Fires, forests, and fish

Story by Peter Kauss, BLM Hydrologist for the BLM Oregon Salem District

This summer, hazard trees from the Beachie Creek Fire became a crucial piece of a salmon habitat restoration project.

The 2020 Beachie Creek Fire burned through almost 200 thousand acres, including nearly 40 thousand acres of BLM-managed public land. The fire left behind countless burned and damaged trees along roads, trails, and other public areas. These weakened trees pose an ongoing safety threat long after the fire itself has been suppressed.

On public lands designated for harvest, the dead and dying trees can be sold as salvage timber, but fires don’t follow land designations. Some of the hazard trees left behind by Beachie Creek Fire were in riparian reserves, areas set aside for habitat and stream protection. Rather than selling these trees, they can be used in restoration projects. ​​​​​​​

Two completed woody debris structures lay across the stream channel. During high winter flows, water will flow over the structures in some areas, creating a series of riffles and pools. Photo by BLM.

​​​​​​​Meanwhile, the Salmon River and Boulder Creek Restoration Project needed trees. Native salmon rely on a complex habitat to support their lifecycle. They need spawning and rearing areas, connected side channels, and functioning floodplains.

Normally, fallen trees, rockslides, and rushing flood waters create this variety. But managed forests don’t have many large, old trees. Without trees to fall, streams don’t get the full benefit of these disturbances.

Instead, hydrologist Peter Kauss (Cascades Field Office) and a team of experts set out to mimic natural processes. They placed woody debris where fallen trees would have naturally lodged. These jams disrupt the flow of the water, recreating a complex, diverse habitat.

To create the most natural aquatic habitat, straight, smooth logs only go so far. Instead, root wads add even more complexity to the stream and prevent the trees from washing downstream.​​​​​​​​​​​​​​​​​​​​​

To collect trees with intact root wads, trees must be tipped over and pulled out of the ground, rather than sawed off at the stump. NWOD Fisheries Biologist Cory Sipher stands in front of a deck of tipped trees from the Beachie Creek Fire. Photo by BLM.

Keeping root wads intact requires tipping trees over to pull them out of the ground. This is a much more complicated process than simply sawing them off at the trunk. Collecting enough trunks with root wads requires advanced planning and collaboration. And in normal times, there aren’t a bunch of spare trees waiting around to be tipped.

So, the Sandy River Partnership reached out to the teams mitigating hazards on the Beachie Creek Fire. The partnership tipped and trucked more than 500 trees — with root wads attached — from within the fire footprint. Then helicopters flew the trees to Boulder Creek, to minimize the impact of heavy machinery in the riparian reserve.

An excavator positions trees across the streambed after being delivered by helicopter. Photo by BLM.

By the end of the summer 2021 — about a year after the Beachie Creek Fire ignited — the team had made significant habitat improvements. They built three new jams in the Salmon River and installed 330 trees along a half mile of Boulder Creek. The work also connected side channels and created a more diverse habitat across the historic floodplain. When the water rises in the winter, sand and gravel carried in the high flows will add the finishing touches to the new habitat.

“After a few heavy winter flows, we expect to see adult salmon spawning and juveniles enjoying new foraging areas and pools,” said Peter.

The unique work took the collaboration of The Fresh Water Trust, the Forest Service, and the BLM. The Sandy Basin Partnership has been working in the basin for over a decade.

“We share technical experience, equipment, time, and materials,” Peter said of the partnership. “And we’ve created stronger projects than any of the entities could on our own.”

A tree with an intact root wad. Photo by BLM.

What are hazard trees?

Wildfires leave behind weakened, burned, and damaged trees. When these trees are close to public areas — like roads, trails, or other infrastructure — they pose a safety threat long after the fire has been suppressed. These hazard trees must be quickly, safely, and efficiently removed to protect the safety of the public, firefighters, and others who work in the forests. Depending on circumstances, hazard trees can be sold for timber, left on the ground, or used for habitat restoration projects.

What is a root wad?

A root wad is the gnarly knot of roots left at the end of a tree truck. It’s the portion of the roots that remain attached when the tree is tipped over. Root wads are an important part of the trees used in habitat restoration projects. They add complexity to the streambed, slow down the flow of the water, and help stabilize the bank.