|Old Man's Beard lichen indicating a WNW 40 knot gale, 8 on the Beaufort Scale|
Usnea, a common type of lichen, also called Old Man's Beard, grows on tree branches. It is made up of a fungus and an algae in a perfectly cooperative, sustainable relationship that humans would be wise to emulate.
The main body that the partners form is called the lichen's thallus, which is the part we can see. Old Man's Beard has a long, threaded thallus that gives the coastal rain forest a classic, drippy look whether it is raining or not.
|Old Man's Beard hangs on a calm day|
When I look out at the storm-twisted Douglas-fir in the yard, and the great strands of greenish-grey lichen hanging from its sweeping branches, I can get all the weather information I need.
Here is what the Old Man's Beard weather station tells me:
- If thallus is hanging down - calm weather prevails
- If thallus is blowing horizontally - gale force winds
- If thalus is wet - raining
- If thalus is dry - no rain
- If thalus has light on it - sunny
- If thalus dies - poor air quality