While the most obvious components of a forest ecosystem are above ground, perhaps the most essential elements are found below the surface. Forest soils are home to millions of microorganisms, such as molds, fungi, algae, cyanobacteria, rotifers, and protozoa, and larger soil invertebrates, including mites, snails, slugs, centipedes, spiders, nematodes, earthworms, and springtails. These perform physical and biological processes needed for a healthy ecosystem, including nutrient recycling, waste

Courtesy of Robert FaustWildfires destroyed more than 3,600 homes and 750,000 acres of southern California's chaparral forests in 2003. Although these ecosystems are adapted to frequent, low-intensity burns, many ecologists say that fuel-load buildup due to years of fire suppression has led to catastrophic blazes. Brent Roath, a soil scientist stationed at the Sierra National Forest, says that once a fire is extinguished, assessing the damage and implementing necessary treatments "can take weeks