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Cutting Edge > Undergraduate Research > 2014 Workshop > Activities > Examining Short-Term Tree Growth and Environmental Variables near Philadelphia, Pennsylvania

Examining Short-Term Tree Growth and Environmental Variables near Philadelphia, Pennsylvania

Laura Guertin, Penn State Brandywine
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This activity has benefited from input from faculty educators beyond the author through a review and suggestion process.

This review took place as a part of a faculty professional development workshop where groups of faculty reviewed each others' activities and offered feedback and ideas for improvements. To learn more about the process On the Cutting Edge uses for activity review, see http://serc.carleton.edu/NAGTWorkshops/review.html.


This page first made public: Aug 8, 2014

Summary

The Smithsonian Institution's Global Tree Banding Project is a citizen science program that contributes to research about tree biomass by tracking how trees respond to climate. Students around the globe are monitoring the rate at which their local trees grow and learn how that rate corresponds to Smithsonian research as well as comparing the work to other students worldwide.

But at Penn State Brandywine, we are going beyond the requirements of the Smithsonian project. Instead of only taking two measurements in the spring and two measurements in the fall, undergraduate researchers are taking measurements every two weeks. We started taking measurements of ten trees on campus April 3, 2012, and we will continue until each and every tree outgrows its tree band. As a result, we have a rich database that not only contributes to scientific research but can serve as a foundation for student inquiry-based projects. The data is available for download in Google Spreadsheets for students to examine changes in tree diameter within one or between growing seasons, supplemented with temperature and precipitation data.

Context

Audience

The setting up of the tree bands and subsequent data collection can be conducted by students in middle grades through the university level. Analysis of the data can be carried out within the same grade levels, pending the depth at which the student wishes to work with the data. The exercise as presented here has been used in an introductory-level geoscience course for non-science majors, with gap width measurements taken on trees banded at the Penn State Brandywine campus, located 15 miles outside of Philadelphia.

Skills and concepts that students must have mastered

Students must know how to work with data in spreadsheets - specifically, how to plot data in Google Spreadsheets or MS Excel. Students should have a basic understanding of how scientists predict current, rising CO2 levels are impacting tree growth.

How the activity is situated in the course

The activity (processing the collected data) is conducted during class time, and can be completed in one laboratory period or two lecture-only classes. If a final analysis/report is requested from the students, this would be completed outside of class time. This exercise is part of a collection of exercises students complete relating to climate science (such as the Mauna Loa CO2 exercise at http://serc.carleton.edu/introgeo/interactive/examples/co2.html). This exercise will typically be the final exercise in a climate unit, as it deals with the most recent record in the local area.

Goals

Content/concepts goals for this activity

The overarching goal is to provide students an authentic data set, collected by students from their own campus environment, that documents local environmental changes that can be compared to global data. Students will have already learned about the global CO2 record over time from previous lectures/in-class exercises. This exercise will show students local data from a much shorter timescale.

Higher order thinking skills goals for this activity

Analysis of data - including plotting, generating plots of data across different scales, and examining multiple data sets (gap width, temperature, precipitation)

Other skills goals for this activity

Ability to examine geographic distribution of data with different tree species; ability to make future predictions and design a similar experiment on their own campus; report writing (if part of the final assignment outcomes)

Description and Teaching Materials

Dendrometer (tree) bands were placed on ten trees at the Penn State Brandywine campus in 2012. Students have been taking measurements every two weeks of the gap in the bands with digital calipers to establish a baseline for growth. The background information and tree measurements for the trees at Penn State Brandywine can be found at: http://sites.psu.edu/treebanding/.

There are many variations of this activity an instructor can implement, depending upon the grade level, mathematics background of students, and time available.

Questions for students:

Teaching Notes and Tips

This exercise presents an opportunity to teach students about the differences between a line graph, scatter graph, bar graph, etc., and how best to represent the data for the research question being asked.

As stated above, instructors may want to download and modify the existing Google Spreadsheets to challenge the students more when working with the data (one suggestion is to remove the Interval Gap Growth and Total Gap Growth column, and have students compute this data themselves using formulas in Spreadsheets/Excel).

Instructors may also want to show students NBC Learn's Changing Climate: Survival of Trees for some background on CO2 increase, the impact on plant growth, and how scientists are looking at records further back in time with tree ring data.

Assessment

The assessment will vary, pending the initial objective for having students work with the existing data set (plotting data from one tree, comparing tree data, examining one season versus across multiple seasons, bringing in temperature/precipitation data, etc.). Grading for this assignment can be based upon the accuracy of working with the data in the spreadsheets, generating graphs that plot the correct data points in the correct format for interpretation, interpretation of the data, and/or suggestions for future directions of the research.

References and Resources

Penn State Brandywine Tree Banding website: http://sites.psu.edu/treebanding/

Smithsonian Institution's Global Tree Banding Project website: https://treebanding.si.edu/

Curriculum resources (K-12), newspaper and journal articles: https://treebanding.si.edu/Resources/

Related modules found on the SERC website include:


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