USFS says new strategies are needed to make forests healthier, more fire-resistant

By Ann McCreary

In an era of increasingly large and destructive forest fires, a strategy for managing Okanogan-Wenatchee National Forest lands to make them more resilient will soon be put to its first test in the Methow Valley.

The nation’s dry forests, especially forests like those surrounding the Methow Valley, have undergone so many changes as a result of a century of fire suppression, logging of large fire-resistant trees, and other human interventions that they can no longer tolerate fires that historically played an important role in keeping them healthy.

Called the “Okanogan-Wenatchee National Forest Restoration Strategy,” the management approach focuses on the goal of restoring forests’ ability to survive fire and a more recent threat — climate change.

The new approach will be applied to a large restoration project planned for the Libby Creek and Buttermilk Creek sub-watersheds, called the “Mission Project,” named after Mission Peak that lies on the border between the two watersheds. (See related story.)

The Restoration Strategy is based on understanding historical conditions of landscapes in the Okanogan-Wenatchee National Forest, as well as considering the future effects on forest ecosystems of a warmer, drier climate resulting from climate change.

The strategy differs from past forest management practices by addressing restoration on a significantly larger scale, developing projects that integrate considerations for vegetation, wildlife, hydrology, road management and habitat across entire watersheds of 10,000-50,000 acres.

The strategy utilizes GIS mapping and sophisticated software to evaluate current forest conditions and compare them to historic conditions and potential future conditions under climate change, in order to develop interventions aimed at restoring resilience.

“The Forest Restoration Strategy is a state-of-the-art ecological restoration approach,” said Lloyd McGee of the Nature Conservancy.

“With the Restoration Strategy we start with a landscape vision. This is not business-as-usual,” said McGee, who is also co-chairman of the North Central Washington Forest Health Collaborative (NCWFHC).

The collaborative is another new factor in restoration planning for the Okanogan-Wenatchee National Forest. Formed in 2013, the collaborative includes timber industry and conservation groups, tribal government, elected officials and local, state and federal land managers.

The goal of the diverse group is to increase the pace and scale of forest restoration in Okanogan and Chelan counties by providing additional staff and expertise to help the Forest Service move projects forward.

Extraordinary megafires

Impetus for creating the forest health collaborative came from recognition of forest conditions that have contributed in recent decades to enormous and devastating fires, as well as disease and insect infestations, and the U.S. Forest Service’s inability to keep up with needed restoration work.

“As a collective, we recognize that a great preponderance of science for dry forest restoration states there is a high need for active management,” McGee said. “Conditions have to change physically in these landscapes or we’re going to continue having the extraordinary megafires that we have now.”

Forests that were once adapted to periodic fire are now so dense and dominated by small trees that they cannot survive fires that have grown exponentially in size and severity.

After decades of fire suppression by humans, forests are overgrown and have lost the natural mosaic pattern — a patchwork of different ages, species, and sizes of trees — that developed when fires periodically burned through forests and then stopped when they reached a previously burned area.

Now many forests have become an unbroken carpet of dense, and often unhealthy, trees that are prime for fire.

A study released earlier this year by The Nature Conservancy and the Forest Service concluded that 500,000 acres in Okanogan and Chelan counties need treatment to become more resilient to natural disturbances like fires, insects and diseases. Currently OWNF treats about 20,000 acres annually, or about 4 percent of the area needing treatment.

The most widely used treatments are thinning to remove small trees and shrubs that have grown up under mature trees, competing for nutrients and water and often carrying fire into the canopy; prescribed burning to reduce debris on the forest floor that results from thinning and from decades of fire suppression; and overstory thinning to open up the upper tree canopy, minimize spread of crown fire, and reduce competition among trees.

Another approach, McGee said, “is allowing wildfire to be controlled but continue to burn where good ecological outcomes can be achieved. That one can be controversial.”

For Okanogan-Wenatchee forest officials, an extreme fire season in 1994 provided a wake-up call about the condition of the national forest, said Richy Harrod, deputy fire management officer for the forest. That year 186,000 acres of the forest burned, costing $70 million for suppression and $18 million for rehabilitation.  Forest officials subsequently developed a “Dry Forest Strategy” to try to bring the forests back into balance.

In 2009 a panel of scientists from the Wenatchee Forestry Sciences Laboratory worked on developing an updated strategy based on current understandings of forest ecology and effective treatments, and incorporating GIS mapping technology and decision making software. The Forest Restoration Strategy was finalized in 2010.

“This strategy takes an interdisciplinary approach to forest management and takes into account climate change. It will be a template for future management,” said Harrod, who was one of the authors.

Landscape-scale planning

The restoration process starts with selecting a large landscape, encompassing as many as three watersheds and 50,000 acres, and using aerial photographs and field studies to evaluate current conditions such as fire impacts, vegetation, wildlife, aquatics, and susceptibility to insects and disease.

The current ecosystem conditions are then compared to past conditions, using historical (pre-fire suppression) photographs, and to potential warmer, drier conditions expected to affect the forest in the future. Forest managers also compare the project area to similar watersheds to evaluate past and future conditions that affect forest resiliency.

The strategy then identifies which areas are most changed from their historical condition. Restoration treatments are designed to focus on specific areas that are most likely to improve the larger landscape.

“By analyzing whole watersheds, we can understand where, why and how terrestrial and aquatic conditions have changed. This approach allows us to develop integrated plans for work over large areas,” Harrod said.

Strategic use

Although the strategy evaluates large landscapes, the actual treatments — thinning, controlled burning, road management — will be conducted on smaller areas within that landscape.

“The main benefit is we strategically place our treatments,” Harrod said. “We’re targeting places that have the largest effect on the landscape … to interrupt fire flow, and impact insects and diseases.”

Forest ecosystems are inherently complex. In order to guide evaluation and project planning, the Restoration Strategy utilizes decision-making software with the imposing name, “Ecosystem Management Decision Support System,” or EMDS.

“We have always looked at historic patterns and reactions to disturbances, and how those have changed,” said Meg Trebon, assistant fire management officer for fuels on the Methow Valley Ranger District.

“What EMDS has done is to introduce a much broader range of different measurements of what is going on in the landscape, in comparison to other landscapes that … are selected for strong similarities in environment, vegetation and disturbance processes,” Trebon said.

“It provides a grounded comparison. When we say we should do this treatment in this area to get this type of stand structure, it’s based on a lot of science about comparable watersheds,” she said.

The analysis guides a landscape “prescription,” that might include identifying areas where naturally occurring fire should be allowed to burn, said Derek Churchill, a University of Washington forestry researcher who is working on a contract basis with the forest collaborative.

The landscape prescription prioritizes treatments that are designed to accomplish goals such as shifting the composition of trees to more fire-tolerant and drought-tolerant species; removing smaller trees and leaving larger, older trees; reducing ladder and surface fuels; and restoring the forest’s natural spatial patterns, Churchill said during a workshop held last month in the Methow Valley.

“Spatial patterns matter,” said Churchill. Forests don’t grow like a tree farm, with uniform spacing between trees, but are a messier combination of large and small clumps of trees, open spaces between the clumps, and individual trees interspersed.

“Forestry in the past was often focused on managing for uniform conditions. We used to do plantation-style thinning. But our main focus is no longer growing wood, now we’re trying to restore ‘clumpy-gappy’ patterns that we think are more resilient to fires and other disturbances,” Churchill said.

Churchill takes treatment prescriptions down to level of individual trees within stands of trees, using patterns from historical forests to determine just how many clumps, openings and individual trees are need to return tree stands to a more natural state.

He helped develop an application that can be loaded onto computer tablets that forest managers can take into the forests to guide how to mark trees for thinning.

“It’s an operationally practical and quantifiable method to create a desired range of spatial patterns,” Churchill said.

Working from the broader landscape perspective down to the level of small stands of trees provides a “holistic approach” to helping forests become less vulnerable to fire and disease, Churchill said.

“We’re looking at habitat, fire, aquatics, insects and disease. We’re looking at all the tradeoffs of those together in one framework. People were thinking about that before but it wasn’t as integrated,” he said.

Applying current technology and decision-making software, he added, provides a “rigorous approach to quantifying departures from historical conditions, and allows us to have some clear targets for how much of the watershed we want to move into a different kind of forest — a less dense, more variable forest.”

Better science, with tradeoffs

“Yes it’s better science,” said Mike Liu, Methow Valley District ranger. But, he added, people who live near forests and value them for recreation and resources may wonder what result they can expect from the Restoration Strategy.

“If we are successful, it means our dry forests will be more open and resilient to stressors such as climate change, insect and disease outbreaks, and wildfire. The more open forest will also mean safer places [for firefighters] to engage wildfire with a higher probability of success,” Liu said.

The forests “will look more natural and less like a plantation,” he said. “We will have fewer large-scale, high-severity wildfires and consequently more productive forests. Our streams will run clearer with less sediment,” he said.

“The trade-off is we will have more prescribed burns, which means smoke in the spring and fall, more acres of thinning … and on the aquatic side, fewer open roads.”