State of the Urban Forest Report Shows Surge in Number, Health, Diversity of City Trees

Bloomington, Ind. - A recent inventory of the City of Bloomington’s public tree population reveals significant increases in the number, health, and diversity of our trees along City streets, in rights-of-way, and within public parks.  The results, from a study conducted from February to August 2019, were presented to the Board of Parks Commissioners at 4 p.m. today, and will again be presented in the State of the Urban Forest Report tonight at 7 p.m. in the Council Chambers at City Hall (401 N. Morton St.).  The report includes the following highlights: 

• The City’s public tree population has increased by 56% in the last twelve years.  The 2019 inventory records 19,013 public trees, up from the 2007 count of 12,169. In 1994, an inventory recorded 10,522 public trees.

• The diversity of City public trees has expanded to 168 species representing 63 genera. Maple trees continue to dominate the City’s forest, although their portion of the total tree population has tapered from 30% in 1994 to 24% in 2019. In addition to maples, the most common genera are oak (13%), ash (11%), pear (7%), and elm (4%).

• The overall condition of the tree population remains healthy. Results of the inventory will be accessible at the City’s website. 

“Trees are both beautiful and essential parts of our community,” said Mayor John Hamilton. “It’s gratifying to know we’re continuing to increase the health, diversity, and number of our public trees.  And assessing their status and health helps us build resilience in the face of climate change. This report confirms the direction of our public forestry plan and equips us with information about where additional forestation would most benefit our ecosystem.”

The City’s Parks and Recreation Department contracted with Davey Resource Group to conduct the inventory and produce the report, which showcases data collected using geographic information systems-based technology by five teams of arborists over more than five months about the size, species, and condition of publicly owned trees.  Using this data, a primary maintenance and planting plan was generated, recommending which trees should be pruned and culled, and where new trees will have the greatest positive impact on environmental health. The report’s recommendation of 1,428 large-growing tree plantings aligns with the City’s 2018 Bicentennial Bond commitment to plant or replace 1,400 trees.  

The report quantifies the economic, environmental, and social benefits conveyed by the public tree population at a value of approximately $1 million per year. Tangible benefits accruing to City trees’ ability to improve air quality, sequester carbon, reduce energy demand, prevent erosion, and contribute aesthetic value have been calculated at approximately $968,823, far outweighing what is required to plant and maintain the urban forest.     

In addition to the data it collected about publicly-owned trees, the new report also assesses the overall tree canopy in the 23 square miles or roughly 15,000 acres of private and public property within the city limits. The assessment measured the current total tree canopy as comprising 38% of the total area. Of the 22% of Bloomington’s total area described as plantable, the report designated 16% of that (532 acres) as “High” and “Very High” priority areas for tree planting in order to minimize the potential for the urban heat island effect and damage from storms and floods.

As the City cares and plans for the trees on publicly owned land, private property owners are encouraged to collaborate on the goal of understanding and increasing the overall tree canopy. Toward that end, the City is developing a new program to allow residential, commercial, nonprofit, and institutional property owners to share information about trees on their own land, which will complement the scientifically generated information about the public trees.  Using crowdsourcing to develop a more complete and detailed picture of Bloomington’s total forestation will better equip the City to mitigate the local impact of climate change and plan sustainably.

Recognizing the City’s commitment to its trees, the National Arbor Day Foundation in 1984 designated Bloomington as Indiana’s first “Tree City USA.” The designation requires that a city maintain a tree board or commission, a tree care ordinance, a community forestry program with an annual budget of at least $2 per capita (Bloomington's is more than $8.50 per capita), and an annual Arbor Day observance and proclamation. The city has successfully met all the criteria to retain its Tree City designation every year since 1984.