- [Miles Berkey] We have Kindbergia Oregana, Polytrichum moss, Rhytidiadelphus Loreus, Hylocomium Splendens, Amblystegiaceae moss.

I can see at least five or six species of moss just with a very cursory assessment here.

But then, once you get closer and closer to what you're looking at, you'll notice more that'll start to pop out.

When you study moss, you have to slow down your pace, get lower towards the ground.

This brings you into what's called the boundary layer.

This is an area where it's relatively still.

There's this zen quality to really getting in touch with moss, and this is getting in touch with the ecosystem at large.

(gentle music) - [Narrator] Moss was among the first land plants to evolve out of the ocean roughly 450 million years ago.

It grows everywhere, from the world's harshest landscapes to cracks in the sidewalk, which may be why it's so easy to overlook.

But could this ancient organism offer a glimpse into our planet's future?

(gentle music) (lively music) - [Jill Silver] The Hoh Rainforest is on the northwest coast of Washington state.

It is known as a biosphere reserve.

We get between 120 and 280 inches of rain a year, depending on the elevation you're at, and it is one of the five temperate, moist, coniferous or rainforests in the world.

- [Lisa Johnston] There are at least 130 described moss species within the Hoh Rainforest area itself.

- [Miles Berkey] One in particular is this big moss that, kind of, festoons and dangles down off of the branches.

That's called Selaginella Oregana.

This, right here, is Rhytidiadelphus Loreus.

It commonly covers everything from soil to the bases of trees.

This is Conocephalum Conicum.

This is a liverwort.

This one, here, is Plagiomnium Insigne.

Badge moss is its common name.

This is one of the first mosses you learn as a student of bryology in the Pacific Northwest.

This one's Hylocomium Splendens.

You could see that there is maybe one, two, three, four, five years of growth.

(gentle music) - [Miles Berkey] Mosses are among a group of plants called Bryophyta.

A Bryophyte is a plant that does not have the ability to transport water through its tissues.

Therefore, they're small, and they're very old.

- [Jill Silver] They grow on top of other things, on the surface of trees, on the surface of boulders, even on concrete, and they are absorbing all of the water coming in from the ocean, from the sky, and the humidity that's created and kept within the shady environments of these big forests.

- [Lisa Johnston] Some moss can absorb about 20 times its weight in water.

If a wildfire were to sweep through all this, everything is covered with a sponge.

- [Miles Berkey] Bryophytes provide, basically, temperature and moisture, buffering to germinating seedlings of all these plants that we're surrounded by.

So, they protect the soil, in a way.

- [Jill Silver] Some of the mosses sequester carbon along with the soil that they hold up in the canopy.

So, canopy soil under mosses, actually, has more carbon and nitrogen and phosphorus in the canopy than do the below ground storage.

- [Miles Berkey] When there is high enough annual precipitation, you get this growing.

And this is in the family Sphagnaceae, and this is otherwise known as peat moss.

Sphagnum is very, very, very important for climate change.

Northern peatlands hold the equivalent of 40% of the atmospheric nitrogen.

(gentle music) - [Lisa Johnston] Because it has such a direct connection to the environment, it's soaking in water directly from the environment, it's also soaking in pollutants, like heavy metals.

And you can do moss samples in urban areas and, actually, locate hotspots for things like cadmium and lead.

And moss is a great indicator on environmental quality and air pollution.

(gentle music) (lively music) - [Jill Silver] When I walk into the forest and everything is draped in moss, what it tells me is that the forest is functioning, that the forest is old enough and healthy enough to continue.

- [Miles Berkey] These temperate rainforests act as a refugium, in a sense.

They're, basically, havens for species that cannot survive in second growth or third growth forests.

The spatial heterogeneity, the big downed logs, the canopy height, all these factors drive, basically, habitat for these species that are, pretty much, imperiled.

(gentle music) - [Jill Silver] As an ecologist, when I'm thinking about these forests, I'm thinking about how every tiny microbe build into a web of intersection and interaction that support each other and live off each other and create a system.

(gentle music) - [Miles Berkey] Don't overlook the green backdrop of the forest.

You can see the diversity of moss if you just slow down and you look closely at the small things around you.

It's full of complexities.

It's full of wonder.

It's full of amazement and reward.

(gentle music)