Fire Regimes, Buff alo and the Presettlement Landscape of Mammoth Cave National Park

摘要

The glory of the caves has long overshadowed other features of the park but the neglected upland landscape has its own extraordinary tale to tell. The park occupies a naturally fire sheltered setting in a historically vast fire landscape of barrens and woodlands once populated by Native Americans, bison and elk. The events above ground, spanning several thousand years before the arrival of Europeans and the subsequent explosive transformation of the land add rich layers of natural and human history, sadly neglected in development and interpretation of the park. This is the tale of the Barrens region itself.We constructed maps of historical fire frequency and vegetation, using 2,681 witness trees compiled from original land surveys beginning in 1781. Original fire frequency was interpreted using tree species and the degree of fire exposure of each tree in the landscape, e.g. fire exposed ridgetops, slopes or grassy barrens versus fire sheltered lower slopes, hollows and bottoms. The topographical setting was examined for characteristics related to fire spread such as pathways for fire fl ow, natural firebreaks and the size of fire compartments. The natural fire relations of each tree species and its distribution on the land were used to assign fire frequency to each site and region. Original fire regimes were complex and extreme: fire frequency ranged from nearly annual fi re in the true prairies and grassy woodlands on the limestone karst plain to the south – and on the plain between the Dripping Springs Escarpment and the Green River – to strongly fire sheltered hollows and bottoms within the park. The most fire sheltered sites were defined by the deep limestone bowls developed by karst topography – formed by millennia of dissolution of limestone by subterranean waters – and the rugged relief provided by the deeply entrenched Green and Nolin Rivers.