In the forest community below 1,800 meters, Douglas fir, lodgepole pine, and western larch predominate. In the valleys, Engelmann spruce and subalpine fir are found. The somewhat lower and much better watered western valleys of the park support western redcedar and western hemlock. See page 54 Prairie At the eastern edge of the park below 1,200 meters, the forest gives way to the prairie community, composed mostly of soft-stemmed plants adapted to the conditions of low precipitation that prevail here in the rainshadow of the mountain range. Clumps of aspen, found in the prairie in sheltered spots, occur here in the transition zone between prairie and forest.] [Illustration: The Forest Community A forest is organized vertically like an apartment house or office building, with layers corresponding to stories. The _canopy_ is the branches and foliage of tall trees that form a roof over the community. Below the canopy are the _understory_ trees: young individuals of the canopy species; and small, shade-tolerant trees that will never become part of the canopy. Beneath the understory branches is the _shrub layer_, occupied by knee-high-to-man-high woody plants; beneath that is the _herb layer_, where most of the ferns, wildflowers, grasses, and smaller woody plants grow. The _forest floor_ is the zone of mosses, mushrooms, creeping plants, and forest litter (leaves, twigs, needles, feathers, bits of bark, animal droppings, etc.). The forest has a “basement,” too, interlaced by plant roots, mycelia of fungi, and tunnels of myriad animals. Each layer of the forest has its characteristic animal species, but most forage over more than one level. Some nest in one story and feed in another. The red squirrel races back and forth from the forest floor to the highest branches. The forest community also has a socio-economic organization. Every animal (and plant) takes up space and consumes a portion of the available nutrients. Each has a place in the community food chain—as, for example, _herbivore_, _carnivore_, or _scavenger_. Each directly or indirectly affects all the other organisms. The Forest Community