Fire severity is the qualitative measure of the effects of fire on soil and site resources that control ecosystem sustainability. Depending on fire severity measures, changes in belowground land soil components can be deleterious to the entire ecosystem with immediate and long lasting effects. As of today the areas burn zone is only 50 percent contained across a profuse 48,831 acres of Multnomah and Hood River counties' forestland. The component of fire severity that results in the greatest below-ground damage to ecosystems, and hence recovery, is duration of the fire and the transfer of heat from burning biomass into the soil system impacting the chemical constituents, and biological components. The estimated complete containment date is an astonishing three months after the fire first began on Thursday November 30th, 2017. But forest service and Burned Area Emergency Response (BAER) teams restoring interventions cannot be immediately initiated upon even then. The forest service is currently predicting that the areas trails impacted by the fire may not be safe for repair and maintenance until Spring 2018 at the earliest, a disheartening reality.
But now, focus must be put on post wildfire facts and ecological fire science sustainability. Fire produces a spectrum of severities that depends on the interactions of burning, intensity, duration, live and dead materials, combustion type and degree of oxidation, vegetation type, climate, slope, topography, soil texture and moisture, soil content, time since last burned, and area burned. Fifteen percent of the Gorge fire suffered high burn severity, meaning all or nearly all of the ground cover and surface organic matter including fine roots have been destroyed. Thirty percent suffered moderate burn severity, and the remaining 55 percent has suffered either low or very low burn severity.
The current negative net effect and uphill battle is the reduction in the soils moisture contents; erosion of nutrient-rich ash and horizon sediments, and ultimately watershed drying. This drying diminishes the soils ability to recover and the recolonize microbes that are involved in biogeochemical cycling. Deterioration of this hydrologic functioning can quickly lead to decreases in the ecosystems sustainability. When the scenario is safe and composed enough the forest service, BAER, and applicable volunteers will start the long road of restoring the area to its original beauty.
For now, due to the fires travesty all National Forest System lands in the Columbia River Gorge National Scenic Area south of the Columbia River, east of Sandy River Delta, north of the National Scenic Area boundary, and west of Hood River currently have a legal closure in effect until further notice. For specific trail, road, and recreation sites affected by the fire in the Columbia River Gorge National Scenic Area and the Mt Hood National Forest, check the Eagle Creek Closure List here updated regularly to reflect current closure statuses.