An aerial shot of Mount Horeb shows how important trees are to this community.
A canopy for partnerships
Want to grow a legacy in your community? Look no further than your backyard.
All of us, even those of us who live in Wisconsin's cities and villages, are forest dwellers. The trees that line our streets and shade our homes and businesses are part of what's called the "urban forest." Trees beautify our communities and provide shelter for birds and other wildlife, and they provide other benefits, too: they reduce stormwater runoff, lower utility bills, increase property values and improve air quality. Foresters, city planners and others are gaining the ability to better measure these benefits and new tools make it easier for everyone to understand and nurture this precious resource.
A better view
"In the past, urban foresters tended to focus on trees in public areas – along streets and in parks," said DNR Urban Forester Dick Rideout. "We want property owners and renters to realize they're part of the urban forest, too. And they can be urban foresters in their own right: they can help the community maximize the benefits that trees can provide."
New technology makes it easy for anyone to see and analyze the tree cover of a city or town. "In the past you'd have to go up in a plane to get a 'canopy view' or bird's-eye view of your home and the surrounding community," Rideout said. "Now all you have to do is go to the Internet on sites like Google Maps or Bing Maps. Use the satellite view option to look at your home from above, and you'll see the rounded treetops that create an interconnected green canopy in your city or town."
Viewing the tree canopy of a city or town allows people to move beyond thinking of city trees as merely a beautification issue, Rideout said. Looking at a satellite image can show areas where trees could be planted throughout the community and, perhaps, identify wooded areas that could be formally preserved.
Planting trees might seem like an unaffordable luxury in these tough economic times, when cities face tight budgets and many property owners and renters have seen their income stagnate or decline. But scientists have begun to realize that trees can actually save money for property owners and municipalities, and they've developed ways to measure and account for those benefits. In broad terms, a community's so-called "grey infrastructure" – the streets, sidewalks, storm drains and buildings that make up our urban and suburban environments – exists side-by-side with the "green infrastructure," or the trees, vegetation, soils, rivers, lakes and other natural features that shape and are shaped by human forces.
Natural systems can help control or mitigate the disturbance that the built community places on the landscape. Furthermore, in contrast to grey infrastructure, the value of trees and other natural features increases over time.
"The value of grey infrastructure is the highest the day it's done," Rideout said. "You lay out a new street, put down a new sidewalk, and immediately it starts to degrade. With trees it's the exact opposite. When you plant a tree, you have to wait a while for it to start providing benefits. But as the tree grows each year, it actually provides more and more benefits over time; it appreciates in value."
New tools help local government officials determine the dollar amounts of those benefits. Various applications at i-Tree allow planners and other decision makers to determine where to plant trees and provide estimated cost-benefit analyses.
For instance, over a 40-year time span, a thousand urban trees will intercept about 55 million gallons of stormwater runoff, sequester more than 6,000 tons of carbon dioxide, and provide heating and cooling savings totaling $1.5 million.
Not surprisingly, the vast majority of the benefits provided by trees within a city are provided by older, large-canopy trees. This concept is particularly important to take into account when communities consider new construction projects. Old conventional wisdom advised taking down mature trees on a building site, leveling the lot and replacing trees with new young trees when construction was completed. But an exponential number of young trees would be required to provide the same benefits as those more mature trees.
Calculate the benefits the trees in your yard are providing by visiting the National Tree Benefit Calculator.
What to plant
Diversity is the spice of life, and it's a good rule of thumb for tree plantings, too. Diverse plantings provide a greater range of habitat and more visual interest. Perhaps more importantly, a varied planting as a whole is more resistant to diseases or pests that might wipe out a single-species planting. A full fifth of all Wisconsin's community trees are currently ash trees, so communities around our state stand to lose 20 percent of their trees as the emerald ash borer continues to spread. In an effort to be sure such a situation doesn't occur again, urban foresters urge planners to ensure that a community contains no more than five percent of one species, 10 percent of one genus and 20 percent of one family.
Tree species vary widely in size and appearance, so it's important to choose the right tree for each particular location. A variety of online resources provide help regarding tree selection (see links in box below), and county extension agents and local nurseries and garden centers can also help.
A living legacy
Everyone can play a part in restoring Wisconsin's tree canopy. Rideout stressed that you don't have to own property to help make a difference.
"One resident, whether they're the owner or not, can get permission to plant a tree and know that tree will grow up to provide benefits to everyone," he said.
"We want people to know that they can be part of their community's legacy by planting trees," Rideout said. "Plan carefully and plant trees on your own property as well as supporting your community's efforts.
Lori Compas is a freelance writer and photographer based in Fort Atkinson.