| Engelmann Spruce - subalpine
fir forests are recognized by their narrow crowns and
dark green color. Sometimes lodgepole pine intermix, but
they are easily distinguished by their yellow - green
color. Walking through the forest you are enveloped by a
cool,dark, humid feeling. The subalpine - fir forest
represents a climax ecosystem. Other species have
difficulty competing because they cannot reproduce in the
shade at these altitudes, hence spruce and fir dominate.
Spruce and fir possess short needles attached to twigs singly rather than in bunches as are pine. Subalpine fir are distinguished from spruce by their cones - fir cones are upright while spruce hang down. Spruce bark is reddish and outer layer flakes off while fir bark is smooth. The spruce-fir forest is the highest, most continuous forest - present from 9,000 feet to treeline, but most abundant between 10,000 and 11,000 feet, the subalpine life zone. Some of the largest and oldest trees in the Indian Peaks region are found in the spruce-fir forest. Trees may exceed 3 feet in diameter and reach a height of 120 feet. Here the climate is cool, moist, and windy with most of the precipitation falling in the form of snow. Spruce-fir forests increase their effective precipitation by catching snow blown down from the tundra which lies above the subalpine zone at higher elevations. The dense trees modify the environment by slowing wind speed decreasing radiation intensity and holding moisture. Soils in the spruce - fir ecosystem are highly variable, forming on glacial deposits, or bedrock of igneous or metamorphic origin. Soils are moist throughout the summer and are subject to frost heave in winter. The forest floor is littered with rotting logs with a patchy understory primarily consisting of low-growing bushes, moisture loving herbs and wildflowers. Wind throw kills trees growing on shallow soils, and trees in overly dense stands that have been recently opened and exposed to strong winds. Lightning damage is frequent.
Protected from fire by moist conditions and logging by their inaccessibility, they have maintained themselves for thousands of years.However if disturbed, recovery is very slow. Lodgepole pine invades quickly, yet are overtaken by spruce - fir within fifty years. Recovery is slowest on disturbed areas adjacent to treeline. Humans have seldom used these forest due to their
remoteness. Most impact by humans has been from miners
purposely setting fires to clear the forest in the late
1800s and early 1900s |
Figure 2.2 Storm building behind
the Continental Divide (Photo
credit: Michael Ritter). 
Figure 2.3 Subalpine
forest ground cover (Photo Credit:
Michael Ritter)