Fire in Montana's Bob Marshall Wilderness: Our ecologist blogs from 'the Bob' - Part 2


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Several days into our trip, we wake up in our sleeping bags to a thick layer of smoke that fogs our brains as much as the views.  A forest fire has been burning for several days just up the valley near Big Salmon Lake.  We’ve watched the smoke plumes gradually increase in size, but now that the fire has blown up to over 2,000 acres the smoke is thick in our campsite.

The landscape itself was once shaped by fire too, which not only limited future fire’s sizes by burning through the forest and reducing fuels, but also created a patchwork of habitat conditions that allowed various forms of life to thrive. For a hundred years or more, we tried to keep fire out of our forests to protect trees and reduce the risk of property loss. Ironically, fire suppression coupled with widespread timber harvesting that left trees, whole forests, and properties at greater, not less, risk of burning. Given these high risks to forests and communities, the Northern Rockies office of the Wilderness Society is working on ways to get fire safety back into the forests, re-establish this important ecological process and restore resilient ecological conditions. This requires keeping local communities safe, reducing fuel loads in some forested stands, and changing the way we ultimately view and manage natural wildfires in the future.

Fortunately for researchers like us, fires are not suppressed within our wilderness study area. This remote valley of the South Fork Flathead River was never logged, and forests are allowed to develop naturally following fires: salvage logging and associated post-logging tree planting are not permitted.  Consequently, the South Fork Flathead River Valley constitutes one of the few places to study the dynamic relationship between fire and natural larch forest development – which is exactly why we’re here.

The significance of a forest fire so close to where we are studying the aftermath of similar fires less than 10 years before isn’t lost on anyone. Fires like the one burning near our research site have shaped the forests of the Northern Rockies for millennia. The species that live here show the imprint that fire has written on them. Through adaptations across generations, some woodpeckers have developed black backs – darkened for camouflage against fire-blackened tree trunks. Trees have evolved thick, fire-resistant bark, and some pine cones open and set seeds only into burned forest floors. Some species of beetles actually thrive in a fire’s aftermath and use their own insect version of smoke detectors to find the shelter of burned trees.

We are here hoping to answer questions like what larch forests looked like before the fires, how trees responded to these fires, how abundant the shrubs and grasses are and how many dead trees are on the ground. These forest conditions, upon which multitudes of species - including ants, bees, wildflowers, birds, and grizzly bears – depend on could give us something to shoot for when trying to restore forest conditions in similar forest types that have been impacted by decades of abuse.

But answering those questions isn’t easy. It means manual field labor, and lots of it. For six days we bushwhack off trail and over downed logs to establish and collect data on forest plots about the size of a small suburban lot (roughly a quarter of an acre). We assess surface fuels, which entails counting the number of sticks of various sizes lying on the ground, measuring tree diameters and heights and recording whether the trees are alive or dead. We collect data on the cover and composition of the understory species of shrubs, grasses, and wildflowers and count the number of seedlings and saplings that have emerged from the forest floor. We also brought along increment borers that take a small core from trees, which we use to count the annual growth rings. This allows us to know the age of these large trees. We also investigate whether trees lying on the ground died before or after the fire, which will tell us what the forest was like before it burned. This involves investigating whether the bark is charred and if the dead tree supports branches, among other things. We call this the CSI portion of our data collection.

By studying the conditions of the larch forests after the big fire years of 2000 and 2003, we hope to use wilderness as a reference to our restoration work in the Southwest Crown of the Continent (SWCC) – a more intensely managed forest system just over the ridge from our study sites that is checker-boarded with old clearcuts and crisscrossed with old roads. The SWCC, including the Swan and Clearwater River Valleys, support thousands of acres of similar forest types that have been altered because of years of logging and fire suppression. Along  with our diverse partners, we’re figuring out the best way to restore these forests to a more natural and wild state.

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