John O’Hara has enjoyed the fall colors near his home in Plymouth for the past 15 years, but this year he’s alarmed: The mature forest in his neighborhood may largely disappear this winter.

“It’s just a shocker,” he said this week in his back yard. “I’m not a hippie or anything, but this is an important part of Plymouth, and you can’t lose all this green space.”

O’Hara’s home on Orleans Lane backs up to several acres of thickly forested oak, elm, ash and basswood owned by the city. It’s a hilly, shady area with a meandering paved trail, intermittent stream and plenty of cover for foxes, deer, hawks, owls and other wildlife.

O’Hara is mystified that the city of Plymouth plans to cut down 800 to 1,000 trees in the area and spend almost $1 million to improve water quality in a stream that is dry most of the year.

The funding would come from local property taxes through the Bassett Creek Watershed Management Commission, which is scheduled to make a final decision on the plan on Thursday.

The project has been in the planning stages for a couple of years, but O’Hara said he and other neighbors heard about it just weeks ago.

The rationale for the project starts with Northwood Lake in New Hope, about one-half mile away. Northwood is polluted with phosphorus and violates state standards, so watershed and city officials are looking for ways to turn the lake’s water quality around.

A study found that much of the pollution comes from Plymouth, specifically through the north branch of Bassett Creek and its tributaries that flow during spring snowmelt and summer downpours. The project calls for cutting down most trees along a 30-foot corridor on each side of the tributary in the park area.

Derek Asche, Plymouth’s water resources manager, said the mature trees have shaded out most plants and undergrowth, so too much forest floor erodes when the unnamed tributary flows. The soil and water contain phosphorus that flushes into the north branch of Bassett Creek and is carried to Northwood Lake, where the pollution causes algae growth and degrades the water.

The proposed corrective action, Asche said, is to remove the trees along 3,700 feet of the creek bed, and rebuild the corridor with diverse grasses, wildflowers and shrubs with dense roots to reduce erosion. The trees need to go, he said, to increase sunlight and enable the plants to grow.

A second piece of the project includes removing additional trees to construct a holding pond to catch runoff from nearby lawns and streets and let phosphorus settle out instead of flushing into the stream.

Big trees draw nature lovers

O’Hara’s neighbor Erich Schroeder said that he is not convinced that the project is needed or will be successful.

The creek tributary flows only about 50 days per year, he said, and the park land is one of the few places in Plymouth that has a mature forest with a trail running through it. “Every time I walk the trail, which is regularly, I run into people,” he said. “It’s not just the people that border this property that will be impacted, it’s the whole neighborhood.”

As Schroeder walked along the heavily shaded trail Monday afternoon, two dog walkers and a jogger breezed by. The stream bed was dry, but erosion along its banks has created gullies and exposed tree roots. Schroeder said he would welcome improvements in the park, such as replacing culverts, removing downed or unsafe trees and repaving the trail. But he said the plan to remove hundreds of trees, many of them oaks more than a hundred years old, is too drastic.

“Sometimes the cure is worse than the ailment,” Schroeder said.

Winter schedule

Asche said cutting down trees is “an unpleasant experience that nobody’s going to like,” and he understands neighbors’ concerns.

“But we’re also under mandates to improve water quality in the lakes, and sometimes those two values are in conflict with each other,” he said. “That’s what we need to work through here.”

Asche has met with some of the neighbors, and promised to spare a few favorite trees. But he is also clear that the park needs restoration. “It’ll be different and it’ll be a change,” he said. “People need to know that and people should expect that.”

If approved by the Bassett Creek Watershed Management Commission, the project would go to the Plymouth City Council later this fall to award a contract for the work. Plans call for tree removal, creek bed work and holding-pond construction between mid-December and the end of February. Asche estimated that the holding pond and the creek restoration will stop about 75 pounds of phosphorus from flowing into Northwood Lake each year, and that the lake will need phosphorus reductions of 350 to 400 pounds annually to improve its water quality. To reach that goal, Plymouth and New Hope will have to employ other practices such as more frequent street sweeping, shoreline restorations, rain gardens and education.

Schroeder said he is not against improving the lake, but said there’s also value in protecting natural spaces and wildlife, especially in urban areas.

“You cut mature trees down and they’re gone forever,” he said. “I’m nervous about this.”