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<br />
<br />Management Situation by Revision Topic
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<br />type. This is the driest zone on the RGNF. , The foothill zone is a mixture of grassland,
<br />mountain big sagebrush, mountain mahogany, and pinyon pine communities. In places
<br />where Gambel oak is found, it bridges the transition from the foothill zone to the montane
<br />zone.
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<br />Pinyon pine communities cover approximately 4 percent of the forested portions of this
<br />Forest, and are the most prominent cover type in this zone. Pinyon pine is shade intolerant,
<br />so stands are typically in abundant sun light. Older pinyon pine trees will generally live up to
<br />400 years old with individuals exceeding 500 years possible.
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<br />Crane (1982) suggests this zone may have burned an average of every 5 to 30 years. Since
<br />pinyon pine is susceptible to fire, especially as a tree under 4 feet tall, the present range has
<br />probably expanded due to past fire suppression (Dywer and Pieper 1967). Wright (1990)
<br />mentions that the Gambel oak type may have burned every 50 to 1 00 years, but stresses that
<br />this is speculative. Fires in Gambel oak are usually spotty and irregular. Also, fires in this type
<br />only occur after a buildup of litter and after a dry period.
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<br />Riparian Ecosystems
<br />Each zone mentioned above contains riparian ecosystems. Riparian ecosystems occur where
<br />there is a transition from aquatic to adjacent terrestrial ecosystems. Riparian ecosystems are
<br />identified by soil characteristics or distinctive vegetation communities that require free or
<br />unbound water sometime during the growing season. Basically, riparian areas form lush,
<br />green strips of vegetation between adjacent, dry, upland vegetation. Riparian areas exist
<br />around streams, springs, lakes, bogs, or wetlands. There is a constant exchange of nutrients,
<br />species, and energy between aquatic, riparian, and adjacent drier terrestrial ecosystems.
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<br />Riparian overstory vegetation on this Forest can be dominated by any of the conifer species
<br />listed in Table 11I-5. It may also be dominated by blue spruce, willow, alder, aspen, or
<br />cottonwood, depending on elevation. The understory may be dominated by a variety of
<br />sedge, bluegrass, reedgrass, bentgrass, tufted hairgrass, rush, or many other water-loving
<br />graminoid (grasses and grasslike plants) or water-loving forb species. Although riparian areas
<br />are generally only a very small percentage of th'e land area, they have high species diversity
<br />and density, and high productivity.
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<br />Riparian areas are obviously critical for fish habitat, but these areas are also important, and in
<br />some cases essential, to many wildlife species. Many western areas report that up to 75
<br />percent or more of all wildlife species are dependent upon riparian zones for at least half of
<br />their life cycles (Chaney et aI1990). Riparian areas provide corridors and connectivity to the
<br />landscape. Riparian vegetation is essential for holding streambanks and filtering sediment,
<br />which builds streambanks and forms floodplains and wet meadows. Riparian ecosystems
<br />influence the timing and quality of water, which has broad economic implications. People
<br />value riparian systems for livestock forage, fishing, camping; and aesthetics.
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<br />Condusion
<br />Finally, each of the vegetation zones listed above is valued by people for recreation, water
<br />production, wood products (except alpine. zone), gathering pinyon nuts (foothill zone only),
<br />livestock grazing, and mining. The foothill zone and the lower end of the montane zone are
<br />important big-game winter range. Historically, these two zones were extensively used by
<br />people because these areas were fairly accessible. Riparian areas are intertwined within all
<br />the vegetation zones and provide connectivity, wildlife habitat, livestock forage, and
<br />recreation for people. There are probably up to 1,000 different species of plants on the
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