(crane humming and clattering) - It's a little jumpy.

- Yeah.

- [Narrator] The Wind River Research Crane, run by the University of Washington, rises through the canopy of an ancient forest.

It's an uncommon experience for Sarah Jovan, and Linda Geiser to dangle 200 feet above the Gifford Pinchot National Forest, but it gives them a great perch from which to study, of all things, lichens.

- [Linda] This is really nice (laughing).

- [Sarah] Oh, look at this one!

Look at that!

Platismacia glouca.

Where's Sphaerophorous?

- That might even be ochralechia oregana.

Look at that; there's cledonia.

- [Sarah] Ragbag lichen.

- [Linda] Tube lichen.

- [Sarah] Bone lichen.

Wow!

- [Guide] You're holding this in your hand and you're saying, "This is so beautiful."

- [Sarah] It is; look at it.

- [Guide] You don't find that funny.

- [Sarah] Not at all!

(Linda laughing) It's gorgeous.

It's just gorgeous.

- [Narrator] Linda and Sarah are used to getting skeptical looks when they rave about lichens.

Lichens are usually considered so common, so uninteresting.

- Even Linnaeus, the famous Swedish botanist who tried to name every organism in the world, called lichens the scum of the earth.

So if even Linnaeus thought that...(laughing) - You see it on a tree, and you might just see, you know, a little yellow crustiness.

And if you actually had a microscope, or a lens, and you zoomed in on it, you would see reproductive structures that sometimes look like olives, or little cups, or little discs.

There's actually a lot of different kinds of lobes and branching patterns that are very beautiful.

And you know what?

Once people take the time to look at them a little more closely, they usually tend to agree.

- [Narrator] In old growth like this, lichens drip off the limbs, some cling to the bark, others wrap around branches, and they have a purpose.

They're used by owls and flying squirrels for nests.

Deer and elk eat them.

And people use them to make antiseptics.

In the case of one lichen, even poison.

- That's wolf lichen.

- Apparently the wolf lichen was used in Scandinavia for poisoning wolves, and they'd grind up the lichen and mix it in along with some glass, and then bait the wolf.

- [Linda] Well, that would make it more poisonous.

- [Sarah] I know, right?

(laughing) - [Narrator] This is the world that sucked Linda and Sarah in.

Sarah grew up in Cleveland, Ohio, and when she moved to the Northwest, she took an interest in lichens, partly because she was hard pressed to find anyone here who could tell her much about something that she thought was beautiful.

- When I was a kid, I was a bit of a nature nut and I played outside all the time.

And one of the things that I never had come across when I grew up in Cleveland was lichens.

And then I was in college and I ended up taking a field course in British Columbia.

And so you go out in the woods there and it's dramatic.

The trees are dripping with lichens.

And I remember just being totally overwhelmed by it - [Narrator] A few college degrees later and Sarah was a full-fledged lichen nerd.

- You know you're with a lichen nerd when you're walking down the street and they're staring up in the trees, or they want to stop every five minutes and look at something on a branch.

They often come home, they have little branches and rocks in their pockets that they saved to look at at a later date.

I'd say we both do that all the time, pretty much.

- [Narrator] For those of us who aren't lichen nerds, here's a little lichen 101: for starters, lichen don't hurt the trees; they're not parasitic.

And as Sarah was quick to correct, they are not the same as moss.

- I wish we had a moss here for comparison.

A moss looks totally different, I'm telling you.

- [Narrator] Unlike moss, lichens aren't even plants.

They're actually a fungus and an algae that come together, has 17,000 distinct species.

- [Sarah] But here's a bone lichen.

It's interesting, these lichens, I mean this fungus-algae association, they can look wildly different.

- [Narrator] Lichens are also common, growing everywhere from the forest to the desert, all over the country.

All they need to survive are air, water, and something to grow on.

But because they get everything they need from the air and the rain rather than the soil, they're extremely sensitive to pollution.

Here in the old growth, they're doing great.

It's a different story, though, in Portland.

- This is a good example of what you see in a lichen community that's highly impacted by nitrogen - [Narrator] To Sarah, these sour yellow patches on the trees in Waterfront Park are a billboard that says "Our air quality stinks."

- These lichens are a really obvious sign of nitrogen pollution.

These are the orange wall lichens.

Grows in some of the most polluted habitats in the world.

- [Narrator] That's what a little lichen education will get you.

Sarah can no longer take a stroll and just see a bunch of pretty street trees.

- Whenever I'm walking around in a forest or a city, I'm always looking at what lichens are growing there just because they are so indicative of what the air quality is like.

- [Narrator] Now, as you might have guessed, reading lichens isn't just Sarah and Linda's hobby.

Sarah is an analyst and Linda is an ecologist with the US Forest Service.

They travel around the country and use lichen to measure air quality.

And when you learn to read lichens as Sarah and Linda can, you learn that lichen don't lie.

Here in the gorge we expected to find more great examples of lichens thriving in what looks like a fairly pristine environment.

Instead, Sarah and Linda walk right up to a tree full of pollution-loving candelaria lichens.

- [Linda] Now this is not right.

- [Sarah] No, not on a conifer.

- This lichen should not be growing on conifers.

The only way it would grow on conifers is if there was a lot more nitrogen than is normal.

- [Sarah] Yeah.

- You know, the interesting thing is, if you look at emissions in Oregon and Washington, the gorge really is not a big polluter.

But the main sources are Portland to the west, and the Columbia Basin and Boardman to the east.

And so sometimes we talk about the gorge being the exhaust pipe of Portland.

Things get pulled through, and in the wintertime there are a lot of inversions in the Columbia Basin, and the gorge becomes the drain pipe.

- [Narrator] The result is a lot of distorted and discolored lichens.

- Very, very sick lichen.

Yeah, it's brittle and it's brown, and... - [Narrator] Sarah brought one sample back from the Wind River Research Area to show the difference a little pollution can make.

On the left is Ragbag lichen from Wind River, which has exceptional air quality.

On the right is the same lichen collected here in the gorge.

- And here this one is very compact.

It's trying to decrease its surface area to avoid the the pollution.

We've been to both the canopy crane and to Memaloose Park here with instrumented monitors.

And we know that the pollution here is 10 times greater than at the canopy crane.

- [Narrator] The Forest Service has analyzed lichens to study air quality in the gorge for almost 20 years now.

And the news isn't all bad.

Remember leaded gas?

In the 1970s, lead, which can cause brain damage, was taken out of gasoline.

Within a few years, lichen samples recorded a corresponding drop in lead in our atmosphere.

- [Linda] This is very good 'cause lead is quite toxic.

- [Narrator] To Linda and Sarah, lichens are like books that few people read.

Books that nonetheless tell us a great deal about where we live.

Reading lichens is a skill and a science, but for these two it's also a passion, and they happen to be in the right place for it.

- I think the Northwest is a lichen wonderland.

The lichen that actually stole my heart of all lichens is this one because, well, it's adorable, right?

It's called Cledonia, and its common name is Pixie Cup.

They look kind of Dr. Seuss-like.

(birds singing)