Many areas within the perimeter of the fire remain largely untouched. Of those areas directly affected, only a fraction are severely blackened. A typical northern rocky mountain forest is highlighted below, with a description of how it responds to fire: MICRO-ORGANISMS: In the most badly affected areas, large numbers of microbes found in topsoils may be destroyed by fire, but they are reintroduced by wind and by traveling on larger forms of life. Given their high reproductive rates, scientists say, they regenerate quickly and are able to support the regrowth of plants. PLANTS: Perennial grasses, bulbs and tubers: though fire may destroy foliage plant structures above ground, the superstructure below remains largely unaffected. Once fire has passed, grasses and small plants revive within eight weeks or less. Areas of Yellowstone National Park which burned earlier in the summer are already showing signs of regrowth. Medium-size plants and trees: Like their smaller counterparts, many larger plants with existing root structures will, in time, revive. Young huckleberries, snowberries, willows, and aspens will reappear in Yellowstone next spring, in about eight months. Large trees: Lodgepole pines, perhaps the best example of the positive effect of fire on the wilderness, generate seeds in tightly closed cones. Extreme heat, such as that brought by forest fire, enables the cone to open and reseed the forest. At Yellowstone, naturalists expect to see lodgepole, spruce, and fir seedlings by next spring. New mature forests, of course, will take years. ANIMALS: In general, animal populations, if reduced by fire, will be replenished in proportion to the regrowth of their food source - plants or other animals lower on the food chain. Fish: Fire returns nutrients from plants back to soil, after which rain may deposit them in rivers and streams. Experts say fish can be helped or harmed depending on the amount and balance of nutrients introduced into their habitat. Small mammals: Though squirrels and other rodents that cannot move quickly over large distances may be killed by fire, those that remain reproduce quickly. Populations are generally replenished to pre-fire levels within one to two years, scientists say. Large mammals: Most respond to fire instinctively, moving in advance of a blaze and out of danger. Naturalists at Yellowstone say they have no evidence of fire having endangered the populations of elk, moose, mule deer, or grizzly or black bears. But they note that in the short term winter food may be scarce, due both to fire and the last few years of drought in the West. Animals will have to range farther afield for food, bringing them into more frequent, and sometimes dangerous, contact with man.