Douglas maple

Muddy Fork Debris Flow at 20 Years

/ Tom Kloster / 4 Comments

20 years later, it’s hard to imagine the massive debris flow that roared down the verdant Muddy Fork valley in 2002…

Earlier this year I posted a “then-and-now” look at the changes to the Cooper Spur area on Mount Hood’s east flank over the past 20 years, including dramatic changes to the Eliot Glacier. This article provides a similar look at forces of nature that have once again reshaped the Muddy Fork canyon, on Mount Hood’s steep western flank. 

The story begins in the winter of 2002-03 with a massive debris flow triggered by a landslide in the upper Muddy Fork canyon. The event occurred sometime during the winter season, when deep snow-covered hiking trails, and thus went unnoticed until the snowpack cleared that spring. The event immensely powerful, mowing down whole forests and raising the valley floor of the upper Muddy Fork by as much as 20 feet. Whole trees were snapped off and carried downstream with the debris, forming huge piles that still give mute testimony to the power of the event.

Stacks of downed trees still give mute testimony to the violence of the 2002 event

Though the exact origins of the initial landslide remain unknown, the event was probably not triggered by a collapse within the Sandy Glacier that looms above the Muddy Fork, as there were few signs of the debris flow near the glacier, above the section of the upper canyon where the landslide scars were obvious. Instead, the debris flow likely began as a major slope collapse within the steep confines of upper canyon, where the Muddy Fork tumbles between sheer rock cliffs and steep talus slopes. 

The scars from the 2002 collapse are still plainly visible today (below), but the debris fields it created downstream are rapidly being reclaimed by new forests. The landslide created new cliffs and steep walls within the upper canyon, including new waterfalls along the Muddy Fork where the stream suddenly plunged over the newly exposed bedrock. 

The massive 2002 cliff collapse in the upper reaches of the Muddy Fork canyon gave birth to a debris flow that spread for miles downstream

Below the cliff-lined section of the upper canyon, the debris flow fanned out, spreading the landslide debris across the broad floor of the Muddy Fork valley. Nobody witnessed the event, so it’s unknown exactly how it played out. However, the wide debris fields of rock and sand clearly resulted from a major event, as did the complete removal of a standing forest. 

Trees swept up in the flow were stacked in piles that suggested a lot of water content in the debris flow – as much mud as it was rock – due to saturated winter soils and possibly a sudden snowmelt, perhaps from an unusually mild winter storm.  Whole trees were rafted on their sides until they were beached in giant log jams against forest stands along the valley margins that somehow survived. Evidence of the flow only became apparent when hikers returned that spring to find the Timberline Trail completely erased where it had crossed the Muddy Fork.

The raw cliffs and talus slopes surrounding McNeil Falls are still recovering from the event after 20 years

Over the course of the two decades that have since passed, the Muddy Fork quickly cut through the new debris to reach the old valley floor, revealing splintered stumps from trees that were snapped off during the event, then buried in the debris (below). This has confined the stream to a deep channel in the upper valley that limits its once-meandering ways across the valley floor, at least for now. However, the event only affected the north branch of the Muddy Fork, leaving the south branch almost untouched. 

Large trees by the thousands were snapped off and upended by the debris flow, then buried on the floor of the Muddy Fork valley

The Muddy Fork quickly excavated a new channel in the debris flow, unearthing trees like these that had been buried on their sides under the debris

While the north branch is currently confined to its newly cut channel, this is a temporary condition. Debris flows along Mount Hood’s glacial streams are a nearly constant reality, and even major events like the one that occurred on the Muddy Fork in 2002 are not uncommon. As jarring as these events are to witness, they also give us a privileged glimpse into the very processes that have shaped the mountain we know today. In time, smaller debris flows will gradually choke the current channel with debris, and the Muddy Fork will once again meander across the valley floor – just 20 feet higher than it was in 2002.

The Muddy Fork debris flow then… and now

Though it wasn’t apparent to casual visitors from a distance, hikers who knew the mountain immediately spotted the debris flow from the open slopes of Bald Mountain, where the Timberline Trail provides a sweeping view of Mount Hood’s west face. Before the debris flow, the two main branches of the Muddy Fork had similar floodways at the head of the valley, below the Sandy Glacier. As the 2003 image (below, left) shows, the north branch was suddenly much wider. Today, forest recovery has nearly erased signs of the debris field (below, right) from this vantage point.

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A closer look at this photo comparison reveals the scale of the debris flow in the summer of 2003, shortly after the event (below, left). The debris field was up to 1/4 mile wide and left up to 20 feet of debris in the channel of the north branch of the Muddy Fork. After 20 years (below, right), a carpet of green, recovering forest has already reclaimed much of the new debris field.

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Down at ground zero, the scene at the head of the Muddy Fork valley in 2003 (below, left) was of astonishing destruction. Whole forests were toppled and piled like matchsticks along the margins of the debris flow, pushing into standing forests just high enough on the valley walls to have escaped the waves of debris. 

Twenty years later (below, right), most of the forest debris remains, though new logs were added to the jumble in the September 2020 wind event (described in this WyEast Blog article) that swept over Mount Hood. The new, mostly decidious forest rapidly emerging on the debris flow can also be seen in the 2023 image as the bright green band in the mid-background.

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The debris flow was still raw and unstable in the summer of 2003 (below, left), but after 20 years, a dense young forest (below, right) of Red Alder, Cottonwood and scattered Douglas Fir is quickly stabilizing the debris field. The health and vigor of this young forest growing on a 20-foot layer of boulders, gravel and sand is testament to the remarkable fertility of volcanic soils. While this new deposit contains almost new organic matter or true soil, the mineral content is rich in iron, potassium, phosphorus and other mineral nutrients essential to plant growth.  

[click here for a large version of this photo pair]

Red Alder and Cottonwood are no surprise, here. Both are pioneer species known for their ability to colonize disturbed areas – but the presence of Douglas Fir is a surprise (two can be seen in the foreground of the 2023 image). If the young firs growing within this largely deciduous new growth can keep pace with their broadleaf neighbors, the new forest could begin to be dominated with evergreen conifers within a few decades, speeding up the succession process that typically unfolds in a recovering forest.

Looking downstream (west) from the center of the debris field in 2003 (below, left) provided a true perspective on the scale of the event, with large debris deposits mounded against heaps of stacked, toppled trees. After 20 years, the recovery (below, right) is rapidly obscuring the view, though Bald Mountain can still be seen over the young tree tops. The tallest of the young trees in the 2023 view are Cottonwood and most of the smaller tree are Red Alder. The conifer in the foreground is a young Douglas Fir – roughly 15 tears old and about eight feet tall.

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Turning back (east) toward the mountain from roughly the same spot, the view in 2003 (below, left) revealed a new channel through the debris that the Muddy Fork had almost immediately begun excavating. By 2023 (below, right) the channel has been widened over the years, though its depth has since stabilized at the old valley floor level. The second photo also shows the new forest quickly hemming the channel in from both sides.

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Still, the Muddy Fork is a glacial stream, and therefore volatile. It continues to expand, then refill its new channel with debris from smaller flood events that occur almost every year.

On one of my first visits to the debris field, I spotted a row of tree stumps (below) that marked the original valley floor – or perhaps an ancient valley floor? In this spot, the Muddy Fork had cut down through the loose flow material, exposing these sure markers of a former level of the valley floor. 

One surprise is how quickly the Muddy Fork settled in to its new landscape after the debris flow. As these photos show, the stream quickly cut its way to the former valley floor then mostly stopped cutting any deeper in the many years that followed, despite its famously volatile flow. These stumps – and even the two large boulders to the left – remain today much as they were 20 years ago, despite being directly adjacent to the stream and exposed to the many flood events that occur here.

[click here for a large version of this photo pair]

Looking downstream (below) from just above the spot where the stumps were revealed, you can see how little change to the new channel has occurred since it was initially carved in the year after the event. The large boulder on the lip of the channel (left side of these images) is still perched there – and the three Noble fir growing it that survived the original event are still thriving today, nearly twice as tall. 

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The most notable difference in the above photo pair is how debris has begun to refill the channel, as evidenced in the 2023 photo on the right. This process will continue over time until the channel has filled and the Muddy Fork is once again meandering across the main valley floor.

I don’t have good photo records of the narrow, upper canyon of the north branch Muddy Fork from prior to the 2002 debris flow. However, I have seen both photos (and even paintings) of this idyllic scene from the 1980s and 90s that show a waterfall here. Based on those earlier images, I do think that a single waterfall existed before the debris flow, roughly where the new falls is located today. Waterfall hunters have dubbed this “McNeil Falls”, referencing nearby McNeil Point – just off to the right in the photo pair, below.

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While the landslide and debris flow that it triggered in 2002 did seem to move McNeil Falls somewhat, the most notable change was to produce a twin waterfall – something waterfall hunters (the author included!) prize. However, as the reshaped falls has continued to evolve over the two decades since the event, the two segments have gradually begun to merge into one – or so I thought until I took a closer look for this article. 

In the following photo pair, you can see that the Muddy Fork has actually been carving away debris from the sloped bedrock, and simply moved the falls northward and down the cliff scarp. You can see the shift by matching the rocks marked “A” on the right, the dark notch to the left of the letter “B” and the protruding rock marked “C” that – surprisingly – used to divide the two tiers of the falls! Today, the south (right) tier of the semi-twin drop is really the original north tier, and a completely new tier has formed to the left of this original tier where landslide debris was cleared from the rock ledge. 

[click here for a large version of this photo pair]

Look closely at the above photo pair and you can also see some very large boulders perched to the left of the falls as they existed in 2003. These have since been eroded away, and contributed to the pile of rock debris that has accumulated at the base of the falls in the 2023 photo –shortening the falls a bit.

What will the future bring for McNeil Falls? My guess is that it will continue to shift north a bit more, likely becoming a single tier – twin waterfalls are rare! But even as it find its way to a lower brink along that cliff scarp, the stream will also gradually move loose rock away from the base of the falls as the canyon walls stabilize, so it might become taller over time. There are other examples of exactly this phenomenon on other big waterfalls around Mount Hood – most notably, Stranahan Falls, on the Eliot Branch, which has gained at least 30 feet in height from an eroding canyon floor at its base. Of course, McNeil Falls will also continue to suffer the brunt of the Muddy Fork’s volatile nature and keep changing and reinventing for centuries (and millennia) to come.

Downstream from the falls, the bed of the Muddy Fork continues to gradually collect new debris as the channel carved in the years immediately after the debris flow continues to fill. This can be seen in the photo pair (below), where large boulders now fill the floor of the new channel – and even support young alder and willow pioneers on small midstream islands.

[click here for a large version of this photo pair]

The downstream effects of the 2002 debris flow on the Muddy Fork were less dramatic, yet still reshaped the way the river flows through its valley. This view of the valley (below) from Bald Mountain is roughly two miles below the source of the debris flow. The large rock and gravel deposits along the stream are still plainly visible twenty years later, though the bright green alder and willow colonies have begun to reforest the flooded area. In this view, you can also see the bleached ghost trees along both sides of the stream that were killed by the debris flow. 

Though riparian trees like Sitka alder and willows are making inroads, the Muddy Fork continues to meander across the debris flow where the valley is less steep and the stream less channeled

These disturbed areas now serve as important habitat for raptors and cavity-nesting birds alike, along with many other species that require standing skeleton trees to survive. The dense new riparian growth (below) is equally important to many species that require streamside habitat. While major events like the 2002 debris flow might be shocking for us, it’s also a reminder that violent processes like this are built into the cycle of the ecosystem – they are required for the species who have adapted over millennia to forests that continually cycle through disruption and recovery. 

Large areas of the debris flow have recovered further downstream from the event, marked by the bright green stands of alder, willow and cottonwood along the Muddy Fork in this view from Bald Mountain

Debris flow pioneers

Whether from fire, debris flow or even human-caused events like logging, watching our forests recover and rebuild provides invaluable insight into the role individual species play in the health of forests. Where we used to value our forests mostly for the lumber that could be harvested (and therefore, mostly for big conifers) we now know that non-commercial species like alder, willow and cottonwood are as essential to forest health as the conifers.

Twenty years into the recovery, I expected to find Sitka alder (below) dominating the young forests returning to the debris flow, as these tough, adaptable trees among the first to reclaim disturbed ground wherever it might occur. They are often called “slide alder” for their ability to survive in avalanche chutes, as they freely bend and give under the heaviest of winter snow loads, often popping new leads from horizontal, snowpack-flattened limbs. But alders have a super-power that is especially important in forest recovery: they are nitrogen fixers that enrich the soil as they grow, making them uniquely suited as pioneers in disturbed areas.

Sitka alder growing on the Muddy Fork debris flow

What I didn’t expect to find in the recovering forest atop the debris flow were Black cottonwood (below). Yet, many are thriving throughout the alder thickets, outpacing the alders since they can easily grow to 50-60 feet in mountain environments compared to just 30-40 feet for alders. Cottonwood are fast growers, too, especially where they can tap into a steady supply of groundwater – something the shallow water table in the Muddy Fork valley provides in abundance. They are important wildlife trees, too, including the browse they provide as young trees and the nesting cavities that form in the trunks of older trees as they mature.

Cottonwood growing on the Muddy Fork debris flow

An even more startling pioneer in the recovering forest on the debris flow are Douglas fir (below). These trees don’t require much of an introduction — as our state tree and a species found all over Oregon. I didn’t expect to find so many here, in part because we’ve been conditioned by the timber industry to believe these native conifers must be hand-planted after logging, and then only after all other vegetation that might compete has been killed with herbicides.  

Douglas fir growing on the Muddy Fork debris flow

Douglas fir are fast growers, and with their early arrival as pioneers in the new forests along the Muddy Fork, there’s a good chance they will keep pace with both the alders and cottonwood and quickly begin to restore a conifer overstory – though “quick” is measured in decades and centuries when describing forest recovery! 

Douglas maple growing on the Muddy Fork debris flow

Another surprise in the new forest growing on the debris flow is Douglas maple (above), a close cousin to our Vine maple, and sometimes called Rocky Mountain maple. These attractive trees are sprinkled throughout the young trees returning to the Muddy Fork and they are positioned to become part of the future understory of a mature conifer stand. Where alder and cottonwood are eventually shaded out by taller conifers, Douglas maple are more tolerant of shade, and can coexist with the big trees. They are also more drought-tolerant than their Vine maple cousins, and thus well-suited to the sandy upper layers of the debris flow that can become quite dry during summer droughts.

The cycle continues… except faster, now

Just as the recent series of wildfires in WyEast country have given us the gift of insight into how a forest regenerates after a burn, the debris flow on the Muddy Fork is providing a glimpse into the resilience of Mount Hood’s forests in the face of growing disturbances from climate-driven floods, landslides and debris flows. There is no way to know if the 2002 landslide in the Muddy Fork canyon was triggered by climate change, yet scientists do know that extreme rain events and unusually saturated soils are increasingly triggering such events. And while these events have always occurred, the extreme and often erratic nature of our storms in recent years has accelerated the pace and scale of flooding and debris-flow events on the mountain. The good news from the Muddy Fork is that our forests are – so far – coping well with these changes, especially in riparian areas where the restored habitat is most critical. 

Early 1900s scene along the upper Sandy River

Historic images and geologic evidence show these events to be part of a timeless cycle of destruction and rebirth. This image (above) show the upper Sandy River valley in the early 1900s, with mix of debris and young streamside vegetation (the willows and alders toward the background) that look much like today’s conditions. Clearly, periodic floods and debris flow events had always played a role, here.

This image (below) is a wider, hand-tinted view from about 1900 that shows the Muddy Fork branch of the Sandy River hugging the left side of the valley, with obvious signs of flooding and debris flows. There’s a story in the young forests covering the balance of the flat Sandy River valley floor, too (known as Old Maid Flat) in this view: at the time the photo was taken, just over a century had elapsed since the Old Maid eruptions on Mount Hood covered this entire valley with a debris flow that extended 50 miles downstream to the Columbia River, creating today’s Sandy River Delta. This very early view also shows burn scars (colorized as white snow) around the western foot of the mountain that have long-since recovered, and are now covered with dense forests of Noble fir.

The Muddy Fork is the open channel on the left in this colorized view of the Sandy River Valley from about 1900

While these events may seem random and jarring in from the perspective of a human lifetime, when you connect the dots between events over geologic time, the continuum is that of a mountain in a perpetual state of both eroding and occasionally rebuilding itself, one catastrophic event after another.

It is this long view that helps us understand and appreciate how our forests have evolved not to a specific end-state (the view from a logging perspective), but instead, have evolved to continually adapt to their conditions in a perpetual state of renewal and rebirth. The fact that our forests are rebounding so readily in places like the Muddy Fork or the scorched slopes of the Gorge fire — even now, in the midst of climate change – is both inspiring and reassuring in a time of unprecedented change in the world around us.

After the Fire: What Recovery Looks Like

/ Tom Kloster / 9 Comments

PCTA trail volunteers at Tunnel Falls in July (Photo: Nathan Zaremskiy)

Rock-star trail volunteer (and friend of the WyEast Blog!) Nate Zaremskiy has shared another update on the forest recovery in the upper Eagle Creek canyon, at the heart of the 2017 Eagle Creek Fire in the Columbia River Gorge (see Nate’s first batch of images in this earlier blog article). Nate captured these images in July as part of a Pacific Crest Trail Association (PCTA) trail stewardship effort to continue restoring the Eagle Creek trail.

We’ll start with a visual rundown of some of the waterfalls that draw hikers to Eagle Creek from around the world. First up is Sevenmile Falls, a lesser-known falls at the head of the series of cascades on Eagle Creek. The fire was less intense here, with some of the forest canopy and intact and riparian zone along Eagle Creek rebounding quickly (below).

Fire recovery at Sevenmile Falls (Photo: Nathan Zaremskiy)

Moving downstream, the area around spectacular Twister Falls is recovering more slowly. The fire burned intensely on the rocky slopes flanking the falls, though many trees in the riparian strip upstream from the falls survived the fire (as seen in the distance in the photo, below).

Fire recovery at Twister Falls (Photo: Nathan Zaremskiy)

Tunnel Falls (opening photo) appears almost as if there had never been a fire, with the cliffs around the falls green and verdant. But a wider view of this spot would show an intensely burned forest above the falls that is only beginning to recover, as we saw in Nate’s earlier photos.

Continuing downstream, the next waterfall in the series is Grand Union Falls, a thundering just below the confluence of the East and main forks of Eagle Creek. The forest here largely dodged the fire, with many big conifers surviving along the stream corridor (below).

Restored “basalt ledge” trail section above Grand Union Falls (Photo: Nathan Zaremskiy)

The handiwork of the PCTA crews can be seen in the above view of the infamous “basalt ledge”, where the Eagle Creek Trail is blasted uncomfortably through solid basalt columns along a sheer cliff face. The fire triggered a cliff collapse here, burying the trail in tons of rock. Over the past several months, PCTA volunteers meticulously cleared this section of trail, tipping huge boulders over the edge on at a time.

Nate’s photo update of the upper waterfalls ends here, but his new images also reveal an encouraging recovery underway in the burned forests of the upper Eagle Creek canyon. In moist side canyons the understory is rebounding in abundance, with familiar forest plants like Devils club, Sword fern and Lady fern covering the once-burned ground (below).

Lush understory recovery in a moist side canyon on the upper Eagle Creek Trail (Photo: Nathan Zaremskiy)

Along other, drier canyon slopes Fireweed (or “Firestar”? See “A Rose by any other name” on this blog) has exploded on the landscape, blanketing the burned soil as would be expected from this ultimate pioneer in forest fire recovery. Nate and his volunteers were sometimes shoulder-deep in Fireweed as they hiked along the upper sections of the Eagle Creek Trail (below).

Fireweed leading the recovery on the upper Eagle Creek Trail (Photo: Nathan Zaremskiy)

Shoulder-high Fireweed on the upper Eagle Creek Trail (Photo: Nathan Zaremskiy)

In other parts of the burn, the unburned roots and stems of the understory that survived the fire underground are now pushing new growth above the burned soil. Even in areas where no trees survived the flames, understory survivors like Vine Maple, Thimbleberry and Oregon grape can be seen in abundance in views like this (below):

Recovering understory in a heavily burned section of the upper Eagle Creek canyon (Photo: Nathan Zaremskiy)

Even the most intensely burned areas in the upper reaches of the Eagle Creek canyon are showing signs of life, with Oregon Grape, Salal and Ocean Spray emerging from roots that survived beneath the ashes (below).

Recovery is slower in the most intensely burned areas, but is still underway (Photo: Nathan Zaremskiy)

The forest recovery in the Eagle Creek burn is just beginning a cycle that has played out countless times before in Western Oregon forests, especially in the steep, thin-soiled country of the Columbia River Gorge. So, what can we expect as the recover continues to unfold? It turns out we have a good preview of things to come with a pair of recent burns in the Clackamas River canyon, fifty miles to the south, where the forests and terrain are very similar to the Gorge.

What’s next? Learning from the Clackamas Fires

Two recent fires have swept through the steep-walled canyon of the lower Clackamas River. In 2014, the 36 Pit Fire burned 5,524-acres in the canyon. This was a scary September blaze that drew required 1,000 fire fighters to contain the fire from burning utility lines and toward homes near the town of Estacada. The 36 Pit Fire burned much of the South Fork Clackamas River canyon, a newly designated wilderness area, as well as several miles of the main Clackamas River canyon.

Forest recovery following the 36 Pit Fire the Clackamas River Canyon

Like Eagle Creek, the 36 Pit Fire burn was the result of careless teenagers, in this case started by illegal target shooters. Five years later, this gives us a look at what the Eagle Creek burn will look like in another 3-4 years. The view below is typical of the 36 Pit Fire, with broadleaf understory species quickly recovering in the burned canyon.

In this view (below) a trio of maples — Bigleaf maple, Douglas maple and Vine maple — dominate the recovery along a canyon slops. Most are growing from the surviving roots of trees whose tops were killed in the fire. This ability to recover from surviving roots gives broadleaf trees a leg up over conifers like Douglas fir.

Five years of slope recovery after the 36 Pit Fire

Another scene (below) from the canyon floor shows how areas with more ground moisture have fared five years after the 36 Pit Fire. Here, the conifer overstory largely survived the fire, and even some of the broadleaf trees have survived, in part because the were less drought-stressed than trees higher up the slopes when the fire swept through. This is typical of burns and can be seen throughout the Eagle Creek burn, as well, with well-hydrated trees in moist areas better able to withstand the intense heat of the fire.

Here, Bigleaf maples on either side of the view are sprouting new growth from midway up their partially burned trunks. These damaged trunks of these trees may not survive over the long term, but most are also sprouting new shoots from their base — an insurance policy in their effort to survive. The understory throughout this part of the canyon floor is exploding with new growth from roots that largely survived the fire and benefit from the moisture here in their recovery. Thimbleberry (in the foreground) is especially prolific here.

Understory growth has exploded along the moist canyon floor

The following scene (below) is also typical of the 36 Pit Fire at five years, with the conifer overstory mostly surviving the fire on this low slope, and the understory rejuvenated by the burn. When scientists describe a “beneficial” fire, this is an example of the benefits. Beneath the surviving conifers in this view, the white, skeletal trunks of burned Vine Maple and Red alder rise above vibrant new growth emerging from the roots of these trees. This lush new growth provides browse for deer, elk and other species, and new habitat for small wildlife, while also protecting the steep forest soils from erosion.

Vine maple emerging from surviving roots of tops killed by the 36 Pit Fire

In September 2002, the much smaller Bowl Fire swept through 339 acres of mature forest along the west end of the Clackamas River Trail, just upstream from Fish Creek. Like the Eagle Creek and 36 Pit fires, the relatively small Bowl Fire was human-caused, with the ignition point along the Clackamas River Trail, likely by a hiker. More than 300 firefighters were called out to fight this blaze.

Fifteen years of recovery has transformed the canyon slopes burned in the Bowl Fire from black to lush green

Today, The Bowl Fire provides a look 15 years into the future for the Eagle Creek burn, and the rate of recovery here is striking. These views (above and below) from the heart of the Bowl Fire show 20-25 foot Bigleaf maple and Red alder thriving among the surviving conifers and burned snags. Vine maple, Douglas maple, Elderberry and even a few young Western red cedar complete this vibrant scene of forest rejuvenated by fire.

The forest recovery from the Bowl Fire give us a glimpse of what the burned areas of the Gorge will look like in another 10-12 years

Growing up in Oregon, I was taught that many of these broadleaf tree species that are leading the fire recovery in the Clackamas River canyon and at Eagle Creek were “trash trees”, good for firewood and little more. But as our society continues our crash course in the folly of fire suppression and ecological benefits of fire, these species are emerging as hard-working heroes in post-fire forest recovery.

The Unsung Heroes of Fire Recovery

It’s worth getting to know these trees as more than “trash trees”. Here are five of the most prominent heroes, beginning with Bigleaf maple (below). These impressive trees are iconic in the Pacific Northwest, and highly adaptable. They thrive as towering giants in rainforest canyons, where they are coated in moss and Licorice fern, but can also eke out a living in shaded pockets among the basalt cliffs of the dry deserts of the eastern Columbia River Gorge. Their secret is an ability to grow in sun or shade and endure our summer droughts.

Forest recovery hero: Bigleaf Maple

As we’ve seen in the Gorge and Clackamas River canyon burns, Bigleaf maple roots are quite resistant to fire. Throughout the Bowl Fire and 36 Pit Fire, roots of thousands of burned Bigleaf maple have produced vigorous new shoots from their base, some of which will grow to become the multi-trunked Bigleaf maple that are so familiar to us (and providing some insight into how some of those multi-trunked trees got their start!). Their surviving roots and rapid recovery not only holds the forest soil together, their huge leaves also begin the process of rebuilding the forest duff layer that usually burns away in forest fires, another critical role these trees play in the fire cycle.

Vine maple (below) are perhaps the next most prominent tree emerging in the understory of the Bowl Fire and 36 Pit Fire. Like Bigleaf maple, they emerge from surviving roots of burned trees, but Vine maple have the added advantage of a sprawling growth habit (thus their name) when growing in shady forest settings, and these vine-like limbs often form roots wherever they touch the forest floor. When the exposed limbs are burned away by fire, each of these surviving, rooted sections can emerge as a new tree, forming several trees where one existed before the fire. Vine maples are abundant in the forest understory throughout the Cascades, so their survival and rapid recovery after fire is especially important in stabilizing burned slopes.

Forest recovery hero: Vine maple

Douglas maple (below) is a close cousin to Vine maple and also fairly common in the Clackamas River canyon and Columbia River Gorge. What they lack in sheer number they make up for in strategic location, as these maples thrive in drier, sunnier locations than Vine maple, and these areas are often the slowest to recover after fire. Douglas maple emerging from the roots of burned trees on dry slopes can play an important niche role in stabilizing slopes and helping spur the recovery of the forest understory.

Forest recovery hero: Douglas Maple

Red elderberry (below) are a shrub or small tree that is a common companion to the trio of maples in the recovering understory of the Clackamas River canyon. Like the maples, they often emerge from the surviving roots after fire. Elderberry also thrive in disturbed areas, so this species is also likely emerge as seedlings in a burn zone, as well.

Forest recovery hero: Elderberry

This is probably as good a place as any to point out that the red berries of Red elderberry are not safe to eat. They contain an acid that can lead to cyanide poisoning in humans (did that get your attention?). However, the berries and leaves are an important food source for birds and wildlife, another important function of this species in a recovering forest.

One of the most prolific species emerging in the Clackamas River burn zone is Thimbleberry (below), a dense, woody shrub related to blackberries and another important food source for birds and wildlife after a fire. Their soft, fuzzy berries are also edible for humans, as most hikers know. Thimbleberry also appear in many of the recovery photos of the upper Eagle Creek canyon that Nate Zaremskiy shared.

Forest recovery hero: Thimbleberry

Finally, a less welcome “hero” in the post-fire forest recovery (to us humans, at least) is Poison oak. This amazingly adaptable, rather handsome shrub (and vine — it can grow in both forms) is found throughout the Columbia River Gorge as well as the lower Clackamas River canyon. In this view (below), Poison oak is emerging in the Clackamas burn zone alongside Thimbleberry, shiny with the oil that causes so much havoc in humans.

Like the other pioneers of the recovery, Poison oak grows from surviving roots and seems to benefit from fire with renewed growth and vigor. Poison oak also likes filtered sun in forest margins, so a tree canopy thinned by fire can create a perfect habit for this species. Like Thimbleberry and Elderberry, Poison oak is (surprisingly) an important browse for deer in recovering forests.

Forest recovery (gulp!) “hero”..? Poison oak!

Many other woody plants and hardy perennials also play an important role in the recovery of the forest understory, including Ocean spray, Oregon grape, Fireweed, ferns, and native grasses. These fast-growing, broad leafed plants are critical in quickly stabilized burned slopes, rebuilding a protective duff layer and providing shade and cover for wildlife to return.

So, if forests are so good at recovering from fire, can they recover from logging in much the same way? Read on.

Learning to be Part of the Fire Cycle?

If logged-over forests were left to their own recovery process, they would follow much sequence as a burned forest, with the understory rebounding quickly. However, fire usually leaves both surviving overstory trees and standing dead wood that are critical in the recovery by helping regenerate the forest with seedlings from the surviving trees, habitat in the form of standing snags and by providing nutrients from fallen, decaying dead wood. But even with the overstory cut and hauled away as saw logs, a clearcut could still recover quickly if the understory… if it were simply allowed to regenerate this way.

“It became necessary to destroy the forest in order to save it..?”

And therein lies the rub. Time is money to the logging industry, and they still view the broadleaf species that lead our forest recovery as “trash trees”, something to be piled up and burned in slash piles. So, the standard practice today is to shortcut the natural recovery process our forests have evolved to do, and simply kill the understory before it can even grow.

This is done by repeated helicopter spraying of clearcuts with massive amounts of herbicide after a forest has been cut, typically a year or two after the logging operation. This produces the brown dead zone that we are sadly familiar with in Oregon. Having killed the entire understory, cloned plantation conifers are then planted among the stumps with the goal of growing another round of marketable conifers in as short a period as possible. Time is money and trees are a “farm” not a forest to the logging industry.

These Douglas fir cultivars were bred for rapid growth and planted to shortcut a necessary stage in the recovery process, which is great for the corporate timber shareholders but very bad for forest health.

It doesn’t take a scientist to figure out that shortcutting the natural recovery process after logging also shortchanges the health of the forest over the long term, robbing the soil of nutrients that would normally be replaced in the recovery process and exposing the logged area to erosion and the introduction of invasive species (a rampant problem in clearcuts). Destroying the understory also robs a recovering clearcut of its ability to provide browse and cover for wildlife — ironically, one of the selling points the logging industry likes to use in its mass marketing defense of current logging practices.

In Oregon, this approach to fast-tracking forests is completely legal, though it is clearly very bad for our forests, streams and wildlife. As Oregon’s economy continues to diversify and become less reliant on the number of raw logs we can cut and export to other countries to actually mill (also a common practice in Oregon), cracks are beginning to form in the public tolerance for this practice. Most notably, private logging corporations are increasingly being held accountable for their herbicides entering streams and drifting into residential areas.

The understory in the uncut forest bordering this corporate logging operation shows what should be growing among the stumps, here. Instead, tiny first seedlings were planted after herbicides were used to kill everything else on this slope directly above the West Fork Hood River. This is standard forest practice in Oregon, sadly.

So, there’s some hope that the logging industry can someday evolve to embracing a natural recovery strategy, if only because they may not be able to afford the legal liability of pouring herbicides on our forests over the long term. Who knows, maybe the industry will eventually move to selective harvests and away from the practices of clearcutting if herbicides are either banned or simply too expensive to continue using?

The recent fires in the Columbia River Gorge, Mount Hood Wilderness and Clackamas River canyon may already be helping change industry our logging industry practices, too. These fires have all unfolded on greater Portland’s doorstep and have engulfed some of the most visited public lands in the Pacific Northwest.

While the initial public reaction was shock at seeing these forests burn, we are now seeing a broad public education and realization of the benefits of fire in our forests, with both surprise and awe in how quickly the forests are recovering.

Skeletons from the 1991 Multnomah Falls fire rise above recovering forests in this scene taken before the 2017 Eagle Creek Fire, when part of this forest burned again to continue the fire and recovery cycle in the Gorge.

That’s good news, because a public that understands how forests really work is a good check against the corporate interests who fund the steady stream of print and broadcast media propaganda telling us how great industrial logging really is for everyone.

Are we at a tipping point where science and the public interest will finally govern how the logging industry operates in Oregon? Maybe. But there’s certainly no downside to the heightened public awareness and appreciation of the role of fires in our forests. We do seem to have turned that corner…