In Bloom Magazine's December/January issue, which graciously featured details about Bloomington's tree canopy and its decline, it is noted that "the city lost 2% of its tree canopy from 2008 to 2018." This information was gleaned from Bloomington's 2018 Urban Tree Canopy Assessment Summary Report prepared for the city by Davey Resource Group. A more in-depth look at the report reveals a more shocking metric – Bloomington's canopy has declined by 54% since 1998.
Because Bloomington's first tree canopy assessment was completed nearly 15 years ago, which is relatively recent in terms of Bloomington's over 200 years in existence, it's difficult to assess how much our canopy cover has changed since an earlier historical benchmark. To attempt to do this, Davey Resource Group used i-Tree Canopy, a modeling tool used to classify tree canopy using aerial imagery, to estimate canopy cover in 1998. The model found that Bloomington's tree canopy has declined by 54%, or approximately 8,034 acres, since 1998. As of 2018, Bloomington's tree canopy covered just over 5,735 acres, about 38% of the city limits boundary. (left) Map from the 2019 Urban Tree Canopy Assessment Summary Report created by Davey Resource Group.
In addition to estimating canopy cover change since 1998, Davey Resource Group also used a forecasting model to project what Bloomington's canopy decline may look like over the next 30 years. The study estimated that Bloomington could lose up to 5% of its canopy cover by 2048. It's worth noting that losing 5% of Bloomington's canopy would equate to approximately 287 acres, an area equal to nearly 4.5 times the size of Switchyard Park. Imagine the impact even this seemingly small loss of canopy would have on our community.
With the looming impact of climate change bringing unprecedented weather patterns and volatile invasions of pests and pathogens jeopardizing the health of our urban forest, it's hard to accurately predict just how fast and how much our tree canopy could change for the worse. The spotted lanternfly, an incoming invasive pest, was first detected nearly 700 miles away in Pennsylvania in 2014; however, it was relatively slow-spreading at the time. In 2020, the pest was detected in Mingo Junction, Ohio, and a year later in 2021, a sighting was confirmed approximately 300 miles west in Switzerland County, Indiana. It continues to spread in Indiana and is spreading relatively fast. For comparison, the Emerald Ash Borer was first detected in southeastern Michigan in 2002, and it took about 10 years to reach Bloomington city limits. The changing climate that makes our region more suitable for these pests and other threats is causing them to spread at a much faster rate.
Confronted with the threats posed by climate change and its consequences, Bloomington's urban forest is in a vulnerable position. Urgent measures, such as preserving current trees and strategically planting hardy and well-adapted species, are essential to make our urban forest resilient against impending challenges. As collective stewards of Bloomington's urban forest, it is our shared responsibility to make informed decisions and stay vigilant to changes and threats. This commitment ensures that future residents can experience the same enjoyment of our urban forest that we cherish today.