting trees to sequester carbon work better in some countries than others?

 

1. Why or why not?

 

 

 

 

 

 

5. Why would planting trees near a coal-fired power plant be more beneficial than planting trees in a pristine environment?

 

 

 

 

 

 

6. Why is burning a forest especially harmful to the global climate?

 

 

 

 

 

 

 

 

 

7. Why are we especially concerned with CO₂?

 

 

 

 

 

 

8. What are some of the limitations of our data set?

 

 

 

 

 

 

 

 

 

 

 

 

9. Would you recommend planting trees to aid in carbon sequestration?

 

1. Why or why not?

 

 

 

 

 

 

 

 

 

1.   What are other things you can do to minimize your carbon footprint?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

You must have the chart with calculations complete to receive credit for this lab!!!

 

END OF LAB