Green: Lodgepole pine forests
- Dominate more than 80% of the total forested area.
- Can be seral (developing) or climax.
- Climax forests underlain by rhyolite.
Pink: Spruce-fir forests
- Engelmann spruce/subalpine fir dominate older forests.
- Usually found on moist and/or fertile substrates.
- Climax forests underlain by andesitic soils.
Yellow: Whitebark pine forests
- Major overstory component above 8,400 feet.
- Major understory component of lodgepole-dominated forests from 7,000 to 8,400 feet.
- Seeds are ecologically important food for a variety of wildlife species.
Purple: Douglas-fir forests
- Associated with the Lamar, Yellowstone, and Madison River drainages below 7,600 feet.
- Often less than 20 inches annual precipitation.
- More frequent historic fire interval (25–60 year) than other forest communities in the park.
- Includes grasslands, sagebrush, alpine meadows, talus, and hydrothermal environments.
- Encompasses the moisture spectrum from dry sagebrush shrublands to wet alpine meadows.
- Provides the winter and summer forage base for ungulates.
Other communities not shown on map
- Aspen—found in small clones interspersed among the sagebrush/forest ecotone (transition zone) along the Yellowstone, Madison, and Snake river drainages.
- Wetland—includes various grass, forb, rush, sedge, and woody species.
- Riparian—typically streamside vegetation includes cottonwoods, willows, and various deciduous shrubs.