What do you call it when a population of podcasts mysteriously drop episodes on the same topic at the same time? It's Critical Mast!

We're so proud to present this nutty experiment in community podcasting, with its roots going back to the very beginning of our show (and the beginning of our dedication to silly puns).

Thanks to help from our pals at Jumpstart Nature, Golden State Naturalist, Learning from Nature: The Biomimicry Podcast, Nature’s Archive, and Outside/In, it's time for a bumper crop of podcasts about (or inspired by) the perplexing phenomenon known as masting: where plants somehow synchronize their seed production across staggering distances.

Give all these pods all a follow, & check out this Spotify playlist (to which episodes will be added as they drop).

— — —

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You are listening to Season Six of

Future Ecologies.

So as traditional with Critical Mass,

we usually have some brief announcements before we start.

So if anyone has any brief announcements, come up to the

microphone, then we'll do a safety talk, and then we'll

ride!

[Cheering, honking]

I don't see anybody clamoring for the

microphone-

Testing, testing. I'm Mendel

and I'm Adam!

and this is the sound of Critical Mass here in

Vancouver. This tape is from 2009 but it's a tradition that

carries on somewhat regularly to this day, here and in cities all

over the world.

For the uninitiated, Critical Mass is a

periodic occurrence where hundreds or even 1000s of

cyclists gather to overwhelm city streets with their

presence, all in a joyous protest for safer bicycle

infrastructure.

This flash mob springs up, seemingly out of

nowhere

Coming out of the woodwork, as it were

and just as quickly, ebbs away, vanishing

until the next. So that's Critical Mass, but this is

Critical Mast... with a T, as in masting. And what is masting? I

hear you ask.

Andrew Hacket Pain: So this is actually quite a difficult

question to answer. Masting is quite a tricky topic to define.

So I think a relaxed definition of masting is useful, and it

helps us to incorporate the real diversity of characteristics or

variation that come under this term. So masting kind of boils

down to highly variable and synchronized seed production in

perennial plants

This is Andrew Hacket Pain.

Andrew Hacket Pain: I'm a senior lecturer at the University of

Liverpool in the United Kingdom. I work on forests generally, but

in particular, I work on forest reproduction and on this strange

phenomenon that we know as masting.

In the simplest terms, masting is when a

population of plants — typically, but not always, trees

— all produce a huge crop of seeds at the same time.

In statistics, I think they call it a crap ton.

Yeah, a crop ton.

Yeah, in a mast year we've got trees or other

plants dropping way more seeds than you would see on average.

Andrew Hacket Pain: So these are long lived plants, and they're

plants that, rather than reproducing regularly each year,

so producing an approximately constant seed crop each year,

instead, they strongly vary their allocation to

reproduction. In a very typical European masting species like

Fagus sylvatica, European beech, one of the most common broadleaf

species in Europe, or actually, the numbers are very similar for

Picea glauca, for white spruce in North America, a big tree in

a very good year might produce half a million seeds. And that's

not just individual trees deciding that this is the year

to go big, but they do that in a synchronized way.

This isn't just one tree here and one tree

there. It's all the trees of a given species in a given area,

all masting at once.

How big of an area, how many trees? Why? How

We're going to get into it. But first, I think

we should say a little bit about how this episode came to be. How

do you recall the germ of this story, Adam?

Yeah. Critical Mast! This one... this one is a

little bit of a blast from the past.

It was a long time ago!

We were on a road trip together recording sounds

for our first season, and we were just spitballing puns on

ecology, I think, right,

yeah, I think this is literally the first time

we started from the title of an episode before we had anything

else.

Yeah, the title came first before the story. But do you

remember any of the other ones?

The only one that I can honestly remember is Galls to the Wall,

which I think we should still do.

Yeah, the ones that stick are the ones that we

should still do. So Critical Mast stuck.

And then, you know, some years go by and we

have another idea. Some might say... it's nuts.

It's nuts!

Basically, we thought to ourselves, wouldn't

it be funny if a whole population of nature podcasts

produced their own stories about masting, or inspired by masting,

and then dropped them all at the same time!

So from Future Ecologies...

and with supporting episodes from our

friends at Outside/In, Nature's Archive, Golden State

Naturalist, Jumpstart Nature, and Learning from Nature (the

biomimicry podcast)...

this is Critical Mast

Broadcasting from the unceded, shared and

asserted territories of the Musqueam, Squamish, and

Tsleil-Waututh, this is Future Ecologies – exploring the shape

of our world through ecology, design, and sound.

Okay, just to drive it home, what is masting?

So masting, as you probably already know at this

point, is a population level phenomenon. An individual tree

does not mast, a population of trees masts. So the problem when

I started, and this was back about 40 years ago now, was that

nobody had really seemed to pay much attention to defining or

figuring out what a population was.

This is Walt Koenig, research zoologist

emeritus at the University of California, Berkeley. And

despite being one of the leading researchers into the mystery of

masting, Walt is, by his own description, more of a bird

person.

What can I say? Masting was just kind of a side

thing. I spent most of my career studying acorn woodpeckers.

Acorn woodpeckers, surprisingly enough, are highly dependent on

acorns. They're famous for storing acorns in what we call

granaries. They use trees, they drill hundreds to 1000s of

little holes in them and stick acorns in them individually. And

so it was clear early on that the birds were highly dependent

on the acorn crop. And so we slowly got interested in trying

to learn something about that. And now that I'm retired, it's

kind of the better project, because I don't have to climb up

to nests, and my wife doesn't want me falling out of a tree.

So now, starting in another couple of days, I go around

every year and count acorns around the state, which can be

done on the ground.

And one of the main questions that cropped up early on was how

spatially synchronous the acorn crop is. So when it's a good

crop here in Upper Carmel Valley, where I live now and

where I did most of my research, does that mean it's a good crop

up in the Bay Area? Does it mean it's a good crop up in the

foothills of the Sierras? Nobody seemed to know the answer.

Andrew Hacket Pain: So this scale of synchrony is really one

of the most remarkable characteristics of masting, I

think.

I just want to underline here that this masting

behavior shows up in all sorts of different plants and in a

diversity of trees, Andrew's research tends to focus on

European beech, while Walt is primarily interested in oaks and

acorns, and there are a lot of different oaks in California.

One of my favorite things about the place

You've got Oregon oak, White oak, Blue oak, Coast

live oak, Interior live oak, Black oak. What's that one in

Southern California? Yeah, it's a Mexican species. It just makes

it up, and we do the Santa Rosa plateau, which has them. And

I'll think of it in, as I like to say, in between five minutes

and 24 hours.

That one is the Engelman oak, or Pasadena oak,

with one of the smallest ranges of any species of oak in

California,

and each species has a different pattern.

Meaning, even just between these different

species of oaks, a given year could be a mast year for some,

but not for others. And the problem of this spatial

synchrony remained central to the mystery.

We spent several years trying to figure out what

scale was appropriate. Started out, for example, by starting at

the coast and counting acorns every 10 kilometers till we got

inland. A ways, we did that for a few years, until it turned out

that it was clear that that was too small a scale. And somewhere

along the line, in the 1990s I had a postdoc who said we really

needed to do this right, and doing it right basically meant

spending a week or so driving around California looking at

marked trees and doing a survey of the acorn crop at different

sites around the state. We go to sites that are over 700

kilometers apart, one end of the Central Valley to the other. And

the question is, do they actually produce acorn

synchronously or not?

... we were kind of hoping you might answer that?

Well, I'm glad you asked. It turns out that, okay,

the way spatial synchrony almost basically always works is that

sites that are closer together are unsurprisingly more

synchronous than sites that are farther apart. And it turns out

they are spatially synchronous over very large distances,

hundreds of kilometers, and we're talking millions, if not

10s or hundreds of millions of trees.

Andrew Hacket Pain: Mast years in Denmark and in Central

Europe, in Sweden, seem to happen generally in the same

years. The pattern is not periodic. It's not strictly

stochastic either. Because while I said there's no periodic

pattern, there is one very important pattern, which is that

we very, very rarely see consecutive years of high seed

production. A year of very high seed production is almost always

followed by a failure year. And it was quite common in the old

literature for masting to be described as some kind of cyclic

pattern. We're still kind of pushing back against this

literature and the way that these ideas have seeded in. Oh,

sorry, that was an accidental pun.

That's okay, and honestly, totally appropriate

for this episode. But myth busted!

Yeah, mast production, as it turns out, is

not like the cycles of cicadas or solar storms. We can't just

count the years between mast years and call that a reliable

pattern. And it's too bad, because we've been trying to

figure out masting for a long, long time. Like Karl Marx wrote

about mast production, didn't he?

[Laughing] Oh my god that's so bad.

Andrew Hacket Pain: Masting has been recognized for a really

long time. Really exceptional years of acorn production,

particularly in Europe, was, I think, noted by the Romans. But

certainly by the medieval period in Europe, there's a lot of

interest in masting in relation to acorns as a food source,

particularly for pigs.

People have been interested in the acorn crop for

many hundreds of years because acorns provided a excellent food

resource, particularly for their hogs. Back in the day, people

spent a lot of time going out there, hitting trees, trying to

knock down the acorns so that they could feed their hogs in

various parts of the world.

Andrew Hacket Pain: That's a process known as pannage. So

when pigs are put into oak woodlands in particular to feed

on the acorns, that was an important right and important

within European legal systems in the medieval period.

And Spain is an interesting case. of course.

In Spain, spacious oak woodlands called dehesas are

iconic for their pasture and their acorn fed Iberian ham,

which is highly prized!

Cue happy pigs in a Dehesa. And dear listener,

just so you know how dedicated we are to getting you audio

straight from the source, I spent a full day pedaling my ass

up into the foothills of Spain outside of Sevilla on a janky

old bike to get this particular soundscape, only to have the

derailleur get sucked into the spokes and break off, leaving me

stranded in the middle of nowhere on a Sunday.

So much for critical mass.

I wish there were like 100 other people biking

with me, because do you know what happens in rural areas in

Spain on a Sunday, Mendel?

...What happens in rural areas in Spain on a

Sunday, Adam?

A whole lot of nothing. We couldn't even

hitchhike out of there. So I recorded this audio while

waiting on the side of the road to be rescued by my own mother,

who was also on vacation. Thanks, mom.

That's lucky.

So you're welcome.

Yeah, whatever the results.

Yeah, I guess it would be better if my sound was

better. I'm sorry I did my best.

It was so high effort, for a very indistinct

recording of some pigs

and that, that that's us in a nutshell, Mendel,

that's us in a nutshell. High effort...

indistinct results! Anyway, back to Walt.

Those Dehesas are well tended, and I can't help

but think that part of the reason that they do so well is

that they've been paying attention to those trees for a

long time and probably choosing trees, selecting trees that

would produce acorns, produce acorns that are edible. I have a

couple of Spanish colleagues who claim that when they get hungry

out there, they can just pick off an acorn from one of those

trees in Spain and eat the thing, which means not that they

don't have tannins, but they do not have the kind of tannins

that the Oaks here in California do.

And according to a chapter that Walt contributed to

an anthology, the oaks of the Spanish Dehesas may have been

selectively cultivated, not only for their palatability, but also

to make them mast less! Regularizing the annual acorn

crop and making it more reliable for the ham economy.

Oh, well, good for me. I made that up, of course,

but my Spanish colleagues did not make me take it out. So I

assume that there's at least some possibility it's true.

In any case, the point stands. People have had

plenty of motivation to notice these irregular bumper crops.

So there are data sets that go way back for some

of these species.

Andrew Hacket Pain: German foresters in particular, were

describing and making observations of masting in the

17th century.

Well, here in California, the famous use of

all those acorns were the Native Americans. There are tribes in

California which have been estimated to get half their

calories from acorns. Now the amount of effort you would have

to go to to collect, protect, and then process enough acorns

to get half your calories, half your food out of those things is

just mind boggling, but it was a critical resource.

Was and is! Acorns continue to be an important

cultural food for the indigenous peoples of California, which we

will come back to in a future episode.

Of course, that's why there are these grinding

rocks everywhere in the foothills of California, because

women spent a vast amount of time hanging out grinding these

acorns up. And then they, of course, had to leach them,

because here in California, they are completely inedible unless

you leach the tannins out of them. But despite that, they've

been an important food resource for humans here for a long time.

Shout out to another wonderful episode from

our friends at Outside/In if you want to know more about how this

traditional food is being revived before we eventually get

to it, cue up The Acorn — an Ohlone Love Story, from 2021

But before you do that, there are more details of

masting to cover. Because it turns out, they've been a hard

nut to crack. It's only in recent decades that we've made

real scientific progress.

You know, like a lot of things that took a while

before they started asking the kinds of evolutionary questions

that we are now focused on.

Andrew Hacket Pain: Yeah, so masting appears across the plant

tree of life. It's very common in conifers. It's very common in

angiosperms. The patterns associated with when masting

appears in the tree of life, and when it doesn't appear in the

Tree of Life, indicate that it's a strategy that has evolved

multiple times over the evolution of plants. So it seems

to be a strategy that that emerges and then perhaps when

it's not beneficial, it disappears again and then can re

emerge.

So masting is a pattern that we see across plant

evolution in different lineages arising independently, which

means it's got to be a decent survival strategy. But remember

that after cashing in all of their energy and resources on a

mast year, plants almost always take the next year off.

Going from tons of seed to... nones of seed.

Andrew Hacket Pain: In a mast year, as much resource might be

allocated to reproduction (so the production of flowers and

the fruits and the seeds) as is allocated to tree growth, as

much as half of all of the resources allocated above ground

might be going into reproduction. And then in a non

mast year, they might produce zero. So it's a phenomenal

switching of resource allocation. These plants

actively miss opportunities for reproduction. So they have a

growing season, they have the opportunity to produce flowers

and fruits in that year, and yet they pass on that opportunity.

Which at first seems a little counterintuitive.

I mean, like after all, reproduction is kind of the name

of the evolutionary game. If masting comes at the cost of

taking a year long break, it's got to be worth it.

But why? Spoiler alert, nobody knows for sure,

but we have a few solid leads, a crop load of seeds, and we're

about to get into the weeds. That's after the break.

Hi! This is Eden. I'm an assistant producer for

Future Ecologies. I think you might be listening to the show

because Future Ecologies combines this love for sound

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Thank you. Let's get back to the show!

And we're back. I'm Mendel,

I'm Adam, and today we are taking our own

silly pun very seriously.

You might call it our masterpiece.

Where we left off, we were just about to get into

why masting, this strange behavior of synchronous seed

superabundance, immediately followed by synchronous seed

scarcity, has evolved time and time again, independently all

across the plant kingdom.

Andrew Hacket Pain: Now there are lots of reasons why masting

might be beneficial to plants and why it might be selected for

but it seems there are two main theories as to why masting is

particularly beneficial under some circumstances.

Once again, we are joined by Andrew Hacket

Pain. And the first rationale for masting is that it makes it

easier for plants to get pollinated. Here's Walt Koenig.

Oaks, for example, most of these masting species

are not self pollinating. They have to be cross pollinated by

other trees. So if you're producing flowers, you're

dependent on pollen from some neighbor or some other tree down

the ways. For true oaks, they're all wind pollinated. There's

lots of pollen out there, but it is just floating around in the

air in no particular direction, and the odds of any one pollen

grain falling on a flower is probably strikingly low, even by

astronomical standards.

Andrew Hacket Pain: It's quite hard to get external pollen into

your flowers. If you're for example, in the forest, they

could just flower very intensely every year, but that has a

pretty major resource cost and would lead to trade offs with,

for example, growth.

If trees sort of get together and decide, okay,

this is going to be a good year. We're going to produce lots of

flowers, female flowers, we're going to produce lots of

catkins, male flowers, lots of pollen. And that's going to be

much more efficient in terms of pollinating everybody, each

other, including myself, than if we don't sort of do this

synchronously.

Andrew Hacket Pain: Years of very high seed production have

higher pollination efficiency. More of the flowers overall are

pollinated. And that's good from a plant's perspective, because

producing a flower that doesn't result in a fruit is ultimately

a waste of resources.

Another factor here is that once you're a plant

in a masting population, there's a pretty severe penalty to you

if you don't play along.

Yeah, if you're the odd one out wasting lots of

pollen when everyone else is taking a break or failing to

capitalize on the mast hysteria, you're far less likely to pass

on your genes into the next generation.

So masting, if you think about it, is kind of a

snowball of selection pressure, and it just keeps rolling. The

second rationale for masting is called the predator satiation

hypothesis.

Almost everybody agrees that predator satiation

is probably often a major, if not the primary, factor,

evolutionary factor driving masting behavior.

Andrew Hacket Pain: So plant seeds generally are full of

carbon and fats proteins. A side effect of that is that those

same nutrients are usually a good source of food for mammals,

insects and various other organisms which like to eat

seeds.

If trees just produce the same number of

acorns every year, the predator populations would presumably end

up reaching a point where they would eat most of those seeds

every year by varying it a lot, from one year to the next. In a

really bad year, they can cut those populations of predators

down.

Andrew Hacket Pain: And then one year or two years or some years

later, when that predator population has been suppressed

through starvation, the plants go all in. They produce bumper

seed crops. And any of those seed predators that are still

around? Well, they have a great year, but their population is so

small and has been suppressed to be so small by the starvation

year that a larger proportion of the seeds escape predation. And

that can actually be remarkably effective.

Here in California, we have a fairly intact predator

populations. We have lots of band tailed pigeons. We got lots

of acorn woodpeckers. We have lots of mice, we have lots of

deer. We got lots of everything that loves eating acorns. But in

most years, if you go out there, you will not see hardly any

acorns on the ground. And if you do, they're usually going to be

gone the next morning because some deer is going to come along

and scarf it up, whereas in a really good acorn year, every so

often, then you'll find acorns lying around on the ground,

because there's just not enough animals out there to eat them

all as hard as they may try.

Andrew Hacket Pain: In the 1980s when masting patterns in

European beach and UK were really strongly expressed,

around 2% of seeds were lost to a specialist seed predator, a

very boring little moth that lives in the canopy. I've

studied them indirectly for a decade. I've never knowingly

seen one, but their larvae feed on beach seeds. They leave a

very characteristic drill hole in the seeds.

Underestimate this specialist seed predator,

the beech moth, at your own peril. It's known to be a weapon

of mast destruction.

Andrew Hacket Pain: In the 1980s when masting cycles were really

pronounced, overall seed predation losses to this

specialist moth were about 2%. In more recent decades, beech

masting patterns in the UK have changed. Masting has become

quite a lot less pronounced, or remarkably less pronounced. So

we don't have such strong failure years anymore. We kind

of have low ish years rather than zero years, and we don't

have super peak years anymore. We have kind of medium to high

years. The whole variability, year to year variability has

been dampened, and now losses to this seed predator have

exploded. It's more like 40% of seeds, of viable seeds are now

destroyed by the seed predator. So it's been a massive shift,

and it's a really alarming but effective natural experiment to

show just how effective masting can be at suppressing seed

predators.

You might be wondering, given how effective

it is at reducing seed predators, why would this

particular tree, European beech, not be masting like it used to?

Nothing masts like it used to anymore.

[Laughing] oh my god... we'll get back to that a

little later. But first a wrinkle in the predator

satiation theory.

One of the contradictory things about oaks

and acorns is that the oaks are producing acorns. The acorns are

how they reproduce, and they want to have a lot of them out

there. And in order to have a lot of them out there, they have

to evade the predators. And this is countered by the fact that

their main dispersers are also some of those predators. The

obvious examples being the Scrub jays and the Stellar jays out

there, because they're the ones that are picking those acorns

and then sticking them in the ground in various places, moving

them uphill even. There's a famous uphill planters paper

written by Joseph Grinnell back in the day. How do oaks disperse

uphills? Well, you know, you get those acorns picked by a Scrub

jay, and they fly uphill to their territory and stick it in

the ground, and there you go.

So they can't do too good a job at, you know, getting rid of all

those predators. I always think of them as kind of half assed

masters. This gets back to a issue with Acorn woodpeckers, if

you don't mind for a minute, which is that they tend to be

restricted to areas that have at least two species of oaks,

presumably, because when you only have one species, it's

going to fail every couple three, four years and. And the

populations of the birds are going to be in trouble. Whereas

when you have two species, they are not likely to be strongly

correlated with each other, and so the odds of both of them

failing in the same year is going to be reduced

significantly. And the more species you have, the lower the

probability that all of them are going to have a bad year in the

same time.

So now we come to the big question, how do plants

do this? The evolutionary benefits of masting rely on

coordination between individuals. So how do all of

the trees of a particular species across a vast region,

sometimes their entire range, synchronize their seed

production.

Could it be a conspiracy of the fungi?

Relaying the signal from root to root across their mycelial fiber

optics?

Okay, so trees may very well communicate over short

distances. You know, groups of trees that are within the same

little meadow or something may communicate in various ways

through their roots or whatever, but they are not doing this over

distances of 10s or hundreds of kilometers. So that's not likely

to be a factor which is really driving the kind of synchrony

that we see.

Andrew Hacket Pain: I think, a good example of how below ground

communication can't explain the patterns of masting that we see

would be something as simple as to see how strongly masting is

synchronized on either side of the English Channel in Europe.

So if you are in the south of England, your masting patterns

will be almost identical to the populations of beech or oak in

northern France. And I don't think anyone is suggesting that

there are mycorrhizal networks that extend under the English

Channel and connect the United Kingdom with Europe.

I mean, at least not since Brexit. Am I right?

Andrew Hacket Pain: So, sorry to disappoint you.

I guess just because it's not mushrooms

doesn't mean it's not cool.

I'm proud of you for saying so. So what is the

most parsimonious explanation? Drumroll please.

It turns out that if you look at weather, so

rainfall, temperature, which are sort of the two main things that

there are data on, if nothing else, they are also highly

spatially synchronous over distances of hundreds, in some

cases, 1000s or more kilometers, basically everywhere in the

World. So there is no problem having rainfall or temperature

having effects, which is what the trees are all sensitive to,

and that is by far the most likely factor which is going to

be synchronizing these trees.

Andrew Hacket Pain: So what's happening here is that plants

are responding to variations in their environment, and in

relation to masting, there, I think two main sources of of

what we might think of as information that they're

responding to. So one is weather variability, photo period as

well, so day length. That's also something that's important. It

helps them to work out when they should be responding to

temperature. There may also be some influences with radiation

as well.

The second source of information is their own internal plant

reserves and their own internal signaling. They're not going to

invest heavily in seed production when their internal

reserves are depleted, either because they simply don't have

the reserves to fuel a super peak year, or because doing that

might deplete their reserves dangerously and lead to trade

offs, for example, with mortality. And so it may be that

this ecological synchrony in terms of masting, is a kind of

emergent property, something that just happens as a

consequence of processes that are happening at local scales

that are regulated by temperature, and temperature

just happens to be spatially synchronized at scales of up to

hundreds of kilometers. We just don't really know at the moment,

it's one of the open questions as to whether that large scale

spatial synchrony has any kind of adaptive benefit for the

trees, or if it's just a kind of thing that emerges.

So there is still lots of mystery. Each

masting species appears to be listening for a different set of

signals. For some, it's wet, winter weather. For others, it's

dry, and plenty more we just don't know!

For the most part, we really have very little idea

why weather correlates with the acorn crop of any of these

species,

And when your research subject is synonymous

with age itself, the venerable oak or the ancient beech tree,

it becomes increasingly important that your data look

back further than just a single scientific career to tackle that

problem, Andrew and his colleague Davide Ascoli took on

an immense project, called MASTREE

Andrew Hacket Pain: Where we focused on European beech and

Norway spruce. That was kind of our first step into compiling

masting records. We were delving into the literature, contacting

foresters and other forest researchers across Europe,

diving into some pretty old archives right back from the

17th, 18th, 19th century, and pulling out records, harvest

records, seed harvest records, all sorts of observations, and

compiling them into one big database for those two species.

And then few years ago, we got some funding to ambitiously

expand that project into MASTREE+ which, rather than

focusing on two species had the ambitious aim of trying to

compile everything we could anywhere for any perennial plant

species

Enter MASTREE+, an enormous Open Access

database, currently containing over 80,000 geo referenced

observations from 974 species of perennial plants in 66 countries

organized into nearly 6000 time series dating back as far as the

year 1677

Enabling scientists like Andrew and Walt

to turn back time and go beyond the question of the year to year

weather to get at that of the climate.

Andrew Hacket Pain: I think the impact of climate change on

masting has become one of the priority questions in the field.

To see how it's changing over time, you need decades and

decades of data. So in beach, mast years typically follow, in

fact, very strongly, follow years of high temperature, high

summer temperatures. What's happened in the last few

decades, as the climate has warmed very rapidly, is that

these years of high summer temperatures are happening much,

much more regularly. So an imperfect analogy is that the

trigger of the gun is now being pulled so regularly that the gun

hasn't always had time to be reloaded. The queues are

happening so frequently. Sometimes every year, every

couple of years, the beech has not been able to replenish the

resources. Or some individuals have others haven't. Some have

partially. But it seems like some species are more resilient

to climate warming than others. This, again, is something that's

very much at the frontier of what we know, and that's

probably because different species have very slightly

different, or in some cases very different ways of regulating

year to year variability in seed production. And so some species,

like beech might have a particular mechanism which just

happens to be really sensitive to climate change. Other species

might have mechanisms which are not so sensitive.

So of course, climate change is starting to

affect mast seeding, and in the case of European beech, it's a

big problem since its primary seed predator

the voracious beech moth

has gone from stochastic famine to prefix, you

know, three square meals a day and the brood to match.

But as we know, different masting species have

wildly varying trigger signals. So just as with climate change,

you can imagine, every plant and every place will be its own

story.

A story about more than an individual, more

than a population of trees, but of ripples moving outward

through an ecosystem

With all of their downstream effects, big and

small.

Rippling into acorn woodpeckers

and ground nesting birds

Into mice and squirrels.

Deer

and ticks

and Lyme disease.

There are like, whole species of bamboo that

flower all together all over the world and then immediately die,

the ultimate mast.

Yeah, a kind of mast suicide. And then you've

got broods of cicadas that sap trees of their energy

literally

to the point where they might not even have enough

to spare to mast when they otherwise would. Masting has all

of these cascading ecological implications, many of them

unknown or under explored. And so we thought it was appropriate

to drop a whole bunch of examples at once here at the end

of the episode.

Especially because if you're hungry for

even more stories about masting, our friends at all of these

wonderful podcasts have made their own episodes for you to

enjoy. Thanks again to Golden State Naturalist, Jumpstart

Nature, Learning From Nature, Nature's Archive and Outside/In.

Thank you for joining us on this wildly zany

experiment.

We've got links in the show notes.

And to put the cap on this little acorn, I want to

reflect for a moment on where we are right now, not to draw too

direct a line from this biological epiphenomenon to our

sort of muddled human lives. But in my early 20s, I took a

permaculture course delivered by a remarkable woman named

Starhawk, and she had just written a book at that time

called The Earth Path. And in that book, she was exploring

natural patterns, right patterns and processes that we find in

nature to learn what they can offer us for our social

movements, not just teach us about how to engineer widgets

right or how to design our architecture, but about how we

organize ourselves, especially for change. And I've been

thinking about masting in this respect, because I, like a lot

of people right now, am feeling a little depleted.

No kidding!

And I have this feeling that that there really

is a need for, you know, a kind of mast movement, for lack of a

better word. And there's something about these plants,

right, their ability to coordinate action on a massive

continental, intercontinental sometimes, scale, without direct

communication, right, without passing information back and

forth, but just because they are all responding together to

signals that they all recognize. I think there's something to

glean there.

I mean, like, Critical Mass is kind of the

perfect example, right, right, right. Like on our own, we're

just singular grains of pollen with impossible odds of actually

making a change. We're scattered aimlessly on the wind and on any

normal day, bikes don't really stand a chance against the car

hegemony. But then when enough people tuned in to the right

signals, you know, they come together and they're undeniable.

And they can change the whole landscape.

So yeah, I guess, as another author, Robin Wall Kimmerer

reminds us, in the context of masting, all flourishing is

mutual.

Thanks for listening and thanks for letting us be our silly,

nerdy selves. In this episode of Future Ecologies, you heard Walt

Koenig and Andrew Hacket Pain. It was produced by me, Mendel

Skulski and Adam Huggins, with help from Eden Zinchik. Music by

Thumbug and Sunfish Moon Light, cover art by Ale Silva. Once

again, check out all the companion episodes from our

friends. Links are in the show notes.

If you want us to keep making this show, the best way to help

is at patreon.com/futureecologies. You

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