In Time for Arbor Day, April 23

By Leslie Shad

Evanston trees lead a challenging life. They must survive road salt, slices from lawn mowers, feet compacting their soil, gas main and sewer replacement projects, street resurfacing, and other stresses. They also get in the way of development projects. Historic old trees need our special attention and protection. As the Chicago Regional Trees Initiative has pointed out, we are losing our oaks, and now hang on to only 17% of our original oak ecosystem.

This comes at a time when Doug Tallamy, University of Delaware entomologist, is releasing his latest book “The Nature of Oaks: The Rich Ecology of Our Most Essential Native Trees” which outlines how critical oaks are to humans and nature. The pre-eminent U.S. keystone tree, only oaks are nurseries to more than 500 U.S. caterpillar species. 

Caterpillars in turn are foundation species for biodiversity.  Caterpillars – Dr. Tallamy calls them “repurposed leaves that can walk” – concentrate the nutrients they eat, making them powerhouse food for songbird nestlings. About 96% of terrestrial bird fledglings rely on caterpillars .

Oaks feed caterpillars, and caterpillars feed other insects, birds, fish, amphibians, reptiles, and mammals and underpin the entire ecosystem on which humans rely. The problem is that insect populations, including caterpillars, are in steep decline, which impacts birds and other creatures.

I am haunted by the whippoorwill that flies our forests with its mouth open to catch moths and other insects. The decline of insects is attributed to many cuts: ubiquitous insecticides infiltrate and drift; gardeners shred or remove leaves in which insects overwinter; turf lawns (the largest irrigated crop in the country) deny crucial food forage; non-native invasive plants overtake habitat; and the decline of native species, including oaks, serves insects a double whammy.

Fewer native plants not only eliminates habitat cover for insects, but also the host plants that 90% of insects must have to develop from larvae or caterpillar to adult, according to Dr. Tallamy. No moths, no whippoorwills. Empty mouths.

We can change these losses readily and in our own yards: reduce lawns and chemicals, and protect our mature native trees, particularly oaks and other keystone species, and plant diverse native trees to build a resilient urban canopy. 

Mature trees are critical now and to build resilience to oncoming climate disruption. Compared to younger or replacement trees, these big trees best hold our carbon, clear our air, absorb our stormwater and cool our streets. But in addition to slowing the untimely loss of mature trees, plant diverse young native trees to turn the tide for our urban canopy.

The City is trying to do just this. Our elms, native to Evanston and almost as much a part of our local tree history as the oak, are devastated by Dutch Elm Disease and urban stresses. 

To replace our dying or declining elms, the City, with funding from the Community Fund for Evanston Trees, this winter purchased 31 American elms. The new elms are clones of native elms that have demonstrated resistance to Dutch Elm Disease. It is an experiment to learn how well these trees will resist the disease when planted in Evanston and still serve the important role of feeding about 215 species of caterpillar, according to Dr. Tallamy.

However, our mature trees also continually lose out to development. Back in 2011, the City approved a plat at the old Kendall College site, 2390 Orrington St., on condition that certain trees remain and others “remain if possible.”

The City passed a resolution to protect the trees. But on  March 9, 2021, the  Preservation Commission approved a single-family home at the site that will kill one old oak and most likely its “sister” even larger oak (32-35-inch diameter) with intertwined roots. 

This despite the developer having agreed that both trees would “remain if possible.” Whether it is possible to preserve the trees has not really been explored since the developer asked for an even larger footprint than earlier options and approaches even closer to the imperiled trees, so it isn’t clear that effort has been made to preserve the big trees. The question is whether the City will enforce its 2011 resolution. About 80 neighbors and community members wrote to the Planning and Development Committee pushing for City enforcement.  As one advocate said, “As in many environmental battles, we have to ‘win’ over and over. The trees only have to lose once.”



Care for your mature trees. 

Water them in dry spells. Add mulch in a “doughnut” pattern to the drip line of the tree (shadow under branches). Leave a 3-inch gap around the trunk for the tree to ‘breathe’ and avoid rot.  A ring of mulch helps protect trees from mowers and competing plants.

Help our Natural Areas expand and add diversity.

The Channel Habitat Fund, with volunteers and park stewards, have accelerated crucial habitat in Ladd Arboretum and Harbert-Payne Woods. The new Fund quickly fulfilled its match, meaning that funds from the Illinois Clean Energy Foundation will be released to plant many more natives and provide educational signage. Donations (unmatched) are welcome HERE.

Clark Street Beach Bird Sanctuary was featured in the Wild Ones conference, and is creating an emblematic lakeshore ecosystem.  More info HERE.

Volunteers are reassembling at the Lorraine Morton Civic Center Habitat Garden, Lovelace Park, Hinman-Main Garden, and Jens Jensen Landscape at the Lighthouse.  Email Habitat@NaturalHabitatEvanston.Org to join in their efforts.

Treeplenish. Striving for sustainability at Evanston Township High School (ETHS), plant a tree to offset the school’s paper use. Choose from redbud, red maple, or quaking aspen, $4.30/tree.  Request your tree HERE.

Tree distribution is April 24 1-4 p.m. at ETHS.

Browse Native Plant Sales.

Bessie Rhodes School. Purchase HERE. For mid- to-late May pickup 

Bird Buzz Evanston Environmental Assn & Natural Habitat Evanston. Purchase HERE  until May 8, then bring your receipt and pick up your order at the Morton Civic Center, 2100 Ridge, on May 22. 

Chicago Audubon Society, for pickup May 23. Info HERE

Go Green Wilmette, in-person sale May 8. Info HERE.

Openlands Native Plant Sale, purchase HERE.

Considering a donation to the Fund for Evanston Trees to plant a shrub ($25), tree ($90) or grove at a school, neighborhood, or park?  Email to brainstorm a planting project, or donate directly. 


Evanston Public Library – Lunch+Learn Why Native Plants? Thursday, April 8 at noon  Register HERE

Canal Shores Tree Planting and Buckthorn Removal. April 17, 9:30 a.m.-noon; meet at the course’s 10th hole. The Metropolitan Water Reclamation District is donating 150 shrub and tree seedlings to Canal Shores, which will plant them in fenced nursery areas till they are big enough to transplant. Join the Citizens’ Greener Evanston Board helping at Isabella Woods (Canal Shores Golf Course holes 10, 11, and 12), and South of Lincoln (holes 14-18). Wear masks and, if you have them, bring gloves, loppers, tree saws, and shovels or spades.

Gardening that Matters.  April 19, 4 p.m. Hosted by WiseUp: Aging with Attitude, presented by Natural Habitat Evanston. How you can take action for climate, community health and biodiversity.  To Register, email and request the Zoom link. 

Keeping Habitat Resilient. April 23, 11 a.m. to noon. Three short presentations, on garden cleanup, soil, and why trees matter (Allison Sloan) Registration TBA- check HERE.

Earth Day Events, April 24: Ecology Center 10 a.m. to noon, Beach and Neighborhood cleanups, Tree Planting.  More info HERE.

Why Preserve Native Trees and Shrubs, and Plant More? April 29, 6:30 to 7:30 p.m. What innovative machine can help slow climate change, raise property values, protect from winter winds and summer heat, filter our stormwater, and fight extinctions?  A tree.  Learn more about why we need to keep our big, old trees and plant more. Register HERE.

Ms. Shad, retired after a 25-year legal career, is focused on a sustainable future for people and wild things. She founded and co-leads Natural Habitat Evanston and serves on the board of Citizens’ Greener Evanston.