UC Davis

Transcribed using AI. May contain errors.

Amy Quinton 

What are we listening to? 

Kat Kerlin 

That sound you're hearing? It's a Clark's nutcracker, a bird that lives high up in pine forests like in the Sierra Nevada Mountains.

Amy Quinton 

And it sounds like we're hearing several of them. They sound a bit like crows or obnoxious scrub jays in my backyard. 

Kat Kerlin 

Yeah, a UC Davis bird biologist described it to me as a raven holding its nose.

Amy Quinton 

That's a great description.

Kat Kerlin 

And these birds just might be reshaping part of California's forests.

Amy Quinton 

Reshaping. Okay, so what do you mean? How does a bird do that?

Kat Kerlin 

A Clark's nutcracker has a habit of burying pine seeds, caching them in rocky slopes as winter food, some of those seeds sprout, becoming trees.

Amy Quinton 

Well, that makes sense, but how can that actually reshape parts of forests? 

Kat Kerlin 

Scientists are now learning that certain trees are showing up in places we wouldn't expect them in extremely high elevations, places that previously would have been frozen are inhospitable to them. 

Amy Quinton 

What kind of trees are we talking about? 

Kat Kerlin 

We are talking about the Jeffrey pine. 

Amy Quinton 

Okay, so I'm terrible at identifying trees, like, if it's taller than me, it's a tree. If it's smaller than me, it's a bush, probably, basically, there's two pine trees, right? There's the kind that look like Christmas trees. And then there's the Jeffrey pine. And the Jeffrey pine stands out to me. Do you know why? 

Kat Kerlin 

Why? 

Amy Quinton 

It's orange bark smells like butterscotch. Sometimes people say it smells like vanilla. I think it smells more like butterscotch. 

Kat Kerlin 

I kind of thought root beer, 

Amy Quinton 

Root beer? 

Kat Kerlin 

I'm probably wrong.

Amy Quinton 

But what other tree can do that? I ran across a lot of these while on the eastern slope the Sierra Nevada Mountains. This was a while ago, back when I could go up mountains. And there are a lot in the Inyo National Forest, and they're also in Yosemite. I went backpacking there once, and we would stop and smell the bark. 

Kat Kerlin 

You gotta do that in life.

Amy Quinton 

 I don't think we were very high up on the mountain, though

Kat Kerlin 

They're typically found between five and 9,000 feet in elevation. It's the most common tree found around Lake Tahoe, Mammoth Lakes. It's not even considered a traditional subalpine tree species. These are the ones that live at the highest elevations. But about a year ago, UC Davis forest ecologist Hugh Safford stumbled upon a Jeffrey pine at 12,657 feet in elevation at Sequoia National Park. It was the highest Jeffrey pine ever recorded, and it was the highest tree recorded in California. 

Amy Quinton 

Oh, wow,

Kat Kerlin 

Yeah, not only the highest Jeffrey pine, but the highest tree in California is a Jeffrey pine, and it's not even supposed to be a subalpine tree species, and he just knew that the Clark's nutcracker played a role in why it was there. 

Hugh Safford 

It was really clear it was a nutcracker. I confirmed it with the real experts, but that wasn't a question anymore. But the question was, 'what the hell is this thing doing here? And why are they caching this, this particular species, up here, and how is it surviving up here?'

Kat Kerlin 

Hugh vowed to return to the high peaks of the Sierra to look for more Jeffreys.

Amy Quinton 

And you obviously got to go along with him.

Kat Kerlin 

I did. Well, for four days with him and his lab students in the Inyo National Forest. This was just a tiny fraction of the time Hugh ultimately spent on the mountains this summer. All told, they camped 30 days, scoured 24 mountain peaks and hiked 240 miles to find these things.

Amy Quinton 

That's amazing. Like, why? I mean, that's a lot. That's like a real lot. And why on earth would anyone want to risk life and limb. No pun intended. Actually, pun totally intended. But like to look for a tree?

Kat Kerlin 

Well, because they're ecologists and they love that stuff. But also it's because of what these trees presence might reveal about our changing climate.

Amy Quinton 

Okay, so these trees, the ones living where they weren't expected, are kind of like sentinels, right? Or indicators? They tell us about our shifting climate?

Kat Kerlin 

Yeah, so yes. With rising temperatures, snows melting earlier, trees are possibly moving up slope, maybe with help from a little bird. Hugh says, If you want to understand what's happening with climate change, you have to look at Earth's extremes, like the poles and the mountains,

Amy Quinton 

And we'll talk about your climb to those extremes in this episode of Unfold. Coming to you from UC Davis, this is Unfold. I'm Amy Quinton.

Kat Kerlin 

And I'm Kat Kerlin. Following the team wasn't just a stroll through green, shady forests, although it did start that way. When you get to high elevations, there are a few scattered pine trees and some gorgeous alpine lakes and meadows. The landscape is also a vast expanse of cream-colored rocky crags and huge, pretty intimidating boulder fields.

Amy Quinton 

Yeah. How did that work out for you?

Kat Kerlin 

I mean, it was gorgeous, but it was also daunting. I mean, I'm kind of a flat lander one living in the super flat Central Valley, no less. Being that high, definitely felt out of my element sometimes. There were days we would hike 10 to 12 miles just to get to where we thought we might find a Jeffrey pine. 

Amy Quinton 

Oh, my god. 

Kat Kerlin 

Yeah, we went up Mount Langley. This is a 14,000 footer and California's ninth highest peak. This is where we'd hoped to find the highest Jeffrey pine.

Amy Quinton 

And did you?

Kat Kerlin 

Nope. Well, we found several on the trip, just not at Mount Langley. 

Amy Quinton 

Were they what you expected to see? 

Kat Kerlin 

Well, they're short for one thing, Even the adults are just a few feet tall, not like 100 feet tall, like some Jeffrey pines can be. They were often damaged, either by cold or by critters, and they'd just be growing there, poking their green, bushy little selves out of a rocky enclosure near the mountain top.

Amy Quinton 

So once the team finds a Jeffrey, what do they do?

Kat Kerlin 

They measure it. 

Researchers 

3.3. That's it? 

Kat Kerlin 

 Log its coordinates, check its condition. And many of these Jeffreys have no cones. Sashi Srivastava, a UC Davis Masters student who led the field work with Hugh says few high elevation Jeffrey pines do.

Sachi Srivastava 

Life up there is hard, like nothing, really nothing's doing its very best.

Kat Kerlin 

That might change with a warming planet, but for now, Hugh says many of these Jeffrey pines seedlings are not all that excited about being there.

Hugh Safford 

This is way above where they want to be. It would be like taking someone's child and dropping them off in Greenland, you know? 'Hey, you're going to be fine. Don't worry about it.'

Amy Quinton 

That's hysterical. I mean, it's sad, but it's hysterical. The trip sounds so grueling, and you get up high and you see these little bitty things struggling to survive. I mean, why not use modern technology, AI, remote sensing, satellites, rather than trekking 240 miles over the summer?

Kat Kerlin 

You know, we talked a lot about that, especially on the last night of the journey. You have to ground proof it. Hugh explains why modern technology, while super helpful, super powerful, it just doesn't provide the full picture of what's happening at these elevations.

Hugh Safford 

You can't see these baby Jeffrey pines from satellites. It's impossible. We can't even barely see him walking by him. You know, you saw a bird serendipitously caching. A machine's gonna pull that off?

Amy Quinton 

You saw a bird caching so burying its seeds for winter. I guess this brings us back to the Clark's nutcracker.

Kat Kerlin 

Right. So let me set the scene for you. Actually, I'll let UC Davis, bird biologist Mike Mahoney set the scene.

Mike Mahoney 

We are currently on Joe Devel peak Devel and we've been working our way slowly up slope, looking for Jeffrey pines, and we've heard Clark's nutcrackers the whole morning, and we had at least a couple of them on the lower slope.

Kat Kerlin 

But then suddenly Mike goes still and alert. He's like a bird dog looking up at the sky.

Amy Quinton 

He sees a Clark's nutcracker?

Kat Kerlin 

Not only does he see one, but he sees one drop its cache. So he beelines it for the cache and as he's digging for the seeds, at least six nutcrackers begin to call loudly, like they were launching an emergency action plan. Here's what it sounded like. And by the way, it was a windy day.

Kat Kerlin 

One flies so closely over us, you could hear its wings.

Mike Mahoney 

It was. It was aware of our presence and and, I mean, if I were to assign a feeling to that bird, I'd say it was not so happy with our appearance. And it's kind of interesting as we've as we left the area, the birds have dispersed.

Amy Quinton 

Yeah. Sounded not happy at all.

Kat Kerlin 

Definitely not. But those caching behaviors are key to understanding why Jeffrey pines are appearing so high up where conditions used to be too harsh. Hugh says climate models make assumptions about how species will move with increased warming, but how and why a species moves is complex. Clark's nutcrackers might have been storing Jeffrey pine seeds in their mountaintop refrigerators for millennia.

Hugh Safford 

We forget that there are species that have the capacity to just leap over these boundaries, you know? And that's hugely important if you want to keep up with climate change, it's true that trees that are just dropping their seeds in the wind or maybe the wind is maybe moving them, you know, a few yards or something, you're not going to be able to keep up. But a species like Jeffrey pine, or a species like whitebark pine, or a species like limber pine, birds can move them five, 10, 15, 20 kilometers without that much effort.

Kat Kerlin 

And that is exactly what these scientists are seeing. Seeds once buried by birds now because of warming temperatures, earlier snow melt are taking root.

Amy Quinton 

So climate change isn't just pushing species uphill, it's allowing these leaps into new zones. So these birds are basically accidental reforesters. 

Kat Kerlin 

Yeah, I kind of like to call them gardeners. And they've done that for whitebark pine for a really long time, but their role as gardeners of Jeffrey pine is something we're just beginning to witness. 

Amy Quinton 

So climate change, tree migration and bird behavior all tied together. So I have to ask, though, do you think those isolated Jeffrey pines are a glimpse of what our future forests could look like, or will they adapt to look more like their downslope ancestors?

Kat Kerlin 

You know I can't predict that, but Nick Parker, an undergraduate on the trip, he had a keen observation on our last night.

Nick Parker 

It was so cool today seeing those like tiny little Jeffreys, just like way up there. You know, there was, like, no other Jeffreys around, like just seeing how small they were and how imagining how far they must have come from the source. It's just like crazy to think how they got there. Yeah, and it's cool. I feel like I don't spend enough time appreciating like saplings.

Amy Quinton 

So what do these scientists plan to do with all the data they collect on these little saplings?

Kat Kerlin 

Yeah, this is where more that modern technology comes in. They plan to combine all their data with all of the verified global records to create a big database that climate modelers, natural resource managers and really anyone interested in Sierra Nevada trees can use.

Amy Quinton 

I have to say, it's created a powerful image in my head. Trees sort of surviving in a place that's just not quite right for them.

Kat Kerlin 

Yeah, and whether it's right for them or not. You know they're there. I can't help but wonder if they know what they're doing and are exactly where they need to be. It all shows how much effort nature and the people studying it put into adaptation. Hugh's team carried heavy packs, hiked miles at high altitudes, all to find these few small pines that may tell us how forests will evolve in a warming world.

Amy Quinton 

It's a reminder that understanding climate change means going to the extremes, sometimes following a bird 

Kat Kerlin 

Exactly.

Amy Quinton 

And Kat, I know you took some gorgeous photos and created watercolor sketches of what you saw along your hike, and you've written a marvelous and much more in depth story to go along with it.

Kat Kerlin 

Well, you can see all of that and find links at our website, UCDavis.edu/unfold or at UCDavis.edu/climate. I'm Kat Kerlin.

Amy Quinton 

And I'm Amy Quinton. Thanks for listening. Definitely check out those photos. They're awesome.

Andy Fell 

Unfold is a production of UC Davis. Original music for Unfold comes from Damien Verrett and Curtis Jerome Haynes. Additional music comes from Blue Dot sessions.