Adrian Das
I am a Research Ecologist with the U.S. Geological Survey's Western Ecological Research Center, stationed at Sequoia and Kings Canyon National Parks.
I direct a multifaceted research program targeted at improving our ability to manage forests in the face of both rapid and chronic environmental change. Current projects include: understanding the drivers of multidecadal changes in forest dynamics; developing tools to assess landscape-level forest vulnerability to severe drought; quantifying and forecasting the risks and consequences of large, high severity wildfires; and assessing the impacts of such wildfires on the persistence of giant sequoias. I also help coordinate large, collaborative forest research efforts involving multiple agencies, universities, and non-profit organizations, with a particular focus on giant sequoia and wildfire research.
Education and Certifications
PhD from University of California at Berkeley, Forest Ecology 2007
BS from University of Michigan, Chemistry and Cellular Molecular Biology, 1995
Science and Products
Filter Total Items: 19
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Filter Total Items: 57
Height-related changes in forest composition, not tree vulnerability, explain increasing mortality with height during an extreme drought Height-related changes in forest composition, not tree vulnerability, explain increasing mortality with height during an extreme drought
Recently, Stovall et al.1 (hereafter SSY) showed that during an extreme drought, remotely sensed mortality of tall trees was more than double that of short trees. They interpreted this to be a consequence of inherently greater hydraulic vulnerability of tall trees, and suggested that tall-tree vulnerability should thus generalize more broadly. Here we reassess their conclusions using...
Authors
Nathan Stephenson, Adrian Das
The Fire and Tree Mortality Database, for empirical modeling of individual tree mortality after fire The Fire and Tree Mortality Database, for empirical modeling of individual tree mortality after fire
Wildland fires have a multitude of ecological effects in forests, woodlands, and savannas across the globe. A major focus of past research has been on tree mortality from fire, as trees provide a vast range of biological services. We assembled a database of individual-tree records from prescribed fires and wildfires in the United States. The Fire and Tree Mortality (FTM) database...
Authors
C. Alina Cansler, Sharon Hood, J. Morgan Varner, Phillip J. van Mantgem, Michelle Agne, Robert Andrus, Matthew Ayres, Bruce Ayres, Jonathan D. Bakker, Michael Battaglia, Barbara Bentz, Carolyn Breece, James Brown, Daniel Cluck, Tom Coleman, R. Corace, W. Covington, Douglas Cram, James Cronan, Joseph Crouse, Adrian Das, Ryan Davis, Darci Dickinson, Stephen Fitzgerald, Peter Z. Fule, Lisa Ganio, Lindsay Grayson, Charles Halpern, Jim Hanula, Brian Harvey, J. Hiers, David Huffman, MaryBeth Keifer, Tara Keyser, Leda Kobziar, Thomas Kolb, Crystal Kolden, Karen Kopper, Jason Kreitler, Jesse Kreye, Andrew Latimer, Andrew Lerch, Maria Lombardero, Virginia McDaniel, Charles McHugh, Joel McMillin, Jason Moghaddas, Joseph O’Brien, Daniel Perrakis, David Peterson, Susan Pritchard, Robert Progar, Kenneth Raffa, Elizabeth Reinhardt, Joseph Restaino, John Roccaforte, Brendan Rogers, Kevin Ryan, Hugh Safford, Alyson Santoro, Timothy Shearman, Alice Shumate, Carolyn H. Sieg, Sheri Smith, Rebecca Smith, Nathan Stephenson, Mary Stuever, Jens Stevens, Michael Stoddard, Walter Thies, Nicole Vaillant, Shelby Weiss, Douglas Westlind, Travis Woolley, Micah Wright
Coming to terms with the new normal: Forest health in the Sierra Nevada Coming to terms with the new normal: Forest health in the Sierra Nevada
The vast conifer forests of California’s Sierra Nevada range inspire awe and create lasting memories. The size and longevity of these trees make them seem both otherworldly and everlasting. Indeed, their grandeur is such that visitors may not appreciate how these forests are connected to the larger landscape, and so there is little understanding that something as common as a drought...
Authors
Jodi Axelson, John Battles, Adrian J. Das, Phillip J. van Mantgem
The influence of pre-fire growth patterns on post-fire tree mortality for common conifers in western U.S. parks The influence of pre-fire growth patterns on post-fire tree mortality for common conifers in western U.S. parks
Fire severity in forests is often defined in terms of post-fire tree mortality, yet the influences on tree mortality following fire are not fully understood. For trees that are not killed immediately by severe fire injury, pre-fire growth may partially predict post-fire mortality probabilities for conifers of the western U.S. Here, we consider the influence of multiple growth patterns on...
Authors
Phillip van Mantgem, Donald Falk, Emma Williams, Adrian J. Das, Nathan Stephenson
Tree mortality in blue oak woodland during extreme drought in Sequoia National Park, California Tree mortality in blue oak woodland during extreme drought in Sequoia National Park, California
Blue oak woodlands in California have been a focus of conservation concern for many years. Numerous studies have found that existing seedling and sapling numbers are inadequate to sustain current populations, and recent work has suggested that blue oak woodlands might be particularly vulnerable to a warming climate. California has recently experienced a drought of historically...
Authors
Adrian J. Das, Nicholas Ampersee, Anne Pfaff, Nathan Stephenson, Tedmund Swiecki, Elizabeth Bernhardt, Patricia Haggerty, Koren Nydick
Size matters, but not consistently Size matters, but not consistently
E. Pennisi (“Forest giants are the trees most at risk,” News, 6 September, p. 962) interprets presentations of three studies as suggesting that “for trees, size is not strength, and forest giants are disproportionately vulnerable.” However, this conclusion is not well supported. The observation that lightning is a major cause of large-tree mortality on Barro Colorado Island (BCI) is best...
Authors
Nathan Stephenson, Adrian J. Das
Negative impacts of summer heat on Sierra Nevada tree seedlings Negative impacts of summer heat on Sierra Nevada tree seedlings
Understanding the response of forests to climate change is important for predicting changes in biodiversity and ecosystem services, including carbon storage. Seedlings represent a key demographic stage in these responses, because seedling establishment is necessary for population persistence and spread, and because the conditions allowing seedlings to survive and grow are often more...
Authors
Emily Moran, Adrian J. Das, Jon Keeley, Nathan Stephenson
Which trees die during drought? The key role of insect host-tree selection Which trees die during drought? The key role of insect host-tree selection
1. During drought, the tree subpopulations (such as size or vigor classes) that suffer disproportionate mortality can be conceptually arrayed along a continuum defined by the actions of biotic agents, particularly insects. At one extreme, stress dominates: insects are absent or simply kill the most physiologically stressed trees. At the opposite extreme, host selection dominates...
Authors
Nathan Stephenson, Adrian J. Das, Nicholas Ampersee, Beverly Bulaon, Julie Yee
Early-warning signals of individual tree mortality based on annual radial growth Early-warning signals of individual tree mortality based on annual radial growth
Tree mortality is a key driver of forest dynamics and its occurrence is projected to increase in the future due to climate change. Despite recent advances in our understanding of the physiological mechanisms leading to death, we still lack robust indicators of mortality risk that could be applied at the individual tree scale. Here, we build on a previous contribution exploring the...
Authors
Maxime Cailleret, Vasilis Dakos, Steven Jansen, Elisabeth M. R. Robert, Tuomas Aakala, Mariano Amoroso, Joe A. Antos, Christof Bigler, Harald Bugmann, Marco Caccianaga, Jesus-Julio Camarero, Paolo Cherubini, Marie Coyea, Katarina Cufar, Adrian J. Das, Hendrik Davi, Guillermo Gea-Izquierdo, Sten Gillner, Laurel Haavik, Henrik Hartmann, Ana-Maria Heres, Kevin Hultine, Pavel Janda, Jeffrey Kane, Viachelsav Kharuk, Thomas Kitzberger, Tamir Klein, Tom Levanic, Juan-Carlos Linares, Fabio Lombardi, Harri Makinen, Ilona Mészáros, Juha Metsaranta, Walter Oberhuber, Andreas Papadopoulos, Any Petritan, Brigitte Rohner, Gabriel Sanguesa-Barreda, Jeremy Smith, Amanda Stan, Dejan Stojanovic, Maria-Laura Suarez, Miroslav Svoboda, Volodymyr Trotsiuk, Ricardo Villalba, Alana Westwood, Peter Wyckoff, Jordi Martínez-Vilalta
Pre‐fire drought and competition mediate post‐fire conifer mortality in western U.S. National Parks Pre‐fire drought and competition mediate post‐fire conifer mortality in western U.S. National Parks
Tree mortality is an important outcome of many forest fires. Extensive tree injuries from fire may lead directly to mortality, but environmental and biological stressors may also contribute to tree death. However, there is little evidence showing how the combined effects of two common stressors, drought and competition, influence post‐fire mortality. Geographically broad observations of...
Authors
Phillip van Mantgem, Donald Falk, Emma Williams, Adrian J. Das, Nathan Stephenson
Leaf to landscape responses of giant sequoia to hotter drought: An introduction and synthesis for the special section Leaf to landscape responses of giant sequoia to hotter drought: An introduction and synthesis for the special section
Hotter droughts are becoming more common as climate change progresses, and they may already have caused instances of forest dieback on all forested continents. Learning from hotter droughts, including where on the landscape forests are more or less vulnerable to these events, is critical to help resource managers proactively prepare for the future. As part of our Leaf to Landscape...
Authors
Koren Nydick, Nathan Stephenson, Anthony Ambrose, Gregory Asner, Wendy Baxter, Adrian J. Das, Todd Dawson, Roberta Martin, Tarin Paz-Kagan
Remote measurement of canopy water content in giant sequoias (Sequoiadendron giganteum) during drought Remote measurement of canopy water content in giant sequoias (Sequoiadendron giganteum) during drought
California experienced severe drought from 2012 to 2016, and there were visible changes in the forest canopy throughout the State. In 2014, unprecedented foliage dieback was recorded in giant sequoia (Sequoiadendron giganteum) trees in Sequoia National Park, in the southern California Sierra Nevada mountains. Although visible changes in sequoia canopies can be recorded, biochemical and...
Authors
Roberta Martin, Gregory Asner, Emily Francis, Anthony Ambrose, Wendy Baxter, Adrian J. Das, Nicolas Vaughn, Tarin Paz-Kagan, Todd Dawson, Koren Nydick, Nathan Stephenson
Science and Products
Filter Total Items: 19
No Result Found
Filter Total Items: 57
Height-related changes in forest composition, not tree vulnerability, explain increasing mortality with height during an extreme drought Height-related changes in forest composition, not tree vulnerability, explain increasing mortality with height during an extreme drought
Recently, Stovall et al.1 (hereafter SSY) showed that during an extreme drought, remotely sensed mortality of tall trees was more than double that of short trees. They interpreted this to be a consequence of inherently greater hydraulic vulnerability of tall trees, and suggested that tall-tree vulnerability should thus generalize more broadly. Here we reassess their conclusions using...
Authors
Nathan Stephenson, Adrian Das
The Fire and Tree Mortality Database, for empirical modeling of individual tree mortality after fire The Fire and Tree Mortality Database, for empirical modeling of individual tree mortality after fire
Wildland fires have a multitude of ecological effects in forests, woodlands, and savannas across the globe. A major focus of past research has been on tree mortality from fire, as trees provide a vast range of biological services. We assembled a database of individual-tree records from prescribed fires and wildfires in the United States. The Fire and Tree Mortality (FTM) database...
Authors
C. Alina Cansler, Sharon Hood, J. Morgan Varner, Phillip J. van Mantgem, Michelle Agne, Robert Andrus, Matthew Ayres, Bruce Ayres, Jonathan D. Bakker, Michael Battaglia, Barbara Bentz, Carolyn Breece, James Brown, Daniel Cluck, Tom Coleman, R. Corace, W. Covington, Douglas Cram, James Cronan, Joseph Crouse, Adrian Das, Ryan Davis, Darci Dickinson, Stephen Fitzgerald, Peter Z. Fule, Lisa Ganio, Lindsay Grayson, Charles Halpern, Jim Hanula, Brian Harvey, J. Hiers, David Huffman, MaryBeth Keifer, Tara Keyser, Leda Kobziar, Thomas Kolb, Crystal Kolden, Karen Kopper, Jason Kreitler, Jesse Kreye, Andrew Latimer, Andrew Lerch, Maria Lombardero, Virginia McDaniel, Charles McHugh, Joel McMillin, Jason Moghaddas, Joseph O’Brien, Daniel Perrakis, David Peterson, Susan Pritchard, Robert Progar, Kenneth Raffa, Elizabeth Reinhardt, Joseph Restaino, John Roccaforte, Brendan Rogers, Kevin Ryan, Hugh Safford, Alyson Santoro, Timothy Shearman, Alice Shumate, Carolyn H. Sieg, Sheri Smith, Rebecca Smith, Nathan Stephenson, Mary Stuever, Jens Stevens, Michael Stoddard, Walter Thies, Nicole Vaillant, Shelby Weiss, Douglas Westlind, Travis Woolley, Micah Wright
Coming to terms with the new normal: Forest health in the Sierra Nevada Coming to terms with the new normal: Forest health in the Sierra Nevada
The vast conifer forests of California’s Sierra Nevada range inspire awe and create lasting memories. The size and longevity of these trees make them seem both otherworldly and everlasting. Indeed, their grandeur is such that visitors may not appreciate how these forests are connected to the larger landscape, and so there is little understanding that something as common as a drought...
Authors
Jodi Axelson, John Battles, Adrian J. Das, Phillip J. van Mantgem
The influence of pre-fire growth patterns on post-fire tree mortality for common conifers in western U.S. parks The influence of pre-fire growth patterns on post-fire tree mortality for common conifers in western U.S. parks
Fire severity in forests is often defined in terms of post-fire tree mortality, yet the influences on tree mortality following fire are not fully understood. For trees that are not killed immediately by severe fire injury, pre-fire growth may partially predict post-fire mortality probabilities for conifers of the western U.S. Here, we consider the influence of multiple growth patterns on...
Authors
Phillip van Mantgem, Donald Falk, Emma Williams, Adrian J. Das, Nathan Stephenson
Tree mortality in blue oak woodland during extreme drought in Sequoia National Park, California Tree mortality in blue oak woodland during extreme drought in Sequoia National Park, California
Blue oak woodlands in California have been a focus of conservation concern for many years. Numerous studies have found that existing seedling and sapling numbers are inadequate to sustain current populations, and recent work has suggested that blue oak woodlands might be particularly vulnerable to a warming climate. California has recently experienced a drought of historically...
Authors
Adrian J. Das, Nicholas Ampersee, Anne Pfaff, Nathan Stephenson, Tedmund Swiecki, Elizabeth Bernhardt, Patricia Haggerty, Koren Nydick
Size matters, but not consistently Size matters, but not consistently
E. Pennisi (“Forest giants are the trees most at risk,” News, 6 September, p. 962) interprets presentations of three studies as suggesting that “for trees, size is not strength, and forest giants are disproportionately vulnerable.” However, this conclusion is not well supported. The observation that lightning is a major cause of large-tree mortality on Barro Colorado Island (BCI) is best...
Authors
Nathan Stephenson, Adrian J. Das
Negative impacts of summer heat on Sierra Nevada tree seedlings Negative impacts of summer heat on Sierra Nevada tree seedlings
Understanding the response of forests to climate change is important for predicting changes in biodiversity and ecosystem services, including carbon storage. Seedlings represent a key demographic stage in these responses, because seedling establishment is necessary for population persistence and spread, and because the conditions allowing seedlings to survive and grow are often more...
Authors
Emily Moran, Adrian J. Das, Jon Keeley, Nathan Stephenson
Which trees die during drought? The key role of insect host-tree selection Which trees die during drought? The key role of insect host-tree selection
1. During drought, the tree subpopulations (such as size or vigor classes) that suffer disproportionate mortality can be conceptually arrayed along a continuum defined by the actions of biotic agents, particularly insects. At one extreme, stress dominates: insects are absent or simply kill the most physiologically stressed trees. At the opposite extreme, host selection dominates...
Authors
Nathan Stephenson, Adrian J. Das, Nicholas Ampersee, Beverly Bulaon, Julie Yee
Early-warning signals of individual tree mortality based on annual radial growth Early-warning signals of individual tree mortality based on annual radial growth
Tree mortality is a key driver of forest dynamics and its occurrence is projected to increase in the future due to climate change. Despite recent advances in our understanding of the physiological mechanisms leading to death, we still lack robust indicators of mortality risk that could be applied at the individual tree scale. Here, we build on a previous contribution exploring the...
Authors
Maxime Cailleret, Vasilis Dakos, Steven Jansen, Elisabeth M. R. Robert, Tuomas Aakala, Mariano Amoroso, Joe A. Antos, Christof Bigler, Harald Bugmann, Marco Caccianaga, Jesus-Julio Camarero, Paolo Cherubini, Marie Coyea, Katarina Cufar, Adrian J. Das, Hendrik Davi, Guillermo Gea-Izquierdo, Sten Gillner, Laurel Haavik, Henrik Hartmann, Ana-Maria Heres, Kevin Hultine, Pavel Janda, Jeffrey Kane, Viachelsav Kharuk, Thomas Kitzberger, Tamir Klein, Tom Levanic, Juan-Carlos Linares, Fabio Lombardi, Harri Makinen, Ilona Mészáros, Juha Metsaranta, Walter Oberhuber, Andreas Papadopoulos, Any Petritan, Brigitte Rohner, Gabriel Sanguesa-Barreda, Jeremy Smith, Amanda Stan, Dejan Stojanovic, Maria-Laura Suarez, Miroslav Svoboda, Volodymyr Trotsiuk, Ricardo Villalba, Alana Westwood, Peter Wyckoff, Jordi Martínez-Vilalta
Pre‐fire drought and competition mediate post‐fire conifer mortality in western U.S. National Parks Pre‐fire drought and competition mediate post‐fire conifer mortality in western U.S. National Parks
Tree mortality is an important outcome of many forest fires. Extensive tree injuries from fire may lead directly to mortality, but environmental and biological stressors may also contribute to tree death. However, there is little evidence showing how the combined effects of two common stressors, drought and competition, influence post‐fire mortality. Geographically broad observations of...
Authors
Phillip van Mantgem, Donald Falk, Emma Williams, Adrian J. Das, Nathan Stephenson
Leaf to landscape responses of giant sequoia to hotter drought: An introduction and synthesis for the special section Leaf to landscape responses of giant sequoia to hotter drought: An introduction and synthesis for the special section
Hotter droughts are becoming more common as climate change progresses, and they may already have caused instances of forest dieback on all forested continents. Learning from hotter droughts, including where on the landscape forests are more or less vulnerable to these events, is critical to help resource managers proactively prepare for the future. As part of our Leaf to Landscape...
Authors
Koren Nydick, Nathan Stephenson, Anthony Ambrose, Gregory Asner, Wendy Baxter, Adrian J. Das, Todd Dawson, Roberta Martin, Tarin Paz-Kagan
Remote measurement of canopy water content in giant sequoias (Sequoiadendron giganteum) during drought Remote measurement of canopy water content in giant sequoias (Sequoiadendron giganteum) during drought
California experienced severe drought from 2012 to 2016, and there were visible changes in the forest canopy throughout the State. In 2014, unprecedented foliage dieback was recorded in giant sequoia (Sequoiadendron giganteum) trees in Sequoia National Park, in the southern California Sierra Nevada mountains. Although visible changes in sequoia canopies can be recorded, biochemical and...
Authors
Roberta Martin, Gregory Asner, Emily Francis, Anthony Ambrose, Wendy Baxter, Adrian J. Das, Nicolas Vaughn, Tarin Paz-Kagan, Todd Dawson, Koren Nydick, Nathan Stephenson