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
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Filter Total Items: 53
What mediates tree mortality during drought in the southern Sierra Nevada?
Severe drought has the potential to cause selective mortality within a forest, thereby inducing shifts in forest species composition. The southern Sierra Nevada foothills and mountains of California have experienced extensive forest dieback due to drought stress and insect outbreak. We used high-fidelity imaging spectroscopy (HiFIS) and light detection and ranging (LiDAR) from the Carnegie Airborn
Authors
Tarin Paz-Kagan, Philip Brodrick, Nicholas R. Vaughn, Adrian J. Das, Nathan L. Stephenson, Koren R. Nydick, Gregory P. Asner
Seasonal and diel environmental conditions predict western pond turtle (Emys marmorata) behavior at a perennial and an ephemeral stream in Sequoia National Park, California
Managers making decisions may benefit from a well-informed understanding of a species' population size and trends. Given the cryptic nature and habitat characteristics of the western pond turtle (Emys marmorata), however, imperfect detection may be high and population estimates are frequently varied and unreliable. As a case study to investigate this issue, we used temperature dataloggers to exami
Authors
Gabrielle Ruso, Erik Meyer, Adrian J. Das
A synthesis of radial growth patterns preceding tree mortality
Tree mortality is a key factor influencing forest functions and dynamics, but our understanding of the mechanisms leading to mortality and the associated changes in tree growth rates are still limited. We compiled a new pan-continental tree-ring width database from sites where both dead and living trees were sampled (2970 dead and 4224 living trees from 190 sites, including 36 species), and compar
Authors
Maxime Cailleret, Steven Jansen, Elisabeth M.R. Robert, Lucia Desoto, Tuomas Aakala, Joseph A. Antos, Barbara Beikircher, Christof Bigler, Harald Bugmann, Marco Caccianiga, Vojtech Cada, Jesus J. Camarero, Paolo Cherubini, Herve Cochard, Marie R. Coyea, Katarina Cufar, Adrian J. Das, Hendrik Davi, Sylvain Delzon, Michael Dorman, Guillermo Gea-Izquierdo, Sten Gillner, Laurel J. Haavik, Henrik Hartmann, Ana-Maria Heres, Kevin R. Hultine, Pavel Janda, Jeffrey M. Kane, Vyacheslav I. Kharuk, Thomas Kitzberger, Tamir Klein, Koen Kramer, Frederic Lens, Tom Levanic, Juan C. Linares Calderon, Francisco Lloret, Raquel Lobo-Do-Vale, Fabio Lombardi, Rosana Lopez Rodriguez, Harri Makinen, Stefan Mayr, IIona Meszaros, Juha M. Metsaranta, Francesco Minunno, Walter Oberhuber, Andreas Papadopoulos, Mikko Peltoniemi, Any M. Petritan, Brigitte Rohner, Gabriel Sanguesa-Barreda, Dimitrios Sarris, Jeremy M. Smith, Amanda B. Stan, Frank Sterck, Dejan B. Stojanovic, Maria L. Suarez, Miroslav Svoboda, Roberto Tognetti, Jose M. Torres-Ruiz, Volodymyr Trotsiuk, Ricardo Villalba, Floor Vodde, Alana R. Westwood, Peter H. Wyckoff, Nikolay Zafirov, Jordi Martínez-Vilalta
Why do trees die? Characterizing the drivers of background tree mortality
The drivers of background tree mortality rates—the typical low rates of tree mortality found in forests in the absence of acute stresses like drought—are central to our understanding of forest dynamics, the effects of ongoing environmental changes on forests, and the causes and consequences of geographical gradients in the nature and strength of biotic interactions. To shed light on factors contri
Authors
Adrian J. Das, Nathan L. Stephenson, Kristin P. Davis
Does prescribed fire promote resistance to drought in low elevation forests of the Sierra Nevada, California, USA?
Prescribed fire is a primary tool used to restore western forests following more than a century of fire exclusion, reducing fire hazard by removing dead and live fuels (small trees and shrubs). It is commonly assumed that the reduced forest density following prescribed fire also reduces competition for resources among the remaining trees, so that the remaining trees are more resistant (more likel
Authors
Phillip J. van Mantgem, Anthony C. Caprio, Nathan L. Stephenson, Adrian J. Das
Improving estimates of tree mortality probability using potential growth rate
Tree growth rate is frequently used to estimate mortality probability. Yet, growth metrics can vary in form, and the justification for using one over another is rarely clear. We tested whether a growth index (GI) that scales the realized diameter growth rate against the potential diameter growth rate (PDGR) would give better estimates of mortality probability than other measures. We also tested wh
Authors
Adrian J. Das, Nathan L. Stephenson
The influence of prefire tree growth and crown condition on postfire mortality of sugar pine following prescribed fire in Sequoia National Park
Tree mortality is a vital component of forest management in the context of prescribed fires; however, few studies have examined the effect of prefire tree health on postfire mortality. This is especially relevant for sugar pine (Pinus lambertiana Douglas), a species experiencing population declines due to a suite of anthropogenic factors. Using data from an old-growth mixed-conifer forest in Sequo
Authors
Jonathan C. B. Nesmith, Adrian J. Das, Kevin L. O'Hara, Phillip J. van Mantgem
Beyond reducing fire hazard: fuel treatment impacts on overstory tree survival
Fuel treatment implementation in dry forest types throughout the western United States is likely to increase in pace and scale in response to increasing incidence of large wildfires. While it is clear that properly implemented fuel treatments are effective at reducing hazardous fire potential, there are ancillary ecological effects that can impact forest resilience either positively or negatively
Authors
Brandon M. Collins, Adrian J. Das, John J. Battles, Danny L. Fry, Kevin Krasnow, Scott L. Stephens
An individual-based growth and competition model for coastal redwood forest restoration
Thinning treatments to accelerate coastal redwood forest stand development are in wide application, but managers have yet to identify prescriptions that might best promote Sequoia sempervirens (Lamb. ex D. Don) Endl. (redwood) growth. The creation of successful thinning prescriptions would be aided by identifying the underlying mechanisms governing how individual tree growth responds to competitiv
Authors
Phillip J. van Mantgem, Adrian J. Das
Rate of tree carbon accumulation increases continuously with tree size
Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest carbon cycle—particularly net primary productivity and carbon storage - increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves t
Authors
N.L. Stephenson, A.J. Das, R. Condit, S.E. Russo, P.J. Baker, N.G. Beckman, D.A. Coomes, E.R. Lines, W.K. Morris, N. Rüger, E. Álvarez, C. Blundo, S. Bunyavejchewin, G. Chuyong, S.J. Davies, Á. Duque, C.N. Ewango, O. Flores, J.F. Franklin, H.R. Grau, Z. Hao, M. E. Harmon, S.P. Hubbell, D. Kenfack, Y. Lin, J.-R. Makana, A. Malizia, L.R. Malizia, R.J. Pabst, N. Pongpattananurak, S.-H. Su, I-F. Sun, S. Tan, D. Thomas, P. J. van Mantgem, X. Wang, S.K. Wiser, M.A. Zavala
Climatic correlates of tree mortality in water- and energy-limited forests
Recent increases in tree mortality rates across the western USA are correlated with increasing temperatures, but mechanisms remain unresolved. Specifically, increasing mortality could predominantly be a consequence of temperature-induced increases in either (1) drought stress, or (2) the effectiveness of tree-killing insects and pathogens. Using long-term data from California’s Sierra Nevada mount
Authors
Adrian J. Das, Nathan L. Stephenson, Alan Flint, Tapash Das, Phillip J. van Mantgem
A natural resource condition assessment for Sequoia and Kings Canyon National Parks: Appendix 14: plants of conservation concern
Sequoia and Kings Canyon National Parks are located in the California Floristic Province, which
has been named one of world‘s hotspots of endemic biodiversity (Myers et al. 2000). The
California Floristic Province is the largest and most important geographic floristic unit in
California and extends from the Klamath Mountains of southwestern Oregon to the northwestern
portion of Baja California
Authors
Ann Huber, Adrian Das, Rebecca Wenk, Sylvia Haultain
Science and Products
Filter Total Items: 14
No Result Found
Filter Total Items: 53
What mediates tree mortality during drought in the southern Sierra Nevada?
Severe drought has the potential to cause selective mortality within a forest, thereby inducing shifts in forest species composition. The southern Sierra Nevada foothills and mountains of California have experienced extensive forest dieback due to drought stress and insect outbreak. We used high-fidelity imaging spectroscopy (HiFIS) and light detection and ranging (LiDAR) from the Carnegie Airborn
Authors
Tarin Paz-Kagan, Philip Brodrick, Nicholas R. Vaughn, Adrian J. Das, Nathan L. Stephenson, Koren R. Nydick, Gregory P. Asner
Seasonal and diel environmental conditions predict western pond turtle (Emys marmorata) behavior at a perennial and an ephemeral stream in Sequoia National Park, California
Managers making decisions may benefit from a well-informed understanding of a species' population size and trends. Given the cryptic nature and habitat characteristics of the western pond turtle (Emys marmorata), however, imperfect detection may be high and population estimates are frequently varied and unreliable. As a case study to investigate this issue, we used temperature dataloggers to exami
Authors
Gabrielle Ruso, Erik Meyer, Adrian J. Das
A synthesis of radial growth patterns preceding tree mortality
Tree mortality is a key factor influencing forest functions and dynamics, but our understanding of the mechanisms leading to mortality and the associated changes in tree growth rates are still limited. We compiled a new pan-continental tree-ring width database from sites where both dead and living trees were sampled (2970 dead and 4224 living trees from 190 sites, including 36 species), and compar
Authors
Maxime Cailleret, Steven Jansen, Elisabeth M.R. Robert, Lucia Desoto, Tuomas Aakala, Joseph A. Antos, Barbara Beikircher, Christof Bigler, Harald Bugmann, Marco Caccianiga, Vojtech Cada, Jesus J. Camarero, Paolo Cherubini, Herve Cochard, Marie R. Coyea, Katarina Cufar, Adrian J. Das, Hendrik Davi, Sylvain Delzon, Michael Dorman, Guillermo Gea-Izquierdo, Sten Gillner, Laurel J. Haavik, Henrik Hartmann, Ana-Maria Heres, Kevin R. Hultine, Pavel Janda, Jeffrey M. Kane, Vyacheslav I. Kharuk, Thomas Kitzberger, Tamir Klein, Koen Kramer, Frederic Lens, Tom Levanic, Juan C. Linares Calderon, Francisco Lloret, Raquel Lobo-Do-Vale, Fabio Lombardi, Rosana Lopez Rodriguez, Harri Makinen, Stefan Mayr, IIona Meszaros, Juha M. Metsaranta, Francesco Minunno, Walter Oberhuber, Andreas Papadopoulos, Mikko Peltoniemi, Any M. Petritan, Brigitte Rohner, Gabriel Sanguesa-Barreda, Dimitrios Sarris, Jeremy M. Smith, Amanda B. Stan, Frank Sterck, Dejan B. Stojanovic, Maria L. Suarez, Miroslav Svoboda, Roberto Tognetti, Jose M. Torres-Ruiz, Volodymyr Trotsiuk, Ricardo Villalba, Floor Vodde, Alana R. Westwood, Peter H. Wyckoff, Nikolay Zafirov, Jordi Martínez-Vilalta
Why do trees die? Characterizing the drivers of background tree mortality
The drivers of background tree mortality rates—the typical low rates of tree mortality found in forests in the absence of acute stresses like drought—are central to our understanding of forest dynamics, the effects of ongoing environmental changes on forests, and the causes and consequences of geographical gradients in the nature and strength of biotic interactions. To shed light on factors contri
Authors
Adrian J. Das, Nathan L. Stephenson, Kristin P. Davis
Does prescribed fire promote resistance to drought in low elevation forests of the Sierra Nevada, California, USA?
Prescribed fire is a primary tool used to restore western forests following more than a century of fire exclusion, reducing fire hazard by removing dead and live fuels (small trees and shrubs). It is commonly assumed that the reduced forest density following prescribed fire also reduces competition for resources among the remaining trees, so that the remaining trees are more resistant (more likel
Authors
Phillip J. van Mantgem, Anthony C. Caprio, Nathan L. Stephenson, Adrian J. Das
Improving estimates of tree mortality probability using potential growth rate
Tree growth rate is frequently used to estimate mortality probability. Yet, growth metrics can vary in form, and the justification for using one over another is rarely clear. We tested whether a growth index (GI) that scales the realized diameter growth rate against the potential diameter growth rate (PDGR) would give better estimates of mortality probability than other measures. We also tested wh
Authors
Adrian J. Das, Nathan L. Stephenson
The influence of prefire tree growth and crown condition on postfire mortality of sugar pine following prescribed fire in Sequoia National Park
Tree mortality is a vital component of forest management in the context of prescribed fires; however, few studies have examined the effect of prefire tree health on postfire mortality. This is especially relevant for sugar pine (Pinus lambertiana Douglas), a species experiencing population declines due to a suite of anthropogenic factors. Using data from an old-growth mixed-conifer forest in Sequo
Authors
Jonathan C. B. Nesmith, Adrian J. Das, Kevin L. O'Hara, Phillip J. van Mantgem
Beyond reducing fire hazard: fuel treatment impacts on overstory tree survival
Fuel treatment implementation in dry forest types throughout the western United States is likely to increase in pace and scale in response to increasing incidence of large wildfires. While it is clear that properly implemented fuel treatments are effective at reducing hazardous fire potential, there are ancillary ecological effects that can impact forest resilience either positively or negatively
Authors
Brandon M. Collins, Adrian J. Das, John J. Battles, Danny L. Fry, Kevin Krasnow, Scott L. Stephens
An individual-based growth and competition model for coastal redwood forest restoration
Thinning treatments to accelerate coastal redwood forest stand development are in wide application, but managers have yet to identify prescriptions that might best promote Sequoia sempervirens (Lamb. ex D. Don) Endl. (redwood) growth. The creation of successful thinning prescriptions would be aided by identifying the underlying mechanisms governing how individual tree growth responds to competitiv
Authors
Phillip J. van Mantgem, Adrian J. Das
Rate of tree carbon accumulation increases continuously with tree size
Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest carbon cycle—particularly net primary productivity and carbon storage - increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves t
Authors
N.L. Stephenson, A.J. Das, R. Condit, S.E. Russo, P.J. Baker, N.G. Beckman, D.A. Coomes, E.R. Lines, W.K. Morris, N. Rüger, E. Álvarez, C. Blundo, S. Bunyavejchewin, G. Chuyong, S.J. Davies, Á. Duque, C.N. Ewango, O. Flores, J.F. Franklin, H.R. Grau, Z. Hao, M. E. Harmon, S.P. Hubbell, D. Kenfack, Y. Lin, J.-R. Makana, A. Malizia, L.R. Malizia, R.J. Pabst, N. Pongpattananurak, S.-H. Su, I-F. Sun, S. Tan, D. Thomas, P. J. van Mantgem, X. Wang, S.K. Wiser, M.A. Zavala
Climatic correlates of tree mortality in water- and energy-limited forests
Recent increases in tree mortality rates across the western USA are correlated with increasing temperatures, but mechanisms remain unresolved. Specifically, increasing mortality could predominantly be a consequence of temperature-induced increases in either (1) drought stress, or (2) the effectiveness of tree-killing insects and pathogens. Using long-term data from California’s Sierra Nevada mount
Authors
Adrian J. Das, Nathan L. Stephenson, Alan Flint, Tapash Das, Phillip J. van Mantgem
A natural resource condition assessment for Sequoia and Kings Canyon National Parks: Appendix 14: plants of conservation concern
Sequoia and Kings Canyon National Parks are located in the California Floristic Province, which
has been named one of world‘s hotspots of endemic biodiversity (Myers et al. 2000). The
California Floristic Province is the largest and most important geographic floristic unit in
California and extends from the Klamath Mountains of southwestern Oregon to the northwestern
portion of Baja California
Authors
Ann Huber, Adrian Das, Rebecca Wenk, Sylvia Haultain