Just when you thought you got out from under one urban forest crisis, here comes another.

In the past several years, Brookfield, Riverside and North Riverside have had to remove hundreds of ash trees (they’re still removing them) from public parkways due to the emerald ash borer, a nasty little beetle that has devastated what was once a popular urban tree species all across the U.S.

When the infestation started, it progressed rapidly, wiping out almost all of the ashes in Brookfield and Riverside within a couple of years. North Riverside, which treats its ash population with an insecticide, saw the trees go at a slower rate, but they weren’t untouched.

Last week, the Illinois Department of Agriculture announced a new threat. The pathogen responsible for a disease known, quite ominously, as Sudden Oak Death has been introduced to the state via rhododendron and lilac plants sold at Walmart this spring.

The plants were grown in Washington state and purchased through a middle man in Oklahoma. The Pacific Northwest and California have lost millions of oak trees since the pathogen was introduced there in the 1990s.

Two of the Walmarts selling the tainted ornamental plants are in Cook County, though not near Riverside, Brookfield or North Riverside. The closest store, in Forest Park, did not receive shipments of the plants, according to an IDOA spokesman. The two Cook County stores that did are in Rolling Meadows and Richton Park.

While it may be unlikely than any rhododendrons or lilacs planted around these parts this spring came from those two stores, we’re asking local gardeners to be particularly vigilant.

The pathogen – a mold, really – can easily be transmitted through soil and water. With the kind of rains we’ve been getting lately and the prospect of water upstream flooding into Riverside and Brookfield – Salt Creek, as fate would have it, runs through Rolling Meadows – is probable.

We can only hope that IDOA officials caught this potential disaster soon enough, though the disease’s appearance would appear inevitable, like the emerald ash borer.

With oak trees such an important part of Riverside and Brookfield’s landscapes, in particular, an outbreak of Sudden Oak Death would be devastating.

To learn more about the disease and how it is passed along, you can visit the website SuddenOakDeath.org. If you believe you have plants from a store where the infected plants were sold, please contact the IDOA office in DeKalb at 815-787-5476 or the University of Illinois Extension office in Westchester at 708-449-4320.

Each of the villages we cover also have trained forestry pros who can help you identify if there’s something wrong with trees. Feel free to give them a shout if you see something that doesn’t look right.

Right now, the goal is to contain the problem as best as possible. It’s going to take everyone’s help to save our oaks.