University of Rhode Island Campus Tree Inventory

A crowd-sourced tree inventory session held on campus during the fall 2016 semester / image: Kyle Zick/KZLA

The URI Kingston Campus is the 1,200-acre flagship campus of the University of Rhode Island (URI), located in the rural town of South Kingstown, Rhode Island. The first of several campuses, the original 140 acres of farmland was purchased in 1888 for the newly chartered Agricultural Experiment Station and Agricultural School of Rhode Island. In 1894, the Boston-based landscape architecture firm Olmsted, Olmsted, and Eliot began to plan the development and organization of the campus, which provided for the base presence of botanically interesting and historically significant trees.

Over the years, several efforts at tree inventory have been initiated, with varying levels of success. In 1989 a former professor and college dean created endowments to support the development and maintenance of the University’s arboretum. A walking tour pamphlet was created that contains information about each significant tree and some of the campus history. In 2004 and 2009, non-digital collections of tree information were developed that help keep track of diagnosed diseases and the history of maintenance applications. The identification tags for the arboretum are different from the tags associated with the ‘04-‘09 inventory data, in that the arboretum tags provide the botanical name, common name, family, and country of origin, as well as the tree number. The ‘04-‘09 inventory tags only indicate the tree identification number.

Aerial view of URI Kingston’s Quadrangle / image: Kyle Zick/KZLA

In 2016-2017, a Landscape Master Plan was developed for the campus, which included an updated inventory of the existing trees and involved faculty, Landscape & Grounds staff, and students. A crowd-sourced tree inventory session was held on campus during the fall 2016 semester. The intent of creating a digital, publicly-accessible inventory of campus trees was to identify the diversity of species, range of ages, and health conditions, as well as creating an educational resource for faculty, students, and visitors. With this information, an appropriate maintenance plan can also be developed to ensure that historic trees are preserved and new plantings will be properly cared for.

Members of the master planning team met with a class of plant sciences and landscape architecture students to collect in-field data and initiate the foundation of a digital campus tree inventory. The application utilized is known as OpenTreeMap, which is a subscription-based online application where trees can be mapped from a phone or tablet and existing data can be uploaded. The application can be customized with data fields specific to site needs, with unlimited users, user roles, and permissions. Edit history can also be tracked, future plantings can be modeled, and green infrastructure benefits tracked. The locations of campus trees to be collected was broken down into sections. Each section had a group assigned to it which was composed of a tree identification expert and several students. Participants collected tree data and photos via the use of personal smartphones.

An example of some of the trees lining Upper College Road (the primary campus entrance road) / image: Kyle Zick/KZLA

The inventory provides a clear snapshot of the campus tree species diversity, condition, age, and needs for the campus tree collection. The campus trees are diverse in species, which positions the collection well against large-scale damage from pest or diseases. The inventory also revealed that about half of the trees are in fair or poor condition, further illustrating that a more intensive maintenance investment is needed in the form of pruning, soil decompaction, watering, and pest/disease management. Many areas of the campus need increased tree planting for aesthetics, ecological benefits, and quality of campus life. This means that a concerted effort is needed to plant many new trees annually and to provide the appropriate aftercare. All of this information will be utilized in developing a smarter, more efficient campus tree maintenance plan.

The master planning team selected a number of criteria that help determine individual tree health and potential concerns. / image: Kyle Zick/KZLA

In addition to the information collected that will result in better campus tree maintenance, the inventory also provides documentation for the value of the trees not just on the Kingston campus, but also locally, regionally, and globally. URI’s motto is “Think big. We do.” and contributing to the overall understanding of the value of trees in the world supports this message. The ecological benefits of the nearly 1,100 trees inventoried within the campus core are significant, with nearly two million gallons of stormwater filtered per year, nearly 500,000 pounds of carbon removed from the air, and over one million kilowatts of energy conserved per year. As new trees are planted and inventoried, this value will only increase.

Trees’ eco-benefits / image: Kyle Zick/KZLA

In addition to the environmental values provided by the campus trees, the inventory also allows for documentation of the monetary value of the campus trees. Monetary values can have a large impact in the decision-making process of protecting or removing campus trees. Tree appraisal can often prove that removing and replacing of a tree can be much costlier than protecting it. The method applied to the University’s campus trees is called the Trunk Formula Method, which is authored by the Council of Tree and Landscape Appraisers (CTLA). The method considers various factors in determining a tree’s monetary value, such as species, condition, size, location, and replacement cost. The formula is: Tree Value = Base Value x Cross-sectional Area x Species Class x Condition Class x Location Class. Base Value is the dollar amount assigned to 1 square inch of a tree’s trunk cross-sectional area and is typically based on the cost of the largest available replacement plant of the same species ($1,000 in our case). The end result is a monetary value of 7.5 million dollars for 1,095 campus trees, which is only a small portion of the overall number of trees located on campus.

As a result of the inventory, the following goals and priorities for URI’s campus trees were developed:

  • Existing trees need more care: structural pruning, buried root flare exposure, construction impact protection, protection from mower damage, etc.
  • Heritage trees should receive special care, including sufficient mulch.
  • Natural areas should be managed as such, including invasive management.
  • A more diverse tree palette, which is supportive of learning, campus aesthetic, ecological goals, etc., should be supported.
  • Street trees should line campus roads.
  • New trees should be selected and located thoughtfully for multi-layered impact (aesthetic, educational, ecological, spatial, etc.).
  • Consider certification of significant tree collection with national horticultural organizations.
  • Maintain tree inventory: record maintenance performed, add tree identification tags to all trees, and continue to inventory trees not included in initial data collection.
  • Plant trees to increase environmental benefits.
  • Expand tree canopy to improve shade coverage and pedestrian comfort.
  • Plant trees each year to achieve long term canopy coverage goal.

As noted above, maintaining and adding to the campus tree inventory is a University goal, although the specific application method is under discussion. It is clear that a publicly-accessible, digital inventory of trees can provide significant value for documenting their environmental, economic and social benefits.

by Karen A. Beck, RLA, FASLA, University Landscape Architect, URI Office of Campus Planning & Design, and; Kyle Zick, RLA, ASLA, Principal, Kyle Zick Landscape Architecture Inc.

For more information on campus tree inventories, see the previous post in this ongoing series: A Brief Survey of Campus Tree Inventories, by Laura L. Tenny, RLA, ASLA, Senior Campus Planner, MIT Office of Campus Planning, and Campus Planning & Design PPN Co-Chair

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