by Troy Pearse, Conservation Director
What do you think of when you see a tree that has fallen into the river? Some people perceive it as ugly--something that needs to be cleaned up. The flood district sees it as a potential flood hazard. Recreational floaters see it as a hazard to avoid. But fish see it as a safe refuge from current and predators.
In our work with Idaho Fish and Game (IDF&G) on the Boise River, they have repeatedly emphasized how important woody cover is to fish, and that it is particularly important to the overwinter survival of trout fry and recruitment into adulthood. Conversations with Tracy Hillman (senior ecologist and CEO at the company BioAnalysts, which specializes in fish habitat restoration) have further reinforced how important woody cover is to fish.
I have had the opportunity to help IDF&G do electro-fishing trout fry surveys on the Boise River several times, including in our side channel after our gravel augmentations. 
Two things that stood out to me are that side channels have significantly higher numbers of trout fry (compared to the main river channel) and that most of the trout fry we found were located near woody cover. For example, when electro-fishing our side channel, we found no trout fry where we started 50 feet below this logjam, but once we got to the edges of it, trout fry, dace and shiners started popping up everywhere! This reinforces that fry use woody cover for refuge and that having more woody cover throughout the river has the potential to increase the number of trout fry that make it to adulthood.
BVFF has been lucky to be working at the Diane Moore Nature Center where they recently completed a side channel restoration project, which included lots of natural woody cover. As a part of this project, BVFF developed and installed this sign emphasizing the importance of side channels and woody cover.
The first spring the side channel had water, Greg Kaltenecker (Executive Director of the Diane Moore Nature Center) reported rainbow trout spawning there. Talking with Greg we wondered how successful their spawning had been and if there were many trout fry in the side channel. One way that IDF&G counts fry is to snorkel the river, so we decided to give it a try! One August afternoon, Klaus Kissman, Dennis Moore and I donned wetsuits and snorkled our way up the side channel. 
As soon as we put our heads underwater we started to see trout fry! One thing that stood out is that they liked to hold by wood in the water, with the largest clusters of fry being around logjams. Snorkeling the side channel reinforced how important woody cover is and increased our motivation to improve woody cover in our own side channel.
Idaho Fish and Game describes the Boise River as “… one of the finest urban trout rivers in the country.” Being an urban river means it runs through a developed area and has to be managed to keep it from wandering into neighborhoods. The Flood District is tasked with removing trees that have fallen into the river to maintain a clear river channel to reduce flood risk and damage to private and public property. However, removing all that wood from the river means that fish have less woody cover. IDF&G has been working with the flood district to improve woody cover on the Boise River and over the years the flood district has looked for ways to keep trees from falling into the river. However, once a tree is in the river, their permits from the Army Corps of Engineers and Idaho Department of Water Resources only allowed them to remove it.
The flood district has been looking into how they could repurpose wood in the river instead of removing it. This summer, conservation team member Jeff Jones and I met with flood district manager Mark Zirschky and IDF&G SW Regional Fisheries Manager, Art Butts, to review woody cover in our side channel, including a tree that had fallen just upstream of the side channel. Mark thought the tree was a good candidate to try securing vs removing, as it was protecting the bank and not a floater hazard. And while Art was describing the benefits to fish (as if on cue…) we saw a nice rainbow trout emerge from the woody cover and start to feed. How cool was that! We all sat and watched it and knew keeping this tree was a good idea!
After meeting with the flood district and IDF&G, I reached out to club member Zeke Willard, who is a master arborist and owner of Idaho Tree Preservation Company, and the person who started the “#FillTheNet” movement. Zeke was very excited about the project as it married two of his passions—fishing and trees. The flood district coordinated an on-site meeting with the permitting agencies and Zeke described how he would secure the tree. The permitting agencies were all very supportive and having a master arborist involved gave the flood district the confidence it needed to proceed. The flood district worked through the additional permitting hurdles to be able to secure and repurpose downed trees where they can safely be used to prevent bank erosion and improve aquatic habitat, and this January they repurposed their first tree. The flood district issued this press release and held a press conference at the site to tell people about the project. Here is a story that ran on KTVB.
This tree is just the first of what we hope will be many repurposed trees along the banks of the Boise River. BVFF plans to float the Boise River in the Fall and identify trees that are good candidates for being retained and then review them with Zeke and Mark. The flood district will then submit for approval from the Idaho Department of Water Resources and the Army Corps to retain trees they feel would help protect the bank, are not a hazard to floaters, and would improve aquatic habitat. After the Flood District gets approval, BVFF will work with Zeke and Idaho Tree Preservation to secure the trees.
This project didn't happen overnight. IDF&G has been talking about the importance of woody cover with stakeholders that manage the river, including the flood district and fire departments. Support from the flood district started with former Chairman Bill Clayton, who was an avid fly fisherman and recognized the need to manage the Boise River for multiple uses. Bill brought in now retired Flood District Manager, Mike Dimmick who worked with the many Boise River stakeholders (including BVFF) and paved the way for changes like this. I am extremely grateful for our partnership with IDF&G, the Flood District and Idaho Tree Preservation Company and the support of the Idaho Department of Water Resources and the Army Corps of Engineers. And I am excited about the potential this effort has to improve the trout population in the coming years. WOOD IS GOOD!
ADDITIONAL INFORMATION ON WOODY COVER
