Lake Michigan, at a high-water mark in 2019. (WTTW News)

Drew Gronewold, an expert in hydrological modeling at the University of Michigan, presented his annual update on Great Lakes’ water levels. Lake Michigan is holding steady, but for how long?

A street tree planted in Chicago in 2022. (Patty Wetli / WTTW News)

When it comes to alleviating the impacts of climate change, trees have been promoted as the ultimate “green infrastructure.” But trees are living organisms, and they can be sensitive to some of the same climate stressors as people. But just how sensitive?

Cottonwood seed is piling up in River Park along the North Branch of the Chicago River. (Patty Wetli / WTTW News)

Yep, it’s the annual appearance of cottonwood fluff, and if you were thinking this year’s showering seems excessive, you’re right. It is.

(WTTW News)

A dense green tree canopy can reduce the effects of air pollution and climate change. A 2019 study by the city found Little Village was among communities burdened by higher air pollution — and now, the neighborhood is planting the seeds for change.

(Patty Wetli / WTTW News)

The Great Lakes was named a global “Hope Spot,” joining the Galapagos Islands, the Great Barrier Reef and the Bering Sea as a place identified as critical to the health of the ocean.

A bur oak, estimated at 250-300 years old, is dismantled at Lincoln Park Zoo, May 2, 2023. (Patty Wetli / WTTW News)

Lincoln Park Zoo said farewell today to a 300-year-old bur oak, but the tree will live on in multiple ways.

Lincoln Park Zoo's ancient bur oak, seen in fall 2022. (Patty Wetli / WTTW News)

Crews are scheduled to begin removal of the ancient bur oak on May 1. The zoo is planning Arbor Day events on April 28 to give the tree a celebratory farewell.

(Patty Wetli / WTTW News)
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The board will help ensure the growth, maintenance and health of Chicago’s tree canopy for generations to come, officials said. The group’s first meeting could come as early as February.

(Patty Wetli / WTTW News)
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The six recommended appointees to the board, which was created in June 2021, all received unanimous support during a key committee hearing. Next up is a full Chicago City Council vote.

Katrina Quint, director of horticulture at Lincoln Park Zoo, stands in the shadow of the zoo's oldest inhabitant, a bur oak that's 250-300 years old. (Patty Wetli / WTTW News)

A bur oak has towered over the zoo’s south lawn, opposite the primate house, since before there even was a zoo. It even predates the founding of the United States of America. 

South Side voters overwhelmingly supported an advisory referendum to stop cutting down trees in Jackson Park and South Shore. (Save Jackson Park / Facebook)
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Voters sent a message to officials by overwhelmingly supporting an advisory referendum calling on the city of Chicago to stop cutting down trees in Jackson Park and South Shore. 

(Patty Wetli / WTTW News)

Chicagoans get to experience two seasons simultaneously this weekend: summer-like temperatures hitting the upper 70s and peak fall color.

Bur oak is one of more than 80 oak species native to the U.S. (Karen Roussel / Flickr Creative Commons)

A team of researchers, led by Morton Arboretum, spent the better part of the past five years creating the first-ever standardized checklist and threat assessment of the nearly 900 species native U.S. trees. Their work provides the foundation on which to build awareness, advocacy and future conservation efforts.

A participant in the Nature Conservancy’s Youth Environmental Thinkers program is pictured. (WTTW News)

As brutal heat waves sweep across the globe, calls to address the effects of climate change have become increasingly urgent. But in addition to large-scale policy efforts, making lasting change often starts with individuals.

Scientists gather around what may be a lateleaf oak, thought to be extinct. In Big Bend National Park, May 2022. (Courtesy of U.S. Botanic Garden)

The lateleaf oak has confounded botanists since it was first discovered in the 1930s. Scientists have been hard-pressed to find a single surviving example in recent decades. But a new discovery, pending genetic testing by Morton Arboretum, could put the tree back on the map. 

A group from Thomas Kelly High School in Chicago help plant trees. (Credit: Openlands)

The nature conservation group Openlands and search engine Ecosia are hoping to boost the number of trees in underserved areas through their TreePlanters Grant Program.