More than half a million acres in southwest Montana have been impacted by conifer expansion. It used to be that fires would come through these landscapes and burn back the trees, but that natural cycle isn’t happening anymore. Now, more trees are encroaching into traditional sagebrush habitat, and that has impacts on our water supply.
Austin Amestoy: Welcome to The Big Why, a series from Montana Public Radio where we find out what we can discover together. I'm your host, Austin Amestoy. This is a show about listener-powered reporting. We'll answer questions, big or small, about anything under the Big Sky. By Montanans, for Montana, this is The Big Why.
Today, we’re returning to a recent subject on the show: groundwater. Reporter Ellis Juhlin is here Ellis, take it away.
Ellis Juhlin: Hey Austin! Excited to talk with you today, this question comes to us from southwest Montana
Pedro Marques: My name is Pedro Marques, and I am the Executive Director of the Big Hole Watershed Committee.
Ellis Juhlin: He reached out after hearing our episode in December about how earlier snowmelt and spring runoff affects our groundwater supply.
Marques thinks about water pretty much constantly in his role on the watershed committee. The group has studied drought and worked on water conservation projects on the Big Hole and its tributaries for the last 30 years.
Marques and his team are always looking into ways to keep enough water in the Big Hole.
Pedro Marques: My question is, with the expansion of forest cover and density of forests in our area, is there an impact on baseline groundwater and water availability for everyone downstream?
My question is, with the expansion of forest cover and density of forests in our area, is there an impact on baseline groundwater and water availability for everyone downstream?Big Why question from Pedro Marques
Austin Amestoy: What kind of forests, or trees is he talking about here?
Ellis Juhlin: Good question Austin. Before we dive into the weeds, or the trees as it were, we need to take a step back and talk about a phenomenon called conifer expansion. It’s where trees grow into habitats where they wouldn’t normally be.
You can think of trees like straws sucking up groundwater and surface water. The more trees, the more straws in the system. And there are lots of other straws that want that water too — other plants, wildlife, livestock and people.
Historically, fires would keep trees from expanding too far beyond the forest. But we’ve suppressed fires, and gotten better at fighting them, so those same fires that reset the habitats don’t really happen anymore. This means trees are competing for water, sticking their straws in the ground in places they didn’t used to be.
Fire suppression made it easier for trees to expand into grassland and sagebrush habitat. And Sean Claffey, with The Nature Conservancy in southwest Montana knows all about it.
Sean Claffey: We're talking about Douglas fir and Rocky Mountain juniper, primarily. And when we say 'conifer expansion,' we're talking about those trees moving beyond their historic range into other habitat types, such as sagebrush or even into aspen.
We're talking about Douglas fir and Rocky Mountain juniper, primarily. And when we say conifer expansion, we're talking about those trees moving beyond their historic range into other habitat types, such as sagebrush or even into aspen.Sean Claffey
Ellis juhlin: Claffey coordinates conservation projects focused on sagebrush habitat. He works collaboratively with groups like the watershed committee, as well as state and federal agencies to protect this ecosystem.
Sean Claffey: It also referencing something, what we call infill, or, you know, stands of historic treed habitat, but ... they're getting denser. There's more trees there, and so those gaps are filling in, in between what was there historically.
Ellis Juhlin: Claffey told me more than half a million acres in southwest Montana have already been impacted by conifer expansion. Like I said before, it used to be that fires would come through these landscapes and burn back the trees, but that natural cycle isn’t happening anymore so we see more and more trees in traditional sagebrush habitat.
Austin Amestoy: Gosh, we humans seem to have inserted ourselves into all aspects of the natural landscape. Some places need reforesting, others need thinning, it can feel so complicated. In this case, though, what’s been the impact of trees growing into new habitats like the Big Hole?
Ellis Juhlin: It’s bad for the sagebrush steppe in several ways. Trees can outcompete the native grasses and shrubs — and this impacts groundwater too.
Sean Claffey: As snow melts, or if we get a heavy rainfall, there's more bare ground and there's fewer pathways for that runoff to infiltrate into the soils and actually be additive to our groundwater supply. With less ground cover, you have less opportunity for that water to slow up and follow those root paths down into the soil.
Ellis Juhlin: Plus, Claffey told me, because trees form such a dense canopy, they hold up snow from falling onto the ground. And we know snow slowly melting on the ground is an important part of refilling groundwater each spring and summer.
Trees also draw up a lot more water than the sagebrush and native bunchgrasses do, so they tap into groundwater that way as well. So in this case, there’s not only more straws drinking out of that underground water supply, but the trees that just moved in have bigger straws that can outcompete the smaller native plants.
Because trees form such a dense canopy, they hold up snow from falling onto the ground. Trees also draw up a lot more water than the sagebrush and native bunchgrasses do.
Austin Amestoy: So what can be done about conifer expansion?
Ellis Juhlin: Well, Claffey’s collaborated with lots of other groups to take the trees out of these areas they weren’t historically in. And I went out to see some of those projects firsthand.
JM Peck: My name is JM Peck, and I'm a rancher from Melrose, Montana. I manage my family's cattle ranch, Trapper Creek Ranch, which is on the banks of the Big Hole River.
Ellis Juhlin: Peck is also part of the Big Hole Watershed Committee, and he’s worked with Marques, Claffey and others, to remove conifers that have expanded down from the forest into sagebrush habitat on his ranch.
He took me out to see some of the conifer removal sites. We navigated around calving cows across dirt roads. Peck knows this land like the back of his hand, and in addition to newborn calves, he pointed out areas where he’s watched the trees come in and water dry up.
JM Peck: This is a huge, you know, it's a huge wetland, so the creek is right in the bottom here, and this was really starting to see a ton of conifer encroachment.
Ellis Juhlin: We stood up on a ridge line and looked out over rolling hills of sagebrush and then up into the mountains where the forest is dense. And the further you look up the more you see these lines of juniper, like spindly fingers running down draws and into the sagebrush steppe. Since they’ve removed conifers, Peck told me he’s seen water come back.
JM Peck: Up that draw where those, you know there's aspen trees at the mouth of it. Up that draw for probably a mile is just step pools. And what used to be a dry draw has now become full of water after we removed all the conifers
Ellis Juhlin: It’s important to clarify here — and everyone I talked to mentioned this as well — they aren’t looking to just go out and take down all the trees. But these projects aim to restore and preserve the sagebrush habitat and take trees out of the places they’re expanding into.
They aren’t looking to just go out and take down all the trees. But these projects aim to restore and preserve the sagebrush habitat and take trees out of the places they’re expanding into.
JM Peck: You have to almost come and see the country to realize, well, this isn't really where trees belong or were historically. They would not be here, if it wasn't for us suppressing wildfire.
Austin Amestoy: Wow, so this is one area in particular where we’ve seen water come back when encroaching conifers are removed. But water is a big deal all over the state, not just in the Big Hole — so how do we deal with this?
Ellis Juhlin: Like I mentioned, there are half a million acres just in southwest Montana where conifers have expanded into other habitats as we’ve kept on putting out fires. We can’t just let all the fires burn since there’s so much private property around, and the scale of the problem is just too large to get all the unwanted trees out of there at the pace we need.
Instead, individuals and organizations are working on projects like what I witnessed on Peck’s property. And groups like the Big Hole Watershed Committee recognize that
But it’s important to note that there’s no single solution that fixes everything. Every drop counts, quite literally, so they’re pursuing a combined approach: restoring wetlands, putting in beaver dam analogs, removing expanding conifers and promoting more efficient water use. And all these things help.
Austin Amestoy: Well, Ellis, we appreciate the broad overview look into conifer expansion. Thanks for being on today.
Ellis Juhlin: Yeah, thanks for talking to me!
Austin Amestoy: Now we want to know what makes you curious about Montana. Submit your questions below, or leave a message at 406-640-8933. Let's see what we can discover together!
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