In February, precious little seems to be growing in the woods. Except lichen. Lichen are a complex of algae and fungi that live together symbiotically, even in the dead of winter. The algae produce energy from sunlight and capture nitrogen from the air, while the fungi create a protective structure for the algae. Lichen absorb water and nutrients directly from the air. Lichen can also absorb pollutants from the air, so have been used for more than a century as indicators of air quality. I often spot lichen on wood—the wood only provides a surface to grow on but not any nutrients—which the lichen will slowly break down. Expanding by as little as a few millimeters a year, lichen are often long-lived and may be some of the oldest living organisms on the planet.
Anne Marie Ruff Grewal is a writer, editor and environmentalist who has recently published her second novel, Beneath the Same Heaven—a story of love and terrorism.
