Mitchell J. Power

Mitchell J. Power
University of Utah | UOU · Department of Geography

Ph.D., Professor, Curator

About

91
Publications
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5,551
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Publications

Publications (91)
Article
Full-text available
Climatic conditions exert an important influence on wildfire activity in the western United States; however, Indigenous farming activity may have also shaped the local fire regimes for millennia. The Fish Lake Plateau is located on the Great Basin–Colorado Plateau boundary, the only region in western North America where maize farming was adopted th...
Article
A 3300 year-long reconstruction of paleoenvironmental moisture conditions was constructed from a sediment core from North Gate Bog (NGB) in the northern section of Range Creek Canyon within the Colorado Plateau. The methods used to analyze the record include loss on ignition (LOI), magnetic susceptibility (MS), elemental analysis with X-ray fluores...
Article
Lake Bottom oxbow is a partially-filled oxbow lake within an alluvium filled sandstone canyon reach of the Dolores River in eastern Utah, USA. Two adjacent sediment cores were obtained from the Lake Bottom oxbow to better understand the depositional and environmental history of the site and region. Depositional ages were determined using radiocarbo...
Article
In contrast to temperate regions, relationships between basin characteristics (e.g., type/size) and fossil pollen archives have received little attention in Amazonia. Here, we compare fossil pollen records of a small palm swamp (Cuatro Vientos; CV) and a nearby large lake (Laguna Chaplin, LCH) in Bolivian Amazonia, demonstrating that palm swamps ca...
Chapter
Beginning with the nineteenth-century territorial surveys, the lakes and lacustrine deposits in what is now the western United States were recognized for their economic value to the expanding nation. In the latter half of the twentieth century, these systems have been acknowledged as outstanding examples of depositional systems serving as models fo...
Technical Report
Full-text available
This Policy Brief results from a workshop held at Royal Holloway University of London and funded by PAGES, the Quaternary Research Association (QRA), and Chrono-environnement CNRS/Université de Franche-Comté. The workshop gathered 30 international participants from 15 countries to discuss ongoing challenges on biodiversity conservation and fire pol...
Article
The long-term response of ancient societies to climate change has been a matter of global debate. Until recently, the lack of integrative studies using archaeological, palaeoecological and palaeoclimatological data prevented an evaluation of the relationship between climate change, distinct subsistence strategies and cultural transformations across...
Article
We used pollen and high-resolution charcoal analysis of lake sediment to reconstruct a 7600 yr vegetation and fire history from Anthony Lake, located in the Blue Mountains of northeastern Oregon. From 7300 to 6300 cal yr BP, the forest was composed primarily of Populus , and fire was common, indicating warm, dry conditions. From 6300 to 3000 cal yr...
Article
Full-text available
Global climate change poses significant threats to the Caribbean islands. Yet, little is known about the long-term disturbance regimes in island ecosystems. This research investigates 2000 yr of natural and anthropogenic fire disturbance through the analysis of a latitudinal transect of sediment records from coastal salt ponds in the British Virgin...
Article
Global climate change poses significant threats to the Caribbean islands. Yet, little is known about the long-term disturbance regimes in island ecosystems. This research investigates 2000 yr of natural and anthropogenic fire disturbance through the analysis of a latitudinal transect of sediment records from coastal salt ponds in the British Virgin...
Article
Full-text available
The primacy of past human activity in triggering change in earth’s ecosystems remains a contested idea. Treating human-environmental dynamics as a dichotomous phenomenon – turning “on” or “off” at some tipping point in the past – misses the broader, longer-term, and varied role humans play in creating lasting ecological legacies. To investigate the...
Article
Full-text available
In the southern Amazon relationships have been established among drought, human activities that cause forest loss, fire, and smoke emissions. We explore the impacts of recent drought on fire, forest loss, and atmospheric visibility in lowland Bolivia. To assess human influence on fire, we consider climate, fire, and vegetation dynamics in an area l...
Article
Full-text available
In the southern Amazon relationships have been established among drought, human activities that cause forest loss, fire, and smoke emissions. We explore the effects of recent drought on fire, forest loss, and atmospheric visibility in lowland Bolivia. To assess human influence on fire, we consider climate, fire and vegetation dynamics in an area la...
Article
Full-text available
A key task in fire-climate research in the western United States is to characterize potential future fire-climate linkages across different elevational gradients. Using thirty-seven sedimentary charcoal records, here we present a 1500-year synthesis of wildfire activity across different elevational gradients to characterize fire-climate linkages. F...
Article
Progresses in reconstructing Earth's history of biomass burning has motivated the development of a modern charcoal dataset covering the last decades through a community-based initiative called the Global Modern Charcoal Dataset (GMCD). As the frequency, intensity and spatial scale of fires are predicted to increase regionally and globally in conjun...
Article
Full-text available
The location, timing, spatial extent, and frequency of wildfires are changing rapidly in many parts of the world, producing substantial impacts on ecosystems, people, and potentially climate. Paleofire records based on charcoal accumulation in sediments enable modern changes in biomass burning to be considered in their long-term context. Paleofire...
Article
Full-text available
Abstract: The current fires raging across Indonesia are emitting more carbon than the annual fossil fuel emissions of Germany or Japan, and the fires are still consuming vast tracts of rainforest and peatlands. The National Interagency Fire Center (www.nifc.gov) notes that 2015 is one of the worst fire years on record in the U.S., where more than 9...
Article
Full-text available
The current fires raging across Indonesia are emitting more carbon than the annual fossil fuel emissions of Germany or Japan, and the fires are still consuming vast tracts of rainforest and peatlands. The National Interagency Fire Center (www.nifc.gov) notes that 2015 is one worst fire years on record in the U.S., where more than 9 million acres bu...
Article
Full-text available
South American seasonally dry tropical forests (SDTFs) are critically endangered, with only a small proportion of their original distribution remaining. This paper presents a 12 000 year reconstruction of climate change, fire and vegetation dynamics in the Bolivian Chiquitano SDTF, based upon pollen and charcoal analysis, to examine the resilience...
Article
Full-text available
The location, timing, spatial extent, and frequency of wildfires are changing rapidly in many parts of the world, producing substantial impacts on ecosystems, people, and potentially climate. Paleofire records based on charcoal accumulation in sediments enable modern changes in biomass burning to be considered in their long-term context. Paleofire...
Article
An important debate has been re-invigorated by new data concerning the size and environmental impacts of human populations in the Amazon Basin during pre-history. Here, we review the history of debates concerning pre-historic human occupation of the Amazon Basin along with the presentation of empirical data from archaeological and palaeoecological...
Article
Full-text available
Cerrãdo savannas have the greatest fire activity of all major global land-cover types and play a significant role in the global carbon cycle. During the 21st century, temperatures are projected to increase by ~ 3 °C coupled with a precipitation decrease of ~ 20%. Although these conditions could potentially intensify drought stress, it is unknown ho...
Article
Full-text available
Cerrãdo savannas have the greatest fire activity of all major global land-cover types and play a significant role in the global carbon cycle. During the 21st century, temperatures are predicted to increase by ~ 3 °C coupled with a precipitation decrease of ~ 20%. Although these conditions could potentially intensify drought stress, it is unknown ho...
Article
Full-text available
Fire is an important process that affects climate through changes in CO2 emissions, albedo, and aerosols (Ward et al. 2012). Fire- history reconstructions from charcoal accu- mulations in sediment indicate that biomass burning has increased since the Last Glacial Maximum (Power et al. 2008; Marlon et al. 2013). recent comparisons with transient cli...
Article
Full-text available
An earth system model of intermediate complex-ity (CLIMate and BiosphERe – CLIMBER-2) and a land surface model (JSBACH), which dynamically represent veg-etation, are used to simulate natural fire dynamics through the last 8000 yr. Output variables of the fire model (burned area and fire carbon emissions) are used to compare model results with sedim...
Data
Full-text available
The eruption of Mt Mazama, c. 7630 yr BP, was the largest North American volcanic event during the Holocene. High-resolution pollen and charcoal analyses were used to examine the impact of Mt Mazama tephra on forest vegetation and possible synergistic interactions with fire activity in the Central Oregon Cascade Range. We selected four small waters...
Article
Full-text available
Fires have played an important role in creating and maintaining savannas over the centuries and are also one of the main natural disturbances in forests. The functional role of fires in savannas and forests can be investigated through examining sedimentary charcoal in order to reconstruct long-term fire history. However, the relationship between ch...
Article
Full-text available
An Earth System model of intermediate complexity, CLIMBER-2, and a land surface model JSBACH that represents vegetation dynamically are used to simulate natural fire dynamics through the last 8000 yr. Output variables of the fire model (burned area and fire carbon emissions) are used to compare model results with sediment-based charcoal reconstruct...
Article
Increased levels of burning in the past 40 years are raising public and scientific concern about the relative importance of rising temperatures, climate variability, and human actions including management practices in initiating and supporting recent conflagrations. Enormous fires in Australia, North America, Europe, and Russia since 2000 have resu...
Article
Fire is one of the most important natural disturbances in the coniferous forests of the US Rocky Mountains. The Rocky Mountains are separated by a climatic boundary between 40° and 45° N, which we refer to as the central Rocky Mountains (CRM). To determine whether the fire regime from the CRM was more similar to the northern Rocky Mountains (NRM) o...
Article
a b s t r a c t Micropaleontological assemblages from two lakes located on the Aquarius Plateau in southern Utah were investigated to evaluate changes in vegetation, fire disturbance, and paleoclimate over the last 8600 years. This paper presents reconstructions of Holocene landscape conditions and wildfire dynamics in the subalpine zone of the Col...
Article
This chapter provides a global perspective on palaeofire activity through the analysis of over 650 stratigraphic sedimentary charcoal records spanning the last 21000 years. Regional time series analysis provides empirical evidence for global-scale trends in fire since the last glacial maximum (LGM), centred at 21000 calendar years before present. S...
Article
Full-text available
We synthesize existing sedimentary charcoal records to reconstruct Holocene fire history at regional, continental and global scales. The reconstructions are compared with the two potential controls of burning at these broad scales – changes in climate and human activities – to assess their relative importance on trends in biomass burning. Here we c...
Article
Natural factors and human activity influence fire variability including changes in temperature and precipitation, increasing greenhouse gas concentrations, altering ignitions, vegetation cover and fuel availability. Ice cores archive chemical signatures of both past climate and fire activity, and understanding this interaction is increasingly impor...
Article
Paleoenvironmental reconstructions are important for understanding the influence of long-term climate variability on ecosystems and landscape disturbance dynamics. In this paper we explore the linkages among past climate, vegetation, and fire regimes using a high-resolution pollen and charcoal reconstruction from Morris Pond located on the Markagun...
Article
Full-text available
The significance and cause of the decline in biomass burning across the Americas after AD 1500 is a topic of considerable debate. We synthesized charcoal records (a proxy for biomass burning) from the Americas and from the remainder of the globe over the past 2000 years, and compared these with paleoclimatic records and population reconstructions....
Article
Full-text available
1] Climate is an important control on biomass burning, but the sensitivity of fire to changes in temperature and moisture balance has not been quantified. We analyze sedimentary charcoal records to show that the changes in fire regime over the past 21,000 yrs are predictable from changes in regional climates. Analyses of paleo-fire data show that f...
Article
Although human activities could have started to regularly influence global biomass burning around 50 000 to 100 000 years ago (Bar-Yosef, 2002), recent simulations based on sedimentary charcoal records suggest that until the late 18th century the global fire regime was primarily controlled by climate factors (mainly changes in precipitation rather...
Article
A 9400-yr-old record from Crevice Lake, a semi-closed alkaline lake in northern Yellowstone National Park, was analyzed for pollen, charcoal, geochemistry, mineralogy, diatoms, and stable isotopes to develop a nuanced understanding of Holocene environmental history in a region of northern Rocky Mountains that receives both summer and winter precipi...
Article
Full-text available
The nature and scale of pre-Columbian land use and the consequences of the 1492 "Columbian Encounter" (CE) on Amazonia are among the more debated topics in New World archaeology and paleoecology. However, pre-Columbian human impact in Amazonian savannas remains poorly understood. Most paleoecological studies have been conducted in neotropical fores...
Article
Full-text available
Understanding the causes and consequences of wildfires in forests of the western United States requires integrated information about fire, climate changes, and human activity on multiple temporal scales. We use sedimentary charcoal accumulation rates to construct long-term variations in fire during the past 3,000 y in the American West and compare...
Article
A 13,100-year-long high-resolution pollen and charcoal record from Foy Lake in western Montana is compared with a network of vegetation and fire-history records from the Northern Rocky Mountains. New and previously published results were stratified by elevation into upper and lower and tree line to explore the role of Holocene climate variability o...
Conference Paper
Background/Question/Methods The extent to which biomass burning declined across the Americas after ca. AD 1500, and its cause, is a topic of considerable debate. To investigate whether climate or human population collapse was responsible for changes in biomass burning over 300 sedimentary charcoal records from the Americas were examined to produce...
Article
High-resolution charcoal analysis of lake sediment cores was used to reconstruct the fire history from two sites in a mesic hardwood forest of south-eastern Wisconsin located in the Kettle Moraine State Forest. Pollen data from the region indicate that the sites, which lie within 5 km of each other, have had a consistent presence of mesic hardwood...
Article
High-resolution charcoal and pollen analyses were used to reconstruct a 12,000-yr-long fire and vegetation history of the Tumalo Lake watershed and to examine the short-term effects that tephra deposition have on forest composition and fire regime. The record suggests that, from 12,000 to 9200 cal yr BP, the watershed was dominated by an open Pinus...
Article
Full-text available
A mid- to late-Holocene synthesis of fire activity from the Mediterranean basin explores the linkages among fire, climate variability and seasonality through several climatic and ecological transitions. Regional fire histories were created from 36 radiocarbon-dated sedimentary charcoal records, available from the Global Charcoal Database. During th...
Article
Full-text available
One of the controlling factors of NEE that is highly sensitive to changes in climate is fire activity. Here we present results form a transient integration with the fully coupled MPI- Earth System Model (MPI-ESM) of the Max-Planck-Institute for Meteorology covering the last 6000 years. The model comprises dynamical components for atmosphere, ocean,...
Article
Full-text available
Version 1 of the Global Charcoal Database is now available for regional fire history reconstructions, data exploration, hypothesis testing, and evaluation of coupled climate–vegetation–fire model simulations. The charcoal database contains over 400 radiocarbon-dated records that document changes in charcoal abundance during the Late Quaternary. The...
Article
Full-text available
In this contribution I will present a synthesis of mid- to late-Holocene fire activity from the Mediterranean basin and explore the linkages among fire, climate variability and seasonality, and people through several climatic and ecological transitions. Regional fire histories were created from 36 radiocarbon-dated sedimentary charcoal records, ava...
Article
The availability of water shapes life in the western United States, and much of the water in the region originates in the Rocky Mountains. Few studies, however, have explicitly examined the history of water levels in the Rocky Mountains during the Holocene. Here, we examine the past levels of three lakes near the Continental Divide in Montana and C...
Chapter
Full-text available
This chapter aims to review current knowledge of the key vegetation types, and their composition, structure, distribution, and fire regime across the South American tropics during the global Last Glacial Maximum ca. 21,000cal yr BP (calendar years before present). We do this by synthesising previously published Last Glacial Maximum fossil pollen an...