What do Students Understand from Schoolyard Ecology?
A Collection of Samples of Student Work related to Harvard Forest Schoolyard Ecology studies
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| This illustrated poem was excerpted from a final report from a High School student in Jana Matthei's Notre Dame Academy Environmental Studies class in Hingham, MA. |
At Harvard Forest, we are very interested in getting a sense of the learning outcomes for students engaged in our Schoolyard Ecology projects. One of the most direct ways to do this is to look at student work related to project themes. Last year's blog of student samples related to the Vernal Pool project. This year, we have some samples related to the ever popular, Buds, Leaves and Global Warming project.
Sample introduction, graphs, and conclusion from students at Notre Dame Academy:
Harvard Forest Introduction:
Over a period of five weeks, my group and I observed two branches on our Red Maple tree. The common name is Red Maple, while the scientific name is Acer rubrum. The Red Maple normally begins budding during late winter-early spring. It buds earlier than most other trees during the springtime and it is one of the first to change color during the fall. Because the leaves on the Red Maple bud earlier than other trees, I predict that senescence will occur earlier than other trees. The Red Maple is one of the most widespread trees found in North America and can grow between 60-75 feet tall. The Red Maple is considered a deciduous tree and is best grown in wet areas. We examined the color change of the leaves and when they fell off of the trees, which marks the end of the growing period. My group and I were nicknamed, “The Tree Huggers” and on both branches we observed six different leaves. We calculated the percentage of leaves that were not green on Branch A and Branch B. Each week, my group and I recorded our outdoor observations about the weather, temperature, and how much of the leaves were eaten by insects. Our Honors Environmental science class is learning about phenology, which is the effect that climate is having on the trees, study of the life cycles, and how the leaves are changing due to climate.
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Sample Graph from Student Report |
Students formed conclusions about what their tree phenology data were saying:
Conclusion:
After reviewing the results of the other trees in my Honors Environmental Science class, I came to the realization that the Red Maple tree does not have the longest growing period. Based on the results in the table, I concluded that one of the Black Oak trees, one of the Black Birch trees and one of the Black Cherry trees began their growing period on the same day as the Red Maple tree. The tree with the longest growing period is the Black Oak tree, while the tree with the shortest growing period is the Black Birch. The Shagbark Hickory has the earliest beginning of the growing period. Although the Red Maple tree is one of the trees that flowers earlier than most trees, it does not have the longest growing season. I predict that the Red Maple tree’s growing period varies depending on the climate in the fall and in the winter. I think that if there is a rainy spring, the leaves will begin to bud earlier verses when there is a dry spring. There are some modifications that I would make to the project. I think that students should upload information onto a class discussion board on the portal. Everyone would be able to share information with one another about various tree growths, leaf fall, weather notes and observations. Next year, I think that students should find a way to use the excel document on the iPads because there were many technological difficulties with the computers.
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Another Sample Student Graph from Notre Dame Academy |
See two complete student Phenology study reports at:
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Samples of data analysis work done at Holyoke Catholic High School:
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Students in Lise Letellier's Holyoke Catholic High School freshman Environmental Science class first input field data onto an Excel worksheet including growing season calculations |
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Students then entered the growing season length from larger table on this individual table in order to develop bar graph to the right. |
After producing a variety of graphs, students formed a conclusion about what the data for their project was indicating.
A student with severe learning challenges, formed the following conclusion from their study:
Conclusion
The purpose of this observational study is to determine if there are any patterns in the lengths
of growing season of different types of trees and the different years of each tree. We are also trying to determine if the growing season length of the trees is getting shorter, longer, or staying the same over the years. At first it seemed that the data of this tree was very random and had no pattern but after comparing it to the data of other trees of the same species I can tell that the trees growing seasons are very slowly getting shorter and shorter every year and may continue to get shorter as the years go on. The average growing season of the tree is about 180 days long but shortens about 5 to 10 days every year. I think this will continue until the tree either stops producing leaves or will eventually die. The earliest growing season started for this tree was in 2012 where the leaves started to bud at around April 13th. The latest growing season it had ended was in 2013 where 100 percent of the leaves had fallen by November 2nd. The latest growing season had started was in 2014 starting at around April 28th and the earliest a growing season had ended was in 2015 ending at around October 25th. So far this information makes me assume that the older the tree gets, the growing seasons may be getting shorter and shorter every year.
An honors student formed this summary from their analysis of project data:
Summary:
The purpose of these observations is to answer the questions of when the growing season starts and ends. It also answers how long the growing season is and if the length of the growing season is changing. In order to answer these questions data was collected on leaf growth and budburst in the spring and on the percent of leaves fallen and the tree color in the fall. This is the data collected for Tree 17. Tree 17 is a crabapple tree on Springfield Street.
Tree 17’s growing season started the earliest in 2012. The leaves started growing the earliest and were the longest this year. The buds were 100% open before the observations started. In 2013, the leaves started growing later and took longer to reach their maximum length. In 2014, the leaves took the longest to start growing and reached 100% budburst the latest. This shows that the growing season has been starting later for Tree 17 over the years.
In 2012, the leaves started falling the earliest. In 2013, the leaves started to fall the latest, but 100% of the leaves were fallen the soonest. Also in 2013, the tree took the longest to start changing color and took the longest to reach 100% not green. In 2014, the tree color started changing the earliest and reached 100% not green the earliest. In 2015, the leaves took the longest to all fall off. As years have progressed, it has taken longer for all of the leaves to fall off, except for 2012, which was in between 2014 and 2015.
There was only enough data to calculate a definite growing season for 2013 and 2014. For 2012, only the minimum growing season could be calculated. There was no data for spring 2015 so no growing season could be calculated for that year. The growing season for 2012 is equal or greater to 228 days. This is the longest of the calculated growing seasons. The growing season for 2013 is 208 days, and the growing season for 2014 was 205 days. 2014 had the shorted growing season of the calculated years. The growing season of Tree 17 decreased over time. There was a large decrease between 2012 and 2013 and a smaller decrease between 2013 and 2014.
Tree 17’s spring and fall data was compared to that of Tree 24. Both trees are crabapple trees. Both trees had their earliest budburst in 2012. In addition, for both trees, the year in which they took the longest to drop all of their leaves was 2015. Unlike Tree 17, Tree 24 started to lose its leaves earliest in 2013.
Tree 17’s data was also compared to that of Tree 12. Tree 12 is an exotic cherry. In all years, the leaves on Tree 24 started falling earlier and reached 100% fallen sooner than the leaves on Tree 17. In 2012, the budburst for Tree 17 started earlier than the budburst for Tree 24. Both trees had very rapid budburst in 2013 and 2014. In 2013, the budburst for both trees started and ended on the same dates and in 2014 the budburst started on the same date for both trees.
Overall, Tree 17’s data shows that the growing season has been starting later, ending later and that the overall growing season has been becoming shorter over time.
A "regular" level student make the following analysis:
Questions:
1. Yes, I can determine how long my tree’s growing season is. In 2012 the growing season started around April 23 and ended around October 28. In 2013, the growing season started around April 26 and ended around October 29. In 2014, the growing season began around May 8 and ended around October 31. In 2015, the growing season began around May 6 and ended on November 9. The growing season was about six months in 2012. In 2013, the growing season was about six months also. In 2014, the growing season was about a little less than six months. In 2015, the growing season was about six months also.
2. The leaves burst out first in 2013 around April 23. The leaves fell off first around in 2012. The leaves burst out last in 2014 around May 8. The leaves fell off last in 2015 around November 9.
3. In comparison to my data, Tree #4, which is a Hawthorn also, in 2012 had the same growing season. In 2013, they again have similar growing seasons. In 2014, there is no data for the start of the growing season, but they end around the same date. In 2015, tree #4’s growing season starts within a week of each other but there is no data of tree #4’s growing season ending.
4. In comparison to my data, Tree #1, which is an Eastern Hornbeam, the growing season in 2012 and 2013 started around the middle of April and ended around the middle of November. In 2014 and 2015 the growing season started around the end of April and the beginning of May and ended around the end of November. Their growing season is longer because it starts around the same time but ends later.
5. The tree’s growing season in the last four years have all been around six months, but each year the leaves burst later each year except for in 2013, and the leaves fell off later each year.
Results Statement:
The growing seasons of the trees on our campus were observed. The growing season of Tree 3 – Hawthorn in 2012 was about 190 days, in 2013 was about 180 days, in 2014 was about 180 days also, and for 2015, we were unable to calculate the data because we did not have the data entered for when the leaves were 50% fallen. Tree 20 – Red Maple’s growing season was about 185 days in 2012, 2013, and 2014. We were unable to determine the growing season for 2015 because the data was not entered for when the leaves reached 50% fallen.
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In order to compare the trends discussed in the student work above, here is a graph by John O'Keefe of his own data recorded at Harvard Forest over 26 years, up through 2015:
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