39 results on '"Collins, Adam D."'
Search Results
2. Dry Season Transpiration and Soil Water Dynamics in the Central Amazon
- Author
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Spanner, Gustavo C, Gimenez, Bruno O, Wright, Cynthia L, Menezes, Valdiek Silva, Newman, Brent D, Collins, Adam D, Jardine, Kolby J, Negrón-Juárez, Robinson I, Lima, Adriano José Nogueira, Rodrigues, Jardel Ramos, Chambers, Jeffrey Q, Higuchi, Niro, and Warren, Jeffrey M
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Agricultural ,Veterinary and Food Sciences ,Biological Sciences ,Ecology ,Plant Biology ,Forestry Sciences ,Life on Land ,allometry ,tropical forests ,ecohydrology ,root water uptake ,basal area ,root distribution ,sap flow ,Crop and pasture production ,Plant biology - Abstract
With current observations and future projections of more intense and frequent droughts in the tropics, understanding the impact that extensive dry periods may have on tree and ecosystem-level transpiration and concurrent carbon uptake has become increasingly important. Here, we investigate paired soil and tree water extraction dynamics in an old-growth upland forest in central Amazonia during the 2018 dry season. Tree water use was assessed via radial patterns of sap flow in eight dominant canopy trees, each a different species with a range in diameter, height, and wood density. Paired multi-sensor soil moisture probes used to quantify volumetric water content dynamics and soil water extraction within the upper 100 cm were installed adjacent to six of those trees. To link depth-specific water extraction patterns to root distribution, fine root biomass was assessed through the soil profile to 235 cm. To scale tree water use to the plot level (stand transpiration), basal area was measured for all trees within a 5 m radius around each soil moisture probe. The sensitivity of tree transpiration to reduced precipitation varied by tree, with some increasing and some decreasing in water use during the dry period. Tree-level water use scaled with sapwood area, from 11 to 190 L per day. Stand level water use, based on multiple plots encompassing sap flow and adjacent trees, varied from ∼1.7 to 3.3 mm per day, increasing linearly with plot basal area. Soil water extraction was dependent on root biomass, which was dense at the surface (i.e., 45% in the upper 5 cm) and declined dramatically with depth. As the dry season progressed and the upper soil dried, soil water extraction shifted to deeper levels and model projections suggest that much of the water used during the month-long dry-down could be extracted from the upper 2-3 m. Results indicate variation in rates of soil water extraction across the research area and, temporally, through the soil profile. These results provide key information on whole-tree contributions to transpiration by canopy trees as water availability changes. In addition, information on simultaneous stand level dynamics of soil water extraction that can inform mechanistic models that project tropical forest response to drought.
- Published
- 2022
3. Homoeostatic maintenance of nonstructural carbohydrates during the 2015–2016 El Niño drought across a tropical forest precipitation gradient
- Author
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Dickman, Lee Turin, McDowell, Nate G, Grossiord, Charlotte, Collins, Adam D, Wolfe, Brett T, Detto, Matteo, Wright, S Joseph, Medina‐Vega, José A, Goodsman, Devin, Rogers, Alistair, Serbin, Shawn P, Wu, Jin, Ely, Kim S, Michaletz, Sean T, Xu, Chonggang, Kueppers, Lara, and Chambers, Jeffrey Q
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Plant Biology ,Biological Sciences ,Ecology ,Carbohydrates ,Droughts ,El Nino-Southern Oscillation ,Forests ,Panama ,Photosynthesis ,Plant Leaves ,Seasons ,Starch ,Sugars ,Trees ,Tropical Climate ,Wood ,climate ,ENSO ,NSC ,storage ,sugars ,tropics ,vegetation ,Agricultural and Veterinary Sciences ,Plant Biology & Botany ,Plant biology - Abstract
Nonstructural carbohydrates (NSCs) are essential for maintenance of plant metabolism and may be sensitive to short- and long-term climatic variation. NSC variation in moist tropical forests has rarely been studied, so regulation of NSCs in these systems is poorly understood. We measured foliar and branch NSC content in 23 tree species at three sites located across a large precipitation gradient in Panama during the 2015-2016 El Niño to examine how short- and long-term climatic variation impact carbohydrate dynamics. There was no significant difference in total NSCs as the drought progressed (leaf P = 0.32, branch P = 0.30) nor across the rainfall gradient (leaf P = 0.91, branch P = 0.96). Foliar soluble sugars decreased while starch increased over the duration of the dry period, suggesting greater partitioning of NSCs to storage than metabolism or transport as drought progressed. There was a large variation across species at all sites, but total foliar NSCs were positively correlated with leaf mass per area, whereas branch sugars were positively related to leaf temperature and negatively correlated with daily photosynthesis and wood density. The NSC homoeostasis across a wide range of conditions suggests that NSCs are an allocation priority in moist tropical forests.
- Published
- 2019
4. Soil water percolation and nutrient fluxes as a function of topographical, seasonal and soil texture variation in Central Amazonia, Brazil
- Author
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Rodrigues, Jardel Ramos, primary, Solander, Kurt C., additional, Cropper, Stephen, additional, Newman, Brent D., additional, Collins, Adam D., additional, Warren, Jeffrey M., additional, Negron‐Juarez, Robinson, additional, Gimenez, Bruno O., additional, Spanner, Gustavo Carvalho, additional, Menezes, Valdiek da Silva, additional, Ríos‐Villamizar, Eduardo Antonio, additional, de Oliveira, Regison Costa, additional, Ferreira, Sávio José Filgueiras, additional, and Higuchi, Niro, additional
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- 2024
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5. Precipitation, not air temperature, drives functional responses of trees in semi-arid ecosystems
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Grossiord, Charlotte, Sevanto, Sanna, Adams, Henry D., Collins, Adam D., Dickman, Lee T., McBranch, Natalie, Michaletz, Sean T., Stockton, Elizabeth A., Vigil, Miguel, and McDowell, Nate G.
- Published
- 2017
6. Patterns and rates of soil movement and shallow failures across several small watersheds on the Seward Peninsula, Alaska
- Author
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Del Vecchio, Joanmarie, primary, Lathrop, Emma R., additional, Dann, Julian B., additional, Andresen, Christian G., additional, Collins, Adam D., additional, Fratkin, Michael M., additional, Zwieback, Simon, additional, Glade, Rachel C., additional, and Rowland, Joel C., additional
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- 2023
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7. Integrating plant physiology into simulation of fire behavior and effects
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Dickman, L. Turin, primary, Jonko, Alexandra K., additional, Linn, Rodman R., additional, Altintas, Ilkay, additional, Atchley, Adam L., additional, Bär, Andreas, additional, Collins, Adam D., additional, Dupuy, Jean‐Luc, additional, Gallagher, Michael R., additional, Hiers, J. Kevin, additional, Hoffman, Chad M., additional, Hood, Sharon M., additional, Hurteau, Matthew D., additional, Jolly, W. Matt, additional, Josephson, Alexander, additional, Loudermilk, E. Louise, additional, Ma, Wu, additional, Michaletz, Sean T., additional, Nolan, Rachael H., additional, O'Brien, Joseph J., additional, Parsons, Russell A., additional, Partelli‐Feltrin, Raquel, additional, Pimont, François, additional, Resco de Dios, Víctor, additional, Restaino, Joseph, additional, Robbins, Zachary J., additional, Sartor, Karla A., additional, Schultz‐Fellenz, Emily, additional, Serbin, Shawn P., additional, Sevanto, Sanna, additional, Shuman, Jacquelyn K., additional, Sieg, Carolyn H., additional, Skowronski, Nicholas S., additional, Weise, David R., additional, Wright, Molly, additional, Xu, Chonggang, additional, Yebra, Marta, additional, and Younes, Nicolas, additional
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- 2023
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8. Leaves as bottlenecks: The contribution of tree leaves to hydraulic resistance within the soil−plant−atmosphere continuum
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Wolfe, Brett T., primary, Detto, Matteo, additional, Zhang, Yong‐Jiang, additional, Anderson‐Teixeira, Kristina J., additional, Brodribb, Tim, additional, Collins, Adam D., additional, Crawford, Chloe, additional, Dickman, L. Turin, additional, Ely, Kim S., additional, Francisco, Jessica, additional, Gurry, Preston D., additional, Hancock, Haigan, additional, King, Christopher T., additional, Majekobaje, Adelodun R., additional, Mallett, Christian J., additional, McDowell, Nate G., additional, Mendheim, Zachary, additional, Michaletz, Sean T., additional, Myers, Daniel B., additional, Price, Ty J., additional, Rogers, Alistair, additional, Sack, Lawren, additional, Serbin, Shawn P., additional, Siddiq, Zafar, additional, Willis, David, additional, Wu, Jin, additional, Zailaa, Joseph, additional, and Wright, S. Joseph, additional
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- 2023
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9. A multi-species synthesis of physiological mechanisms in drought-induced tree mortality
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Adams, Henry D., Zeppel, Melanie J. B., Anderegg, William R. L., Hartmann, Henrik, Landhäusser, Simon M., Tissue, David T., Huxman, Travis E., Hudson, Patrick J., Franz, Trenton E., Allen, Craig D., Anderegg, Leander D. L., Barron-Gafford, Greg A., Beerling, David J., Breshears, David D., Brodribb, Timothy J., Bugmann, Harald, Cobb, Richard C., Collins, Adam D., Dickman, L. Turin, Duan, Honglang, Ewers, Brent E., Galiano, Lucía, Galvez, David A., Garcia-Forner, Núria, Gaylord, Monica L., Germino, Matthew J., Gessler, Arthur, Hacke, Uwe G., Hakamada, Rodrigo, Hector, Andy, Jenkins, Michael W., Kane, Jeffrey M., Kolb, Thomas E., Law, Darin J., Lewis, James D., Limousin, Jean-Marc, Love, David M., Macalady, Alison K., Martínez-Vilalta, Jordi, Mencuccini, Maurizio, Mitchell, Patrick J., Muss, Jordan D., O’Brien, Michael J., O’Grady, Anthony P., Pangle, Robert E., Pinkard, Elizabeth A., Piper, Frida I., Plaut, Jennifer A., Pockman, William T., Quirk, Joe, Reinhardt, Keith, Ripullone, Francesco, Ryan, Michael G., Sala, Anna, Sevanto, Sanna, Sperry, John S., Vargas, Rodrigo, Vennetier, Michel, Way, Danielle A., Xu, Chonggang, Yepez, Enrico A., and McDowell, Nate G.
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- 2017
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10. Patterns and rates of soil movement and shallow failures across several small watersheds on the Seward Peninsula, Alaska
- Author
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Del Vecchio, Joanmarie, primary, Lathrop, Emma, additional, Dann, Julian B., additional, Andresen, Christian G., additional, Collins, Adam D., additional, Fratkin, Michael M., additional, Zwieback, Simon, additional, Glade, Rachel C., additional, and Rowland, Joel C., additional
- Published
- 2022
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- View/download PDF
11. Supplementary material to "Patterns and rates of soil movement and shallow failures across several small watersheds on the Seward Peninsula, Alaska"
- Author
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Del Vecchio, Joanmarie, primary, Lathrop, Emma, additional, Dann, Julian B., additional, Andresen, Christian G., additional, Collins, Adam D., additional, Fratkin, Michael M., additional, Zwieback, Simon, additional, Glade, Rachel C., additional, and Rowland, Joel C., additional
- Published
- 2022
- Full Text
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12. Dry Season Transpiration and Soil Water Dynamics in the Central Amazon
- Author
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Spanner, Gustavo C., primary, Gimenez, Bruno O., additional, Wright, Cynthia L., additional, Menezes, Valdiek Silva, additional, Newman, Brent D., additional, Collins, Adam D., additional, Jardine, Kolby J., additional, Negrón-Juárez, Robinson I., additional, Lima, Adriano José Nogueira, additional, Rodrigues, Jardel Ramos, additional, Chambers, Jeffrey Q., additional, Higuchi, Niro, additional, and Warren, Jeffrey M., additional
- Published
- 2022
- Full Text
- View/download PDF
13. Dry Season Transpiration and Soil Water Dynamics in the Central Amazon
- Author
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Spanner, Gustavo C, Gimenez, Bruno O, Wright, Cynthia L, Menezes, Valdiek Silva, Newman, Brent D, Collins, Adam D, Jardine, Kolby J, Negrón-Juárez, Robinson I, Lima, Adriano José Nogueira, Rodrigues, Jardel Ramos, Chambers, Jeffrey Q, Higuchi, Niro, and Warren, Jeffrey M
- Subjects
tropical forests ,basal area ,sap flow ,Life on Land ,allometry ,root distribution ,Plant Biology ,Plant Science ,ecohydrology ,root water uptake - Abstract
With current observations and future projections of more intense and frequent droughts in the tropics, understanding the impact that extensive dry periods may have on tree and ecosystem-level transpiration and concurrent carbon uptake has become increasingly important. Here, we investigate paired soil and tree water extraction dynamics in an old-growth upland forest in central Amazonia during the 2018 dry season. Tree water use was assessed via radial patterns of sap flow in eight dominant canopy trees, each a different species with a range in diameter, height, and wood density. Paired multi-sensor soil moisture probes used to quantify volumetric water content dynamics and soil water extraction within the upper 100 cm were installed adjacent to six of those trees. To link depth-specific water extraction patterns to root distribution, fine root biomass was assessed through the soil profile to 235 cm. To scale tree water use to the plot level (stand transpiration), basal area was measured for all trees within a 5 m radius around each soil moisture probe. The sensitivity of tree transpiration to reduced precipitation varied by tree, with some increasing and some decreasing in water use during the dry period. Tree-level water use scaled with sapwood area, from 11 to 190 L per day. Stand level water use, based on multiple plots encompassing sap flow and adjacent trees, varied from ∼1.7 to 3.3 mm per day, increasing linearly with plot basal area. Soil water extraction was dependent on root biomass, which was dense at the surface (i.e., 45% in the upper 5 cm) and declined dramatically with depth. As the dry season progressed and the upper soil dried, soil water extraction shifted to deeper levels and model projections suggest that much of the water used during the month-long dry-down could be extracted from the upper 2–3 m. Results indicate variation in rates of soil water extraction across the research area and, temporally, through the soil profile. These results provide key information on whole-tree contributions to transpiration by canopy trees as water availability changes. In addition, information on simultaneous stand level dynamics of soil water extraction that can inform mechanistic models that project tropical forest response to drought.
- Published
- 2021
14. Foliar respiration is related to photosynthetic, growth and carbohydrate response to experimental drought and elevated temperature
- Author
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Collins, Adam D., primary, Ryan, Michael G., additional, Adams, Henry D., additional, Dickman, Lee Turin, additional, Garcia‐Forner, Núria, additional, Grossiord, Charlotte, additional, Powers, Heath H., additional, Sevanto, Sanna, additional, and McDowell, Nate G., additional
- Published
- 2021
- Full Text
- View/download PDF
15. Investigating Vegetation Responses to Underground Nuclear Explosions Through Integrated Analyses
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Solander, Kurt C., primary, Collins, Adam D., additional, Swanson, Erika, additional, Margolis, Ellis Q., additional, Crawford, Brandon, additional, Miller, Elizabeth, additional, Chen, Min, additional, Lavadie‐Bulnes, Anita, additional, Ryan, Max, additional, Borrego, Isaac, additional, Sevanto, Sanna, additional, and Schultz‐Fellenz, Emily, additional
- Published
- 2021
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16. Stem radial growth and water storage responses to heat and drought vary between conifers with differing hydraulic strategies
- Author
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Manrique-Alba, Àngela, Sevanto, Sanna, Adams, Henry D., Collins, Adam D., Dickman, Lee T., Chirino Miranda, Esteban, Bellot, Juan, McDowell, Nate G., Universidad de Alicante. Departamento de Ecología, Universidad de Alicante. Instituto Multidisciplinar para el Estudio del Medio 'Ramón Margalef', and Gestión de Ecosistemas y de la Biodiversidad (GEB)
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Juniperus monosperma ,Water potential ,LVDT ,Growth ,Ecología ,Increased temperature ,Pinus edulis - Abstract
We investigated stem radial growth and water storage dynamics of 2 conifer species differing in hydraulic carbon strategies, Juniperus monosperma and Pinus edulis, under conditions of ambient, drought (∼45% reduction in precipitation), heat (∼4.8 °C temperature increase), and the combination of drought + heat, in 2013 and 2014. Juniper maintained low growth across all treatments. Overall, the relatively isohydric piñon pine showed significantly greater growth and water storage recharge than the relatively anisohydric juniper across all treatments in the average climate year (2014) but no differences in the regionally dry year (2013). Piñon pine ceased growth at a constant predawn water potential across all treatments and at a less negative water potential threshold than juniper. Heat has a greater negative impact on piñon pines' growth and water storage than drought, whereas juniper was, in contrast, unaffected by heat but strongly impacted by drought. The whole‐plant hydraulic carbon strategies, in this case captured using the isohydric/anisohydric concept, translate into alternative growth and water storage strategies under drought and heat conditions. This study was supported by DOE—Office of Biological and Environmental Research and the Spanish Ministry of Economy and Competitiveness (MINECO) via competitive grant CGL2015‐69773‐C2‐1‐P. N.G.M. was additionally supported by Pacific Northwest National Laboratories LDRD program. This research is part of the doctoral thesis of A.M.‐A. at the University of Alicante, supported by an FPI scholarship.
- Published
- 2018
17. The response of stomatal conductance to seasonal drought in tropical forests
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Wu, Jin, primary, Serbin, Shawn P., additional, Ely, Kim S., additional, Wolfe, Brett T., additional, Dickman, L. Turin, additional, Grossiord, Charlotte, additional, Michaletz, Sean T., additional, Collins, Adam D., additional, Detto, Matteo, additional, McDowell, Nate G., additional, Wright, S. Joseph, additional, and Rogers, Alistair, additional
- Published
- 2019
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18. Hyperspectral vegetation identification at a legacy underground nuclear explosion test site
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Redman, Brian J., primary, van der Laan, John D., additional, Anderson, Dylan Z., additional, Craven, Julia M., additional, Miller, Elizabeth D., additional, Collins, Adam D., additional, Swanson, Erika M., additional, and Schultz-Fellenz, Emily S., additional
- Published
- 2019
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19. Stem radial growth and water storage responses to heat and drought vary between conifers with differing hydraulic strategies
- Author
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Universidad de Alicante. Departamento de Ecología, Universidad de Alicante. Instituto Multidisciplinar para el Estudio del Medio "Ramón Margalef", Manrique-Alba, Àngela, Sevanto, Sanna, Adams, Henry D., Collins, Adam D., Dickman, Lee T., Chirino Miranda, Esteban, Bellot, Juan, McDowell, Nate G., Universidad de Alicante. Departamento de Ecología, Universidad de Alicante. Instituto Multidisciplinar para el Estudio del Medio "Ramón Margalef", Manrique-Alba, Àngela, Sevanto, Sanna, Adams, Henry D., Collins, Adam D., Dickman, Lee T., Chirino Miranda, Esteban, Bellot, Juan, and McDowell, Nate G.
- Abstract
We investigated stem radial growth and water storage dynamics of 2 conifer species differing in hydraulic carbon strategies, Juniperus monosperma and Pinus edulis, under conditions of ambient, drought (∼45% reduction in precipitation), heat (∼4.8 °C temperature increase), and the combination of drought + heat, in 2013 and 2014. Juniper maintained low growth across all treatments. Overall, the relatively isohydric piñon pine showed significantly greater growth and water storage recharge than the relatively anisohydric juniper across all treatments in the average climate year (2014) but no differences in the regionally dry year (2013). Piñon pine ceased growth at a constant predawn water potential across all treatments and at a less negative water potential threshold than juniper. Heat has a greater negative impact on piñon pines' growth and water storage than drought, whereas juniper was, in contrast, unaffected by heat but strongly impacted by drought. The whole‐plant hydraulic carbon strategies, in this case captured using the isohydric/anisohydric concept, translate into alternative growth and water storage strategies under drought and heat conditions.
- Published
- 2018
20. Reductions in tree performance during hotter droughts are mitigated by shifts in nitrogen cycling
- Author
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Universidad de Alicante. Departamento de Ecología, CEAM (Centro de Estudios Ambientales del Mediterraneo), Grossiord, Charlotte, Gessler, Arthur, Reed, Sasha C., Borrego, Isaac, Collins, Adam D., Dickman, Lee T., Ryan, Max, Schönbeck, Leonie, Sevanto, Sanna, Vilagrosa, Alberto, McDowell, Nate G., Universidad de Alicante. Departamento de Ecología, CEAM (Centro de Estudios Ambientales del Mediterraneo), Grossiord, Charlotte, Gessler, Arthur, Reed, Sasha C., Borrego, Isaac, Collins, Adam D., Dickman, Lee T., Ryan, Max, Schönbeck, Leonie, Sevanto, Sanna, Vilagrosa, Alberto, and McDowell, Nate G.
- Abstract
Climate warming should result in hotter droughts of unprecedented severity in this century. Such droughts have been linked with massive tree mortality, and data suggest that warming interacts with drought to aggravate plant performance. Yet how forests will respond to hotter droughts remains unclear, as does the suite of mechanisms trees use to deal with hot droughts. We used an ecosystem‐scale manipulation of precipitation and temperature on piñon pine (Pinus edulis) and juniper (Juniperus monosperma) trees to investigate nitrogen (N) cycling‐induced mitigation processes related to hotter droughts. We found that while negative impacts on plant carbon and water balance are manifest after prolonged drought, performance reductions were not amplified by warmer temperatures. Rather, increased temperatures for 5 years stimulated soil N cycling under piñon trees and modified tree N allocation for both species, resulting in mitigation of hotter drought impacts on tree water and carbon functions. These findings suggest that adjustments in N cycling are likely after multi‐year warming conditions and that such changes may buffer reductions in tree performance during hotter droughts. The results highlight our incomplete understanding of trees' ability to acclimate to climate change, raising fundamental questions about the resistance potential of forests to long‐term, compound climatic stresses.
- Published
- 2018
21. A multi-species synthesis of physiological mechanisms in drought-induced tree mortality
- Author
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Adams, Henry D, Zeppel, Melanie J B, Anderegg, William R L, Hartmann, Henrik, Landhäusser, Simon M, Tissue, David T, Huxman, Travis E, Hudson, Patrick J, Franz, Trenton E, Allen, Craig D, Anderegg, Leander D L, Barron-Gafford, Greg A, Beerling, David J, Breshears, David D, Brodribb, Timothy J, Bugmann, Harald, Cobb, Richard C, Collins, Adam D, Dickman, L Turin, Duan, Honglang, Ewers, Brent E, Galiano, Lucía, Galvez, David A, Garcia-Forner, Núria, Gaylord, Monica L, Germino, Matthew J, Gessler, Arthur, Hacke, Uwe G, Hakamada, Rodrigo, Hector, Andy, et al, University of Zurich, and Adams, Henry D
- Subjects
1105 Ecology, Evolution, Behavior and Systematics ,Ecology ,Behavior and Systematics ,UFSP13-8 Global Change and Biodiversity ,Evolution ,570 Life sciences ,biology ,2303 Ecology - Published
- 2017
22. Tree water dynamics in a drying and warming world
- Author
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Grossiord, Charlotte, Sevanto, Sanna, Borrego, Isaac, Chan, Allison M., Collins, Adam D., Dickman, Lee T., Hudson, Patrick J., McBranch, Natalie, Michaletz, Sean T., Pockman, William T., Ryan, Max, Vilagrosa, Alberto, McDowell, Nate G., Universidad de Alicante. Departamento de Ecología, and CEAM (Centro Estudios Ambientales del Mediterráneo)
- Subjects
Sap flux ,Juniperus monosperma ,Vapour pressure deficit ,Hydraulics ,Xylem anatomy ,Megadrought ,Stomatal conductance ,Ecología ,Acclimation ,Pinus edulis ,Transpiration - Abstract
Disentangling the relative impacts of precipitation reduction and vapour pressure deficit (VPD) on plant water dynamics and determining whether acclimation may influence these patterns in the future is an important challenge. Here, we report sap flux density (FD), stomatal conductance (Gs), hydraulic conductivity (KL) and xylem anatomy in piñon pine (Pinus edulis) and juniper (Juniperus monosperma) trees subjected to five years of precipitation reduction, atmospheric warming (elevated VPD) and their combined effects. No acclimation occurred under precipitation reduction: lower Gs and FD were found for both species compared to ambient conditions. Warming reduced the sensibility of stomata to VPD for both species but resulted in the maintenance of Gs and FD to ambient levels only for piñon. For juniper, reduced soil moisture under warming negated benefits of stomatal adjustments and resulted in reduced FD, Gs and KL. Although reduced stomatal sensitivity to VPD also occurred under combined stresses, reductions in Gs, FD and KL took place to similar levels as under single stresses for both species. Our results show that stomatal conductance adjustments to high VPD could minimize but not entirely prevent additive effects of warming and drying on water use and carbon acquisition of trees in semi-arid regions. The Los Alamos Survival-Mortality (SUMO) Experiment was funded by the US Department of Energy, Office of Science, Biological and Environmental Research. C.G. and S.M. were supported by a Director’s Fellowship from the Los Alamos National Laboratory. A.V. was supported by a fellowship from Generalitat Valenciana (BEST/2016/289) and the project Survive-2 (CGL2015-69773-C2-2-P MINECO/FEDER) from the Spanish Government. CEAM is funded by Generalitat Valenciana.
- Published
- 2017
23. The response of stomatal conductance to seasonal drought in tropical forests.
- Author
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Wu, Jin, Serbin, Shawn P., Ely, Kim S., Wolfe, Brett T., Dickman, L. Turin, Grossiord, Charlotte, Michaletz, Sean T., Collins, Adam D., Detto, Matteo, McDowell, Nate G., Wright, S. Joseph, and Rogers, Alistair
- Subjects
TROPICAL forests ,DROUGHT management ,DROUGHTS ,THROUGHFALL ,VAPOR pressure ,HUMIDITY ,TROPICAL dry forests - Abstract
Stomata regulate CO2 uptake for photosynthesis and water loss through transpiration. The approaches used to represent stomatal conductance (gs) in models vary. In particular, current understanding of drivers of the variation in a key parameter in those models, the slope parameter (i.e. a measure of intrinsic plant water‐use‐efficiency), is still limited, particularly in the tropics. Here we collected diurnal measurements of leaf gas exchange and leaf water potential (Ψleaf), and a suite of plant traits from the upper canopy of 15 tropical trees in two contrasting Panamanian forests throughout the dry season of the 2016 El Niño. The plant traits included wood density, leaf‐mass‐per‐area (LMA), leaf carboxylation capacity (Vc,max), leaf water content, the degree of isohydry, and predawn Ψleaf. We first investigated how the choice of four commonly used leaf‐level gs models with and without the inclusion of Ψleaf as an additional predictor variable influence the ability to predict gs, and then explored the abiotic (i.e. month, site‐month interaction) and biotic (i.e. tree‐species‐specific characteristics) drivers of slope parameter variation. Our results show that the inclusion of Ψleaf did not improve model performance and that the models that represent the response of gs to vapor pressure deficit performed better than corresponding models that respond to relative humidity. Within each gs model, we found large variation in the slope parameter, and this variation was attributable to the biotic driver, rather than abiotic drivers. We further investigated potential relationships between the slope parameter and the six available plant traits mentioned above, and found that only one trait, LMA, had a significant correlation with the slope parameter (R2 = 0.66, n = 15), highlighting a potential path towards improved model parameterization. This study advances understanding of gs dynamics over seasonal drought, and identifies a practical, trait‐based approach to improve modeling of carbon and water exchange in tropical forests. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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24. Lack of acclimation of leaf area:sapwood area ratios in piñon pine and juniper in response to precipitation reduction and warming
- Author
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McBranch, Natalie A, primary, Grossiord, Charlotte, additional, Adams, Henry, additional, Borrego, Isaac, additional, Collins, Adam D, additional, Dickman, Turin, additional, Ryan, Max, additional, Sevanto, Sanna, additional, and McDowell, Nate G, additional
- Published
- 2018
- Full Text
- View/download PDF
25. Reductions in tree performance during hotter droughts are mitigated by shifts in nitrogen cycling
- Author
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Grossiord, Charlotte, primary, Gessler, Arthur, additional, Reed, Sasha C., additional, Borrego, Isaac, additional, Collins, Adam D., additional, Dickman, Lee T., additional, Ryan, Max, additional, Schönbeck, Leonie, additional, Sevanto, Sanna, additional, Vilagrosa, Alberto, additional, and McDowell, Nate G., additional
- Published
- 2018
- Full Text
- View/download PDF
26. Stem radial growth and water storage responses to heat and drought vary between conifers with differing hydraulic strategies
- Author
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Manrique‐Alba, Àngela, primary, Sevanto, Sanna, additional, Adams, Henry D., additional, Collins, Adam D., additional, Dickman, Lee T., additional, Chirino, Esteban, additional, Bellot, Juan, additional, and McDowell, Nate G., additional
- Published
- 2018
- Full Text
- View/download PDF
27. Hyperspectral vegetation identification at a legacy underground nuclear explosion test site.
- Author
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Redman, Brian J., van der Laan, John D., Anderson, Dylan Z., Craven, Julia M., Miller, Elizabeth D., Collins, Adam D., Swanson, Erika M., and Schultz-Fellenz, Emily S.
- Published
- 2019
- Full Text
- View/download PDF
28. Tree water dynamics in a drying and warming world
- Author
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Universidad de Alicante. Departamento de Ecología, CEAM (Centro Estudios Ambientales del Mediterráneo), Grossiord, Charlotte, Sevanto, Sanna, Borrego, Isaac, Chan, Allison M., Collins, Adam D., Dickman, Lee T., Hudson, Patrick J., McBranch, Natalie, Michaletz, Sean T., Pockman, William T., Ryan, Max, Vilagrosa, Alberto, McDowell, Nate G., Universidad de Alicante. Departamento de Ecología, CEAM (Centro Estudios Ambientales del Mediterráneo), Grossiord, Charlotte, Sevanto, Sanna, Borrego, Isaac, Chan, Allison M., Collins, Adam D., Dickman, Lee T., Hudson, Patrick J., McBranch, Natalie, Michaletz, Sean T., Pockman, William T., Ryan, Max, Vilagrosa, Alberto, and McDowell, Nate G.
- Abstract
Disentangling the relative impacts of precipitation reduction and vapour pressure deficit (VPD) on plant water dynamics and determining whether acclimation may influence these patterns in the future is an important challenge. Here, we report sap flux density (FD), stomatal conductance (Gs), hydraulic conductivity (KL) and xylem anatomy in piñon pine (Pinus edulis) and juniper (Juniperus monosperma) trees subjected to five years of precipitation reduction, atmospheric warming (elevated VPD) and their combined effects. No acclimation occurred under precipitation reduction: lower Gs and FD were found for both species compared to ambient conditions. Warming reduced the sensibility of stomata to VPD for both species but resulted in the maintenance of Gs and FD to ambient levels only for piñon. For juniper, reduced soil moisture under warming negated benefits of stomatal adjustments and resulted in reduced FD, Gs and KL. Although reduced stomatal sensitivity to VPD also occurred under combined stresses, reductions in Gs, FD and KL took place to similar levels as under single stresses for both species. Our results show that stomatal conductance adjustments to high VPD could minimize but not entirely prevent additive effects of warming and drying on water use and carbon acquisition of trees in semi-arid regions.
- Published
- 2017
29. Responses of two semiarid conifer tree species to reduced precipitation and warming reveal new perspectives for stomatal regulation
- Author
-
García Forner, Núria, Henry D. Adams, Sevanto, Sanna, Collins, Adam D., Dickman, Lee T., Hudson, Patrick J., Zeppe, Melanie, Martínez Vilalta, Jordi, and McDowell, Nate G.
- Subjects
Drought ,Iso- vs. anisohydric behavior ,Hydraulic conductivity ,fungi ,food and beverages ,Carbon starvation ,Stomatal conductance ,Mortality ,Global change ,Increased temperature ,Hydraulic failure - Abstract
Relatively anisohydric species are predicted to be more predisposed to hydraulic failure than relatively isohydric species, as they operate with narrower hydraulic safety margins. We subjected co-occurring anisohydric Juniperus monosperma and isohydric Pinus edulis trees to warming, reduced precipitation, or both, and measured their gas exchange and hydraulic responses. We found that reductions in stomatal conductance and assimilation by heat and drought were more frequent during relatively moist periods, but these effects were not exacerbated in the combined heat and drought treatment. Counter to expectations, both species exhibited similar gs temporal dynamics in response to drought. Further, whereas P. edulis exhibited chronic embolism, J. monosperma showed very little embolism due to its conservative stomatal regulation and maintenance of xylem water potential above the embolism entry point. This tight stomatal control and low levels of embolism experienced by juniper refuted the notion that very low water potentials during drought are associated with loose stomatal control and with the hypothesis that anisohydric species are more prone to hydraulic failure than isohydric species. Because direct association of stomatal behaviour with embolism resistance can be misleading, we advocate consideration of stomatal behaviour relative to embolism resistance for classifying species drought response strategies.
- Published
- 2016
30. Tree water dynamics in a drying and warming world
- Author
-
Grossiord, Charlotte, primary, Sevanto, Sanna, additional, Borrego, Isaac, additional, Chan, Allison M., additional, Collins, Adam D., additional, Dickman, Lee T., additional, Hudson, Patrick J., additional, McBranch, Natalie, additional, Michaletz, Sean T., additional, Pockman, William T., additional, Ryan, Max, additional, Vilagrosa, Alberto, additional, and McDowell, Nate G., additional
- Published
- 2017
- Full Text
- View/download PDF
31. Lack of acclimation of leaf area:sapwood area ratios in piñon pine and juniper in response to precipitation reduction and warming.
- Author
-
McBranch, Natalie A, Grossiord, Charlotte, Adams, Henry, Borrego, Isaac, Collins, Adam D, Dickman, Turin, Ryan, Max, Sevanto, Sanna, and McDowell, Nate G
- Subjects
ACCLIMATIZATION ,CLIMATE change ,PINE ,JUNIPERS ,TEMPERATURE - Abstract
The leaf area to sapwood area ratios of trees (A
l :AS ) can shift to maintain homeostatic gas exchange per unit leaf area in response to climate variability. We tested the hypothesis that trees alter their Al :AS ratios in response to long-term warming and reduced precipitation in order to maintain leaf-specific gas exchange rates under more stressful conditions. Whole-tree Al :AS was measured on mature piñon pine (Pinus edulis Engelm.) and one-seed juniper (Juniperus monosperma (Engelm.) Sarg.) trees after 5 years (2012–16) of chronic exposure to increased temperature (+4.8 °C), precipitation reduction (−45%), or both simultaneously. No difference was found in Al :As among treatments for either species. Associated with this lack of shift in Al :As were large changes in pre-dawn leaf water potential and stomatal conductance, consistent with theoretical expectations of interactions between leaf and whole-tree hydraulic supply. Our results suggest that a lack of whole-tree acclimation in Al :As results in the reductions in plant gas exchange and water status associated with long-term warming and reduced precipitation in semi-arid woodlands. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
32. Precipitation, not air temperature, drives functional responses of trees in semi‐arid ecosystems
- Author
-
Grossiord, Charlotte, primary, Sevanto, Sanna, additional, Adams, Henry D., additional, Collins, Adam D., additional, Dickman, Lee T., additional, McBranch, Natalie, additional, Michaletz, Sean T., additional, Stockton, Elizabeth A., additional, Vigil, Miguel, additional, and McDowell, Nate G., additional
- Published
- 2016
- Full Text
- View/download PDF
33. Warming combined with more extreme precipitation regimes modifies the water sources used by trees
- Author
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Grossiord, Charlotte, primary, Sevanto, Sanna, additional, Dawson, Todd E., additional, Adams, Henry D., additional, Collins, Adam D., additional, Dickman, Lee T., additional, Newman, Brent D., additional, Stockton, Elizabeth A., additional, and McDowell, Nate G., additional
- Published
- 2016
- Full Text
- View/download PDF
34. Experimental drought and heat can delay phenological development and reduce foliar and shoot growth in semiarid trees
- Author
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Adams, Henry D., primary, Collins, Adam D., additional, Briggs, Samuel P., additional, Vennetier, Michel, additional, Dickman, L. Turin, additional, Sevanto, Sanna A., additional, Garcia-Forner, Núria, additional, Powers, Heath H., additional, and McDowell, Nate G., additional
- Published
- 2015
- Full Text
- View/download PDF
35. Responses of two semiarid conifer tree species to reduced precipitation and warming reveal new perspectives for stomatal regulation
- Author
-
Garcia‐Forner, NúRIA, primary, Adams, Henry D., additional, Sevanto, Sanna, additional, Collins, Adam D., additional, Dickman, Lee T., additional, Hudson, Patrick J., additional, Zeppel, Melanie J.B., additional, Jenkins, Michael W., additional, Powers, Heath, additional, Martínez‐Vilalta, Jordi, additional, and Mcdowell, Nate G., additional
- Published
- 2015
- Full Text
- View/download PDF
36. Warming combined with more extreme precipitation regimes modifies the water sources used by trees.
- Author
-
Grossiord, Charlotte, Sevanto, Sanna, Dawson, Todd E., Adams, Henry D., Collins, Adam D., Dickman, Lee T., Newman, Brent D., Stockton, Elizabeth A., and McDowell, Nate G.
- Subjects
METEOROLOGICAL precipitation ,ATMOSPHERIC physics ,PLANT water requirements ,PLANT-water relationships ,TREES - Abstract
The persistence of vegetation under climate change will depend on a plant's capacity to exploit water resources. We analyzed water source dynamics in piñon pine and juniper trees subjected to precipitation reduction, atmospheric warming, and to both simultaneously., Piñon and juniper exhibited different and opposite shifts in water uptake depth in response to experimental stress and background climate over 3 yr. During a dry summer, juniper responded to warming with a shift to shallow water sources, whereas piñon pine responded to precipitation reduction with a shift to deeper sources in autumn. In normal and wet summers, both species responded to precipitation reduction, but juniper increased deep water uptake and piñon increased shallow water uptake., Shifts in the utilization of water sources were associated with reduced stomatal conductance and photosynthesis, suggesting that belowground compensation in response to warming and water reduction did not alleviate stress impacts for gas exchange., We have demonstrated that predicted climate change could modify water sources of trees. Warming impairs juniper uptake of deep sources during extended dry periods. Precipitation reduction alters the uptake of shallow sources following extended droughts for piñon. Shifts in water sources may not compensate for climate change impacts on tree physiology. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
37. Responses of two semiarid conifer tree species to reduced precipitation and warming reveal new perspectives for stomatal regulation.
- Author
-
Garcia ‐ Forner, NúRIA, Adams, Henry D., Sevanto, Sanna, Collins, Adam D., Dickman, Lee T., Hudson, Patrick J., Zeppel, Melanie J.B., Jenkins, Michael W., Powers, Heath, Martínez ‐ Vilalta, Jordi, and Mcdowell, Nate G.
- Subjects
ARID regions ,CONIFERS ,STOMATA ,PLANT species ,HYDRAULICS - Abstract
Relatively anisohydric species are predicted to be more predisposed to hydraulic failure than relatively isohydric species, as they operate with narrower hydraulic safety margins. We subjected co-occurring anisohydric Juniperus monosperma and isohydric Pinus edulis trees to warming, reduced precipitation, or both, and measured their gas exchange and hydraulic responses. We found that reductions in stomatal conductance and assimilation by heat and drought were more frequent during relatively moist periods, but these effects were not exacerbated in the combined heat and drought treatment. Counter to expectations, both species exhibited similar g
s temporal dynamics in response to drought. Further, whereas P. edulis exhibited chronic embolism, J. monosperma showed very little embolism due to its conservative stomatal regulation and maintenance of xylem water potential above the embolism entry point. This tight stomatal control and low levels of embolism experienced by juniper refuted the notion that very low water potentials during drought are associated with loose stomatal control and with the hypothesis that anisohydric species are more prone to hydraulic failure than isohydric species. Because direct association of stomatal behaviour with embolism resistance can be misleading, we advocate consideration of stomatal behaviour relative to embolism resistance for classifying species drought response strategies. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
38. Foliar respiration is related to photosynthetic, growth and carbohydrate response to experimental drought and elevated temperature
- Author
-
Collins, Adam D., Ryan, Michael G., Adams, Henry D., Dickman, Lee Turin, Garcia-Forner, Nuria, Grossiord, Charlotte, Powers, Heath H., Sevanto, Sanna, and McDowell, Nate G.
- Subjects
thermal-acclimation ,carbon balance ,atmospheric co2 ,food and beverages ,trees ,isohydry ,fine-root respiration ,tree ,anisohydry ,gas-exchange ,thermal acclimation ,climate-change ,tree mortality ,leaf respiration ,plant respiration ,nonstructural carbohydrates ,pinyon-juniper woodland ,stomatal control - Abstract
Short-term plant respiration (R) increases exponentially with rising temperature, but drought could reduce respiration by reducing growth and metabolism. Acclimation may alter these responses. We examined if species with different drought responses would differ in foliar R response to +4.8 degrees C temperature and -45% precipitation in a field experiment with mature pinon and juniper trees, and if any differences between species were related to differences in photosynthesis rates, shoot growth and nonstructural carbohydrates (NSCs). Short-term foliar R had a Q(10) of 1.6 for pinon and 2.6 for juniper. Pinon foliar R did not respond to the +4.8 degrees C temperatures, but R increased 1.4x for juniper. Across treatments, pinon foliage had higher growth, lower NSC content, 29% lower photosynthesis rates, and 44% lower R than juniper. Removing 45% precipitation had little impact on R for either species. Species differences in the response of R under elevated temperature were related to substrate availability and stomatal response to leaf water potential. Despite not acclimating to the higher temperature and having higher R than pinon, greater substrate availability in juniper suggests it could supply respiratory demand for much longer than pinon. Species responses will be critical in ecosystem response to a warmer climate.
39. Leaves as bottlenecks: The contribution of tree leaves to hydraulic resistance within the soil-plant-atmosphere continuum.
- Author
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Wolfe BT, Detto M, Zhang YJ, Anderson-Teixeira KJ, Brodribb T, Collins AD, Crawford C, Dickman LT, Ely KS, Francisco J, Gurry PD, Hancock H, King CT, Majekobaje AR, Mallett CJ, McDowell NG, Mendheim Z, Michaletz ST, Myers DB, Price TJ, Rogers A, Sack L, Serbin SP, Siddiq Z, Willis D, Wu J, Zailaa J, and Wright SJ
- Subjects
- Water physiology, Plant Transpiration physiology, Plant Leaves physiology, Trees physiology, Soil
- Abstract
Within vascular plants, the partitioning of hydraulic resistance along the soil-to-leaf continuum affects transpiration and its response to environmental conditions. In trees, the fractional contribution of leaf hydraulic resistance (R
leaf ) to total soil-to-leaf hydraulic resistance (Rtotal ), or fRleaf (=Rleaf /Rtotal ), is thought to be large, but this has not been tested comprehensively. We compiled a multibiome data set of fRleaf using new and previously published measurements of pressure differences within trees in situ. Across 80 samples, fRleaf averaged 0.51 (95% confidence interval [CI] = 0.46-0.57) and it declined with tree height. We also used the allometric relationship between field-based measurements of soil-to-leaf hydraulic conductance and laboratory-based measurements of leaf hydraulic conductance to compute the average fRleaf for 19 tree samples, which was 0.40 (95% CI = 0.29-0.56). The in situ technique produces a more accurate descriptor of fRleaf because it accounts for dynamic leaf hydraulic conductance. Both approaches demonstrate the outsized role of leaves in controlling tree hydrodynamics. A larger fRleaf may help stems from loss of hydraulic conductance. Thus, the decline in fRleaf with tree height would contribute to greater drought vulnerability in taller trees and potentially to their observed disproportionate drought mortality., (© 2022 John Wiley & Sons Ltd.)- Published
- 2023
- Full Text
- View/download PDF
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