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Trees absorb CO2 from the atmosphere by the leaves and then store the carbon in their wood. As scientists observations like these are nice but questions are what we live for. Every good observation has questions buried inside if we look for them. If trees store carbon we can ask how much carbon is in the tree outside your window? We will start by weighing a tree in your neighborhood. Using that weight we can find out how much carbon there is in the tree. If we know how much carbon the tree is sequestering we can ask how much CO2 has the tree removed from the atmosphere.
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Trees are very large and grow very slowly. Being scientists, we will use computer models to explore our trees. We can model our trees using Excel and JavaScript models.
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Through this lesson you will discover how to:
Estimate a tree's weight using its diameter and height.
Determine the weight of carbon in the tree based on its weight.
Calculate the CO2 the tree consumed to store this Carbon.
Calculate the gallons of gasoline burned to produce this CO2.
Determine the miles driven by your favorite car to produce this CO2.
Your school uses energy for lights, heat, etc. Therefore, your school is responsible for putting CO2 into the atmosphere. You will determine the number of trees required to sequester the CO2 your school is responsible for each year.
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Different species of trees have different densities and shapes. Pine and balsa wood is light. Oak and hickory wood is dense and heavy. Pine trees are tall and relatively thin. Oak trees are tall and broad.
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Therefore, the first thing we need to do is determine the kind of tree we are looking at.
If you know the kind of tree that you are weighing you can start WEIGHING YOUR TREE.
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There are two ways to identify a tree. You can use a tree identification book and start on the first page. Compare your tree with every picture in the book. If it is a good tree book that could take a long time. Some trees are related and can be confused if you aren't trained to look for the subtle differences. The faster/better way is to use a tree identification key. An identification key groups trees according to their characteristics. The first two big groups are trees with needles and trees with broad leaves. With that simple decision you can eliminate half of the trees in the book. For trees with needles the next decision is between scaly needles and longer individual needles. Again, your decision can eliminate half of the remaining trees. A few more questions and you have identified your tree. There are several good identification keys on the web that you can use:
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ID It Virginia Tech tree Identification Key using leaves and twigs
Identification of Common Trees of Iowa Iowa State University Extension Forestry, discussion of tree types and tree identification.
Trees for the Pacific Northwest College of Forestry, Oregon State University
Upper Peninsula TREE IDENTIFICATION KEY from Michigan State University Extension
Basics of Tree ID Key to Leaves of Virginia Trees (for use with the 4-H tree identification project) by Dr. Jeff Kirwan and James Ward
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After you have found the name for your tree, you can investigate the math needed to weigh your tree.
