To most visitors, Island Center Forest’s rugged landscapes look healthy and beautiful, swaths of firs, alders, maples and more that provide a home to birds and small mammals and a place for people to experience nature.

But Paul Fischer, King County’s senior forester, and Derek Churchill, a county consultant with a PhD in forest ecology, see something else when they walk through the forest: Patches of root rot where trees are dying from the top, spindly firs crammed together and even-aged stands that lack the structural diversity needed for forest health.

This summer and fall, they plan to oversee an ecological thinning project that they say will help to address these problems. All told, the equivalent of 110 loaded log trucks will remove Douglas fir, red alder and other tree species from 45.4 acres of Island Center Forest, the largest thinning project since King County took ownership of the forest 20 years ago. In another 4.7 acres, loggers will cut aging alders and leave them on the ground.

The goal is forest health, Fischer said, or what he calls “a self-sustaining forest ecosystem” that can naturally recover from an array of expected climate-induced threats — longer, drier summers, high winds, intense heat, even fire.

“Climate resilience is our overarching framework,” he said.

The project will enable foresters to increase species’ diversity and age variation; establish buffers to keep root rot — a naturally occurring but potentially devastating fungus — from spreading; and create canopy openings that will allow for a more diverse understory.

Thinning will also help address the drier conditions expected in the future, Fischer said. “When we have a high density of trees, they’re all struggling for water. Each tree is like a straw in the ground, trying to suck out water, and there’s often just not enough.”

“A well-resourced tree with a lot of water and light can fight off root rot. A tree that is stressed is less able to do so.”

But Fischer also noted that the project will have an impact on recreationalists, who will not be able to use a large section of Island Center Forest for about two months this summer and fall.

The project, which still needs a forest practices permit from the state Department of Natural Resources (DNR), is expected to go out for bid in early July and start in July or August. The county just completed its environmental analysis under the State Environmental Policy Act, which is now open to public comment until June 4. (See box for more information.)

Under the county’s proposal, the parking lot near Mukai Pond will be closed — it will serve as a yarding area for downed trees. A section of a trail called 115th Bypass will be widened and used as a logging road. Several other trails will be closed during the operation, including portions of the Land Trust Trail, Valley of the Firs and The Gallops. The project will largely take place in the eastern half of the forest, between the entrances off of S.W. Bank Road and S.W. Cemetery Road.

Once the project is completed, signs of disturbance will linger. Loggers will use heavy equipment to do the work, including a feller-buncher, which is a large harvester that grabs trees, cuts them and places them on a skidder to be hauled to the yard.

“These are big gnarly projects with a lot of immediate and short-term impacts,” Fischer said. “It will look rough. It is sometimes hard to understand why we cut trees when we want forests.”

“But the actions we’re taking today are setting ourselves up for better functioning ecosystems in the future, when a lot of our lands will be suffering from the impacts of climate change,” he said.

Pieced together over the years, Island Center Forest now comprises 440 acres of public ownership, a beloved place for walkers, runners, horseback riders and other users. Ten miles of trail lace the forest, skirting past two ponds, through ravines and near wetlands. The forest is also a birding hotspot — migratory songbirds are found there in the spring and summer; ducks with rafts of babies are seen on the ponds each spring; year-round birds like chickadees, nuthatches and kinglets are spotted every winter.

As Fischer and Churchill made their way through the project area last week, they acknowledged the short-term impact it will have on habitat. But they also pointed out the problem areas — trees that are dying due to root rot or crowded together with little room for a healthy understory.

“Not doing something is a greater risk,” Churchill said.

Churchill, who works as a forest health scientist at DNR, obtained his PhD in forest ecology at the University of Washington, where he studied under Jerry Franklin, legendary in forest ecology circles for his foundational role in identifying and protecting old-growth forest ecosystems in the Northwest.

An islander, Churchill also helped to write the county’s 2006 management plan for Island Center Forest, establishing a large portion of the forest as “working resource lands” administered to demonstrate sustainable forest management. Churchill oversaw a 20-acre thinning project in 2007 and a 59-acre project in 2014, both in Island Center Forest.

The current project is smaller in acreage than the one in 2014, but it’s larger in the amount of timber that will be removed. In 2014, 239,000 board feet of timber was harvested; in this new project, 508,000 board feet will be removed.

Churchill waded into the woods and put his arms around a Douglas fir, estimating its girth at 18 inches and its height at 120 feet. It’s a tree that will likely be felled, he said, because of the root rot in the area; next to it was a tree nearly dead from the fungal disease, identified by DNR’s forest pathologist.

But he then sidled up to another Douglas fir, this one 30 inches in diameter. Under the prescription Churchill and Fischer developed for the thinning project, this Douglas fir will not come down, he said — the company that wins the bid will not be allowed to cut any trees that are larger than 24 inches at breast height.

“If they’re cutting big trees, we’ll shut them down,” Fischer said.

Other actions will be taken to limit the impact of the project, Churchill and Fischer said. Trees, for instance, will be bucked — or cut into smaller lengths — on the forest floor before they’re hauled to the yarding area. They’ll also be limbed in place, with their limbs left to decompose in the forest.

To guard against a forest fire, the company that takes on the project will be required to have a 300-gallon water truck with a hose and pump on site. One member of the crew will also be required to remain an hour after operations cease each day to watch for fire. Churchill, Fischer or another member of the team will visit the site every day to monitor operations.

Churchill is a veteran of these projects — he also played a lead role in a forestry project at Agren Park in 2004, when more than 50 truckloads of Douglas fir and red alder were removed to enhance forest health. After touring Island Center Forest, Churchill and Fischer headed over to Agren to show the difference 20 years can make in a healthy forest.

In the dripping rain, the woods shimmered — there were dark-green Douglas firs and red cedars, bright-green vine maples, light-colored hazelnuts, and flowering dogwoods. Churchill pointed to one area where a road had been carved for a logging truck — the road was no longer visible, swallowed up by firs, alders and maples.

“This is what we’re trying to achieve, this kind of variability,” Churchill said. “It’s dark in some places, light in others — that’s what we’re striving for.”

“Over time,” Fischer added, “we expect our project in Island Center Forest will look and feel a lot like this.”

To submit comments about the Island Center Forest Bypass Thinning Project, email kcparks.sepa@kingcounty.gov or call 206-477-7372. Reference “Island Center Forest Bypass Thin” in the subject line. Read the county’s SEPA checklist, spelling out details of the project, here: tinyurl.com/VashonForestThinning.

Leslie Brown is a former editor of The Beachcomber.

Paul Fischer, King County’s senior forester (left), and Derek Churchill, a consultant, stand in a portion of the forest where thinning will take place. The tree next to Fischer won’t be cut because of its size. Churchill touches a tree that could be cut due to its size and proximity to trees with root rot (Leslie Brown Photo).