Less than 1 percent of San Diego County's land area is covered by native trees, and much of that tiny fraction consists of narrow strips of oak woodland tracing the narrow confines of various ravines and small watercourses. Fallbrook has some terrific examples of coast live-oak woodland in its parks, plus a trail along Rainbow Creek that visits what surely must be one of the most densely shaded hollows in the county -- dark and gloomy even at noon. The Rainbow Creek trail departs from a bridge on Willow Glen Road, 1.3 miles north of Mission Road. Hike .9 mile downstream on the trail to reach the aforementioned spooky grove of live oaks. Call the Fallbrook Land Conservancy, (760) 728-0889, for more information.