Restoring and protecting Belle Isle's valuable forestry heritage


(Photos courtesy of Michigan Department of Natural Resources)

By Kathleen Lavey

Michigan Department of Natural Resources

As the son of Belle Isle’s engineer, Fred Rottach pretty much grew up on the 982-acre park in the Detroit River.

When he was a small child, his dad would let him flip the switches in his office that changed the color of the lights illuminating the 125-foot-tall spray of the James Scott Memorial Fountain.

As a teenager and a college student, Rottach worked the island’s golf course, its concession stands and its canoe rental.

He even spent time working with foresters in Belle Isle’s 200-acre woods, a rare wet-mesic flatwood forest that covers 20 percent of the island and includes rare pumpkin ash and Shumard oak trees, as well as a variety of other hardwood trees.

Rottach even helped turn some of those trees – and trees removed from other Detroit parks – into usable lumber at Belle Isle’s sawmill.

“We had a couple of guys who were foremen. They lived down south or out west or up north, and they knew how to run a sawmill,” Rottach recalled. “We had a ‘Fat Jack’ and a ‘Whiskey’ and
‘Big Benny.’ They knew what they were doing, especially Fat Jack and Whiskey. They could run a sawmill blindfolded.”

The date is uncertain, but the Belle Isle sawmill closed sometime around 1980 – doors locked with a 4-foot, circular sawblade rusting in place.

The forest, which thrives on the proper balance of water, has been challenged by the loss of trees to the emerald ash borer (an invasive insect pest) and a fungal disease known as oak wilt, as well as things such as roads and culverts that changed water flow through the woods.

However, efforts are under way to protect and restore the unique forest and the sawmill and its building, which were falling into decay when the Michigan Department of Natural Resources first leased the park from the City of Detroit late in 2013.

First comes the forest

Walk through Belle Isle’s forest today, and you’ll see water pooled on the ground and dead ash trees lying in the woods. To restore the unique forest to its former glory, the DNR – with the help of EA Engineering, Science and Technology, Inc. – is starting at the bottom: by studying the soil and water where the trees take root.

That’s key in a wet-mesic forest. Belle Isle’s is near the northern end of the range of this forest type, which usually is found on glacial lake plains, and it’s the largest of six remaining high-quality examples in Michigan. The ground in a wet-mesic forest is typically damp and level, meaning even small alterations can change forest dynamics.

“It’s really a flat site, and because of that, microtopography is really important,” said Glenn Palmgren, ecologist with the DNR’s Parks and Recreation Division. “A few inches of rises and falls makes a difference.”

The study includes a look at soil and water, and what changes – such as making alterations to roads and trails or moving fallen trees that block water flow – could make a difference to improve forest health.

A headcount of animals that live in the woods is also included in the study, from tiny water-borne invertebrates to reptiles, amphibians, birds, coyotes and beavers that have built a dam across one of the island’s canals.

Migrating songbirds find seasonal haven in the trees of Belle Isle’s forest. Non-native European fallow deer munched their way through the forest’s understory for decades, but they have since been removed from the island.

The forest once was home to a record-holding pumpkin ash tree – a rare variety and state-threatened species in Michigan – that was killed by the emerald ash borer.  A champion Shumard oak tree – with a girth of more than 13 feet and a crown spread of up to 70 feet – is still hanging on, thanks to human intervention.

Belle Isle is the northern end of the range for Shumard oaks, which are rare in Michigan and a species of special concern here. The trees are in the red oak family, which are most susceptible to death from oak wilt.

In 2017, with the help of the Belle Isle Conservancy and the Michigan Invasive Species Grant Program, which funded portions of the project, workers removed 112 oak trees from the forest on Belle Isle to prevent the spread of the deadly fungus.

The trees were lifted from the island with helicopters to help protect the unique ecology of the forest.

Another 181 were protected from oak wilt by injecting them with a solution that keeps any infection from getting worse.

The forest also includes maples and many other varieties of oak. The understory includes spicebush and a white version of the usually yellow trout lily.

“Trout lily itself is pretty common, but the white variety that is on Belle Isle is more unusual,” Palmgren said.

Data collection for the $525,000 grant-funded hydrology study started last fall and will continue through August. Design work is expected to be completed in September.

The goal is not to return the forest to its previous state – before European settlers arrived in Detroit – but to restore the forest’s soil-water balance and allow it to thrive into the future. The changes also could make the forest more people-friendly.

“It will also be something people will enjoy more,” said Heidi Frei of the DNR Parks and Recreation Division’s stewardship team. “If you go there now, there’s a lot of standing water.”

Even in its current state, the forest serves important functions, including as a home for birds and other animals. Frei recalls walking through the forest shortly after the DNR signed the Belle Isle lease, tramping 5 or 6 miles throughout the woods.

“Even in the state it is now, there are certain pieces of the forest where it’s beautiful, it’s spectacular,” she said. “Then we popped out of the forest and there was the skyline of Detroit. For a minute, I had forgotten I was in Detroit.”

Refurbishing the sawmill

Walk into the building that houses Belle Isle’s sawmill, and it’s like stepping back in time.

A rusty, 4-foot-high sawblade still stands in place as if workers were about to slide logs towards it. A hand-penciled diagram with the notation “do not erase” on a whitewashed stair support near the mill shows the diagram for putting belts in place on the equipment.

This is where Rottach worked with all of those colorfully named colleagues in the early 1970s. It’s also a building that Joe Aiken and others with the Arboriculture Society of Michigan Foundation would like to see used to teach Belle Isle visitors the history of forestry, particularly the urban variety.

He said the city sawmill dates to the early 1900s.

“They were so ahead of their time in a lot of things,” Aiken said. “Back then, they didn’t go to Home Depot. Trees that came down in the city of Detroit were carried to Belle Isle and processed for material.”

Rottach recalls that lower-grade wood produced at the mill would be used to build park benches or repair other outdoor installations.

“If it was really nice wood like oak or maple or ash, it would be cut to the specs that they had given us at the carpenters’ shop,” he said. “Some of it was made into coat racks, book cases and cabinets for use in city offices.”

A Detroit News newsreel from the 1920s era shows a crew of workers pushing logs into a steam-powered sawmill. Aiken said he believes the mill was converted to electricity in the 1940s, when the current building was constructed.

After decades of neglect, a membrane covering was placed on the building’s roof in 2016. Coming this spring is a physical assessment of the building, to figure out how much it might cost to save it. The next step after that is a historic structures report, to guide the building’s restoration.

“Then we could start talking about programming and interpretation,” said Amanda Treadwell, urban area planner for the DNR.

Aiken is looking forward to that.

“The Foundation really wants to be the lead on the fundraising, the restoration and supplying the volunteers to walk people through the sawmill and the historical building,” Aiken said. “We’ve got all these people ready to donate.”

Do you want to help?

The DNR makes volunteer opportunities available on Belle Isle and in other state parks. If you’d like to help, go to and click on the Volunteer Calendar link. You can search by month.

Opportunities include Belle Isle Stewardship Saturdays, where volunteers help to restore the flatwoods by removing invasive species.