Indigenous Impacts on North American Great Plains Fire Regimes of the Past Millennium

Fire use has played an important role in human evolution and subsequent dispersals across the globe, yet the relative importance of human activity and climate on fire regimes is controversial. This is particularly true for historical fire regimes of the Americas, where indigenous groups used fire for myriad reasons but paleofire records indicate strong climate–fire relationships. In North American grasslands, decadal-scale wet periods facilitated widespread fire activity because of the abundance of fuel promoted by pluvial episodes. In these settings, human impacts on fire regimes are assumed to be independent of climate, thereby diminishing the strength of climate–fire relationships. We used an offsite geoarchaeological approach to link terrestrial records of prairie fire activity with spatially related archaeological features (driveline complexes) used for intensive, communal bison hunting in north-central Montana. Radiocarbon-dated charcoal layers from alluvial and colluvial deposits associated with driveline complexes indicate that peak fire activity over the past millennium occurred coincident with the use of these features (ca. 1100–1650 CE). However, comparison of dated fire deposits with Palmer Drought Severity Index reconstructions reveal strong climate–fire linkages. More than half of all charcoal layers coincide with modest pluvial episodes, suggesting that fire use by indigenous hunters enhanced the effects of climate variability on prairie fire regimes. These results indicate that relatively small, mobile human populations can impact natural fire regimes, even in pyrogeographic settings in which climate exerts strong, top-down controls on fuels

Fire Suppression Impacts on Fuels and Fire Intensity in the Western U.S.: Insights from Archaeological Luminescence Dating in Northern New Mexico

Here, we show that the last century of fire suppression in the western U.S. has resulted in fire intensities that are unique over more than 900 years of record in ponderosa pine forests (Pinus ponderosa). Specifically, we use the heat-sensitive luminescence signal of archaeological ceramics and tree-ring fire histories to show that a recent fire during mild weather conditions was more intense than anything experienced in centuries of frequent wildfires. We support this with a particularly robust set of optically stimulated luminescence measurements on pottery from an archaeological site in northern New Mexico. The heating effects of an October 2012 CE prescribed fire reset the luminescence signal in all 12 surface samples of archaeological ceramics, whereas none of the 10 samples exposed to at least 14 previous fires (1696–1893 CE) revealed any evidence of past thermal impact. This was true regardless of the fire behavior contexts of the 2012 CE samples (crown, surface, and smoldering fires). It suggests that the fuel characteristics from fire suppression at this site have no analog during the 550 years since the depopulation of this site or the 350 years of preceding occupation of the forested landscape of this region

Draw the lightning down: Benjamin Franklin and electrical technology in the Age of Enlightenment

Most of us know - at least we've heard - that Benjamin Franklin conducted some kind of electrical experiment with a kite. What few of us realize - and what this book makes powerfully clear - is that Franklin played a major role in laying the foundations of modern electrical science and technology. This fast-paced book, rich with historical details and anecdotes, brings to life Franklin, the large international network of scientists and inventors in which he played a key role, and their amazing inventions. We learn what these early electrical devices - from lights and motors to musical and medical instruments - looked like, how they worked, and what their utilitarian and symbolic meanings were for those who invented and used them. Against the fascinating panorama of life in the eighteenth century, Michael Brian Schiffer tells the story of the very beginnings of our modern electrical world. The earliest electrical technologies were conceived in the laboratory apparatus of physicists; because of their surprising and diverse effects, however, these technologies rapidly made their way into many other communities and activities. Schiffer conducts us from community to community, showing how these technologies worked as they were put to use in public lectures, revolutionary experiments in chemistry and biology, and medical therapy. This story brings to light the arcane and long-forgotten inventions that made way for many modern technologies - including lightning rods (Franklin's invention), cardiac stimulation, xerography, and the internal combustion engine - and richly conveys the complex relationships among science, technology, and culture