Learning with lichens

By Roberta Burnes

Division for Air Quality

What can forests tell us about the air we breathe?  On a misty October morning, a group of people gathered in the shadow of Pine Mountain to help answer just that question.  One by one, each approached a tree with clipboards and hand lenses ready.  The clues were there on each tree trunk, hidden in colorful patterns known as lichens.

Susan Brown coordinates environmental education at the Pine Mountain Settlement School (PMSS) in Harlan County.  She also leads the Lichen Biomonitoring Project, which focuses on the connection between lichens and the air we breathe.  Biomonitoring is the measurement and tracking of organisms, such as lichens, for the purpose of monitoring the long-term effects of environmental pollution or environmental change.

“Lichens have a lot to tell us about air quality,” said Brown.  “Some lichens are very sensitive to air pollution, while others can tolerate it quite well,” continued Brown.  By surveying the lichens found in a particular area over time, we can get a sense of whether certain pollutants are present and how those pollutants might be impacting lichen communities.”

Thanks to a grant from Eastern Kentucky University’s Center for Appalachian Regional Engagement and Stewardship (EKU CARES), the Lichen Biomonitoring Project was born.

The grant enables project team members from EKU and PMSS to establish lichen monitoring plots in the James E. Bickford State Nature Preserve, located at Pine Mountain and in the Lilley Cornett Woods, which is part of EKU’s Division of Natural Areas.

Team member Dr. Melinda Wilder is the director of EKU’s Division of Natural Areas. “We chose these sites for two reasons,” said Wilder.  “First, these sites are located far from significant sources of air pollution that might influence the results of the data.  Second, they are managed natural areas that are readily accessible to the public.”

Accessibility is important, especially since the project utilizes volunteer citizen-scientists to collect the data.  “Citizen Science offers a chance for people to learn about their environment by getting outdoors and participating in the scientific process,” said Wilder.  “This is important because a positive experience in the outdoors directly correlates with increasing environmental stewardship.”

To participate in the project, volunteers must attend a free workshop where they learn the basics of identifying lichens and proper data collection.  Ten eager students attended the first workshop that was held last fall at Pine Mountain Settlement School.

Workshop participants learn how to record the presence or absence of pollution-sensitive lichen species on the trunks of forest trees. First, a transparent plastic grid is tied to the side of a tree.  Using a hand lens, a volunteer then examines the surface of the trunk through each space on the grid, to determine whether it contains one of three types of lichens (see sidebar).  Another volunteer records the data.

At the workshop, staff from the Division for Air Quality helps put the project in context by providing an overview on air quality.  Students learn how some pollutants can be transported by the wind over long distances, which means that upwind sources many miles away may possibly contribute to sulfur dioxide pollution, even in these remote sites.  Sulfur dioxide and sulfates are major contributors to acid deposition (typically called acid rain) and certain lichens are especially sensitive to them.

Normal rainwater has a pH value of between 5.0 and 5.5, which is only slightly acidic.  However, when rain mixes with sulfur or nitrogen compounds in the air, which are commonly emitted by burning fossil fuels, the rain becomes much more acidic.

Lilley Cornett Woods has operated an acid deposition monitoring station for more than three decades.  Data from this site and many others are housed on the National Atmospheric Deposition Program (NADP) website.

When the site began operation in 1984, acid rain was becoming recognized as a serious threat to the health of forests and lakes.  Data from the site show that, since 1990, sulfate levels have steadily decreased while rainfall pH has risen (meaning the rainfall has become less acidic).  But how have the slow-growing lichens responded, and are they still being impacted?  These are some of the questions Brown and Wilder hope to answer.

As volunteers collect lichen data over the coming months and years, project leaders will upload it to a national database known as Hands on the Land.  This website provides opportunities for educators to share citizen science data and to see what others are doing and discovering on public lands.

While biomonitoring alone cannot provide an accurate measure of pollution in an area, it can be a useful tool to help scientists gain a more complete picture of the health of the entire forest and how it is responding to air quality trends.

“Biomonitoring takes time and patience, and lots of data collection,” said Brown.  “It may take years before we see results.”  That however, doesn’t bother Brown, who sees a more immediate benefit to the volunteer citizen scientists and their communities.  “Participants in this project will gain a deeper understanding about lichens and air quality, and have the satisfaction of knowing they contributed to something larger than themselves,” said Brown.

If you are interested in joining the Lichen Biomonitoring Project as a citizen scientist, please contact Susan Brown at 606-558-3571 or email to find out about future workshops.


Lichenology 101

Touch the trunk of any tree in eastern Kentucky and chances are you’ll be touching lichens.  Lichens are a diverse group of organisms that combine fungi with algae or other photosynthetic organisms. Lichens are found on every continent and can grow on rocks and buildings as well as on trees.

The relationship between the fungi and the algae is often described as mutually beneficial or symbiotic, but there’s some debate about this among scientists.  The algae provide food to the fungi through photosynthesis, while the fungi provide structure and protection to the algae.  As one lichenologist described, “Lichens are fungi that discovered farming.”

Taxonomically, lichens are classified as fungi, but they are often grouped by their shape into three broad categories:

  • Crustose – These crust-like lichens grow flat and are firmly attached to the substrate.
  • Foliose – These lichens often resemble foliage, anchored to the substrate at one spot in each leafy lobe. Foliose
  • Fruiticose – These delicate, slow-growing lichens often resemble clumps of greenish hairs, dangling from tree branches or trunks.Types of Lichens

Lichens are sensitive to sulfur, nitrogen and fluorine.  In general, sensitivity increases with surface area from crustose lichens, which are most tolerant to pollutants, to foliose lichens, which are less tolerant, to fruiticose lichens, which are highly sensitive to pollutants.

For more information:

United State Forest Service’s National Lichens and Air Quality Database:

Hands on the Land:

Photos by Roberta Burnes




Categories: Air, Air Quality, Testing

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