Urban Tree Canopy Assessments: Part 1
Part 1: Why do trees matter?
Trees are the answer! Across cities and other urbanized areas, trees along streets, in parks, yards, and natural areas constitute a valuable urban and community forest. This resource is a critical element of the region’s green infrastructure, contributing to environmental quality, public health, water supply, the local economy, and aesthetics.
Trees are one of the few infrastructure investments that grow in value over time.
Trees throughout the world face many threats, but trees in an urban environment are especially vulnerable. Clear-cutting, compacted soils, and vandalism are just a few of the many threats these trees face. This valuable resource is under attack from many different directions in communities, small and large, across the globe. The following maps and images show examples of large-scale changes that can occur in an urban forest.
Charlotte, North Carolina, in the southeastern United States, is a rapidly growing city. With high rates of growth often comes a high level of development. Large, forested areas are quickly being cleared to make way for new housing developments, schools, and other amenities. Fortunately, the City has been planting new trees to make up for the losses, but those trees take time to grow and mature. The left image shows conditions in 2014, and the right image shows the same area in 2020 after a new school has been built where a forest once stood.
Panama City, Florida, on the coast of the Gulf of Mexico, was devastated by category 5 hurricane, Michael, in October of 2018. It’s estimated that the strong winds and rain took down 1,000,000 trees in Panama City alone. Local residents are now literally feeling the impacts of losing their tree canopy with reports of higher than normal temperatures and the threat of wildfires and flooding due to the downed trees. The map shows pre-storm (left-2014) and post-storm (right-2020) conditions. Read our blog post to learn more about trees and natural disasters.
Pests and Diseases
Invasive species, pests, and disease present one of the most serious threats to urban and community forests. The City of Milwaukee, Wisconsin experienced a significant loss of urban tree canopy due to Dutch elm disease. This led to the removal of over 140,000 elms from the late 1950s to the present time. This image shows the dramatic change that occurred in many areas throughout the city. Once fully canopy covered streets became open and exposed corridors due to monoculture planting and the subsequent disease outbreak. Read more about it in our report.
Around the world, the value that trees provide to people and the environment is being realized. Many cities are initiating tree planting programs in order to engage the community and expand their urban forest. Tree canopy assessments provide detailed information on where there are trees and also where there is available space to plant new trees. Seen in the map, the City of Mercer Island, Washington, has placed strong emphasis on their tree planting program. Their efforts can be seen in the large number of trees planted along the Mountains to Sound Greenway. These trees were planted in the late-1990s and have seen tremendous growth in the last 20 years (left-2002, right-2015), providing enhanced recreation opportunities, increased wildlife habitat connections, and improved air and sound quality.
This blog series will continue to explore the necessity of urban tree canopy assessments and how one will positively impact your community. Please join us over the next month as we continue to share on this valuable topic.
Blog Series: Urban Tree Canopy Assessments