Mountain forest of Douglas fir and Ponderosa pine covers the tops of the hills of the Bison Range and surrounding area. Forests are complex ecosystems. The type of trees that make up the forest provide a special environment that affects the kinds of other plants and animals that can live there. Most forests can develop wherever there is an average temperature greater than 50 degrees in the warmest months and where there is an annual rainfall of about 13 inches. This area is on the edge of forest survival. Moisture levels have created the natural tree patterns you see on the surrounding hills with trees taking hold at higher elevations where it is cooler and moister, on the cooler north slopes, or where there are depressions to hold the moisture.
Spend some time looking closely at trees in the forest. Leaves act as solar collectors, using the heat of the sun to process their food through photosynthesis. The conifer trees of this mountain forest are tiered with the upper branches shorter so the sun may reach all the branches. Since these trees are evergreen and keep their leaves all year, their leaves are slender needles with a tight waxy surface to retain moisture through dry periods and long winter months when water is frozen.
Birds of the conifer forest are adapted to food sources found here. They eat the pine nuts from cones, new tree buds, seeds and berries plus insects that live in bark or burrow into the wood. Since most of these things are available all year, many forest birds such as chickadees, jays, and woodpeckers do not migrate.
Other animals use the forest for shelter and food. Deer and elk browse on woodland plants for winter survival.