Forest Park, Wildfires and Homes

By Laura Foster

Goals for the Park and How You Can Reduce Your Own Risk
Forest Park (and the forest land it borders) burns, it is estimated, in cycles ranging from 75 years to 400 years, according to Fred Nilsen of Portland Parks and Recreation. Fires, when they do come, are catastrophic, “stand replacing” fires such as the Tillamook Burn (three separate fires). As Portland Parks’ North Side Natural Resources Manager, Nilsen has worked in Forest Park for 29 years. In November 2007, he spoke to Skyline Ridge Neighbors about the City’s plans to help reduce the risk of wildfires in and adjacent to Forest Park.

A few years ago, FEMA told the City to plan for hazards: wind, fire, floods, earthquakes, etc. Portland Parks, the Bureau of Environmental Services, the Fire Bureau and Portland’s Office of Emergency Management applied jointly for a $900,000 grant to reduce fire risk in three areas: Powell Butte, the East Bluffs (Waud’s Bluff near the University of Portland and the bluffs above Oaks Bottom) and Forest Park. So far, they have done a prescribed burn for grasses on Powell Butte and Oaks Bottom.
In Forest Park, the project is called the Forest Park Wildfire Risk Reduction Project. George Sowder, SRN’s Land Use Chair, is on the project’s Citizens Advisory Committee.

The goals of the project are three, presented in order of priority:

  1. Reduce wildfire risk to homes and businesses.
  2. Remove flammable, non-native vegetation such as blackberry and Scot’s broom.
  3. Improve wildlife habitat.

Summer and fall of 2008 are when projects will be implemented. As of late February, specific project details were not available.

History of Fires in Forest Park

Fires came to what is now Forest Park in 1889. A fire fed by east winds started near the bottom of Balch Creek Canyon (adjacent to today’s Willamette Heights neighborhood). It raced uphill, topped the ridge at Cornell and Barnes and ran downhill into Cedar Mill. A very big fire.

In August 1940, 1000 acres burned south of Saltzman and east of Skyline. The winds were out of the northwest. In August 1951, after a dry spring and summer came another fire, this one 2000 acres. It burned between Leif Erikson Drive and the crest of the ridge, running down into what is now Forest Heights. Nilsen said that most of Forest Park’s slopes are steeper than 40 degrees, a slope very conducive to spreading wildfires; other fire friendly features of the topography are chutes, saddles and chimneys. The south facing slopes, being drier, are at increased risk.

Another risk in a woodland fire here is the proximity of Highway 30 with its petroleum storage, rail lines and industry. Both BPA and PGE have two sets each of power lines. Under the power lines is flammable vegetation that Nilsen termed “fine [small] fuels that easily catch and burn.” Other challenges are fires started by transients camping in the woods, housing jutting into the park boundaries, low water pressure to fight fires, and more and older conifers as natural succession takes place, succeeding the less fire prone maple.

One good firebreak is Leif Erikson Drive, because it traverses the slope. Firelanes, which provide access, are not fire breaks, as they generally run from the bottom of the slope to the top along ridges.

Vertical roads do not act as firebreaks. Nilsen noted that the present fuel buildup in the park itself is low; that 70% of the park is hardwood and mixed stands, which are not too flammable and that fir stands are flammable only when the fire is of sufficient size to reach the canopy.

When a House Burns

Nilsen said are three ways buildings in and adjacent to wooded areas burn in wildfires, with percentages of occurrence:

  1. 60% burn when dry vegetation is in close proximity to a building.
  2. 30% catch fire via radiant heat from an intense crown fire.
  3. 10% ignite due to windborne embers landing on a roof.

Therefore, the ways to reduce risk in Forest Park (keeping in mind the primary goal is to save homes and businesses) is to reduce risk at and near homes, not to reduce fire hazard deep within the park.

This is where homeowners can mitigate their own risk. Landscaping is key. Nilsen used the term “a park-like landscape” to describe the best scenario around a home or outbuildings: limbed up conifers with native understory or groundcovers. He recommends irrigating areas adjacent to the home; and building, when possible, of fire-resistant material.

The Planning Bureau is trying to work with Portland Parks to make it easier for homeowners in environmental overlay zones to cut trees that are too close to the home. Tualatin Valley Fire and Rescue will come to your property and assess it for fire vulnerability, and provide a checklist on how to make it more defensible.

With fire management, Portland Parks’ desired 50-year outcome for Forest Park is:

  1. A maturing forest
  2. Oak woodlands restored in dry areas along east slopes. Native Oregon White Oaks (Quercus garryana) grow in the park in small patches along Highway 30; they grow up to the 200 feet elevation mark on north-facing slopes and up to the 300 foot mark on dryer, south facing slopes. Nilsen notes that the oaks are losing ground. Because they leaf out late, Douglas fir are sprouting around them.
  3. Power line corridors managed for native plants
  4. Conifer forest in coolest areas (north aspects and ravines)
  5. Maple-fir forests in intermediate areas
  6. Strategic fire breaks