SCOTT DETROW, HOST:

The nation's first official wilderness turned 100 this year. But today, the definition of wilderness is being tested. KALW reporter Marissa Ortega-Welch has been hiking in the wilderness for over 20 years. And recently, she started to notice a lot of changes - more fires and smoke, more trees killed off from insects, more people on the trail. In "How Wild," a new podcast from KALW, Marissa set out across the country to explore the history of wilderness and its future. Let's join her now on the trail.

MARISSA ORTEGA-WELCH, BYLINE: We're in California's Sequoia National Park, and we're headed off trail to a remote rugged corner, which is kind of the whole point.

ANDREW BISHOP: And I can actually pull out a map. So...

ORTEGA-WELCH: This is the person I'm relying on not to get us lost.

And then, will you say your name and your title?

BISHOP: Yeah. This is Andrew Bishop. I'm the restoration ecologist at Sequoia & Kings Canyon National Park.

ORTEGA-WELCH: I'm excited.

BISHOP: OK.

ORTEGA-WELCH: Yeah.

BISHOP: Yeah. Same here.

ORTEGA-WELCH: And nervous.

BISHOP: I did mention rattlesnakes.

ORTEGA-WELCH: Oh.

BISHOP: We should be aware that in the lower elevation part of this hike, there's a good potential for rattlesnakes.

ORTEGA-WELCH: Plus there's poison oak and these annoying flies that keep getting in our face.

The sunglasses are helping for the face flies...

BISHOP: Oh, good.

ORTEGA-WELCH: ...Just for the record.

BISHOP: Yeah.

ORTEGA-WELCH: I wouldn't be putting up with all this if I wasn't getting to see something today that not a lot of people have seen. It's 2022, and we're heading to Board Camp, the name of a grove of giant sequoias that burned two years before in the Castle Fire. Giant sequoias, the biggest trees on Earth, only live here in California, and nearly half are found in Sequoia Kings Canyon National Parks. But since 2020, severe fires burned up to a fifth of the world's giant sequoias. Some scientists are worried that we could face a future with no giant sequoias in Sequoia National Park.

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ORTEGA-WELCH: The national park wants to replant giant sequoias in the wilderness. Other people say that goes against the very definition of wilderness. The debate is really around the question, what is natural, and how much should humans intervene? That's why we're here today. Almost as soon as we leave the trailhead, we're in what's called the John Krebs Wilderness.

BISHOP: I'm curious if we'll see a wilderness sign, that say we're entering the designated wilderness.

ORTEGA-WELCH: Yeah. Well, let's pause if we do. I love those signs.

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BISHOP: It's like, nothing says wilderness like a sign.

(LAUGHTER)

ORTEGA-WELCH: The fact that we're in an area designated as capital-W wilderness is really important. Wilderness areas are the most protected public lands in the U.S. Maybe you've been to Yosemite Valley. You drove there or took the bus to see Yosemite Falls. Maybe you've just seen pictures. It's beautiful, but the valley isn't technically wilderness. If you headed out on the trail, away from the roads, within a few miles, you'd enter into a designated wilderness zone.

Starting in the 19-teens, as tourists flocked to national parks and forests, roads and buildings were built to accommodate them. Environmentalists got worried that the land that was supposed to be protected was getting developed, so they came up with an idea for setting aside some areas from development, an extra level of protection, as what they called wilderness.

UNIDENTIFIED ACTOR: A wilderness is an area where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain.

ORTEGA-WELCH: And in 1964, the president signed into law the Wilderness Act.

UNIDENTIFIED ACTOR: An area of wilderness is further defined to mean in this act an area of undeveloped federal land, retaining its primeval character and influence without permanent improvements or human habitation, which is protected and managed so as to preserve its natural conditions.

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LYNDON B JOHNSON: This is a very happy and historic occasion for all who love the Great American outdoors, and that, needless to say, includes me.

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ORTEGA-WELCH: More recently, land managers broke down the Wilderness Act into five measurable qualities of wilderness character - untrammeled...

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ORTEGA-WELCH: ...Undeveloped...

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ORTEGA-WELCH: ...Natural...

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ORTEGA-WELCH: ...With opportunities for solitude and primitive unconfined recreation...

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ORTEGA-WELCH: ...And other features of value.

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ORTEGA-WELCH: Today, wilderness managers work hard to make sure they're meeting these standards. They do surveys to make sure people are experiencing enough solitude. They only put in trail signs if absolutely necessary so as to not take away from the primitive recreation experience.

I hear land managers talk a lot about the idea of restraint. They only intervene if absolutely necessary. Generally speaking, ecologists like my guide, Andrew, can only do restoration work in wilderness if the damage they're trying to restore was directly caused by humans, so like pulling out invasive plants introduced by pack horses or restoring a meadow that was impacted by an old trail.

Sequoia National Park is a fascinating example in a growing debate. How much should people intervene to restore wilderness? - because with climate change, every part of the planet is affected by humans, even wilderness.

BISHOP: And we'll kind of go around the back a little bit and over a ridge that you can't quite see from here. And that's where Board Camp is.

ORTEGA-WELCH: A couple of miles into our hike, Andrew and I stopped to look up the steep canyon where we're headed.

And we can see burned trees. I see a bunch of - I mean, I think I'm just seeing skeletons of trees up there, right?

BISHOP: Yeah. This fire just ripped up that. You can imagine that's where we really saw high-severity fire in the Castle Fire.

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ORTEGA-WELCH: The strategy for over the last hundred years has been to put out wildfires in California to protect homes and timber. Right in this valley, fire crews extinguished dozens of lightning fires over the years. But fire is important. Without it, smaller trees and shrubs grow unchecked, like match sticks waiting to be lit. All that fuel on the ground plus a hotter and drier climate means California's fires now burn hotter, faster and bigger, like the Castle Fire. It was started by lightning in August of 2020 and burned for months.

CHRISTY BRIGHAM: In the moment of the fire, it's very hard to know what you're going to find afterwards.

ORTEGA-WELCH: This is Christy Brigham, chief of resource management and science at Sequoia & Kings Canyon National Parks. As the fire kept spreading, she checked on the sequoia groves the way you might check on a loved one after an emergency.

BRIGHAM: It's smoky. You don't know what's happening. So we were getting these different reports. I was calling people who had connections and like - has anybody seen this grove or that grove?

ORTEGA-WELCH: As a biologist, Christy knows that giant sequoias need fire. The heat from the flames below triggers the cones to open and drop their seeds, and the fire clears the ground of underbrush and creates soft mineral soil, perfect growing conditions. But Christy could sense that something different might be going on here, and then she got signs confirming her fear downwind in the town of Three Rivers.

BRIGHAM: Large chunks of sequoia needles were falling on the ground in Three Rivers. And so those were indications when the fire was burning that the fire was destroying a lot of sequoias.

ORTEGA-WELCH: That's when Christy and her team started to plan. Board Camp wasn't the only sequoia grove that burned, and because most of the fire occurred in a wilderness area, the team knew they'd have to take special considerations. Now, the Wilderness Act asks land managers to not trammel the land unless absolutely necessary.

BRIGHAM: And trammel is kind of a beautiful, poetic, old-timey word, so people might not know what that means.

ORTEGA-WELCH: A trammel is a device used to shackle a horse's gait, so to be untrammeled means to be unshackled, unrestrained, free.

BRIGHAM: But what it's been generally interpreted to mean within the Wilderness Act context is that we're supposed to let nature take its course. Humans aren't supposed to hinder or interfere with natural processes.

ORTEGA-WELCH: Another one of the qualities of wilderness character is that the area is to remain natural.

BRIGHAM: To have a place that's allowed to change and evolve and undergo the - its natural evolution - but that is really not what we're seeing with wildfire in California and with these impacts to these sequoia groves.

ORTEGA-WELCH: Christy and other scientists agree that even though this fire was started by a natural cause, lightning, the severity of the fire was a result of human causes.

BRIGHAM: They're driven by 100 years of fire suppression, which were poor decisions that we made as managers and made worse by climate change-driven hotter drought.

ORTEGA-WELCH: That's why scientists feel that they should try and restore the groves by replanting sequoia trees from seeds from surviving cones, which sets up this sort of catch-22. If the burning down of these thousand year old fire resilient trees wasn't natural and the park wants to restore the groves, it might need to do a little bit of trammeling.

DETROW: That was an excerpt of the new podcast "How Wild" from KALW Public Media. You can listen to "How Wild" wherever you get your podcasts. Transcript provided by NPR, Copyright NPR.

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