In last week’s column, I discussed the threats to our urban forests in Federal Way. Invasive species, habitat loss and fragmentation all pose challenges to keeping Federal Way’s natural forested areas healthy. This week, in search of solutions, we’ll turn to the West Hylebos Wetlands Park

It may seem counterintuitive that a large, 120-acre protected forest like the West Hylebos Wetlands would need a forest health plan. The reality, though, is that life ain’t easy for trees in the city.

The West Hylebos Wetlands forest is only a remnant of a much larger forest that once stretched across the entire Federal Way plateau and into the Puyallup and Green River Valleys. Today, the forest is surrounded on all sides by roads, Himalayan blackberry, Scot’s broom and other invasives that provide a constant source of seeds and threat of invasions. Since the forest has shrunk so dramatically, its trees are more susceptible to the impacts of windstorms and flooding.

Over the last decade, I noticed an increasing number of “blowdowns” in the park, areas where wind or disease caused trees to fall, creating openings in the tree canopy. These canopy gaps are prime entry points for invasive species to begin colonizing forests. Could the West Hylebos Wetlands be in danger of losing its forests? We had to learn more about the health of the wetlands’ forest.

In urban forest management the first step is to understand the size of your forest resources and their health problems. Then, you can prioritize action based on the urgency of the health threat and the value of the environmental resource.

With the support of the city of Federal Way, we began surveying and mapping the forest in 2007. (We were able to survey 60 percent of the forest. The remaining area will be mapped this year and rolled into the forest health plan.)

Surveys noted the location and size of every blowdown, as well as the location of invasive species infestations. We brought in a forest ecologist to assess the health of the forest and help us develop an action plan.

The result is the West Hylebos Wetlands Forest Health Plan, which identifies just over 10 acres of forest that need invasive plant removal and supplemental planting with native tree and shrub species. The sites are ranked in order of priority so that we can effectively marshall limited resources to address the most important health threats first.

The good news is that the park’s forest is in excellent condition overall. The number and size of blowdowns in the forest were within normal range for a lowland Pacific Northwest forest, and we found no unusual tree diseases at work. In fact, our forest ecologist called the West Hylebos Wetlands one of the healthiest urban forests she’d seen.

Maintaining that health now is our goal. It turns out that the biggest threat to the forest is the invasive species at the park’s edge. Over the past seven months, with involvement of a small army of volunteers and the support of the city of Federal Way and King County, we’ve been removing those nasty plants. As you drive by the park on S. 348th Street you may be able to see large areas of black landscape fabric where blackberry was removed.

A series of future planting efforts will fill these cleared areas with native trees and shrubs. It will take another three to five years of occasional maintenance to keep invasive weeds in check and to nurture the trees to a point where they will be self-sufficient. Ultimately, the result will be a larger forest for the West Hylebos Wetlands.

While the park’s forest is in relatively good health, completing all the action recommendations will cost more than $200,000 over several years. This points up a fundamental truth about urban forest health; It’s too big a job for any one government agency or nonprofit to go it alone. Keeping our forests healthy will require community partnerships between government, businesses, nonprofits and volunteers.

Completing the work done this year at the park involved the generous support of the city of Federal Way, King County, REI, Banrock Station Wines and HomeStreet Bank’s Tree Challenge matching grant program. More than 60 brave volunteers donated over $4,000 of volunteer labor helping us battle the blackberry.

With the West Hylebos Wetlands Forest Health Plan in hand, we can ensure that the Wetlands remain healthy and green, and that Federal Way’ers will have a wonderful park to visit and enjoy for years to come.