article by Irwin Brodo
Trail & Landscape 2000; 34(2): 63-71
“Did you ever wonder why some Greenbelt trees seem to be painted orange, or why your backyard trees are developing a grey scaly coat, or why certain trees are bright yellow where the rain flows down over the trunk?” If so, you will want to read this fascinating article on lichens in the Ottawa region.
Lichens, which are made up of two organisms — a fungus and an alga or a cyanobacterium. Although lichens can withstand long periods of drought and other hardships, they are very sensitive to air pollution. As a result, we see few species in our cities.
Dr Brodo describes lichen species that do manage to survive in an urban environment, all growing on tree bark. A glossary is included as well as detailed drawings by Susan Laurie Bourque.
Note: See also, Lichens of the Ottawa region by Irwin Brodo.