Novel Stream Restoration Method for Wild Trout and Ecosystem Health

[Sanford Smith] Hi Sanford Smith here with Penn State Extension.

Today I'm joined by Luke Bobnar.

He's with the Western Pennsylvania Conservancy where he's a watersheds project manager.

And Luke, you've been doing work throughout western Pennsylvania, and it all involves improving water quality, improving wildlife habitat.

That much I know.

[Luke Bobnar] Yeah, we've been working in this larger watershed to improve water quality, fish habitat, but also a host of ecosystem level benefits by reintroducing woody materials to stream channels and their valleys. Between, you know, 80 and several hundred years ago, Pennsylvania was cut, pretty heavily with harvest going all the way down in the stream, sometimes even pulling logs out of it.

And that was at a time when we needed to make lumber to build America.

But also it left our streams bereft of woody habitat, which for millennia was incredibly important.

And also it robbed us of the cohort of trees that should have been falling in for the past 200 years.

They should have been growing, living, dying, and adding themselves naturally.

And even though our forests, especially this one, looks beautiful and pristine to our eyes, but we've got this shifted baseline of perception that it's not quite what it once was.

[Sanford Smith] Yeah, right.

Tell me a little bit more about this method.

Is there a name for what you're doing out here?

[Luke Bobnar] Yeah, there is.

In general we call it large wood restoration or large wood replenishment.

A lot of times we call it chop and drop.

[Sanford Smith] Sure.

[Luke Bobnar] it takes quite a bit of skill to put a tree right where you want it and also leave the forest canopy, the rest of the forest canopy, intact.

If you walk downstream on this property right now, if you didn't look down at the stumps, you wouldn't really notice much canopy gap at all.

We like to call it giving, giving nature a little gentle nudge in the right direction.

It would take decades to centuries even, to get to pre-disturbance levels of wood in our channels and valleys.

And, we're just trying to help out a little bit by cutting trees down and strategically placing them within the channel and in the floodplain sometimes.

[Sanford Smith] So to the casual observer, the method that you use is to cut trees down and drop them into streams and tributaries.

But there's a lot of technique to that.

Can you talk a little bit more about that?

[Luke Bobnar] Yeah.

So we're not just willy nilly dropping everything and making a clear cut on the side of the stream.

We space them out usually maybe every 50 meters or so, with, say, 1 to 3 trees per placement.

And the fine limbs are just as important as the big bowl of a tree.

They, they help to catch fines and sediment and also we're in the fall right now.

The leaves that are coming down, the sticks that are coming down are hugely important for macro invertebrates, which are the base of our aquatic food chains.

And if you want fish, you've got to have macros and what the fish eat and leaves and sticks that are produced right here on site.

We'll get caught in our logjams and make this a healthier system.

So we're standing here at the stump of the tree that you just saw felled into this unnamed tributary creek here.

That's about a 15 inch diameter hemlock tree.

It's perfect for our application.

And I would say that this is a fairly typical representative structure, if you will, of what we build.

You can see on the far side of the stream bank, off to that side of me there some smaller stumps.

We fell in a few small hemlocks and a small maple, or two, to get those fine limbs really down by the tip of that tree and down in the channel.

They’re really what does a lot of the work in holding back everything that we want done here, and you can see that in these other sections of the stream where it's already happening naturally, and we're just really trying to augment that.

And we use the larger tree, the larger bowl of this hemlock, to help hold them down.

Depending on stream size, the size and number of pieces or logs that we'll use differs.

But for this application, this was the perfect tree.

And we've got, still a lot of shade and canopy here as well.

[Sanford Smith] Well, Luke, I want to thank you very much for joining me today.

[Luke Bobnar] Thank you, Sandy.

[Sanford Smith] Well, thank you for coming, teaching us about this.

You've learned some interesting things, I hope, here today.

And I want to thank you, too, for listening.