The story of burns, what can they tell you?

Typical roadside burn: I-5, Yolo County in the median, photo taken June 13, 2000.
By looking at this photo, what can you tell about the presence or absence of perennial native grasses
prior to the burn? How can accidental burns be used to locate stands of native grasses?

Photo and text copyright © 2000 by Craig Dremann, The Reveg Edge, Box 609, Redwood City, CA.