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Unlike
most of the United States, Yellowstone National Park, located
in the Rocky Mountains, has nearly all of its original species
and ecological processes intact. Because of this, the area
offers a powerful sense of wilderness and exceptional research
opportunities. Over 80% of the landscape is covered by mountain
forests in this 9259 km2 national park and the average elevation
in the park's Central Plateau is 2377 m. The Central Plateau
provides ideal conditions for studying the spectral reflectance
characteristics of coniferous forests for several reasons.
First, the ecology and succession of the Yellowstone forest
have been well documented (Despain, 1990; Romme and Despain,
1989). Also, much of the temperate Yellowstone coniferous
forest occurs as a mosaic of succession stages on extensive,
gently rolling plateaus, with easilycorrectable
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topographic
effects. Finally, 83% of the forest canopy of Yellowstone is dominated
by lodgepole pine (Pinus contorta var. latifolia), minimizing
variations potentially introduced by mixtures of tree species, in
particular mixtures of coniferous and deciduous trees.
Fire is an important
natural agent of change in this ecosystem. The large fires of 1988
in Yellowstone National Park demonstrated how dramatically and rapidly
the vegetation and consequently the condition of an ecosystem can
change. The 250,000 ha of burnt forest created a striking mosaic
of burn severities on the landscape of the park. Both the ecological
and economic impacts of these fires have been significant (YNP,
1993; Polzin et al., 1993). As the burns have begun to naturally
regenerate with lodgepole pine seedlings (Reed et al., 1999), the
patchwork left upon the landscape has inspired numerous efforts
to document and analyze the impacts of this natural disturbance
(Stevens, 1990; Renkin and Despain, 1992; Turner et al., 1994; Hardy-Short
and Short, 1995).
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