GIS at Dickinson College

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Author: digiorgm

How Diverse are our Trees? An Analysis of the Trees on Dickinson College’s Campus

Urban forests, much like those of college campuses can be unbalanced in species diversity, and richness, which can lead to devastation. By determining these factors and applying a standard guide, the health of the forest is able to be established, and in doing so creating a better way to manage the trees. The standard guide used is the 10-20-30 rule, which says that no more than 10% of the trees should be of the same species, no more than 20% of the trees should be from the same genus, and no more than 30% should be from the same family. The 10-20-30 rule is often used as a standard to determine if the species diversity is acceptable, inadequate, or a possible cause for concern in the urban forest. Dickinson College currently has no reference to the standard of its urban forest. There is also concern of using non-native trees in the urban forest, and if that has a negative impact on the overall forest. The project was started in the spring of 2010 by Mark Scott and Jim Ciarrocca to document all of the trees on campus, so that Dickinson could become an arboretum. This project explores species diversity in eight different sections of campus, the overall richness of the campus trees, the location of the non-native trees, as well as designating location of water accumulation on the campus. Since the start of this project 814 trees have been tagged, and there are 132 unique tree species. Overall the species diversity of the campus is acceptable. There are no trees with greater than 6% of the same species, three are no trees with greater than 18% of the same genus, and there are no trees with greater than 18% of the same family, thus Dickinson’s campus is all within the 10-20-30 rule, and has acceptable species diversity.

This project specifically looked at ways to assist Mr. Scott in managing Dickinson College’s trees. The richness and species diversity were determined using the Marine Geospatial Ecology Toolset, created at Duke University.  Using 3-meter elevation data from USGS, areas of depression were identified, where water would collect on Dickinson’s campus. This was done by filling in the depression using the fill tool, using the raster calculator the original elevation data was subtracted from the filled elevation data, this then gave the depression areas. This information will be used to assist Mr. Scott in making management decisions.


An Analysis of the Trees on Dickinson College's Campus

An Analysis of the Trees on Dickinson College’s Campus

Dickinson College Arboretum


To become an accredited arboretum there are certain professional standards that need to be met by an accreditation program. That can be done by either the Morton Registration for accreditation (1) or the Tree Campus USA program (2). The use of which program will be used for Dickinson’s future ambition to become an arboretum has not yet been decided, however work has begun to fulfill the general basic requirements for Dickinson to become an arboretum. Dickinson College has been mapping the trees on campus since the spring of 2010. Kristin Meseck, a student at the time at Dickinson, started the project as a part of the Advanced GIS course offered at Dickinson. She worked in collaboration with Mark Scott, Dickinson’s own arborist. Since then multiple students and GIS interns have worked with Mr. Scott and have contributed to the data collection over the years. Mr. Scott has since then strived to turn Dickinson College into a arboretum by starting the general process of surveying and identifying the trees on Dickinson’s campus. The data that is collected includes tree number, common name, family, genus, species, variety, height, diameter, if the tree is native, condition of the tree, if there are insects and disease, if it is dedicated, pruning requirements, miscellaneous work, comments, if the tree has been removed and the type (deciduous or coniferous). After the collection of this data and the exact GPS coordinates of each tree are recorded, the data is all entered into a database so the data can be projected onto a map. Since 2010 over 700 trees have been surveyed and that is not even 50% of trees on Dickinson’s campus. For my final project in the Introduction to GIS course I have taken all of the data collected thus far and have created an interactive web map application available to any individual who would like to learn about the trees on Dickinson’s campus.


To begin the process of making a map on ArcMap, I was given the collected tree data from Jim Ciarrocca, Dickinson College’s GIS Specialist. Using that data I constructed a map of the trees on Dickinson’s campus. I created a map with specific levels of details on the trees present in that area. The data attribute tables were edited to show every tree’s information in a more uniform way. The first level has five trees indicating specific tree areas, for example, Morgan Field, Academic Quad, and more. The next detail level separates the trees into whether they are coniferous or deciduous trees and there are symbols differentiating the two. The last and closest level of detail available separates the trees by family; each family has a different symbol indicated in the legend. There are also layers indicating Dickinson College buildings, for spatial reference for the user.

After the map was created in ArcMap, I began the uploading process to ArcGIS online to publish the map. I signed into my account through ArcMap and followed the prompts to publish the map online. Once the map was up online I needed to choose a web map application template in order to create a web map application to share the map online. I chose the Storytelling Basic application because it allowed me to display the map effectively. After the Web Map Application was finished I was able to share it with everyone using a URL, anyone could see it even without an ArcGIS account.


An effective part of using a web map application are the pop-up windows available for each symbol on the map. This allows users to click on a tree and find out the information available on that particular tree. The pop-up seen in this image example is how all of the pop-ups in the map look.








These three images show the three different detail layers of the web map application, which were described in the methods above.

First level of detail.

First level of detail. The tree areas.


Second level of detail.

Second level of detail. The tree types (deciduous or coniferous).

Third level of detail.

Third level of detail. The tree families.





















The Dickinson College Arboretum Web Map Application can be seen at:



ArcGIS online is an incredible tool that allows you to make a map available and interactive to so many people. The application allows you to better show the story you want to tell because it is interactive and the different templates allow you to decide how exactly you would like to tell that story. This tool is new, so there were some challenges in learning how everything works and including everything you want to do. For example, there is not a way to include labels on the map, which is why the pop-up windows are necessary to give the user information about the items on the map. A feature that I hope will be added to the templates is that if photographs could be added to the pop-up windows, because then for this particular web map I could have added a photo of what a particular tree species looked like, for better understanding by the user. Overall, it is an extremely beneficial tool and continues to change and offer more services to a mapmaker.





More information on the progress of this project  can be found at:


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