Fall has arrived. As the leaves collect on the ground, and we begrudgingly begin the process of raking up the colorful remnants of summer into endless piles, it is a good time of year to remember what urban trees provide for us.
Urban trees are the public or private trees that line or flank our downtowns and neighborhoods. These trees offer enormous benefits to us that we might not immediately realize.
As many of us learned in science class, trees help immensely with air pollution by transforming carbon dioxide into breathable oxygen. They provide shade that cools the air, pavement and buildings, which lessens the impact of the heat island effect.
Something you may not know about urban trees is that they help manage stormwater by catching rain in their leafy canopies. The canopy helps slow down the rate of runoff from a rain event, reducing the amount of water that hits the pavement where it collects sediment, chemicals and pollutants and deposits these into nearby rivers and lakes.
Urban trees prevent runoff by providing pervious space under their canopies in the form of a tree pit or tree lawn. These areas help catch rainwater and allow it to infiltrate into the soil to be absorbed by roots and recharge the groundwater supply.
If you aren't familiar with these terms, a tree pit is the area under the tree that contains its root system. A tree lawn, also known as a boulevard, greenway, curb strip or verge, is the grassy area between sidewalk and street.
Green streets, designed to capture rainwater at its source, are another approach to stormwater management used in many communities. They integrate trees and other vegetation, soil and engineered systems such as permeable pavements to slow, filter and clean stormwater runoff from streets, sidewalks and other impervious surfaces.
What else can urban trees do?
They provide habitat, shelter and food for birds, insects and small mammals in areas that are mostly paved, impervious or developed. A continuous section of street trees on a road or in a neighborhood can help wildlife move safely between tracts of natural land and find food and shelter.
These trees have social and economic benefits as well. They help dampen noise from streets, cars and people living in close proximity. Urban trees also add to property values. Studies have shown that properties sell for higher amounts when there are street trees compared to properties without them.
Urban trees also collectively save us money in terms of management costs for stormwater, pollution and carbon. The U.S. Department of Agriculture's Forest Service has developed a free digital tool called MyTree (https://mytree.itreetools.org) that can help you quickly determine how much money a tree on your property saves each year.
The type of tree, diameter and location all factor into that annual dollar value. A young tree will start out saving only a few cents per year but ends up saving many dollars as it grows larger. If we think about how many trees there are in our neighborhoods, or how many there could be, the savings for us and our communities can really add up.
Finally, urban trees connect us in our increasingly urbanized world to the beauty of nature. These trees breathe life into our public spaces and streets, making our downtowns and neighborhoods more friendly and welcoming.
Take a walk down a road in your downtown or neighborhood and notice how you feel in different environments. I guarantee that you will feel better, safer and enjoy the space far more when there is a tree nearby.
Check out the Vermont Urban and Community Forestry Program, a partnership between University of Vermont Extension and the Vermont Department of Forests, Parks and Recreation, at www.vtcommunityforestry.org. You will find tons of resources, grants and opportunities to support and grow trees in your community.
So, as the piles of leaves overtake us, let's give thanks for what our lovely tree friends have given us this summer, and look forward to seeing them pop back to life again come spring.
By Bonnie Kirn Donahue
Extension Master Gardener
University of Vermont