Snow on fruticose lichen. photo by John F. Williams

These high-flying organisms are some of nature’s most creative concoctions. They’re a symbiotic mashup of fungi and algae, with three airborne properties that set them apart in the Salish woodland.

First, they turn air into life

Lichens do not have roots. They are epiphytic. That means they absorb nutrients and moisture directly from the air and rain, like a collection of mini mops.

Within the lichen, fungus and alga work in tandem to process what they collect. Fungal cells provide structure and protection, while the alga acts like a metabolic engine, using the nutrients absorbed from air to make food through photosynthesis.

Since the organisms absorb everything present in the air, they’re sensitive to pollution and can indicate air quality, like a canary in a coal mine. Scientists often analyze amounts of heavy metals, carbon, and sulfur within the organisms, and their results help monitor and predict atmospheric changes that affect the Salish ecosystems.

Second, fruticose lichens live the single high life

While many lichens use tiny fruiting spores to reproduce sexually, fruticose lichens in the Salish canopy primarily reproduce with asexual, aerial propagation.

The process begins with fragmentation. A lichen, perhaps swinging in the breeze, gets blown a bit too hard, and a fragment breaks free.

This fragment is made up of a tiny bit of algal cells wrapped in a few strands of fungus, and it sails through the forest air. The wind or rain may transport it further. Or a bird or a squirrel may carry the snippet to another branch or a nearby conifer. When the fragment finally lands and settles, it forms a new lichen structure: baby lichen.

Third, fruticose lichens support the forest’s airborne creatures

While lichens are sometimes considered their own ecosystem, many birds rely on them for raising their young. More than 50 species of North American birds, including hummingbirds near the Salish Sea, use lichen when building their nests. Flying squirrels also add lichen to their nests because of its insulating properties. Fruticose lichens, like witch’s hair and old man’s beard, are especially accessible to wildlife living amongst the trees and shrubs.

So, the next time you visit the Salish woods, don’t forget to look up, enjoy, and remember the likability of lichen.

Celeste Hankins is a freelance writer and nature guide living in the Pacific Northwest, just a short hike from the Salish Sea. She has an MA in Science Writing from Johns Hopkins University and is a certified marine naturalist from the San Juan Whale Museum. Celeste also volunteers as a habitat interpreter at the Seattle Aquarium and as a citizen scientist monitoring sea birds and harbor porpoises. Come rain or shine, you can find Celeste narrating scenic cruises on the fjord, swimming with seals, or leading family beach walks.

Table of Contents, Issue #26, Winter 2024-25