Assessment

* FIRE-ALTERNATIVE VIEWS

* Careless and Indiscriminate Fire Use

Strategies

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All SNEP scientists agree that fire has played a significant if not dominant role in shaping the vegetation pattern; the departure of views begins with the relative certainty of fire frequency and spatial intensity in presettlement times. There is too little compelling evidence and incomplete rangewide research to conclude a precise pattern of fire frequency or severity in presettlement times. There were very probably areas that burned frequently (less than ten-year intervals), but some areas within the same vegetation type probably escaped burning for much longer periods and built up sufficient fuel loads to burn with high intensity if ignition occurred under favorable burning conditions. This point of difference in views centers on the belief that there were probably many variations in the return frequencies and fire intensity patterns that contributed to the mosaic of vegetation patterns on the landscape today.
A second major point of difference relates to the relative "openness" of forests before the disturbances caused by settlers. The alternative view concludes, from the same evidence, that forest conditions were not largely "open or parklike," in the words of John Muir; rather, there was a mix of dark, dense, or thick forests in unknown comparative quantities. Select early accounts support an open, parklike forest, but there were many similar accounts that describe forest conditions as dark or dense or thick. J. Goldsborough Bruff, a forty-niner who traveled the western slopes of the Feather River drainage between 1849 and 1851, kept a detailed diary. He clearly distinguished between open and dense forest conditions and recorded the dense condition six times more often than the open. Many other accounts of early explorers (e.g., John C. Frémont, Peter Decker, William Brewer) identify dark or impenetrable forest; the presettlement forest was far from a continuum of open, parklike stands. From these records it seems clear that Sierran forests were a mix of different degrees of openness and an unknown proportion in dark, dense, nearly impenetrable vegetative cover with variations from north to south and foothill to crest.
A third point of departure has to do with the frequency of stand-terminating fires in presettlement times. One group concludes that such events were rare or uncommon. The alternative view is that stand-threatening fires were probably more frequent. They were heavily dependent upon combinations of prolonged drought, an accumulation of dead material resulting from natural causes (e.g., insect mortality, windthrow, snow breakage), and severe fire weather conditions of low humidity and dry east winds coupled with multiple ignitions, possibly from lightning associated with rainless thunderstorms. Such fires were noted during the last half of the nineteenth century by newspaper accounts, official reports (John Leiberg, U.S. Geological Survey, 1902), and diaries; most were apparently caused by settlers, stockmen, or miners. Fuel loads were obviously sufficient at that time, thus strongly suggesting that similar conditions existed in earlier times with unknown frequencies.