Adrian Das
I am an Ecologist with the U.S. Geological Survey's Western Ecological Research Center, stationed at Sequoia and Kings Canyon National Parks. I study tree dynamics with a particular focus on tree mortality processes. My work is aimed at improving our understanding of western forests and increasing our capacity to assess how they will be affected by a changing climate.
RESEARCH INTERESTS
- Forest ecology
- Forest dynamics
- Tree mortality
- Tree growth
- Climatic change
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: 14
Sequoia foliage dieback data from Sequoia National Park
These datasets provide spatially-explicit estimates of the magnitude of giant sequoia foliage dieback along selected trail corridors in Sequoia and Kings Canyon national parks, California, from 2014 through 2017. They additionally provide giant sequoia tree-ring measurements, through the year 1989, for two locations in the Giant Forest grove, Sequoia National Park, California.
Mortality factors for dead trees from a subset of plots from the Sierra Nevada Forest Dynamics Plot Network from 1998 to 2010
This dataset was used to summarize and analyze the mortality factors recorded on dead trees in the Sierra Nevada Forest Dynamics Plot Network, which is managed by the Sequoia and Kings Canyon Field station of the U.S. Geological Survey's Western Ecological Research Center. Each row of the dataset represents an individual dead tree. These are dead trees that were recorded in the network from 1998 t
Filter Total Items: 51
Mapping the vulnerability of giant sequoias after extreme drought in California using remote sensing
Between 2012 and 2016, California suffered one of the most severe droughts on record. During this period Sequoiadendron giganteum (giant sequoias) in the Sequoia and Kings Canyon National Parks (SEKI), California, USA experienced canopy water content (CWC) loss, unprecedented foliage senescence, and, in a few cases, death. We present an assessment of the vulnerability of giant sequoia populations
Authors
Andres Baeza, Roberta E. Martin, Nathan L. Stephenson, Adrian Das, Paul Hardwick, Koren R. Nydick, Jeff Mallory, Michèle Slaton, Kirk Evans, Gregory P. Asner
Continent-wide tree fecundity driven by indirect climate effects
Indirect climate effects on tree fecundity that come through variation in size and growth (climate-condition interactions) are not currently part of models used to predict future forests. Trends in species abundances predicted from meta-analyses and species distribution models will be misleading if they depend on the conditions of individuals. Here we find from a synthesis of tree species in North
Authors
James S. Clark, Robert A. Andrus, Melaine Aubry-Kientz, Yves Bergeron, Michal Bogdziewicz, Don C. Bragg, Dale G. Brockway, Natalie L. Cleavitt, Susan Cohen, Benoit Courbaud, Robert Daley, Adrian Das, Michael Dietze, Timothy J. Fahey, Istem Fer, Jerry F. Franklin, Catherine A. Gehring, Gregory S. Gilbert, Catheryn H Greenberg, Qinfeng Guo, Janneke Hille Ris Lambers, Ines Ibanez, Jill F. Johnstone, Christopher L. Kilner, Johannes MH Knops, Walter D. Koenig, Georges Kunstler, Jalene M. LaMontagne, Kristin L Legg, Jordan Luongo, James A. Lutz, Diana Macias, Eliot J. B. McIntire, Yassine Messaoud, Christopher M. Moore, Emily V. Moran, Orrin B Myers, Chase Nunez, Robert Parmenter, Scott Pearson, Renata Poulton Kamakura, Ethan Ready, Miranda D. Redmond, Chantal D. Reid, Kyle C. Rodman, C. Lane Scher, Wiliam H Schlesinger, Amanda M Schwantes, Erin Shanahan, Shubhi Sharma, Michael A. Steele, Nathan L. Stephenson, Samantha Sutton, Jennifer J. Swenson, Margaret Swift, Thomas T. Veblen, Amy V. Whipple, Thomas G. Whitham, Andreas P. Wion, Kai Zhu, Roman Zlotin
Why is tree drought mortality so hard to predict?
Widespread tree mortality following droughts has emerged as an environmentally and economically devastating ‘ecological surprise’. It is well established that tree physiology is important in understanding drought-driven mortality; however, the accuracy of predictions based on physiology alone has been limited. We propose that complicating factors at two levels stymie predictions of drought-driven
Authors
Anna T Trugman, Leander D.L. Anderegg, William RL Anderegg, Adrian Das, Nathan L. Stephenson
Seed production patterns of surviving Sierra Nevada conifers show minimal change following drought
Reproduction is a key component of ecological resilience in forest ecosystems, so understanding how seed production is influenced by extreme drought is key to understanding forest recovery trajectories. If trees respond to mortality-inducing drought by preferentially allocating resources for reproduction, the recovery of the stand to pre-drought conditions may be enhanced accordingly. We used a 20
Authors
Micah C. Wright, Phillip J. van Mantgem, Nathan L. Stephenson, Adrian Das, Jon Keeley
Effects of postfire climate and seed availability on postfire conifer regeneration
Large, severe fires are becoming more frequent in many forest types across the western United States and have resulted in tree mortality across tens of thousands of hectares. Conifer regeneration in these areas is limited because seeds must travel long distances to reach the interior of large burned patches and establishment is jeopardized by increasingly hot and dry conditions. To better inform p
Authors
Joseph A E Stewart, Phillip J. van Mantgem, Derek J N Young, Kristen L. Shive, Haiganoush K. Preisler, Adrian Das, Nathan L. Stephenson, Jon Keeley, Hugh D. Safford, Micah C. Wright, Kevin R Welch, James H. Thorne
Compounding effects of white pine blister rust, mountain pine beetle, and fire threaten four white pine species
Invasive pathogens and bark beetles have caused precipitous declines of various tree species around the globe. Here, we characterized long‐term patterns of mountain pine beetle (Dendroctonus ponderosae; MPB) attacks and white pine blister rust, an infectious tree disease caused by the pathogen, Cronartium ribicola. We focused on four dominant white pine host species in Sequoia and Kings Canyon Nat
Authors
Joan C Dudney, Jonathan C B Nesmith, Matthew Cahill, Jennifer E Cribbs, Dan M Duriscoe, Adrian Das, Nathan L. Stephenson, John J. Battles
Mortality predispositions of conifers across western USA
Conifer mortality rates are increasing in western North America, but the physiological mechanisms underlying this trend are not well understood.We examined tree‐ring‐based radial growth along with stable carbon (C) and oxygen (O) isotope composition (δ13C and δ18O, respectively) of dying and surviving conifers at eight old‐growth forest sites across a strong moisture gradient in the western USA to
Authors
Wenzhi Wang, Nathan B. English, Charlotte Grossiord, Arthur Gessler, Adrian Das, Nathan L. Stephenson, Christopher H. Baisan, Craig D. Allen, Nate G. McDowell
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 contemporan
Authors
Nathan L. Stephenson, Adrian Das
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 includes records
Authors
C. Alina Cansler, Sharon M. Hood, J. Morgan Varner, Phillip J. van Mantgem, Michelle C. Agne, Robert A. Andrus, Matthew P. Ayres, Bruce D. Ayres, Jonathan D. Bakker, Michael A. Battaglia, Barbara J. Bentz, Carolyn R. Breece, James K. Brown, Daniel R. Cluck, Tom W. Coleman, R. Gregory Corace, W. Wallace Covington, Douglas S. Cram, James B. Cronan, Joseph E. Crouse, Adrian Das, Ryan S. Davis, Darci M. Dickinson, Stephen A Fitzgerald, Peter Z. Fule, Lisa M. Ganio, Lindsay M. Grayson, Charles B. Halpern, Jim L. Hanula, Brian J. Harvey, J. Kevin Hiers, David W. Huffman, MaryBeth Keifer, Tara L. Keyser, Leda N. Kobziar, Thomas E. Kolb, Crystal A. Kolden, Karen E. Kopper, Jason R. Kreitler, Jesse K. Kreye, Andrew M. Latimer, Andrew P. Lerch, Maria J. Lombardero, Virginia L. McDaniel, Charles W. McHugh, Joel D. McMillin, Jason J. Moghaddas, Joseph J. O'Brien, Daniel D. B. Perrakis, David W. Peterson, Susan J. Pritchard, Robert A. Progar, Kenneth F. Raffa, Elizabeth D. Reinhardt, Joseph C. Restaino, John P. Roccaforte, Brendan M. Rogers, Kevin C. Ryan, Hugh D. Safford, Alyson E. Santoro, Timothy M. Shearman, Alice M. Shumate, Carolyn H. Sieg, Sheri L. Smith, Rebecca J. Smith, Nathan L. Stephenson, Mary Stuever, Jens Stevens, Michael T. Stoddard, Walter G. Thies, Nicole M. Vaillant, Shelby A. Weiss, Douglas J. Westlind, Travis J. Woolley, Micah C. Wright
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 could lead to
Authors
Jodi Axelson, John J. 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
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 post-fire
Authors
Phillip van Mantgem, Donald A. Falk, Emma C. Williams, Adrian J. Das, Nathan L. Stephenson
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 unprecedented severi
Authors
Adrian J. Das, Nicholas J. Ampersee, Anne Hopkins Pfaff, Nathan L. Stephenson, Tedmund J Swiecki, Elizabeth A Bernhardt, Patricia Haggerty, Koren R. Nydick
Science and Products
- Science
- Data
Filter Total Items: 14
Sequoia foliage dieback data from Sequoia National Park
These datasets provide spatially-explicit estimates of the magnitude of giant sequoia foliage dieback along selected trail corridors in Sequoia and Kings Canyon national parks, California, from 2014 through 2017. They additionally provide giant sequoia tree-ring measurements, through the year 1989, for two locations in the Giant Forest grove, Sequoia National Park, California.Mortality factors for dead trees from a subset of plots from the Sierra Nevada Forest Dynamics Plot Network from 1998 to 2010
This dataset was used to summarize and analyze the mortality factors recorded on dead trees in the Sierra Nevada Forest Dynamics Plot Network, which is managed by the Sequoia and Kings Canyon Field station of the U.S. Geological Survey's Western Ecological Research Center. Each row of the dataset represents an individual dead tree. These are dead trees that were recorded in the network from 1998 t - Publications
Filter Total Items: 51
Mapping the vulnerability of giant sequoias after extreme drought in California using remote sensing
Between 2012 and 2016, California suffered one of the most severe droughts on record. During this period Sequoiadendron giganteum (giant sequoias) in the Sequoia and Kings Canyon National Parks (SEKI), California, USA experienced canopy water content (CWC) loss, unprecedented foliage senescence, and, in a few cases, death. We present an assessment of the vulnerability of giant sequoia populationsAuthorsAndres Baeza, Roberta E. Martin, Nathan L. Stephenson, Adrian Das, Paul Hardwick, Koren R. Nydick, Jeff Mallory, Michèle Slaton, Kirk Evans, Gregory P. AsnerContinent-wide tree fecundity driven by indirect climate effects
Indirect climate effects on tree fecundity that come through variation in size and growth (climate-condition interactions) are not currently part of models used to predict future forests. Trends in species abundances predicted from meta-analyses and species distribution models will be misleading if they depend on the conditions of individuals. Here we find from a synthesis of tree species in NorthAuthorsJames S. Clark, Robert A. Andrus, Melaine Aubry-Kientz, Yves Bergeron, Michal Bogdziewicz, Don C. Bragg, Dale G. Brockway, Natalie L. Cleavitt, Susan Cohen, Benoit Courbaud, Robert Daley, Adrian Das, Michael Dietze, Timothy J. Fahey, Istem Fer, Jerry F. Franklin, Catherine A. Gehring, Gregory S. Gilbert, Catheryn H Greenberg, Qinfeng Guo, Janneke Hille Ris Lambers, Ines Ibanez, Jill F. Johnstone, Christopher L. Kilner, Johannes MH Knops, Walter D. Koenig, Georges Kunstler, Jalene M. LaMontagne, Kristin L Legg, Jordan Luongo, James A. Lutz, Diana Macias, Eliot J. B. McIntire, Yassine Messaoud, Christopher M. Moore, Emily V. Moran, Orrin B Myers, Chase Nunez, Robert Parmenter, Scott Pearson, Renata Poulton Kamakura, Ethan Ready, Miranda D. Redmond, Chantal D. Reid, Kyle C. Rodman, C. Lane Scher, Wiliam H Schlesinger, Amanda M Schwantes, Erin Shanahan, Shubhi Sharma, Michael A. Steele, Nathan L. Stephenson, Samantha Sutton, Jennifer J. Swenson, Margaret Swift, Thomas T. Veblen, Amy V. Whipple, Thomas G. Whitham, Andreas P. Wion, Kai Zhu, Roman ZlotinWhy is tree drought mortality so hard to predict?
Widespread tree mortality following droughts has emerged as an environmentally and economically devastating ‘ecological surprise’. It is well established that tree physiology is important in understanding drought-driven mortality; however, the accuracy of predictions based on physiology alone has been limited. We propose that complicating factors at two levels stymie predictions of drought-drivenAuthorsAnna T Trugman, Leander D.L. Anderegg, William RL Anderegg, Adrian Das, Nathan L. StephensonSeed production patterns of surviving Sierra Nevada conifers show minimal change following drought
Reproduction is a key component of ecological resilience in forest ecosystems, so understanding how seed production is influenced by extreme drought is key to understanding forest recovery trajectories. If trees respond to mortality-inducing drought by preferentially allocating resources for reproduction, the recovery of the stand to pre-drought conditions may be enhanced accordingly. We used a 20AuthorsMicah C. Wright, Phillip J. van Mantgem, Nathan L. Stephenson, Adrian Das, Jon KeeleyEffects of postfire climate and seed availability on postfire conifer regeneration
Large, severe fires are becoming more frequent in many forest types across the western United States and have resulted in tree mortality across tens of thousands of hectares. Conifer regeneration in these areas is limited because seeds must travel long distances to reach the interior of large burned patches and establishment is jeopardized by increasingly hot and dry conditions. To better inform pAuthorsJoseph A E Stewart, Phillip J. van Mantgem, Derek J N Young, Kristen L. Shive, Haiganoush K. Preisler, Adrian Das, Nathan L. Stephenson, Jon Keeley, Hugh D. Safford, Micah C. Wright, Kevin R Welch, James H. ThorneCompounding effects of white pine blister rust, mountain pine beetle, and fire threaten four white pine species
Invasive pathogens and bark beetles have caused precipitous declines of various tree species around the globe. Here, we characterized long‐term patterns of mountain pine beetle (Dendroctonus ponderosae; MPB) attacks and white pine blister rust, an infectious tree disease caused by the pathogen, Cronartium ribicola. We focused on four dominant white pine host species in Sequoia and Kings Canyon NatAuthorsJoan C Dudney, Jonathan C B Nesmith, Matthew Cahill, Jennifer E Cribbs, Dan M Duriscoe, Adrian Das, Nathan L. Stephenson, John J. BattlesMortality predispositions of conifers across western USA
Conifer mortality rates are increasing in western North America, but the physiological mechanisms underlying this trend are not well understood.We examined tree‐ring‐based radial growth along with stable carbon (C) and oxygen (O) isotope composition (δ13C and δ18O, respectively) of dying and surviving conifers at eight old‐growth forest sites across a strong moisture gradient in the western USA toAuthorsWenzhi Wang, Nathan B. English, Charlotte Grossiord, Arthur Gessler, Adrian Das, Nathan L. Stephenson, Christopher H. Baisan, Craig D. Allen, Nate G. McDowellHeight-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 contemporanAuthorsNathan L. Stephenson, Adrian DasThe 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 includes recordsAuthorsC. Alina Cansler, Sharon M. Hood, J. Morgan Varner, Phillip J. van Mantgem, Michelle C. Agne, Robert A. Andrus, Matthew P. Ayres, Bruce D. Ayres, Jonathan D. Bakker, Michael A. Battaglia, Barbara J. Bentz, Carolyn R. Breece, James K. Brown, Daniel R. Cluck, Tom W. Coleman, R. Gregory Corace, W. Wallace Covington, Douglas S. Cram, James B. Cronan, Joseph E. Crouse, Adrian Das, Ryan S. Davis, Darci M. Dickinson, Stephen A Fitzgerald, Peter Z. Fule, Lisa M. Ganio, Lindsay M. Grayson, Charles B. Halpern, Jim L. Hanula, Brian J. Harvey, J. Kevin Hiers, David W. Huffman, MaryBeth Keifer, Tara L. Keyser, Leda N. Kobziar, Thomas E. Kolb, Crystal A. Kolden, Karen E. Kopper, Jason R. Kreitler, Jesse K. Kreye, Andrew M. Latimer, Andrew P. Lerch, Maria J. Lombardero, Virginia L. McDaniel, Charles W. McHugh, Joel D. McMillin, Jason J. Moghaddas, Joseph J. O'Brien, Daniel D. B. Perrakis, David W. Peterson, Susan J. Pritchard, Robert A. Progar, Kenneth F. Raffa, Elizabeth D. Reinhardt, Joseph C. Restaino, John P. Roccaforte, Brendan M. Rogers, Kevin C. Ryan, Hugh D. Safford, Alyson E. Santoro, Timothy M. Shearman, Alice M. Shumate, Carolyn H. Sieg, Sheri L. Smith, Rebecca J. Smith, Nathan L. Stephenson, Mary Stuever, Jens Stevens, Michael T. Stoddard, Walter G. Thies, Nicole M. Vaillant, Shelby A. Weiss, Douglas J. Westlind, Travis J. Woolley, Micah C. WrightComing 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 could lead toAuthorsJodi Axelson, John J. Battles, Adrian J. Das, Phillip J. van MantgemThe 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 post-fireAuthorsPhillip van Mantgem, Donald A. Falk, Emma C. Williams, Adrian J. Das, Nathan L. StephensonTree 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 unprecedented severiAuthorsAdrian J. Das, Nicholas J. Ampersee, Anne Hopkins Pfaff, Nathan L. Stephenson, Tedmund J Swiecki, Elizabeth A Bernhardt, Patricia Haggerty, Koren R. Nydick - Software
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