KENWOOD — The mercury was climbing toward 40 degrees the morning of March 5 when a pickup climbed a curb on Lake of the Isles Parkway, eased down a steep wooden ramp and landed on the frozen lake surface.
Where truck tires had dug ruts in the snow, pools of water glistened on the ice.
"We’re doing ice checks every other day just to make sure" it’s safe, Bruce Monteith, who was behind the wheel of the Minneapolis Park and Recreation Board vehicle, said. "… We measured the ice and we’re sitting at 19 inches, which is going to hold just about any of the vehicles we have."
Monteith, a forestry division foreman, pointed the truck toward Raspberry Island, following a temporary roadway plowed into the lake’s slowly melting ice sheet. Out on the island, parks crews were continuing a job they started last spring.
Last year, warm weather cut short restoration efforts on 7.1-acre Raspberry Island, where parks crews used chain saws to hack through a tangle of mulberry and buckthorn. There had been enough time, though, to clear most of those invasive species from 3.5-acre Mike’s Island just to the north.
Once again this year, work was scheduled for late winter so parks crews could drive out to the islands on the ice. Cut limbs were disposed of in small fires scattered across Raspberry Island, and a bit of snow cover also lessened the danger of a fire spreading.
In the end, the ice held and crews wrapped up work in just a week’s time. Sometime this fall or next spring, forestry staff will return to the islands to plant native trees and shrubs, the next step in an effort to restore native vegetation and wildlife habitat.
The work this year required only about a dozen members of the forestry staff, less than half the number who were on the islands last March. For the crew, who volunteer for island duty, a week on Lake of the Isles is a break from tree trimming on city streets.
Standing next to a smoldering fire pit, forestry crew leader Fred Herby said last year’s effort already had dramatically reduced undergrowth on the islands.
Before last spring, they were so choked with mulberry and buckthorn that young native plants lacked the space to grow. Now, there was room between the mature native trees — including box elders, cottonwoods and hackberries — for more sunlight to hit the forest floor.
Still, buckthorn is tenacious. Some shrubs cut back to the roots last year had sent up bristles of new growth.
"You can see how quick this stuff grows back," Herby said, pointing to a cluster of skinny buckthorn shoots, each a few feet tall and holding its withered, dark brown leaves from last summer.
"That’s all stuff that was cut last year and came back that fast," he continued. "It doesn’t take long for it to grow up enough to make it look like we weren’t even here."
Monteith said the planting of native species should discourage the spread of mulberry and buckthorn. If all goes to plan, he added, the restored island environment should encourage native wildlife to return, as well.
"I know at one point it was, I believe, a heron rookery," Montieth said. "You get these invasive species that allow predators out here and it just, for whatever reason, changes [the herons’] view of the best place to nest, and we just don’t see them out here anymore."
Last year the plumes of smoke rising off the islands attracted a lot of attention from neighbors to Lake of the Isles, not all of it positive. Some wondered if burning was the best and safest way to dispose of cut vegetation.
This year, though, workers on the islands said they had relatively few visitors.
Darcy Berglund and Anne Hessian, neighbors in Kenwood, came across the ice with three dogs, walking within a few yards of the islands. They said they supported the restoration.
"I’m eager to see native habitat," Berglund said. "I’m very happy to see the invasive species get removed."
It may be some time, yet, before those watching from the shore of Lake of the Isles see significant changes on the islands. After all the cutting and planting, it will still be years before native plants make a comeback, Dan Uhlenkott, a city tree inspector said.
"It’s not going to be pretty for a while," Uhlenkott said. "… But once native plants start taking over, I think we’ll be in good shape.
"It’s a work in progress."
Reach Dylan Thomas at email@example.com.