Likin' the forests
The bright orange fuzz on old stone walls and the rubbery strands hanging on orchard trees are lichens, a part of nature that can tell us something about air pollution.
Freezing fog permeates the streamside forest in Lithia Park across from Pioneer Hall. Ashland-based consultant Scot Loring stops to examine a pencil-thick tree branch. The branch is covered with greenish-white lichen about an inch long that look like highly-branched deer antlers.
"There are at least 10 species of lichen growing on this branch," says Loring. "This one — evernia prunastri — is very common on orchard trees. It's fast growing."
The predominance of this species tells Loring something about environmental conditions.
"It's pollution tolerant," Loring explains. "For other species, this chilling, killing valley fog accumulates pollutants. Lichens absorb the pollutants and many of them will die off."
To prove his point, Loring hops in his pickup truck and drives a mile up Granite Street and parks above the reservoir.
Attached to an oak is a green, papery lichen. He rubs it between his fingers. The lichen resembles human lung tissue.
"This is lobaria pulmonaria — lungwort," says Loring. "It's very sensitive to pollution. You won't see these down below."
Lichens are composite organisms, a coming together of a fungus and algae in a symbiotic relationship, an ideal marriage in which each partner gets and gives up something.
"It's really a fungus that has discovered agriculture," says Loring.
The fungus part of a lichen gets its nutrients from the algae. The algae produce nutrients through photosynthesis. The fungus provides shelter for the algae in places it could not normally survive.
Lungwort contains not only green algae but blue-green algae — cyanobacteria — as well. Lichen species with cyanobacteria tend to be more sensitive to air pollution than lichens with green algae exclusively.
Some cyanobacteria in lichen can absorb nitrogen from the air.
"The nitrogen-fixing lichens serve as fertilizers in old-growth forests," Loring explains.
In addition to the ecological role of many lichens in replenishing the soil, humans have long used lichens for medicinal purposes, for dyes and even for food. For these reasons, Loring is among a growing number of specialists often called upon by the federal government to search for rare lichens and fungi in areas proposed for timber harvest and other projects.
"Two hundred species of lichens have been discovered in the Pacific Northwest in the past 10-15 years," Loring says. "A lot of that is due to the (federal) Northwest Forest Plan."
The Northwest Forest Plan, completed in 1994, is a legal roadmap for ensuring ecologically sound land management for federal agencies in the Pacific Northwest. It was created to serve as a compromise between environmental and timber interest groups over future management of federal forests in the Northwest in the midst of a virtual shutdown in timber harvest in the late 1980s due to concerns over impacts to the northern spotted owl.
During his survey work, Loring has made several discoveries, including a new genus of mushroom, found in the Illinois Valley.
In the streamside forest in the Ashland watershed, Loring stops to examine a dead tree.
"You'll see dead trees covered in lichen and people will think the lichen killed it," says Loring. "That's not the case, it's the other way around, the tree died, the leaves fell and the lichens are doing better because they have more light."
Another common local misconception about lichens, according to Loring, has to do with maple and red alder trees that grow along streams.
"The white splotches on the bark are actually crustose lichens that grow in the bark," Loring explains. "You get close to the source of heavy pollution like down below, where we were, and these things disappear. Funny, people think of alder as having white bark. It has brown bark. You take away the lichens and it's just this dark brown."
One of the most amazing thing about lichens, says Loring, is their adaptability. Lichens can survive in harsh environments where no other life can.
"You can find lichens in Antarctica and on high mountain peaks," says Loring. "The last living thing you'll see climbing Mt. McLoughlin is the orange crustose lichen growing on the rocks."
Daniel Newberry is a freelance writer living in the Applegate Valley. You can reach him at firstname.lastname@example.org