Pierce County Master Gardeners Annual Meeting
Keynote Speaker
Presentation on lichens, relating their presence to air quality, garden & soil health.
Lichens are an essential part of the forest ecosystem in western Washington. They
have been monitored by the forest service, for evaluating forest health and air
quality, and are now being studied for their importance in range land areas, along
with other biotic crusts on soil. These symbiotic organisms play a major role in
nitrogen and carbon fixation as well as mineral cycling. The ecological study of
lichens is becoming more essential in our understanding of how to manage
terrestrial ecosystems.
The association of a fungus with a green algae and/or cyanobacteria defines
lichens. This unique relationship has such a long evolutionary history, that neither
individual can survive without their symbiotic partner.These secondary
compounds may be a deterrent to insect pests that can attack plants in your
garden. Humming birds use lichens when building their nests in the Pacific
Northwest, perhaps to prevent insect infestation.
Common urban lichens will be presented and discussed to help us understand what
their existence may indicate about plants and air quality.