Forests are hugely complex ecosystems and while trees are near and dear to a forester’s heart, there are a gazillion other plants and critters that all interact with each other in myriad fascinating ways.

So living/working/playing in the woods presents all kinds of opportunities to observe and learn about some pretty cool stuff.

Lichens, for example.

Lichens are just about everywhere – you’ve seen all those multi-colored splashes of funny looking vegetation clinging to rocks and trees. Interesting to look at perhaps, but usually not a big attention getter so it’s pretty easy to take them for granted. But lichens are amazing things in their own right, and provide a number of important functions and benefits to the forest ecosystem.

These organisms have been around a long, long time, first showing up in the fossil record about 400 million years ago. Lichens are not actually plants and are informally grouped with mosses, liverworts, free-living fungi, and algae, which reproduce by spores instead of seeds.

Lichens arise from a symbiotic union between a fungus and a green algae and within this union, each member plays a crucial role. The algae are photosynthetic and supply the fungus with carbohydrates and vitamins, while the fungus extracts necessary water and minerals from the air and colonized surfaces for both it and the algae.

Often called “nature’s pioneers,” lichens will colonize just about any stable and reasonably well-lit surface. They are not parasitic and do not harm or feed on the host; it’s just a place for them to grow. And these guys are tough – they donít just survive drought well, they can be completely dehydrated but once moisture becomes available again, fully rehydrate to their former state.

Lichens intercept and absorb nutrients and water from the atmosphere which eventually influences the composition and concentration of nutrients in the forest soils. Unlike plants, lichens are able to capture atmospheric nitrogen so when lichens die and decompose, the nitrogen is then available for plants which is a real benefit for forest soils that are typically deficient in nitrogen. Also, lichens growing on rocks release chemicals that speed up the process of decomposing rocks, contributing to the production of new soils.

Lichens are high in carbohydrates and animals from mites to musk oxen use them for food or shelter. Birds and squirrels use lichens to build and line nests and lichens make up 90 percent of the winter diet of caribou and reindeer. White-tail and mule deer, moose, elk, mountain goats, and pronghorns all look at lichens as tasty treats.

Humans too make use of lichens. Horsehair lichens were a popular food for Native Americans and many species are used to make beautiful dyes. Others are used for medicines, poisons and even perfumes. Current research has shown some lichens exhibit anti-tumor activity and others inhibit the HIV-virus.

Lichens are very sensitive to pollutants and are now being used as early warning systems to detect declining air quality and as indicators of ancient forests.

So next time you’re out in the woods, try looking for all the different kinds of lichens you can find – there are over 3,600 species in North America. And they might be edible, but I’d still recommend packing a peanut butter and jelly sandwich for a snack.

Bob Parker is an OSU Extension forestry agent.