THE FACELIFT OF A TREE
STUDENT GENERATED LAB PACKET
This student generated lab serves the purpose of helping ourselves as well as you to understand why the American Sycamore Tree sheds it's bark. Through background information it is seen that this process allows the tree to further mature, but we are also looking for an answer concerning the rate of peeling. Do certain weather patterns speed up the process; does the location of the tree effect the peeling? In order to answer these questions more than background knowledge is needed. Instead, a hands on approach will give us the insight we are looking for. By taking samples of bark from trees, recording the amount of peeling, and taking pictures we feel this lab will prove to be conclusive to our initial questions.
The purpose of our lab is to find out why some trees peal and others don't. Although the Sycamore tree is easy to identify during any season of the year because of its characteristic scalding and shedding, it is wondered why this tree, like a few others exfoliates old bark leaving the younger, more sensitive bark exposed? According to Richard Jauron of Iowa State University, the shedding bark on some trees is completely normal in the tree's development. This is because as the tree ages the bark layer thickens with the outermost tissue eventually dying. Thus, any continued growth causes the outer layers to crack, which in turn causes, the dead outer layer to drop off, or peel. Unlike other species of trees, the Sycamore tree is unable to stretch along with its growth, so this cracking and peeling provides excess room for additional maturity. It is then that a new, mottled brown and white color bark becomes visible, according to the Blair Park Tree Classification web page. In addition, we want to understand what pealing does for the tree, and/or if the peelings can be used for anything after they have left the tree?
Our hypothesis is that trees peel as they age and grow in diameter, but also that the rate at which they peel is effected by the weather such as rain, wind, and temperature. "This summer the sycamores have lost larger than normal amounts of bark. The dry fall and record cold of last winter may have loosened more bark than normal leading to the heavy loss of bark," said Jauron. In continuation, "Despite the loss of large amounts of outer bark, there is no cause for concern as the sycamore trees appear to be healthy." This is because the sycamore tree is generally considered the largest hardwood tree in North America. It grows to a height of 170 feet with a diameter in mature trees of up to twelve feet, and thus is seldom damaged by weather action, according to the wildlife neighbors home page. Although weather may not harm the tree, it can still be considered that the weather plays an important role in the tree's peeling.
It is understood that bark on trees protects the tree from physical injury, water loss, diseases, and insect and animal pests. What is more difficult to understand is the idea that with each year of a trees life an additional layer is being formed, that will then be shed. Why would a tree grow, only to peel? This is because the trees do not peel at the rate of which they grow. Normally most trees retain several years of growth to the point where the bark becomes thick before the peeling process takes place, according to Joseph R. Thomasson. In connection to this, Thomasson completed a study at the Fort Hays State University dealing with the unique and distinctive patterns as a result of the way different trees peeling processes occur. He found that the Honey Locust tree bark peels in rings. By this the bark peels in many different horizontal rings that cover the entire diameter of specific parts of the trunk. The Paper Mulberry tree peels in long vertical strips. He also found this tree to one that allows several more years of growth before peeling begins. The American sycamore tree, which has previously been discovered, tends to peel in pieces. Although the peeling begins at the top of the tree while working its way down to the trunk, this tree has no specific order to its peeling.
Through this study we plan to accomplish fully understanding why the sycamore trees have this need to peel. This includes how often it peels, the rate at which it peels, what natural occurrences influence the peeling, and finally why this process is relevant to humans. As noted from the Platanus occidentalis web page, "wood is used for boxes, crates, baskets, yokes, furniture, butcher's blocks, automobile parts, and woodenware." Another use of the sycamore tree is based upon its roots. Even though this has nothing to do with the bark, the tree's interlacing roots make it very suitable for planting along the water because they minimize stream bank erosion. As a result, this tree is able to thrive in moist areas, with rich soil along streams and lakes. Obviously, the actual wood of a tree contributes greatly to human society, but more importantly, it is the growth of the tree, and the peeling of the dead bark that allows for this growth, hence such products can de derived from the mature wood. Although this process of peeling is not common for all tree species, we hope that through this study a better understanding is available for why it is vital in the aging and continuation of the American sycamore.
MATERIALS AND METHODS:
To complete this lab we will closely observe the pealing of three different sycamore trees within Miami's campus. All three trees are located in completely different areas, such as the presence of people, other trees, and water. After selecting the three trees we are going to observe, we came up with the way in which we will observe them. On each tree there have been four specific parts that will be watched, measured, and photographed. These four parts include two on either side of the trunk, and then two on different branches, which are on opposite sides of the tree. We came up with these four spots because we wanted to cover whether more bark peeled from the trunk or the branches, while also taking into consideration whether one side peeled faster than the other side. With a ruler we will actually measure the amount of bark that has peeled from each spot. Then we will take a picture of each of the four spots on the tree (although not as often as our sampling will be done since noticable differences will probably not be seen day to day), followed by the recording of these numbers, which will actually make up our statistical data. This process will continue to occur 2-3 times each week until the beginning of December. It is then that all of this data will be combined, and that the pictures will be put on a board next to each other so that the numerical statistics and the visual sight of the peeling rate can be seen. Although this process will continue until the beginning of December, we will divide our data, and pictures into each week beginning with Monday and ending with Sunday, so that the weather patterns can be taken into consideration. This way, if it were to rain the day before measurements were taken, the rainfall would still be noted as effecting the rate of peeling. This division into weeks will also allow us to consider the temperature, and wind speeds into our data. Otherwise, we are afraid that if high wind speeds, and rainfall did not occur on the day measurements were taken, their effects would be overseen. Our weather collection will be based on internet weather web sites, which report weather on a week to week basis.
We will be using disposable cameras to take pictures of the peeling, a tape measure to measure to amount of bark that has peeled for each observation, a chair so measurements can be taken on higher parts of the tree, a calculator to find the mean, median, mode, and standard deviation of the pealing rates, and film that will be processed so the physical changes can be seen.
We believe our lab is statistically sound because our sampling is random in the fact that we are not trying to obtain certain outcomes. This can be said even though according to David Raup, of EXTINCTION bad genes or Bad luck, "Most scientists and philosophers now agree that nothing is truly random in the natural world. The motion of molecules in a gas, the advance of a glacier, the formation of a hurricane, the occurrence of an earthquake, and the spread of an epidemic all have causes." (pp.50). Although we have specifically chosen the trees we will be studying, this is because we want to account for more than one type of location and surroundings. If only one tree is observed or only trees in a certain area, our outcome might be completely different from the peeling of a majority of sycamore trees in America. In addition, by taking samples from different locations on the trees, we will be able to observe peeling rates of one location on the tree in comparison to other locations on the tree. We are not trying to collect one type of data; however, we are wanting to obtain data that will give a better understanding pertaining to sycamore peeling rates. For these reasons our sampling is statistically sound because of the uncontrolled outcomes.
We plan to involve the class by dividing you all into three groups where each group will be taken to a different tree. There you will make our observations for the day including measurements, pictures, and the recording of the data. You will also be factoring in the weather for the day such as the temperature, and then the weather patterns for the week. In order to make these measurements and recordings; each of us (lab members) will be at one tree helping them with what you need to do. In addition, you will each be given a handout with all requirements included. This is so we can monitor the measurements each class group came up with, and to make sure no group left out any observation or important piece of information. We hope that through these hands on experiences you will become more interested in why the tree peels, what makes it peel, and why you should learn more about our research plan. We also feel that having you take an active part in our lab will allow you to feel apart of our presentation, since you helped collect our data.
1. Godfrey, R.K. 1988. Trees, Shrubs, and Woody Vines of Northern Florida and Adjacent Georgia and Alabama. University of Georgia Press, Athens. 734 pp.
2. Godfrey, R.K. and J.W. Wooten. 1981. Aquatic and wetland Plants of Southeast United States - Dicotyledons. University of Georgia Press, Athens. 933 pp.
3. Harrar E.S. and J.G. Harrar. 1962. Guide to Southern Trees. Dover Publications, Inc. New York. 709 pp.
4. Thomasson, Joseph R. 1998. All Bark and No Bite, Bark of Common Deciduous Trees.
5. Jauron, Richard. 1996. Shedding Bark. Department of Horticulture Iowa State University, Ames, Iowa. 129 pp.
6. Wild life Neighbors Home Page. Sycamore (buttonwood).
7. Raup, David M. 1991. EXTINCTION: Bad Genes or Bad Luck? W.W Norton and Company, New York.
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