Those who live in or visit the Twin Cities probably have seen how many trees we have along our streets, avenues and boulevards.
Recently, a first-of-its-kind study was completed that used high-resolution satellite technology to analyze the tree canopy of the Twin Cities. The study was carried out by a team of University of Minnesota researchers. High-resolution satellite technology was used to examine Minneapolis from above on a clear and cloudless day, recording and analyzing how much tree cover there, down to each individual property.
They study estimated Minneapolis' overall tree coverage to be 31.5%, higher than previous estimates using less precise methods. In St. Paul, the canopy cover rate was 32.5%.
Minneapolis' estimated 979,000 trees offer many benefits, including:
- Cleaning the air
- Sucking up water that would otherwise flood stormwater pipes
- Increase the attractiveness of homes
- Drive up property values
- Reducing the need for cooling during hot summer days by providing shade
"In terms of energy conservation, it doesn't get any easier than planting a tree on the west side of your house if you can," [Minneapolis project coordinator June Mathiowetz] said.
The Lynnhurst neighborhood off the southeast shore of Lake Harriet had the most urban tree cover. Nearly 49% of its area is covered, which includes a portion of Minnehaha Creek. Other neighborhoods that rank high for shadiness have residential lots and extensive parkways, mostly along Minnehaha Creek in southern Minneapolis, West River Road, and along the city's western border.
The research will be helpful in multiple ways. The study shows gaps in the urban tree cover, which could help city planners and foresters target areas in need of improvement or develop low-cost programs to encourage more saplings on private land. It also provides a useful benchmark to monitor how the urban canopy changes in the future as some species succumb to old age, invasive pests and other problems. About 22% of the city's trees are ash, which are susceptible to the dreaded Emerald Ash Borer.
Minneapolis has already increased its tree plantings on boulevards and other public land. It planted 4,000 trees this spring and will plant 1,500 saplings in the fall. The city planted just 3,000 last year.
The U study also calculated what is under the tree canopy across the rest of Minneapolis: grass and shrubs (about 20 percent), buildings (15.5 percent), streets (9.5 percent), water (6.2 percent), and other impervious surfaces, such as driveways, sidewalks and parking lots (17.5 percent).
The only other city evaluated in Minnesota was Woodbury, where the tree cover is 21.5% due to predominant cropland and trees in newer residential developments are young and small.
Twin Cities is in the middle of urban areas for tree coverage, with less than Washington, D.C., at 35%, and more than Boston at 29%. Other cities include Baltimore at 4%, Burlington, Vt., at 43%, Des Moines at 27% and New York at 24%.