Groups partner to ensure a healthy 'regional forest'

Trees are a treasure and those who plant them on their private property are investing in a living organism that will give back to them and to subsequent homeowners and community members for years to come.

But like any investment, the purchase and planting of trees should be studied and carefully planned, not done on a whim.

Homeowners pay a lot of money for trees and they have a right to expect those trees to give them shade and ambience for many years. But if a homeowner just goes to a nursery or a big-box store and picks a tree at random, they may not get the results they are seeking, said Lydia Scott, director of the Chicago Region Trees Initiative, a collaboration of The Morton Arboretum, The Nature Conservancy, the Illinois Landscape Contractors Association, the Cook County Forest Preserve District and six other concerned entities that are working to build a healthier, more diverse regional forest.

Pests and diseases that have attacked our trees over the last 50 or 60 years — Japanese beetle, Dutch elm disease, emerald ash borer, to name a few — prove the importance of diversifying the tree species you plant in a private yard or on the parkways in a community. Don't fill your yard with only one kind of tree because some insect or disease could arrive and attack that particular species, leaving you will nothing more than the bill to have the dead trees cut down and stumps removed.

“Species diversification is critical,” Scott said, “but so is choosing species that are native to this area. I tell people, for instance, don't plant Austrian or Scotch pines here. White pines are better suited to the Chicago area, as long as you can plant them where the drainage is good, there is full sun and it is away from the road salt.”

A homeowner should also think about age diversity in their trees.

“Trees are living things and they don't last forever. Some do 'age out,' while others that are planted in particularly good locations can live for hundreds of years. But the average life span of urban trees is between 19 and 28 years so you need to prepare for their eventual demise by planting a wide variety of other species underneath and around your aging trees,” she said.

No one expects a homeowner to automatically know which trees would be best in their yards. That is why the Morton Arboretum has a tree and plant selector tool on its website (www.mortonarb.org). You are asked to answer a variety of multiple choice questions about where you want to plant a tree (wet or dry area, full sun or shade, type of soil, parkway or not, under power lines, etc.) and what you want the tree to provide (spring blooms, fall color, shade, windbreak, screening, etc.) and then you will be presented with a list of species that are native to northern Illinois and will meet your requirements, Scott said.

Certain trees, for instance, are perfect for helping to suck up moisture in very wet yards and those include river birches, weeping willows and cypress.

But crabapples, for example, are susceptible to a type of rust and other trees, such as Bradford pears, often fall apart in storms. Pears also tend to migrate and become invasive, so Scott strongly recommended against planting them.

She also warned against buying trees from big-box stores because they tend to import them from suppliers in other parts of the country, not ensuring that they are species that will survive and thrive here. In addition, trees that begin in a local nursery will become acclimated to our climate and survive better than a tree of the same species that may have been started in a different part of the country, Scott added.

Once they are planted, Scott cautions that you need to actively think of your trees as living things that need air and water to their roots. They aren't going to thrive if there are lots of people and machinery pounding over the dirt around them. They also need care, especially if subjected to stressful situations.

“Periodically walk your property and look carefully at your trees' canopies. If you see brown spots or branches that appear to be drying up, you can send samples to the plant clinic at the Morton Arboretum or the University of Illinois for diagnosis. If problems are caught early, trees can often be resurrected,” Scott said.

Periodic trimming of your trees is also important if you want to keep them healthy.

“If you trim your trees on a four- to seven-year schedule, you will reduce your costs if a bad storm comes along and brings down branches because not as many of your branches will come down. Regular trimming also helps prevent infections from getting into your trees through areas of minor damage that you might not even see,” she said.

The Openlands program and the U.S. Forestry Service, two of the partners in the Chicago Region Trees Initiative, even jointly offers eight-week Tree Keepers courses that teach community members to become advocates for trees in their communities. This course is offered in several local communities. The initiative also sends speakers out to address small groups of people who want to become “community tree champions” by learning how to help local trees by watering and mulching correctly.

“Seventy percent of the trees in our Chicago area 'regional forest' are located on private land, so the way in which homeowners care for their trees has a significant impact on the overall environment,” Scott said. “Without our trees, we would have a far worse quality of life, far worse air quality, much more flooding. So when homeowners plant trees wisely, they are making an investment in the health of the entire region.”