Forest Disturbances and Fire Ecology: Columbia River Gorge

Date of Visit: May 31, 2019 

Type of event: Study tour
Topic: Forest Disturbances and Fire Ecology
Organization: U.S. Forest Service, Columbia River Gorge National Scenic Area
Location: Herman Creek Trail, Cascade Locks, Oregon
Host: Robin Shoal, Staff Officer for Planning and Resources
International Fellows: Richard Banda (Malawi), Fen-hui Chen (Taiwan), Temitope Dauda (Nigeria), Zhongyuan Ding (China), Ana Kanoppa (Brazil), Will Maiden (United Kingdom), Romain Matile (France), Rodolfo Vieto (Costa Rica)
WFI Staff: Shadia Duery / International Fellowship Program Manager, Rick Zenn / Senior Fellow.

Now that the snow is away, let’s go hiking, Fellows! On this day, the International Fellows were VIPs accompanied by Robin Shoal from the U.S. Forest Service as we visited a forest recovering from a recent fire. We went to “The Gorge”, one of nine National Scenic Areas (NSA) in the United States.  The Columbia River Gorge NSA is Portland’s backyard, and about 4 million visitors per year visit Multnomah Falls and other gorgeous waterfalls while others hike the trails that were left undisturbed by the Eagle Creek Fire.

The Gorge was designated as a National Scenic Area in 1986 and consists of a 292,500-acre patchwork of public and private lands. It is divided into three zones, each with different land use regulations. The Urban area (about 10% of total area) contains 13 towns and communities which serve as the focus of local economic development programs, while activities in the General Management Area (50% of total area and includes the Columbia River) are mostly forestry and agriculture-related with some residential development permitted. The Special Management Area (40% of total area) consists of the most environmentally or visually sensitive lands, so activities are more restricted here than in other parts of the Scenic Area. It includes the 65,822- acre Mark O. Hatfield Wilderness area.

Robin Shoal explaining ongoing trail rehabilitation work
to the International Fellows

After the International Fellows introduced ourselves, Robin told us the story of the Eagle Creek Fire. On Saturday, September 2, 2017, after a long summer drought, a carelessly tossed firework landed in a canyon just off the Eagle Creek Trail. In the hours that followed, the U.S. Forest Service and Hood River County Sheriff's Office worked side by side to fight the fire and rescue more than 170 hikers. By September 4, east winds and excessive heat pushed the rapidly growing blaze west across the ridges of the National Scenic Area. In the days that followed, it became a 48,000-acre conflagration that rained down ash on Portland, smoldered near the city's water supply at Bull Run, and closed transportation arteries through the only sea-level route in the Cascades Mountain Range, including Interstate 84, the Union Pacific railroad, and even the Columbia River.

Two years after the fire, under a shining spring sun, the Fellows followed the newly reopened Herman trail and observed eroded slopes and destabilized rocks. Of the two hundred miles of pre-existing trails, only seventy miles have been secured and rehabilitated.  Trail rehabilitation when in the designated wilderness area, is done manually without any mechanical tools and is performed most often by volunteers supervised by the Gorge Trail Recovery Team, an organization comprised of four associations.

Continuing along our hike, we could also appreciate that the great majority of second-growth Douglas fir stands are still alive and that the understory vegetation has once again taken its place. We were inside the wilderness area, where no fire suppression has been done in recent years, except where human safety is concerned. Even though today the vegetation has changed, tree trunks that have been burnt are sending out new sprouts, and poison oak is covering everything! If not for the burnt traces on the bark of the trees, one could almost forget that this forest was overcome with fire just two years ago! But the trail we were on was not necessarily the one most impacted!

Within the National Scenic Area, precise monitoring of fire disturbance is carried out by field floristic surveys and aerial photographic inventories. The purpose of these studies is to monitor and measure the effects of fire over years. What emerged from the first analysis is the landscape has transformed from a second-growth forest with a closed canopy to a mosaic of landscapes.

The burn "mosaic" left behind after the Eagle Creek Fire

Instead of leaving behind a completely scorched dead zone, fire leaves a patchwork of brown and blackened areas with some green oases known as a burn “mosaic.” In this mix, severely burned areas have large groves of standing dead trees. Moderately burned areas will have a mixed canopy, where some trees survive while others eventually succumb to their damage. Finally, lightly burned and unburned areas will have an intact, healthy tree canopy but the ground vegetation is burned away, opening up bare soil that is ready for new growth. Here, a "seed bank" of many decades’ worth of seeds will be ready to spring to life, bringing rapid new growth. This complex mix of forest stands creates more diverse conditions for plant species and more types of habitat for animal species, even boosting the forest's biodiversity in the years following a fire. One challenge, however, is to prevent areas that burned from being colonized by invasive plants rather than by a mix of native species.

Lessons Learned

For almost everybody, wildfire is catastrophic, and it is! Preservation of life, conservation of property, and environment protection are top priorities and under the gaze of the media. From 1999 to 2010, the United States spent $19 billion fighting fires on 100 million acres which destroyed 1,100 homes and killed 230 people.

But fire is a natural phenomenon, too, even in the wet forests of the West Cascades, so the forest ecosystem has a natural process for regenerating and has done so for millions of years! Recent history shows us that at the close of the 20th century, nearly all old-growth mixed-conifer forests had been harvested (only 2% left) and fire suppression had been applied, meaning no fire was allowed and aggressive firefighting was the general rule of thumb. As a consequence, one century later, tree regeneration has grown, leading to today’s forests with high fuel accumulation, thus increasing drastically wildfire risk, especially in areas close to human populations.

Today’s “do nothing” attitude has led to large fires which will theoretically restore climax forest conditions composed of large trees and minimal understory. But it will take centuries for that to happen! Instead, throughout the Gorge, the U.S. Forest Service uses management tools, such as forest thinning and prescribed burns, to mimic a natural fire interval. This is beneficial for recreating the area's natural history, supporting plant and animal biodiversity, and decreasing risks of catastrophic future fires by reducing fuel loads.

Romain Matile, International Fellow from France,
 becoming friends with Bigfoot

An International Fellow’s Thoughts and Perspectives

The Eagle Creek fire story expresses well the stakes attributed to a forest close to an urban center: issues of landscape protection, recreational use, ecological and habitat restoration, watershed protection. It reminded me of Provence, France with Marseille and its 1.5 million inhabitants. In some neighborhoods, it literally takes just the simple act of crossing the street to end up in the Calanques National Park, an area with high visitor frequency, many environmental protection issues, and a stack of regulations that renders it impossible to carry out wildfire protection work. The job that a forester must do today goes much further than managing trees on a parcel of land; he/she must first and foremost manage human beings!