If you go by their names alone, the villages of Oak Park and River Forest have something fairly basic in common: both were once forested areas before the introduction of paved streets and blocks of homes and businesses. 

Today, both villages tout their green space and while little of the native forests survive, trees lining the parkways remain a major selling point for living in the suburbs.

Summer is prime season for tree removal, and while residents can’t always tell if a tree is diseased, it’s hard to ignore the buzz of chainsaws and the remaining stump when a tree is removed. This time of year can bring unwanted changes to streetscapes, and local forestry experts are here to explain what is happening.

Oak Park’s Forestry Superintendent Robert Sproule says that trees are susceptible to weather changes and pests.

He calls 2018 a fairly standard year in terms of problems with trees, and notes that some residents might have had problems with their fruit trees due to wet spring weather, which can cause problems with fungus, but the village typically plants ornamental trees which are more fungus-resistant. When it comes to Dutch elm disease, he says this year has been a bit odd.

“We’re not seeing strong symptoms,” Sproule said. “Trees are still getting it, but they are not always showing the typical flags. It can be hard to tell homeowners you have to remove a tree in front of their house when they are not seeing the symptoms.”

Emerald ash borer is under control in the village, primarily because most infested trees have been removed, and the white ash trees that remain are less prone to infestation.

In River Forest, Public Works Director John Anderson says the emerald ash borer led to significant tree loss a few years ago. Today the village is trying to protect the ash trees that remain. 

“We have a little over 100 ash trees that we inject every other year,” Anderson said. “It keeps the emerald ash borer from infesting the tree.”

Oak Park is currently experiencing a problem with its maple tree population, which were commonly planted in response to earlier waves of Dutch elm disease. Sproule says that the silver maples, which were planted in the 1950s and 1960s, and the Norway maples and lindens, which were planted in the 1970s and 1980s, are now showing signs of decline.

“These are not long-lived cultivars,” Sproule said. “We call this ‘maple decline,’ and it’s a combination of the urban factor and the quality of the trees. We always love maples, but we have to remember they are riparian, bottom-dwelling trees. They like wet roots, and we don’t have that on our parkways.”

Inspection and removal

Every year, the Oak Park prunes one quarter of the village parkway trees. Prior to pruning, a consultant inspects the trees and flags any issues that may mark a tree for removal. 

Residents call in issues with the trees in front of their homes, and on their way to pruning or inspections, employees often see a problematic tree while driving in the village.

All of these methods of spotting trees which are in need of removal due to disease or decline typically lead to 500 to 600 trees being removed every year. To date, this year has been better than most says Sproule. 

“This year, we’re hovering around 200 to 300 removals,” Sproule said. “In the spring, we planted 289 trees. This fall, we’re on schedule to plant around 300 or so. We’re pretty close to full stocking based on village standards.”

When a parkway tree is marked for removal, residents get a notice from the village telling them the tree will be removed and informing them if the tree is approved for a new tree or replacement. Stump grinding takes place in spring and fall, so a replacement tree is typically provided a season or two after the tree is removed.

In River Forest, the village trims trees on a five-year cycle. Anderson says that the village planted 90 new parkway trees this spring and plans to plant another 30 this fall. 

River Forest has also been using GPS to create an interactive map of the trees in the village. 

Anderson says that interested residents can “go to the Public Works section of the website, click on Forestry and click on tree location map to see each tree identified by name, size of tree and date of inspection.”

The resource can be used as an aid for tree trimming and removal as well. 

New plantings

River Forest buys its trees in bulk, so it does not give residents a say in the size of the replacement tree, but Anderson says residents can ask for a certain type of tree, with a few caveats.

“They can request a specific variety, and if there are not a large number of those already in the area, we try our best to meet their request,” Anderson said. “We don’t want a monoculture. It’s not healthy.”

Anderson says that London plane trees, American hornbeam, white oak and Kentucky coffee trees are some of the many varieties of trees planted in River Forest this year, 

In Oak Park, residents can choose from a variety of replacement trees, but Sproule says the village can’t guarantee what will be planted. 

“Too many of one variety leaves us really exposed,” Sproule said. “We already are about 25 percent maples on the parkway. If we got an infestation of Asian long-horned beetle, it could wipe out 25 percent of our stock.”

Sproule says the village’s forestry division maintains roughly 18,000 trees in the parkways of Oak Park and they are constantly trying new trees to maintain a healthy landscape. 

There is a lot of interest in native species, which for Oak Park is, not surprisingly, the oak tree. This fall, the forestry division will be planting over 40 different species and cultivars of trees. 

Some of these new varieties include hybrid elm trees that are resistant to Dutch elm disease, an ornamental cherry tree which is doing well, and the Exclamation London Plane tree that was developed by the Morton Arboretum and which Sproule says is related to the sycamore family.

Residents are also often concerned about the size of the replacement tree, and Sproule says the village uses the best science they have to determine the appropriate planting size. He likens the ideal diameter for planting to a soda can.

  “We typically plant two-inch to two-and-a-half-inch caliber trees,” he said. “Depending on the variety of the tree, this will be about 10 to 15 feet tall. Bigger trees cost more to buy and cost more to plant. And, the bigger they get, the less likely they are to succeed.”

Sproule says that planting bigger trees does not result in getting a canopy faster, often because it is difficult to transplant the entire root system necessary for a big tree to thrive. 

“Studies show that within five years, that two-inch tree will be bigger than a four-inch tree because the smaller tree overcomes transplant stress faster,” he said.

If residents have concerns or questions about their parkway trees, Sproule urges them to reach out to the Department of Public Works at 708-358-5700. In River Forest, Public Works can be reached at 708-714-3550.

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