In 2006, the Bluegrass Fire raced along Bluegrass Ridge, torching the subalpine forests above Elk Meadows on Mount Hood’s east flank. In 2008, the Gnarl Fire burned a much larger swath of the east slope, from just above Elk Meadows to the Eliot Branch canyon, nearly destroying century-old Cloud Cap Inn, Snowshoe Lodge and the historic structures at nearby Tilly Jane Campground. Heroic efforts by Forest Service firefighters spared these priceless jewels of Mount Hood’s history, with the fire burning within a few yards of these old structures.

In August 2011, the Dollar Lake Fire was the third in a string of major fires that would ravage the slopes of Mount Hood in a period of just five years, this time burning the north slopes of the mountain. Lightning started the Dollar Fire started on a weekend, just below the popular Elk Cove trail and was immediately reported by hikers in the area.

The Dollar Fire soon erupted to become one of the most fiercely fought and carefully documented fires in recent memory as it swept to the west, eventually threatening Bonneville Power Administration transmission lines at Lolo Pass and the nearby Bull Run Watershed, source of Portland’s drinking water.

The fire wasn’t fully contained until the end of September of that year, eventually burning more than 6,200 acres of forest (maps and photos of the fire can still be viewed on the InciWeb interagency website).

Firefighting efforts were initially slow to arrive at the Dollar Fire, and some (including the media and members of Oregon’s Congressional delegation) accused the Forest Service of purposely allowing the fire to grow because it was inside the Mount Hood Wilderness where it didn’t threaten areas open to commercial logging. But a subsequent investigation pointed to overstretched firefighting resources, a growing problem as the federal land agencies struggle to fund the spiraling forest fire phenomena across the west.

 [click here for a large map]

By the time fall rains arrived, the fire had burned almost the entire north slope of Mount Hood, a 5-mile swath stretching from the Eliot Branch on the east to Cathedral Ridge on the west. Almost all of the burn was subalpine Noble fir forest, though a few old-growth mountain hemlock stands along the Timberline Trail were burned at Elk Cove and Cairn Basin.

[click here for a large map]

The eastern extent of the Dollar Burn contained large stands of Western larch, a fire forest species adapted to frequent, low intensity fires. Most of these trees did not appear to survive the fire, however, due to its extreme heat and intensity.

 [click here for a large map]

In fact, very few trees survived the fire except along its margins, where a beneficial mosaic burn pattern left standing trees and some undergrowth to help begin the recovery phase. This is the new reality facing our forests, as a century of fire suppression continues to fuel catastrophic fires that completely destroy forest on a massive scale.

Summer 2012: Immediate Aftermath

The dense network of trails that cross through the Dollar Burn provide a front-row seat to how (and if) our forests recover from catastrophic fires inside a protected wilderness, without human intervention. In the immediate aftermath of the Dollar Fire, the picture was bleak. In the heart of the burn, the forest kill was nearly complete, as even the duff layer on the forest floor was burned away, exposing a thin layer of volcanic soils vulnerable to erosion.

One of the first lessons of the fire was the importance of tree debris in stabilizing the unprotected soil. The living trees in this forest weren’t burned so much as boiled alive as their living cambium layer was superheated beneath their bark. The surprising result in the first season after the fire was scorched bark peeling away to reveal untouched wood underneath.

The piles of peeled bark provided an immediate layer of mulch over the exposed soil, with smaller twigs and limbs also helping to form the beginnings of a new duff layer on the burnt soil.

The roots of some understory plants in the worst of the burn zone also survived the fire, including huckleberry, beargrass and avalanche lilies. Two years after the fire, seeds blown into the burn began to establish, and the recovery was underway in surprisingly short order. Read more about the initial recovery in this 2012 WyEast Blog article.

2016: Five Years of Recovery

This year marks the five-year anniversary of the fire, and the recovery within the Dollar Burn is in full swing, though it will take a century or more for the area to fully recover – more on that in a moment.

How does the Dollar Burn of today compare to the first summer after the fire? As the July scenes along the Vista Ridge Trail (below) show, the understory is recovering rapidly.

In 2012, avalanche lilies sprung from bulbs spared by the heat of the fire, creating striking stripes of white blossoms and bright green foliage where these plants survived. A few beargrass (a close relative of the lily family) also survived, thanks to deep underground roots that escaped the fire. A few scattered huckleberry and other understory shrubs also sprouted from surviving roots in the first summer after the fire.

In recent years, the beargrass and avalanche lily display in the Dollar Burn has become a spectacular attraction for early season hikers on the Vista Rigde Trail as these fire survivors continue flourish and spread in the bright new conditions. Other shrubby survivors, like huckleberry, have also continued to recover, thriving in the bright new conditions created by the fire.

But the story in the last few years of the recovery has been the arrival of new plants in the burn zone, blown in by seed or deposited by wildlife. These include more understory species, but also the first few conifers to take root.

After five years, most of the scorched bark has fallen from the torched trees, and the trunks underneath have bleached from their initial golden shades of newly exposed wood to weathered silver and gray shades of a “ghost forest”.

The standing ghost trees still retain a surprising number of their limbs, and perhaps more surprising, very few have toppled in the five years since the fire. This is testament to the fact that the core of these trees didn’t burn. Most will stand for decades before insects and decay finally bring them down.

A few trees in the burn zone were cut by firefighters in an attempt to create fire lines. Today, these cut stumps provide a look at the age of this forest. While the trees in the Dollar Burn aren’t particularly large by Pacific Northwest standards, they were actually quite old. The cut tree shown above was more than 300 years old and stump below is from a tree that had grown on Vista Ridge for 360 years!

The extreme weather conditions and thin soils make for a hard life for subalpine trees, stunting their relative size compared to lower-elevation forests.

The relatively modest size of these trees compared to their impressive age is another reminder of the vulnerability of our subalpine Noble fir forests that are still being logged commercially. While they continue to be “harvested” in unprotected areas under the premise of sustainability, these trees take centuries to reach a size worthy of commercial cutting, making the “harvest” more like mining than tree farming.

The Pioneers

The understory in the Dollar Burn is noticeably greener just five years after the fire, and a closer look reveals a handful of plant species doing the heavy lifting at this stage in the forest recovery. At the top of the list of pioneer species is fireweed, (described here in the previous article in this blog).

True to its name, fireweed has evolved to be the first in line to resettle burned or disturbed areas. These plants produce massive quantities of winged seeds that can quickly reach very large areas. They are also hardy perennials with large root systems, so also play an important role in stabilizing exposed soil.

In the Dollar Burn, fireweed has already colonized large areas, creating a spectacular flower displays from mid-summer through fall.

Look between the drifts of fireweed and you’ll find other pioneers taking root. One surprising species is the diminutive wild dwarf bramble (sometimes called wild strawberry for its resemblance of its runners and leaves to domestic strawberries). These tiny plants are now found throughout the burn, threading through piles of bark and limbs.

Huckleberries also continue their comeback, mostly from the surviving roots of established plants that grew before the fire but also as seedlings. In a few spots, the understory was not completely destroyed, and in these areas huckleberry is responding strongly to the bright conditions with abundant berry production.

Though they were among the few understory survivors, the recovery of beargrass has been more gradual than expected. Most plants seem to be growing from roots that survived the fire, though the first big bloom of these survivors (and the seeds they produced) only arrived over the past two years.

Clumping grasses have also arrived throughout the burn, as well as the occasional rush in moist, protected pockets.

Elderberry is among the few woody understory pioneers to arrive in this stage of the Dollar Burn recovery. These plants are scattered widely, growing in less burned areas, and may also be growing from surviving roots.

Conifers are just getting started five years after the Dollar Fire. Almost all of the conifer seedlings at this point in the recovery are Mountain hemlock and Noble fir, the dominant evergreens in Mount Hood’s subalpine forests.

By counting branch tiers, a few young trees as old as four years can be found, but most are one or two year-old seedlings. But if you look closely, there are also many seedlings that have not survived the harsh summers in the burn zone, where there is little shade and the sandy mountain soils are extremely dry by the time rain reappears in the fall.

This is the sorting process at work, where only a few seedlings will survive winter cold, summer heat and competition from understory plants to someday become part of the new forest canopy.

Though most of the Dollar Fire was an overheated catastrophe for the forest, killing almost everything, there are a few spots where the fire cooled and burned in a “mosaic” pattern, leaving a few surviving trees and much of the understory.

These areas are lush islands of life just five years after the fire, underscoring their importance in the recovery and why cooler mosaic burns can be beneficial to the long-term health of a forest. Pioneer species are much more abundant in heavily burned areas that are immediately adjacent to these surviving patches than in other parts of the burn, as plants quickly spread from these islands of green.

While the Dollar Burn is recovering at nature’s pace, without human intervention, the Forest Service has given the nearby Gnarl Burn section along Cloud Cap Road a recovery boost by planting conifer seedlings. These trees were planting in 2010, about a year before the Dollar Lake Fire and following commercial removal of burned trees along the historic road.

Today, these trees are thriving, and the main effect of replanting is the diversity of species, including lodgepole pine, western larch, Western white pine, Englemann Spruce and even whitebark pine at higher elevations. Noble fir and mountain hemlock do not seem to have been part of the replanting, perhaps because these species are the most likely to recover without human intervention.

The Long View?

Hikers on the north side of Mount Hood will continue to have a front-row seat to the forest recovery in the Dollar Burn. Already, there are some surprising lessons.

First, the main victims of blowdown since the fire have often been the few trees that survived the fire intact. This is because of the sudden exposure of their canopy to winter winds and snow loads, and is a surprising blow to the forest recovery these trees would otherwise be helping to seed the burn zone.

The Dollar Burn generally stayed well below timberline (and the Timberline Trail), leaving most of the alpine zone intact. But where the fire did burn into places like Elk Cove, Eden Park and Cairn Basin, we will also have an opportunity to watch how alpine ecosystems react to fire.

Some of Mount Hood’s most ancient forests grow in this zone, and have presumably survived because they are somewhat isolated from lower-elevation forests and often grow in moister conditions where snowpack is greater and summer days are cooler. But the forest could take centuries to recover in these areas, impacting the many species of plants and wildlife that live exclusively at this elevation.

In human terms, it’s hard to see forest fire cycles in perspective, but in the case of the Dollar Burn, we have the benefit of early photographs from the area. Forest surveys show that the Red Hill area on the north edge of the Mount Hood Wilderness burned in the early 1900s, and were barely recovering by the 1950s (see below).

[Click here for a larger version]

Today, the forest in this northern edge of the wilderness has substantially recovered after a century of regrowth, and now the view is reversed: the silvery ghost forests of the Dollar Fire now mark the once-green slopes of Mount Hood as viewed from Owl Point, while green forests and beargrass meadows cover the former Red Hill burn in the foreground.

So far, so good, but the larger question in an era of climate change is whether our forests will continue to recover from catastrophic fire – or logging – in the way that we have always assumed they will.

As the recovery unfolds in the Dollar Lake, Gnarl and Blue Ridge burns on Mount Hood we’ll learn how resilient our forests really are, and hopefully make better decisions in protecting them for the benefit of future generations.