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Is it fines.

This is a rip Current bonus episode.

You don't have to listen to follow the rip Current storyline, but it provides more information, context, and analysis to enhance the main podcast.

Enjoy Sometimes when you're making a podcast or writing a book, you end up leaving out some really interesting stuff in the cause of keeping the narrative flowing.

Making Rip Current season two, I had originally intended to spend some time looking at redwood trees themselves.

They are fascinating above and beyond just their sheer size, but I made the decision to not get into that in the main podcast.

I had, however, already interviewed Lucy Carhulis, who is an assistant professor of forestry at California Polytechnic Humboldt.

I think her perspective helped me understand the reverence in which so many people hold the redwoods.

We talked about many things, including redwoods as a species, their unique properties, and the possible new threats brought by climate change.

Here's that interview.

My name is Lucy Carhulis, and I'm an associate professor in forestry at cal Poly Humboldt.

What kind of got you into the redwood forest area.

I grew up in Santa Refel, California, which is just a little bit north of San Francisco, in the suburbs, and I came up to Humble in two thousand and three to go to school.

So I went here and was a botany major, and on the north coast of California, you can't help but become kind of enamored with the coast redwoods.

So I ended up staying here and doing my master's degree here.

And my master's degree was focused on redwood physiology.

Just a start of the very very basic level.

What's sort of the evolutionary function for redwoods being so much bigger than what we have out in New Hampshire.

That's a good question.

I'm not totally sure why they grow so tall.

I mean it's a race for light, you know, you got to in that forest type kind of outcompete your neighbors grow a little bit taller.

There.

Wood is so structurally sound with.

All of the heartwood that they produce.

That's very resistant to rot and decay that they can kind of afford to live so long and not succumb to rot and kind of structural failure for.

Thousands of years.

So why they grow so tall, Like I think, it's just kind of been a long arms race of one upping your neighbor in a race for the light in the north coast to where redwoods and their ancestors used to be a lot more widespread, you know, millions of years ago, back in the Conifer heyday, if you will, before the rise of the angiosperms and the hardwoods, they were way more widespread.

And now you know, continents have moved around, mountain ranges have uplifted.

Now they've been able to kind of eke out this stronghold on this narrow strip of the coast of the North American continent, and that's just kind of where we find them now.

And the climate here and the conditions kind of are reminiscent of back in the Conifer heyday when the conifers kind of reigned supreme, and so they've been able to sort of persist here in this kind of refugium of conditions that are similar to back when they had a much larger range.

When you say they're more structurally sound, what does that mean exactly?

Like other species, say, some of the true furs, like in a genus Abes, they don't really invest in their wood the same way that redwood does, and a lot of the kuper Sacee the Cyprus family that redwood is in a lot of those trees, they don't make resin ducts like you see in the pines in their wood like anatomically, but their approach to having strong rot resistant wood is to invest in really bomber heartwood, so putting in tannins and a bunch of kind of chemicals and secondary compounds, secondary metabolic compounds like waste products into their wood that make the wood extremely anti fungal and really rot resistant.

And so other species, like I was mentioning the true furs, for example, they don't really make that type of heartwood, and they also don't have resin ducts.

And so a lot of the species of true furs like red fur, white fur, grand fur, or a lot of those have structurally not a sound of wood like it succumbs to rot and stem failure really often.

So if you're walking through a mature forest, you might see a lot of standing snags of say like grand fur here on the coast, just they've sort of, you know, in a storm came by and it just sort of snapped the stem of the tree because it wasn't it had rot in it and stuff like that.

Whereas redwood is pretty bomber a lot of times.

Though instead of the stem actually breaking it's so strong.

A lot of times, what will kill a redwood is that it gets wind thrown.

They have really shallow root systems, and so rather than the weak point being the stem of the tree breaking, it will often just be that the tree like they've been there for two thousand years and literally the soil kind of like erodes around their roots, and some really big windstorm maybe happens in the winter when the soils are really wet from all of the rain that we get here in the temperate rainforest, that the tree will just kind of keel over and be wind thrown, where you'll see the roots kind of sticking up in the air.

What would you know, absent man, what would cause like a redwood to die?

It's another really good question.

Yeah, fire could come through and kill a redwood.

Although even that we saw in the Santa Cruz fires recently in twenty twenty where Big Basin State Park burned to a crisp basically and Douglas fir and old growth for US, Douglas Fir had I think essentially one hundred percent mortality, and redwood looked burned to a crisp too, just these black standing chunks, zero green for miles to see.

But then like you know, the next spring lo and behold all of the redwoods leafed out like little chia pets with this green fuzz and they just produced a new leaf set.

And so even high severity fire, they seem pretty resilient to that.

Interestingly, I think this species was incredibly well named Sequoia semper virons.

Semper virons.

The specific epithet is always lives, lives forever, and so it really is kind of magical in that sense.

I mean, I don't really know what kills a redwood for, like you know, the ultimate coup of gras, because they even sprout.

It's kind of like psych Yeah.

Right here I come again.

So a lot of times like a tree will fall over, Say you have a fifteen hundred year old stem, it gets blown over or knocked over by a neighbor, and then the root system will just send up a bunch of new sprouts, and then they'll kind of duke it out for a couple hundred years, and then they'll maybe be you know, four or five winners, and they'll grow up to be kind of a fairy ring of redwoods that are all the same.

But how many times has that genetic individual gone through that process of kind of keeling over and then re sprouting, sort of rising from the ashes.

It's hard to say that's cool?

Yeah, So how I mean they're huge.

I think it's hard for people if you haven't been.

I was talking to a friend.

It's like, I think you see these pictures of redwoods and you sort of have in your mind like how big a tree is.

So you see the redwoods and you sort of tag on the fact that it's a tall tree.

But it's more like seeing a picture of like a person in a field, and then when you actually meet them, they turn out like they're eighteen feet tall.

It's just like the scale is so like not what you're expecting when you're actually there.

That being a long way of saying, how with like sort of a smaller roots system, how does that keep them upright over two thousand years.

Yeah, I know, it's like this huge saale, you know, this three hundred foot plus sail up in the wind, that standing upright against gravity, and then this kind of pinner root system that's maybe ten feet deep or so.

So it's kind of disproportional, but the root system is extremely vast, like horizontally, So I think that's the saving grace.

It's kind of a beautiful thing just thinking about like the wood wide web, you know that it's like all connected.

So the root systems of these neighboring trees are very innerwoven, and they even can graft to one another below ground, and so it creates this like mesh that I think has a lot of stability, and so looking at the forest as a whole rather than these individual trees, and so, yeah, the root system isn't very deep.

It's not like it has some huge tap root that's really anchoring the tree to the earth, but it's extensive laterally and also interwoven with other trees throughout the forest, and so together they're pretty strong against the wind and able to stay upright.

So what's the state right now of redwood forest?

I know, just from doing reading that we're like five or ten percent of what it was when you know, in seventeen fifty or whenever it was that people first started coming and checking it out.

So how does that work ecologically?

I guess it's the size of the redwood force.

Now.

Is that adequate to continue vitally or are we at a tipping point where it's going to become too small and collapse?

Where are we right now?

Yeah, that's a good question.

You know, back in the Conifer heyday, redwood and its relatives are much more widespread.

You know, major shifts happened.

It's now in this kind of relictual distribution that's extremely narrow.

You can plant redwood anywhere in the world, and if you can nurse it along during its kind of establishment phase, it can grow anywhere.

The Central Valley of California, you know, it's planted along the highway, but in its natural distribution, like where it will naturally regenerate and perpetuate.

It's an extremely narrow range.

And so of that now extremely narrow range, ninety five plus percent of it was clear cut logged back in the day, and so the amount of old growth that remains today is really precious, and it's you know, less than five percent of the species range.

That means that ninety five ish percent of the redwood's natural range is kind of like not great forest.

It's second growth forest, it's working timber lands.

It's third growth forest, fourth growth forests.

These lands that have been cut and recut kind of like a lawn of timber growing at like a crop.

And it's a great wood product.

Like I'm all for.

Wood products, like we all want a wooden table, you know, or a wood house.

It's a great renewable resource.

It stores carbon, and especially redwood that stores really amazing carbon, like because it's so route resistant and long lived.

It's wood products.

You know, live forever too, and so it's a really it's a great renewable resource.

But a lot of the lands are these kind of cutover lands across much of the species range, and there's pretty widespread efforts to restore those and try to accelerate them into more mature forests through like Save the Redwoods League and Redwood National and State Parks.

Up north in California and dal nort and Humboldt Counties, there's this program called Redwood's Rising that is trying to restoratively thin about seventy thousand acres of redwood forest over the next thirty years.

It's a pretty cool program.

I think in the United States, or maybe it's even North America, the three largest restoration projects are the Everglades and then the Klimate dam removal, which is happening here in the Humboldt region, and then redwood's rising.

So it's a really large scale restoration project that's happening.

And the idea is that because redwood is so shade tolerant, and because these dog hair thickets of second growth, plus redwood forests are sort of a human product from clear cut logging and then often aerially seeding, like flying over with airplanes and dropping seeds, these forests are really naturally dense.

And then couple that with like fire suppression for one hundred years, it's led to like a turf just this, you know, lawn of really suppressed, unhealthy forests.

There's not much wildlife diversity, there's not much understory.

The trees are not rocking out like they're pretty suppressed and not sequestering as much carbon as they could be if they were released from that competition.

And so these restoration efforts are underway to try to go in and thin those forests because redwood is so shade tolerant it could take centuries to self thin in the phase of forest stand dynamics called stem exclusion, where there's kind of winters and losers and trees do get out in a race for light.

And so there's these efforts underway to go in and kind of accelerate that process by removing say like forty percent of the trees in a stand.

They're kind of like little toothpicks.

They're these really small, small diameter, are very tall stems with a tiny tuft of foliage at the top because there's like no growing space to develop more structurally complex crowns.

So is this effort on private land?

So is it on timberland or is it public land that was previously caught?

These are public lands.

The Redwood's Rising work is happening on in Redwood National Park and then also in California State parks.

Can you kind of explain the difference between old growth and new growth forests, Like why is that such a big deal?

Yeah, the old growth forests are kind of like the primary forests.

They were the forests that we haven't messed with, you know, they're untouched.

So they are these primary forests.

They're kind of primeval, if you will, Like we walk through them and you feel like you're going back in time to a time before humans started kind of messing with the land.

So they're kind of like our historical reference point, if you will, for what the red w forest would be like, kind of in its fully mature state.

Non old growth forests are forests that have been logged and then various levels of management have been sued.

So sometimes they were just clear cut, logged and allowed to come back, and then sometimes we've done other things like planting other species there or coming in and planting specific clones that are wanted.

There's all sorts of different things that can happen after the slate has been cleared via clearcut like what will.

Come after that.

But because redwood is so valuable as far as the timber species, a lot of times once the old growth forest was logged, the forest was sort of treated as a crop, you know, to make money and create a really great timber product.

So old growth forests typically have a lot more wildlife habitat and larger, much larger carbon storrege as far as kind of climate change mitigation and taking CO two out of the atmosphere and locking it up so carbon storage ecosystem function, and then habitat for wildlife that has really limited habitat.

A lot of species in the Pacific Northwest are dependent on mature forest structures like large branches, nesting cavities, those types of things for their habitat, and so we're seeing a lot of things like marble Nearlet's, northern spotted owls, fisher Martin, these types of things that can be really habitat limited, and so the old growth forests serve as sort of this reservoir where those species can persist.

One of the things I kind of ran across when I was doing research is that people and I think those are more sort of corporate timber people kept referring to old growth redwoods as being decadent.

Is that something you're familiar with.

I'm trying to wrap my head around that because it's like, it's such a loaded term to use on a plant, you know.

It's yeah, I know, it is a really weird term to use.

There's sort of this old school, you know, and I don't studying carbon storage is not like my.

Area of expertise.

I'm a little out of my wheelhouse with this.

But there is sort of this old school concept in forestry that the older, larger trees have kind of stopped doing their thing and they should be cut in more vigorous young trees should be put in that are growing faster.

And yeah, you can look at this through a lot of different sides, but it depends sort of what lens you're using to define growth.

So if you're just looking at radial growth, like the size of the rings of growth that the tree is putting on each year in terms of like millimeters per centimeters, how much is it growing via diameter per year?

The alme tree of it is is if you have a really small tree and it puts on a donut of growth of wood each year, that donut can be pretty fat, and it's a small tree.

The circumference of the tree is small.

But if you actually took that donut of growth and kind of like swished it into a little square, you know, like how much wood would that actually be versus you have some huge giant tree it puts on a donut of growth.

It's like microscopically thin right the tree ring itself.

But if you take that whole donut around the whole circumference of the tree and swished it into a square, it actually would be probably more wood production than the smaller tree.

And then more recent research has shown if you scale it to the entire tree, so you can look at growth radially, let's say centimeters per year of diameter increase, or you can look at growth on an area basis like centimeters squared of growth per year, or you can scale it up even further and look at volumetric So if you look at the whole cone of wood, not just the doughnut in a two dimensional fashion, but the whole cone of wood that was produced across the entire trunk of the tree, and smashed that into a cube, and you looked at say meters cubed of growth that was produced that year on an old growth, huge tree, it's way more than some tiny tree that's producing wood.

So it's been shown both in the redwood in the redwoods like Coast redwood and giant Sequoia by Steve Sillett and his team, and then Nate Stevenson, another great forest researcher, kind of scaled it up and looked globally at these growth patterns, and it holds, like what sille it found in the redwoods that the larger trees are actually having greater volumetric growth than the smaller trees.

It holds true across all the continents and like one hundred plus species.

It was a nature of paper that Nate Stevenson published.

So this old school thinking in forestry that the large trees are decadent and are kind of sinessing, and they should you're removed in the landscape to make room for younger, more vigorous trees.

It sort of depends what lens you're looking at and what your objectives are.

If you're looking at carbon storage, actually it makes more sense to have these giants on the landscape because they're sequestering a lot more carbon and storing it away, especially in redwood's with like bomb or heartwood that's going to be persistent for thousands of years, even rotting on the forest floor if it fell over.

Hopefully that answers your question.

No, No, it's I you know, it's just one of those things where I was reading I was like, did I read that right?

They just say decadent trees, and it's what would be lost if there weren't, Like what if redwood just got clear cut completely?

What gets lost there?

I'm sort of interested in what the assuming that there would be quite a bit of a loss, I'm just not sure what that would be.

Yeah, it would almost be like an extinction.

I mean, yeah, redwood wouldn't be extinct.

Like we're actually cutting redwood, right, we're doing these restoration treatments because there's too many redwood trees like on the landscape.

But to all redwood in that precious five percent that's still like in primary forest old growth condition.

If that were just clear cut and gone from our planet, I mean, there's no getting it back.

There's no replacing old growth redwood forests in our human understanding of life, in our in our timelines, you know.

I mean it would eventually, hopefully self you know, come back, but it'd be a really long time, like many generations, and so multiple generations of humans would be deprived of ever being able to experience that place on our planet.

Red old growth redwood forests are really special.

It's hard to describe verbally if you've never been in them, but they're palpably ancient and I feel like they really are helpful for understanding like our presence on the planet and really humbling and kind of give life a lot of perspective.

Like I read a book one time by EO.

Wilson, like on the Meaning of Life or something like that, and he had this cool analogy in it where he described like our human lives as something I'm just going to paraphrase, but it was something like, you know, my life is the equivalent of like the twelfth and Tennis segment on an aphed on a leaf in Central Park in New York on this one afternoon at three pm, you know, like just putting it into context, like.

What our lives are.

And so I feel like being in a redwood forest is something where you can like directly experience that feeling of like we are, you know, dust mites in the grand scheme of things.

And so I think that for humans, for you know, depending on who you are, sometimes that can be helpful to just know, put life in context and the greater picture outside of your little microcosm that you've created for yourself and your own life.

So I think it's really rare to be around things like that, Like you can find spaces like that in the mountains, and the redwood forest offers one such kind of refuge where I think you can connect with the larger meaning of life being in that in that place.

Yeah, I mean it is, It's unique, at least in my experience.

So let's see, do the old growth redwoods?

Is there really a threat to them?

Now?

Are they pretty pretty well, you know, tied up in public lands that aren't going to be aren't going to be sought up at least in the near future.

Yeah, like most old growth redwoods at this point are protected.

Okay, yeah, say the Red Words League is done.

I think an amazing job at doing that.

Like there as an organization, I know, you know, they're not perfect at all, but they spent the first century sort of buying up old growth redwood forests.

They've been around.

In twenty eighteen they celebrated their centennial anniversary.

So from nineteen eighteen to twenty eighteen, their focus was really purchasing and then donating to the state.

So most of our redwood state parks were from Save the Redwoods League, Like the red old growth redwoods that we have today were largely because of Save the Redwood League.

And again they have a sorted past, and there's different ways that you can look at their history.

But I mean net net, like, you know, they did conserve a lot of the old growth for us, and those are the parks that we have today.

And so I think like because of that, yeah, most of the old growth redwood that is persistent on a landscape that wasn't logged back in the day is protected.

And that's why in the second century of Save the Redwood League, with their centennial vision, they kind of decided to shift their focus to have into like restoring the young redwood forests, which make up ninety five percent of the species range, just because it's like, well, we've pretty much like conserved most of the old growth redwood, So let's shift focus a little bit and work on trying to fast track some of the rest of the species range towards those more mature conditions.

I mean, I think there are threats to it still, you know, just with climate change and fire suppression.

So we saw with Santa Cruz because you think, oh, the redwood forest, it's a temperate rainforest.

It's very wet and moist and foggy, and they get tens of rain and it really wouldn't burn that hot probably, but we saw with those Santa Cruz fires.

I think it was the Czu fires that actually know, like old growth readwood forests can burn it high severity and it can be really catastrophic the aftermath of that.

So I think things like that, the fire situation with there being a lot of fuel on the landscape and then things being hotter and drier and crispier, you know, is.

A threat for redwood.

And then also they're finding like you kind of like take it for granted that oh, redwood is super resistant.

It's really anti fungal.

Redwood is you know, the bomb like, it's got no natural enemies.

There's no pester pathogens that really mess with it because it's so you know, it has all these secondary compounds and tannins and chemicals in it that make it very anti fungal and resistant.

But even that, we're starting to see if you study kind of forest health, there's more pathogens that folks are noticing on the redwoods.

And again that's getting out.

Of my wheelhouse, like I'm not I'm not a forest health expert, but talking with people who are, they're like, no, there's like these weird things now we're starting to see in the coast redwood and then also the giant Sequoia, which we thought was totally resistant to bark beetles.

They've been finding that in this climate change, when it's persistently kind of chronically water stressed and you're getting lower snowpack in the sierras, that there's more beetles attacking the giant sequias, which we thought couldn't really happen.

So I think there are definitely still threats, even if it's not clear cut logging.

There's still threats to these species, and given how limited their ranges are, it makes it of like paramount importance to try to do everything we can to protect them from these threats.

Yeah, what haven't I asked you that you think is important for people to know about redwoods?

I think I study tree physiology, so I think redwoods are super cool, Like they're just kind of a wow factor of a species, just something to be like, you know, knock your socks off kind of thing, like as far as plants on our planet and kind of plant intelligence and.

How neat they are.

So there's just some kind of cool stuff about redwoods that maybe we haven't talked about But I'm not sure if that's like really the direction of the podcast.

Maybe you could just like when you say plan intelligence, like what does that?

What does that mean?

And how does that sort of manifest itself.

Yeah, And I'm not like touchy feely, like I'm not like, you know, thinking that like the Redwood is a person or something like that, But just they seem to live that long and be that stoic and be in one place where you can't like it's hot, it's dry, like I can't get up and move, I'm anchored.

Here, you know kind of thing.

There's just a lot that Redwood seem to have kind of cleverly adapted to to be able to be a champ for this long, so they can absorb fog water.

Through their leaves.

It's physiologically really complicated to be that tall.

Just like I'll spay all the details, but it's complicated, and so a lot of the tall conifers like Redwood have kind of developed these crafty ways of you know, taking water from the clouds that are enveloping all the leaves and kind of using the water more locally up there.

They've also like in Redwood, one of my colleagues.

Alana Chin kind of did this cool study that was a part of two.

But they have this sort of division of labor with their leaf types in redwood, and they can shift kind of where these different leaf types are within the crown and even latitudinally, say from like Oregon to Big sur like from the north to the south portion of the range, the ratios of these different leaf types can change.

So there's leaves that are really good at uptaking fog water but not that great at doing photosynthesis, and then there's leaves that are really good at photosynthesis but not that great at uptaking water.

And so this kind of like specialization or division of labor among their leaves kind of speaks to a long evolutionary history for this species of living in a foggy climate where it can kind of tap into those types of resources.

So I think that's something that's unique about redwood and pretty cool.

Another kind of cool wow factor that I thought was just really neat was in that Santa Cruz fire when all of the redwoods burned to it crisp, and then you know, next spring they all leafed out and they looked like these little chia pets, like all covered in green fuzz.

Some folks did a neat study where they because it kind of begs the question, well where did that carbon come from?

Like how did they leaf out?

How did they afford that?

Like how did they have sugars around and stuff to make that happen?

Because they looked like, for all intents and purposes, just these charred stems.

And some folks led by Drew Peltier and some folks at Northern Arizona University, they did this cool study where they looked at the C fourteen, the radioactive carbon in the tissues that were produced, and they found that the carbon that the redwoods used to produce that new flesh of leaves, a lot of it had been captured via photosynthesis like fifty plus years ago.

So just kind of showing how the redwoods can store carbon for a really long time and still have it be mobile and usable and can be used to so, you know, from the ashes kind of rise again.

So again kind of circling back to the species name, so Quia sempervirons lives forever, that it's this really resilient species.

And I think in this era where people maybe are feeling kind of bummed out about you know, the political state of things or whatever, climate change, all that kind of stuff.

It's sort of neat to see this tree species that is kind of like the honey badger, Like it just kind of rocks on and keeps coming even though, if you know, despite what punches might be thrown its way.

Oh, that's a great place to end.

Thank you to Lucy Carhulas for talking with me.

I'm to we ball.

This has been a bonus episode for the second season of Rip Current