(gentle music) - [David] Most of the Southwest is desert but a group of mountain ranges in Arizona and New Mexico jut out from the desert and as we ascend these island ranges we pass throughout what biologists call life zones.

They end in a thick forests at the highest elevation which is why they're called sky islands.

There are more than 20 and each has its own personality.

(bright upbeat music) - [Narrator] Funding for "In the Americas with David Yetman" was provided by Agnese Haury.

"Funding for In the Americas with David Yetman" was also provided by the Guilford Fund.

(gentle music) (people chattering) - This is better than gold.

(gentle music) Sky islands are tall mountain ranges that jut out of the desert.

They're surrounded by desert and at the top they have different vegetation, generally forests.

They are 21 of them in southeastern Arizona and southwestern New Mexico.

They are found only in our part of the country.

Because you can start out where it's dry and wind up where it's much more moist.

From here you can look south and see sky island ranges in New Mexico.

You can also see basin and range.

Basin, range.

Basin, range.

On and on and on.

That's the sky islands.

These are the Pinaleno Mountains, the Piny Mountains.

It's the tallest range of all the sky islands, the tallest in southern Arizona and Mount Graham, the high point, is the highest point above a base of any mountain range in the southwest.

It's the epitome of the sky island.

It has thick, dense, coniferous forests at the top, deserts at the bottom.

And the advantage of the highway that has been built there, the Swift Trail, is that it takes us through all of those different life zones as we move from the desert up into the thick forest.

(bright music) We're only about 1,500 feet up from the base of the mountain and we're looking out at the town of Safford, Arizona, and part of the Gila River.

The Gila originates about 100 miles east of here but already at this little bit of elevation gain we see the difference.

We're in a different kind of desert.

We see the ocotillo with its green leaves come out.

We see different kinds of prickly pear cactus, and we see different kinds of grasses here.

This is a richer habitat because it gets a little more rain.

12 to 15 inches here as opposed to eight to 10 down on the bottom.

(gentle music) Another thousand feet up the mountain, about 5,000 feet, things change again.

We see the first of our oaks, the red barked manzanita, and everywhere we see junipers.

We also see an area that was burned, part of 30,000 acres that burned in a fire in 2004.

Down below there was really not enough dead matter or even living matter for the fire to catch but here with the oaks, the junipers, the manzanita, and all the grasses it was primed for burning and burn it did.

(birds chirping) (gentle music) One of the stalwarts of the oak woodland, a little above 5,000 feet, is the alligator juniper.

It's a stout, strong tree.

Fire resistant and these critters live very, very long.

One virtue that they have is that their wood is not very good for lumber so nobody was ever tempted to cut this down.

It will be here for another few hundred years.

The Pinalenos with Mount Graham are one of 21 different mountain ranges that are classified as Madrean Sky Islands.

Madrean refers to the Sierra Madre in Mexico which has pretty much a tropical plus a northern vegetation.

It's highly unusual.

But the oak woodland is one of the richest and most diverse areas in all of the sky islands.

As a matter of fact, in all of the United States.

One of the most important of the oak trees is the Emory oak.

They usually produce an abundance of edible acorns and those acorns were a staple in the diet of native peoples here in the Southwest for hundreds, probably thousands of years before the advent of Europeans.

The great shade is wonderful.

The acorns are wonderful, but unfortunately for the bellota or the Emory Oak, it's great firewood and the chainsaw will take it down all too quickly.

The Yucca, this particular soaked tree, yucca, was also a very, very important plant.

It is right at its upper limit elevation lies here, and as you can see these are very potentially lethal foreign spines they have on the end of these needles.

But the yucca, if you dig up its roots, you can make soap out of it.

But on the other hand you can also peel off these little branches and make it into a fiber that can be woven into baskets.

This was an extremely important part of native people's habitat right here in the oak woodland.

(gentle music) Once you get over about 6,000 feet and you're on the more or less northern side you get into pine forests.

This is mostly Ponderosa pine.

There are a few others.

But this is the cool place.

This is where people come when they want to get out of the heat of the desert.

It's not just pines, there are a number of oaks and there's even some Douglas firs.

Oddly enough, the pine forest is not as rich in resources, food resources, as the oak forest below.

So while this is beautiful if you want to try to survive you want to spend more time in the oak woodland than in the pine forest.

(birds chirping) (gentle music) At about 9,000 feet you can look south and see mountains in Mexico.

You can also see why these are called sky islands.

These ranges that jut out of the desert.

They come up, they have a different kind of vegetation at top, and they go down the other side back to the desert.

In the mixed conifer forest, which is usually found only over about 8,000 feet in the sky islands, you have firs and spruces.

The difference between the two is easiest to tell by the needles.

A simple saying helps you remember and that is fir, flat, spruce, square.

And that's the needles and if you look very carefully you'll find this bluish thing which is a blue spruce.

The needles are square-ish.

For flat, spruce, square, and that's what you find in mixed conifer forests.

The mixed conifer forest is the wettest part of all the sky islands and it resembles forests way to the northwest in the United States and Canada.

Some of the same species.

The snow pack here is critical for the watershed in this area.

Without the snow the trees will dry out and in recent years they have been infested with various diseases caused by prolonged drought and a forest fire that took out nearly half of the highest spruce fir in the Southwest right here in the Graham Mountains.

(gentle music) If we were to excavate away the hundred feet or so of soil beneath us here in this meadow we would find rock that is 1.7 billion years old.

Some of the oldest rock in Arizona.

It's up here because it was tilted from about six or seven miles below the ground's surface and rotated Mount Graham up about 90 degrees.

So what was ancient rock buried beneath thousands and thousands and thousands of meters of sediment now sticks way up in the sky and it makes this particular sky island different from any of the others.

(gentle music) Less than 100 miles to the southeast is another sky island, quite different from the Pinalenos, the Dragoons.

It's not terribly high, just a little over 7,500 feet.

It's not terribly long.

It's only about 25 miles long, but in terms of its geology, its culture, and its human history there is no other range like it.

- This mountain range here, more commonly known as Cochise Stronghold, was a favorite area for the Chiricahua Apaches and the Chief Cochise spent most of his time living in these mountains right here.

- [David] The Apaches had had agreements with the U.S. Government repeatedly broken.

They were massacred in some cases and they did not trust the U.S. Government and they had very good reason for that.

The fact that Cochise finally agreed to make peace was a great accomplishment.

- [Derek] This was a spot between Bowie, Fort Bowie, and Tucson, that often travelers had issues passing by and so General Howard and a group of four other men came here to meet with Cochise and broker a peace which would then create the Chiricahua Apache reservation.

- This is Mucilla de Dragoon and she is a Spanish Barb.

The Spanish Barbs, those are the horses that Father Kino was breeding.

Well, she's my girl.

I've had her since she was two, although she was born right over there at the foot of the Dragoon Mountains.

She was born and I was the first one that saw her so I got to name her.

My husband and I just fell in love with this space here.

We have 80 acres of land and very few neighbors and we can just saddle up the horses and off we go.

- [David] And there are the Dragoons in the background.

- [Deni] I think they hold a lot of secrets.

- They do.

Some day we may find out where Cochise is buried but maybe not.

- [Deni] Supposedly somebody knows but are they telling?

- Yeah.

(both laughing) The Apaches were expert horsemen but out here horses are fine but when you get in the Dragoons they're not much use because it is so rocky.

So they had the best of both worlds.

- [Deni] We just knew it was the right place for us to be.

The history that's here, just the wide-open spaces.

And if you talk to real locals that have grown up here they talk about when they used to come back and camp here and it was a horse ranch at one time and I think it's been a lot of different things.

(dogs barking) - [David] It's kind of nice to have the Dragoons behind you and the Whetstones across from you.

- [Deni] So the Whetstones are over there and the sun sets that way and then those are the Huachucas and then of course the sun and the moonrise come up over the Dragoons.

We are surrounded, too, by state land, and then it backs up.

That's the National Forest.

- [David] I love the notch in there.

Can always use that as a locator.

It's pretty evident to me that Morongo people or whoever were here chose a good place.

- [Derek] Absolutely, you have a 360 degree view of the valley below, good shade cover, a creek nearby.

- [David] And rock art.

Faded but it's definitely there.

If you like rock this is a place to be.

- Sure is.

- If you like granite it's even better.

Here we got mortars.

And what do you suppose?

Acorns and mesquite pods?

- [Derek] Perhaps, they could have been using it to create paint, some sort of mash to eat as well.

- [David] That's a good point.

Yeah, you look at the range from a distance and you see this steep, cracked granite.

How could anybody live in there?

But when you come in here it's a place where you would spend a lot of time, particularly in the summertime when it's beastly hot down in the valley.

If you're tall it could be disadvantaged and I think Cochise was tall.

- He was about six foot two.

- Yeah.

- [Derek] According to Captain Sladen's journal.

- The way that granite weathers always seems to produce relatively smooth surfaces, rounded, edges, and where the joints occur they're never really sharp.

So flat pieces will break off rounding pieces so you have this very friendly rock.

And thanks to this dead mesquite, oak, whatever it is, oh, my.

- [Derek] Well, this really symmetrical hill over here is called Naiche Knob and that is where Cochise sent his son Naiche with a white flag during the negotiations with General Howard in 1872.

- The Dragoon Mountains are a hodgepodge geologically and they're pretty tough to understand.

There's the granite we're standing on.

They call it, believe it or not, stronghold granite and it's 20 to 25 million years old.

But there are parts them, range, that are over one billion years old.

And because of the various tilting and thrusting and faults they're all mixed up but somewhere around 25 million years ago this granite, which was in the form of magma, pushed its way through all that other rock.

The top layer has been eroded away and we see the granite and nowhere in the world can you see it as well exposed as in the Dragoon Mountains.

(gentle music) Texas Canyon is the highest point on Interstate 10.

It's not in Texas, it's in Arizona, and it's part of the Little Dragoon Mountains which are a northern extension of the Dragoon Mountains.

The granites here, which people love to climb, are 50 to 55 million years old.

Much older than the granites of the Dragoon Mountains, which are only 20 to 25 million years old.

Those 30 million extra years of weathering make these easier to climb on but it's also part of a completely different geological setting.

Interstate 10 runs right through it and millions of people each year have a chance to see what this famous granite looks like and, many of them, to climb the rocks.

(upbeat music) 50 miles to the east of the Dragoons sits my favorite sky island, the Chiricahua Mountains.

I lived in the range for four years and it is close to my heart.

This is Portal Peak on the east side of the Chiricahua Mountains.

It's about 8,500 feet high and I'm standing at about 4,500 feet in very dry, tough, hardscrabble desert.

And the Chiricahuas, because of their peculiar geological and natural history, are the best place to come to study sky islands.

- If your business is trying to understand the planet we live on then you need to go to the places that are the most rich, complex, and diverse.

I could make a compelling argument that this is the most biologically diverse place in the United States.

It can be viewed as a stepping stone from, for some migratory species, from the Sierra Madres through the Rocky Mountains.

So these act as little stepping stones.

For other species it's a terminus, particularly subtropical species.

It's their northern terminus.

So if you want to see an elegant trogon or a jaguar in the United States, the only place you'll find it is in the sky islands.

We also have, in the seas surrounding the islands, we have the convergence of the Sonoran Desert and the Chihuahua Desert.

So a lot of species mix here.

You also have the drastic elevational gradient.

So you could be in Rodeo, New Mexico where there's creosote and prickly pear and roadrunners and Kangaroo rats and Mojave rattlesnakes, take a 19 miles drive to the top of the mountain and you're in aspen and lupine, black bears, twin-spot rattlesnakes, and stellar jays.

And in that 19-mile drive you pass through five life zones.

And one of those life zones is the Madrean Pine Oak Forest which is considered a biodiversity hotspot.

The byproduct of working with Chiricahuan Leopard Frogs is you're also protecting water.

Water is the most important thing in the desert, Southwest.

If frogs are doing well then you've got a rich, aquatic habitat.

- [David] Well they say that a healthy jaguar is a sign of a healthy ecosystem.

Here we're saying that a healthy leopard frog is a sign of a healthy ecosystem.

That's nice.

- Absolutely, but we'll take jaguars, too.

- Yeah.

(bright music) One aspect of the biodiversity of sky islands is the proliferation of ants, ant species, ants of every kind, and how they relate to everything else.

- In the Chiricahuas, I could probably find 150 species or more.

In Arizona, if we expand the deserts, there are at least 360 ant species which is an abundance similar to abundance in tropical regions of the world.

Ants fill all kinds of ecological roles.

They can be herbivores.

They can be predators.

They can be detritivores.

They farm fungus.

They farm aphids.

They predate on each other.

They raid each other.

We have ants that actually are called slave-making ants that go and steal young ants from other colonies and raise them up to do the work.

We have honeypot ants that are actually capable of storing large amounts of sugary liquids in their body for a long time underground and they swell up like little grapes.

So the diversity of interactions around here is just astounding and they're kind of a microcosm of the diversity at large.

(gentle music) (birds chirping) - The hummingbirds at the Southwestern Research Station in the Portal area in general are internationally famous for their number and their variety.

And the feeders are set out.

The feeders are filled with sugar water.

They take great advantage and this becomes hummingbird central for a lot of the year.

Why thank you.

- They're gorgeous so (chattering faintly).

A lot of my research involves looking at very small things and so I have the equipment to take pictures that are basically microscopic of my ants and other things.

So when I started helping with the hummingbird monitoring here and we had hummingbirds in our hand.

- [David] One of those tiny feathers is a foot long.

Look at the color.

- [Michele] There are no pigments in these feathers.

These feathers are brown and black and what's making the color are very fine layers in the keratin and those layers, the distance between them, is the distance in nanometers of the color of light that they're going to refract.

So it's like if you had a CD and you turned it and you saw those rainbow colors, that's the distance in nanometers between the grooves on the CD.

- [David] I see.

- [Michele] And those layers are held apart by fine layers of oil on these birds.

That's how they keep that separation.

This is a blue-throat.

- So it swerves a little bit.

- Oh wow.

- They're unbelievable birds.

- I don't know how.

(gentle music) The story of the Chiricahua Mountains as we see them is a story of explosive volcanoes, violently explosive volcanoes.

As I look down into Cave Creek Canyon, up at Portal Peak and see Silver Peak behind me, those are the edges of a massive caldera called the Portal Caldera, that exploded here about 27 million years ago.

It would have had enough force to change earth's climate for probably several thousand years.

Volcanoes made the Chiricahuas and made for this wildly diverse area.

The Chiricahuas are surrounded by desert on the east, very dry Chihuahuan desert.

And on the west you face grasslands seemingly unending.

Out of that semi-plain the range juts up high enough to capture moisture.

That additional moisture means you get more vegetation, more trees, and here we see oaks and pinyon pines.

Higher up we see pines and firs and spruce.

That difference means that there's a greater possibility of forest fires and all of the sky islands in the last 30 years have been burned, charred, by massive forest fires.

(gentle music) This place is known as Rustler Park.

It was long-known as one of the fairest and most sought-after campgrounds in all of the Southwest.

The 2011 fire changed all that.

Some fires are good.

They clean out excess fuel, open up the landscape, and make for better wildlife and plant habitat.

This was an extremely hot fire, the result of climate change, drying out, high temperatures, a 20-year drought, and ultimately destroyed what was once a fair forest.

It may come back someday but it will be very different.

This pine is about probably two to 300 years old and managed to escape the fire.

It's a healthy tree and it also escaped the woodcutter's chainsaw.

It will not survive many more fires but fortunately it remains as a source of seed to plant any areas that have been burned.

(gentle music) Each of the 21 Madrean Sky Islands is different.

Almost all of them have experienced forest fires in the last couple of decades.

In spite of that, some of them recover.

Most of them recover in some way but some of them will recover almost completely and they will remain as long as we are around as islands.

Islands of different vegetation, different animals, different plants, rising above the desert.

Join us next time "In The Americas" with me, David Yetman.

- [Woman] Gracias.

(upbeat music) - [David] Day of the Dead is observed throughout Middle America and each region celebrates in its own fashion.

One town in Guatemala has decidedly different take.

(man speaking in foreign language) A festival of kites.

If you're a squirrel living up here, it will do rather well because the squirrels can harvest the nuts, the seeds, of these cones, and they can see what they do.

And they just peel off these individual parts of the cone and get at the seed and, when they're done, discard it.

They are putting away a lot of seeds and fat for the cold months coming ahead when temperatures up here will get close to zero.

(bright music) (upbeat music) - [Narrator] Funding for "In the Americas with David Yetman" was provided by Agnese Haury.

Funding for "In the Americas with David Yetman" was also provided by the Guilford Fund.

Copies of this and other episodes of "In the Americas with David Yetman" are available from the Southwest Center.

To order call 1-800-937-8632.

Please mention the episode number and program title.

Please be sure to visit us at intheamericas.com or intheamericas.org.

(bright music)