The trail is sun-dappled. 

It begins in the gravel parking lot of Callahan Grove at Cermak and Desplaines and winds invisibly south through dew-wet grass. 

It’s early enough that traffic is still light and the natural sounds of the grove — cicadas tuning up loudly, jays bleating in the riverine woodlot, wind passing through black walnut and maple trees — can be heard above the cars and crossovers and roaring, monster pick-ups that are already starting to thicken. 

My wife and child have joined me on an arboreal scavenger hunt for few old white oaks that appear on an online map compiled by the Chicago Region Trees Initiative marking so-called “witness trees.” Also known as bearing trees, these trees were used as natural landmarks by land surveyors in the 19th century as they platted Illinois. 

The witness tree project is based at the Morton Arboretum and involves the Field Museum, the federal government and several research universities, and the idea is to get people out into the local woods and local parkways to search for any of these surviving landmark trees — all of which would now be older than 200 years. 

The witness tree map showed three possible specimens at Callahan Grove, all white oaks. All were marked with GPS coordinates based on old logbooks. Melissa Custic, coordinator of the Chicago Region Trees Initiative, warned me that most of these trees are long gone.

In fact, many were used to mark planned roadways and did not survive the horse-drawn carriage era. The Chicago Region map has about 14,000 witness tree locations on it, and since that map went live earlier this year only about 25 trees have been identified, Custic said. 

The situation in Callahan Grove is much the same. There are no surviving witness trees in the grove. At least one gave way to Cermak Road and who knows what happened to two others that GPS coordinates place south of 22nd Street. The grove lacks white oaks of any size and is now home to a pretty sizable community of walnut trees and a smaller, more sickly clumping of maples. 

Visitors to Schuth’s Grove across Cermak will find two excellent white oaks just off the west side of the parking lot near the picnic gazebo but neither is marked on the map as a Chicago Region witness tree. One of these oaks is at least three-feet around; it deserves a visit, and it also deserves to have fewer charcoal briquets dumped at its base.  

Back at Callahan Grove, there is no gazebo, no grill, no paved parking lot. It’s refreshingly rustic and still features a hand-pump for drinking water. The walnut trees on the west side of the property have established a thick overstory that beckons visitors to step beneath and pause for a bit. A comically large spider tends its web. Mallards hurtle by overhead toward the river. 

Later, driving past on Desplaines, I see a family has spread a picnic blanket beneath the walnuts. Another couple walks a golden lab nearby.

Late summer beneath the witness trees of tomorrow. 

The Chicago Region Tree Initiative witness tree map and project details are at Multiple other witness tree locations are marked in Riverside and Brookfield, and one more is marked along the Salt Creek Trail in North Riverside.

Trail Conditions explores the woods, waters and trails out our back doors. Brett McNeil lives in North Riverside. Write to him at