1
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Gomez‐Gallego M, Galiano L, Martínez‐Vilalta J, Stenlid J, Capador‐Barreto HD, Elfstrand M, Camarero JJ, Oliva J. Interaction of drought- and pathogen-induced mortality in Norway spruce and Scots pine. PLANT, CELL & ENVIRONMENT 2022; 45:2292-2305. [PMID: 35598958 PMCID: PMC9546048 DOI: 10.1111/pce.14360] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 05/11/2022] [Accepted: 05/14/2022] [Indexed: 06/15/2023]
Abstract
Pathogenic diseases frequently occur in drought-stressed trees. However, their contribution to the process of drought-induced mortality is poorly understood. We combined drought and stem inoculation treatments to study the physiological processes leading to drought-induced mortality in Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) saplings infected with Heterobasidion annosum s.s. We analysed the saplings' water status, gas exchange, nonstructural carbohydrates (NSCs) and defence responses, and how they related to mortality. Saplings were followed for two growing seasons, including an artificially induced 3-month dormancy period. The combined drought and pathogen treatment significantly increased spruce mortality; however, no interaction between these stressors was observed in pine, although individually each stressor caused mortality. Our results suggest that pathogen infection decreased carbon reserves in spruce, reducing the capacity of saplings to cope with drought, resulting in increased mortality rates. Defoliation, relative water content and the starch concentration of needles were predictors of mortality in both species under drought and pathogen infection. Infection and drought stress create conflicting needs for carbon to compartmentalize the pathogen and to avoid turgor loss, respectively. Heterobasidion annosum reduces the functional sapwood area and shifts NSC allocation patterns, reducing the capacity of trees to cope with drought.
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Affiliation(s)
- Mireia Gomez‐Gallego
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
- Université de Lorraine, INRAE, IAMNancyFrance
| | - Lucia Galiano
- CREAF, Bellaterra (Cerdanyola del Vallès)CataloniaSpain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès)CataloniaSpain
| | - Jordi Martínez‐Vilalta
- CREAF, Bellaterra (Cerdanyola del Vallès)CataloniaSpain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès)CataloniaSpain
| | - Jan Stenlid
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
| | - Hernán D. Capador‐Barreto
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
| | - Malin Elfstrand
- Department of Forest Mycology and Plant PathologySwedish University of Agricultural SciencesUppsalaSweden
| | | | - Jonàs Oliva
- Department of Crop and Forest SciencesUniversity of LleidaLleidaSpain
- Joint Research Unit CTFC‐AGROTECNIOLleidaSpain
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2
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Morcillo L, Muñoz-Rengifo JC, Torres-Ruiz JM, Delzon S, Moutahir H, Vilagrosa A. Post-drought conditions and hydraulic dysfunction determine tree resilience and mortality across Mediterranean Aleppo pine (Pinus halepensis) populations after an extreme drought event. TREE PHYSIOLOGY 2022; 42:1364-1376. [PMID: 35038335 DOI: 10.1093/treephys/tpac001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Drought-related tree mortality is a global phenomenon that currently affects a wide range of forests. Key functional variables on plant hydraulics, carbon economy, growth and allocation have been identified and play a role in tree drought responses. However, tree mortality thresholds based on such variables are difficult to identify, especially under field conditions. We studied several Aleppo pine populations differently affected by an extreme drought event in 2014, with mortality rates ranging from no mortality to 90% in the most severely affected population. We hypothesized that mortality is linked with high levels of xylem embolism, i.e., hydraulic dysfunction, which would also lead to lower tree resistance to drought in subsequent years. Despite not finding any differences among populations in the vulnerability curves to xylem embolism, there were large differences in the hydraulic safety margin (HSM) and the hydraulic dysfunction level. High mortality rates were associated with a negative HSM when xylem embolism reached values over 60%. We also found forest weakening and post-drought mortality related to a low hydraulic water transport capacity, reduced plant growth, low carbohydrate contents and high pest infestation rates. Our results highlight the importance of drought severity and the hydraulic dysfunction level on pine mortality, as well as post-drought conditions during recovery processes.
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Affiliation(s)
- L Morcillo
- Mediterranean Center for Environmental Studies (CEAM Foundation), Joint Research Unit University of Alicante-CEAM, University of Alicante, Alicante 03690, Spain
| | - J C Muñoz-Rengifo
- Department of Ecology, University of Alicante, Alicante 03690, Spain
- Department of Earth Science, Universidad Estatal Amazónica, Pastaza 160150, Ecuador
| | - J M Torres-Ruiz
- Université Clermont-Auvergne, INRAE, PIAF, Clermont-Ferrand 63000, France
| | - S Delzon
- Université Bordeaux, INRAE, BIOGECO, Pessac 33615, France
| | - H Moutahir
- Mediterranean Center for Environmental Studies (CEAM Foundation), Joint Research Unit University of Alicante-CEAM, University of Alicante, Alicante 03690, Spain
| | - A Vilagrosa
- Mediterranean Center for Environmental Studies (CEAM Foundation), Joint Research Unit University of Alicante-CEAM, University of Alicante, Alicante 03690, Spain
- Department of Ecology, University of Alicante, Alicante 03690, Spain
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3
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Physiological and Biochemical Dynamics of Pinus massoniana Lamb. Seedlings under Extreme Drought Stress and during Recovery. FORESTS 2022. [DOI: 10.3390/f13010065] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In recent years, global forests have been facing an increase in tree mortality owing to increasing droughts. However, the capacity for plants to adjust their physiology and biochemistry during extreme drought and subsequent recovery is still unclear. Here, we used 1.5-year-old Pinus massoniana Lamb. seedlings and simulated drought conditions to achieve three target stress levels (50%, 85%, and 100% loss of stem hydraulic conductivity (PLC)), followed by rehydration. Needle water status, gas exchange, and biochemical parameters were assessed during drought and recovery. The results showed that drought had significantly negative impacts on needle water status and gas exchange parameters, with gas exchange declining to 0 after PLC85 was achieved. Soluble protein concentration (SPC), soluble sugar concentration (SSC), malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, and needle water-use efficiency showed fluctuations. The activity of antioxidant enzymes and the values of osmotic regulators were then gradually decreased as the physiological and biochemical functions of seedlings were disturbed. Seedlings showed a stronger ability to recover from PLC50 than PLC85 and PLC100. We conclude that the physiological and biochemical recovery of P. massoniana seedlings is more likely to be inhibited when plants experience increasing drought stress that induces 85% and greater loss of hydraulic conductance.
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4
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Erbilgin N, Zanganeh L, Klutsch JG, Chen SH, Zhao S, Ishangulyyeva G, Burr SJ, Gaylord M, Hofstetter R, Keefover-Ring K, Raffa KF, Kolb T. Combined drought and bark beetle attacks deplete non-structural carbohydrates and promote death of mature pine trees. PLANT, CELL & ENVIRONMENT 2021; 44:3636-3651. [PMID: 34612515 DOI: 10.1111/pce.14197] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/23/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
How carbohydrate reserves in conifers respond to drought and bark beetle attacks are poorly understood. We investigated changes in carbohydrate reserves and carbon-dependent diterpene defences in ponderosa pine trees that were experimentally subjected to two levels of drought stress (via root trenching) and two types of biotic challenge treatments (pheromone-induced bark beetle attacks or inoculations with crushed beetles that include beetle-associated fungi) for two consecutive years. Our results showed that trenching did not influence carbohydrates, whereas both biotic challenges reduced amounts of starch and sugars of trees. However, only the combined trenched-bark beetle attacked trees depleted carbohydrates and died during the first year of attacks. While live trees contained higher carbohydrates than dying trees, amounts of constitutive and induced diterpenes produced did not vary between live and beetle-attacked dying trees, respectively. Based on these results we propose that reallocation of carbohydrates to diterpenes during the early stages of beetle attacks is limited in drought-stricken trees, and that the combination of biotic and abiotic stress leads to tree death. The process of tree death is subsequently aggravated by beetle girdling of phloem, occlusion of vascular tissue by bark beetle-vectored fungi, and potential exploitation of host carbohydrates by bark beetle symbionts as nutrients.
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Affiliation(s)
- Nadir Erbilgin
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Leila Zanganeh
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
- Department of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran
| | - Jennifer G Klutsch
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
- Department of Forestry, New Mexico Highlands University, Las Vegas, New Mexico, USA
| | - Shih-Hsuan Chen
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Shiyang Zhao
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Guncha Ishangulyyeva
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Stephen J Burr
- Forest Health Protection, USDA Forest Service, Milwaukee, Wisconsin, USA
| | - Monica Gaylord
- Forest Health Protection, USDA Forest Service, Flagstaff, Arizona, USA
| | - Richard Hofstetter
- School of Forestry, Northern Arizona University, Flagstaff, Arizona, USA
| | - Ken Keefover-Ring
- Departments of Botany and Geography, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kenneth F Raffa
- Department of Entomology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Thomas Kolb
- School of Forestry, Northern Arizona University, Flagstaff, Arizona, USA
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5
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Kannenberg SA, Guo JS, Novick KA, Anderegg WRL, Feng X, Kennedy D, Konings AG, Martínez‐Vilalta J, Matheny AM. Opportunities, challenges and pitfalls in characterizing plant water‐use strategies. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13945] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
| | - Jessica S. Guo
- Department of Geology and Geophysics University of Utah Salt Lake City UT USA
- Arizona Experiment Station, College of Agriculture and Life Sciences University of Arizona Tucson AZ USA
| | - Kimberly A. Novick
- O’Neill School of Public and Environmental Affairs Indiana University Bloomington IN USA
| | | | - Xue Feng
- Department of Civil, Environmental, and Geo‐Engineering University of Minnesota Minneapolis MN USA
- Saint Anthony Falls Laboratory University of Minnesota Minneapolis MN USA
| | | | | | - Jordi Martínez‐Vilalta
- CREAF, Bellaterra (Cerdanyola del Vallès) Catalonia Spain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès) Catalonia Spain
| | - Ashley M. Matheny
- Department of Geological Sciences Jackson School of Geosciences University of Texas Austin TX USA
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6
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Mashukov DA, Ben’kova AV, Ben’kova VE, Shashkin AV, Prokushkin AS. Distribution of Tracheid Lumen Areas within Annual Rings at Different Heights of Larch Stem under Permafrost Conditions. Crown Dieback. RUSS J ECOL+ 2021. [DOI: 10.1134/s1067413621050106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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Valeriano C, Gazol A, Colangelo M, González de Andrés E, Camarero JJ. Modeling Climate Impacts on Tree Growth to Assess Tree Vulnerability to Drought During Forest Dieback. FRONTIERS IN PLANT SCIENCE 2021; 12:672855. [PMID: 34512680 PMCID: PMC8426521 DOI: 10.3389/fpls.2021.672855] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 08/02/2021] [Indexed: 06/12/2023]
Abstract
Forest dieback because of drought is a global phenomenon threatening particular tree populations. Particularly vulnerable stands are usually located in climatically stressing locations such as xeric sites subjected to seasonal drought. These tree populations show a pronounced loss of vitality, growth decline, and high mortality in response to extreme climate events such as heat waves and droughts. However, dieback events do not uniformly affect stands, with some trees showing higher symptoms of drought vulnerability than other neighboring conspecifics. In this study, we investigated if trees showing different vulnerabilities to dieback showed lower growth rates (Grs) and higher sensitivities to the climate in the past using dendroecology and the Vaganov-Shashkin (VS) process-based growth model. We studied two Pinus pinaster stands with contrasting Grs showing recent dieback in the Iberian System, north-eastern Spain. We compared coexisting declining (D) and non-declining (ND) trees with crown defoliation values above and below the 50% threshold, respectively. The mean growth rate was lower in D than in ND trees in the two stands. The two vigor classes showed a growth divergence prior to the dieback onset and different responsiveness to climate. The ND trees were more responsive to changes in spring water balance and soil moisture than D trees, indicating a loss of growth responsiveness to the climate in stressed trees. Such an interaction between water availability and vigor was reflected by the VS-model simulations, which provided evidence for the observation that growth was mainly limited by low soil moisture in both sites. Such an interaction between water availability and vigor was reflected by the VS-model simulations, which provided evidence for the observation that growth was mainly limited by low soil moisture in both sites. The presented comparisons indicated different stand vulnerabilities to drought contingent on-site conditions. Further research should investigate the role played by environmental conditions and individual features such as access to soil water or hydraulic traits and implement them in process-based growth models to better forecast dieback.
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Affiliation(s)
- Cristina Valeriano
- Instituto Pirenaico de Ecología (IPE-CSIC), Zaragoza, Spain
- Departamento de Sistemas Naturales e Historia Forestal, Universidad Politécnica de Madrid, Madrid, Spain
| | - Antonio Gazol
- Instituto Pirenaico de Ecología (IPE-CSIC), Zaragoza, Spain
| | - Michele Colangelo
- Instituto Pirenaico de Ecología (IPE-CSIC), Zaragoza, Spain
- School of Agricultural, Forest, Food and Environmental Sciences, University of Basilicata, Potenza, Italy
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8
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Ray DM, Savage JA. Seasonal changes in temperate woody plant phloem anatomy and physiology: implications for long-distance transport. AOB PLANTS 2021; 13:plab028. [PMID: 34234934 PMCID: PMC8255074 DOI: 10.1093/aobpla/plab028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 05/21/2021] [Indexed: 06/13/2023]
Abstract
Seasonal changes in climate are accompanied by shifts in carbon allocation and phenological changes in woody angiosperms, the timing of which can have broad implications for species distributions, interactions and ecosystem processes. During critical transitions from autumn to winter and winter to spring, physiological and anatomical changes within the phloem could impose a physical limit on the ability of woody angiosperms to transport carbon and signals. There is a paucity of the literature that addresses tree (floral or foliar) phenology, seasonal phloem anatomy and seasonal phloem physiology together, so our knowledge of how carbon transport could fluctuate seasonally, especially in temperate climates is limited. We review phloem phenology focussing on how sieve element anatomy and phloem sap flow could affect carbon availability throughout the year with a focus on winter. To investigate whether flow is possible in the winter, we construct a simple model of phloem sap flow and investigate how changes to the sap concentration, pressure gradient and sieve plate pores could influence flow during the winter. Our model suggests that phloem transport in some species could occur year-round, even in winter, but current methods for measuring all the parameters surrounding phloem sap flow make it difficult to test this hypothesis. We highlight outstanding questions that remain about phloem functionality in the winter and emphasize the need for new methods to address gaps in our knowledge about phloem function.
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Affiliation(s)
- Dustin M Ray
- Department of Biology, University of Minnesota Duluth, Duluth, MN 55811, USA
| | - Jessica A Savage
- Department of Biology, University of Minnesota Duluth, Duluth, MN 55811, USA
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9
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Wang W, English NB, Grossiord C, Gessler A, Das AJ, Stephenson NL, Baisan CH, Allen CD, McDowell NG. Mortality predispositions of conifers across western USA. THE NEW PHYTOLOGIST 2021; 229:831-844. [PMID: 32918833 DOI: 10.1111/nph.16864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
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 (δ13 C and δ18 O, respectively) of dying and surviving conifers at eight old-growth forest sites across a strong moisture gradient in the western USA to retrospectively investigate mortality predispositions. Compared with surviving trees, lower growth of dying trees was detected at least one decade before mortality at seven of the eight sites. Intrinsic water-use efficiency increased over time in both dying and surviving trees, with a weaker increase in dying trees at five of the eight sites. C starvation was a strong correlate of conifer mortality based on a conceptual model incorporating growth, δ13 C, and δ18 O. However, this approach does not capture processes that occur in the final months of survival. Ultimately, C starvation may lead to increased mortality vulnerability, but hydraulic failure or biotic attack may dominate the process during the end stages of mortality in these conifers.
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Affiliation(s)
- Wenzhi Wang
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
- The Key Laboratory of Mountain Environment Evolution and Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu,, 610041, China
| | - Nathan B English
- School of Health, Medical and Applied Science, Central Queensland University, Townsville, QLD, 4810, Australia
| | - Charlotte Grossiord
- Functional Plant Ecology, Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape WSL, Lausanne,, CH-1015, Switzerland
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne,, CH-1015, Switzerland
| | - Arthur Gessler
- Functional Plant Ecology, Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape WSL, Lausanne,, CH-1015, Switzerland
- Institute of Terrestrial Ecosystems, ETH Zurich, Universitaetsstrasse 16, Zurich, 8092, Switzerland
| | - Adrian J Das
- Western Ecological Research Center, US Geological Survey, Three Rivers, CA, 93271, USA
| | - Nathan L Stephenson
- Western Ecological Research Center, US Geological Survey, Three Rivers, CA, 93271, USA
| | | | - Craig D Allen
- Fort Collins Science Center, New Mexico Landscapes Field Station, US Geological Survey, Los Alamos, NM,, 87544, USA
| | - Nate G McDowell
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
- School of Biological Sciences, Washington State University, Pullman, WA, 99164-4236, USA
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10
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Reed CC, Hood SM. Few generalizable patterns of tree-level mortality during extreme drought and concurrent bark beetle outbreaks. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 750:141306. [PMID: 32846245 DOI: 10.1016/j.scitotenv.2020.141306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/14/2020] [Accepted: 07/26/2020] [Indexed: 06/11/2023]
Abstract
Tree mortality associated with drought and concurrent bark beetle outbreaks is expected to increase with further climate change. When these two types of disturbance occur in concert it complicates our ability to accurately predict future forest mortality. The recent extreme California USA drought and bark beetle outbreaks resulted in extensive tree mortality and provides a unique opportunity to examine questions of why some trees die while others survive these co-occurring disturbances. We use plot-level data combined with a three-proxy tree-level approach using radial growth, carbon isotopes, and resin duct metrics to evaluate 1) whether variability in stand structure, tree growth or size, carbon isotope discrimination, or defenses precede mortality, 2) how relationships between these proxies differ for surviving and now-dead trees, and 3) whether generalizable risk factors for tree mortality exist across pinyon pine (Pinus monophylla), ponderosa pine (P. ponderosa), white fir (Abies concolor), and incense cedar (Calocedrus decurrens) affected by the combination of drought and beetle outbreaks. We find that risk factors associated with mortality differ between species, and that few generalizable patterns exist when bark beetle outbreaks occur in concert with a particularly long, hot drought. We see evidence that both long-term differences in physiology and shorter-term beetle-related selection and variability in defenses influence mortality susceptibility for ponderosa pine, whereas beetle dynamics may play a more prominent role in mortality patterns for white fir and pinyon pine. In contrast, incense cedar mortality appears to be attributable to long-term effects of growth suppression. Risk factors that predispose some trees to drought and beetle-related mortality likely reflect species-specific strategies for dealing with these particular disturbance types. The combined influence of beetles and drought necessitates the consideration of multiple, species-specific risk factors to more accurately model forest mortality in the face of similar extreme events more likely under future climates.
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Affiliation(s)
- Charlotte C Reed
- USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, 5775 US Highway 10 W, Missoula, MT 59808, USA.
| | - Sharon M Hood
- USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, 5775 US Highway 10 W, Missoula, MT 59808, USA
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11
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Keen RM, Voelker SL, Bentz BJ, Wang SYS, Ferrell R. Stronger influence of growth rate than severity of drought stress on mortality of large ponderosa pines during the 2012-2015 California drought. Oecologia 2020; 194:359-370. [PMID: 33030569 DOI: 10.1007/s00442-020-04771-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 09/25/2020] [Indexed: 11/29/2022]
Abstract
Forests in the western United States are being subject to more frequent and severe drought events as the climate warms. The 2012-2015 California drought is a recent example, whereby drought stress was exacerbated by a landscape-scale outbreak of western pine beetle (Dendroctonus brevicomis) and resulted in widespread mortality of dominant canopy species including ponderosa pine (Pinus ponderosa). In this study, we compared pairs of large surviving and beetle-killed ponderosa pines following the California drought in the southern Sierra Nevadas to evaluate physiological characteristics related to survival. Inter-annual growth rates and tree-ring stable isotopes (∆13C and δ18O) were utilized to compare severity of drought stress and climate sensitivity in ponderosa pines that survived and those that were killed by western pine beetle. Compared to beetle-killed trees, surviving trees had higher growth rates and grew in plots with lower ponderosa pine basal area. However, there were no detectable differences in tree-ring ∆13C, δ18O, or stable isotope sensitivity to drought-related meteorological variables. These results indicate that differences in severity of drought stress had little influence on local, inter-tree differences in growth rate and survival of large ponderosa pines during this drought event. Many previous studies have shown that large trees are more likely to be attacked and killed by bark beetles compared to small trees. Our results further suggest that among large ponderosa pines, those that were more resistant to drought stress and bark beetle attacks were in the upper echelon of growth rates among trees within a stand and across the landscape.
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Affiliation(s)
- Rachel M Keen
- Division of Biology, Kansas State University, Manhattan, KS, USA.
| | - Steve L Voelker
- Department of Environmental and Forest Biology, SUNY ESF, Syracuse, NY, USA
| | - Barbara J Bentz
- USDA Forest Service, Rocky Mountain Research Station, Logan, UT, USA
| | - S-Y Simon Wang
- Department of Plants, Soils and Climate, Utah State University, Logan, UT, USA
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12
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Timofeeva G, Treydte K, Bugmann H, Salmon Y, Rigling A, Schaub M, Vollenweider P, Siegwolf R, Saurer M. How does varying water supply affect oxygen isotope variations in needles and tree rings of Scots pine? TREE PHYSIOLOGY 2020; 40:1366-1380. [PMID: 32589748 DOI: 10.1093/treephys/tpaa082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 04/01/2020] [Accepted: 06/19/2020] [Indexed: 06/11/2023]
Abstract
In many regions, drought is suspected to be a cause of Scots pine decline and mortality, but the underlying physiological mechanisms remain unclear. Because of their relationship to ecohydrological processes, δ18O values in tree rings are potentially useful for deciphering long-term physiological responses and tree adaptation to increasing drought. We therefore analyzed both needle- and stem-level isotope fractionations in mature trees exposed to varying water supply. In a first experiment, we investigated seasonal δ18O variations in soil and needle water of Scots pine in a dry inner Alpine valley in Switzerland, comparing drought-stressed trees with trees that were irrigated for more than 10 years. In a second experiment, we analyzed twentieth-century δ18O variations in tree rings of the same forest, including a group of trees that had recently died. We observed less 18O enrichment in needle water of drought-stressed compared with irrigated trees. We applied different isotope fractionation models to explain these results, including the Péclet and the two-pool correction, which considers the ratio of unenriched xylem water in the needles to total needle water. Based on anatomical measurements, we found this ratio to be unchanged in drought-stressed needles, although they were shorter. The observed lower 18O enrichment in needles of stressed trees was therefore likely caused by increased effective path length for water movement within the leaf lamina. In the tree-ring study, we observed lower δ18O values in tree rings of dead trees compared with survivors during several decades prior to their death. These lower values in declining trees are consistent with the lower needle water 18O enrichment observed for drought-stressed compared with irrigated trees, suggesting that this needle-level signal is reflected in the tree rings, although changes in rooting depth could also play a role. Our study demonstrates that long-term effects of drought are reflected in the tree-ring δ18O values, which helps to provide a better understanding of past tree physiological changes of Scots pine.
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Affiliation(s)
- Galina Timofeeva
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), Villigen 5232, Switzerland
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
- Forest Ecology, Institute of Terrestrial Ecosystems, ETH Zurich, Zurich 8092, Switzerland
| | - Kerstin Treydte
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
| | - Harald Bugmann
- Forest Ecology, Institute of Terrestrial Ecosystems, ETH Zurich, Zurich 8092, Switzerland
| | - Yann Salmon
- Department of Physics, University of Helsinki, Helsinki 00014, Finland
- School of GeoSciences, University of Edinburgh, Edinburgh EH9 3FF, UK
| | - Andreas Rigling
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
| | - Marcus Schaub
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
| | - Pierre Vollenweider
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
| | - Rolf Siegwolf
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), Villigen 5232, Switzerland
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
| | - Matthias Saurer
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), Villigen 5232, Switzerland
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
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13
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Vázquez-González C, Zas R, Erbilgin N, Ferrenberg S, Rozas V, Sampedro L. Resin ducts as resistance traits in conifers: linking dendrochronology and resin-based defences. TREE PHYSIOLOGY 2020; 40:1313-1326. [PMID: 32478382 DOI: 10.1093/treephys/tpaa064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 05/26/2020] [Indexed: 05/20/2023]
Abstract
Conifers have evolved different chemical and anatomical defences against a wide range of antagonists. Resin ducts produce, store and translocate oleoresin, a complex terpenoid mixture that acts as both a physical and a chemical defence. Although resin duct characteristics (e.g., number, density, area) have been positively related to biotic resistance in several conifer species, the literature reporting this association remains inconclusive. Axial resin ducts recorded in annual growth rings are an archive of annual defensive investment in trees. This whole-life record of defence investment can be analysed using standard dendrochronological procedures, which allows us to assess interannual variability and the effect of understudied drivers of phenotypic variation on resin-based defences. Understanding the sources of phenotypic variation in defences, such as genetic differentiation and environmental plasticity, is essential for assessing the adaptive potential of forest tree populations to resist pests under climate change. Here, we reviewed the evidence supporting the importance of resin ducts in conifer resistance, and summarized current knowledge about the sources of variation in resin duct production. We propose a standardized methodology to measure resin duct production by means of dendrochronological procedures. This approach will illuminate the roles of resin ducts in tree defence across species, while helping to fill pivotal knowledge gaps in plant defence theory, and leading to a robust understanding of the patterns of variation in resin-based defences throughout the tree's lifespan.
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Affiliation(s)
- Carla Vázquez-González
- Misión Biológica de Galicia, National Spanish Research Council (MBG-CSIC), Carballeira 8, Salcedo, Pontevedra 3614, Spain
| | - Rafael Zas
- Misión Biológica de Galicia, National Spanish Research Council (MBG-CSIC), Carballeira 8, Salcedo, Pontevedra 3614, Spain
| | - Nadir Erbilgin
- Department of Renewable Resources, University of Alberta, Edmonton, T6G 2H1 Alberta, Canada
| | - Scott Ferrenberg
- Department of Biology, New Mexico State University, 1305 Frenger St., Las Cruces, 88001, NM, USA
| | - Vicente Rozas
- iuFOR-EiFAB, Campus Duques de Soria, Universidad de Valladolid, Soria 42004, Spain
- Laboratorio de Dendrocronología y Cambio Global, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Valdivia 5090000, Chile
| | - Luis Sampedro
- Misión Biológica de Galicia, National Spanish Research Council (MBG-CSIC), Carballeira 8, Salcedo, Pontevedra 3614, Spain
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14
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Bittencourt PRL, Oliveira RS, da Costa ACL, Giles AL, Coughlin I, Costa PB, Bartholomew DC, Ferreira LV, Vasconcelos SS, Barros FV, Junior JAS, Oliveira AAR, Mencuccini M, Meir P, Rowland L. Amazonia trees have limited capacity to acclimate plant hydraulic properties in response to long-term drought. GLOBAL CHANGE BIOLOGY 2020; 26:3569-3584. [PMID: 32061003 DOI: 10.1111/gcb.15040] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 12/30/2019] [Accepted: 02/02/2020] [Indexed: 05/29/2023]
Abstract
The fate of tropical forests under future climate change is dependent on the capacity of their trees to adjust to drier conditions. The capacity of trees to withstand drought is likely to be determined by traits associated with their hydraulic systems. However, data on whether tropical trees can adjust hydraulic traits when experiencing drought remain rare. We measured plant hydraulic traits (e.g. hydraulic conductivity and embolism resistance) and plant hydraulic system status (e.g. leaf water potential, native embolism and safety margin) on >150 trees from 12 genera (36 species) and spanning a stem size range from 14 to 68 cm diameter at breast height at the world's only long-running tropical forest drought experiment. Hydraulic traits showed no adjustment following 15 years of experimentally imposed moisture deficit. This failure to adjust resulted in these drought-stressed trees experiencing significantly lower leaf water potentials, and higher, but variable, levels of native embolism in the branches. This result suggests that hydraulic damage caused by elevated levels of embolism is likely to be one of the key drivers of drought-induced mortality following long-term soil moisture deficit. We demonstrate that some hydraulic traits changed with tree size, however, the direction and magnitude of the change was controlled by taxonomic identity. Our results suggest that Amazonian trees, both small and large, have limited capacity to acclimate their hydraulic systems to future droughts, potentially making them more at risk of drought-induced mortality.
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Affiliation(s)
- Paulo R L Bittencourt
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
| | - Rafael S Oliveira
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
- Biological Sciences, UWA, Perth, WA, Australia
| | | | - Andre L Giles
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
| | - Ingrid Coughlin
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Patricia B Costa
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
- Biological Sciences, UWA, Perth, WA, Australia
| | - David C Bartholomew
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | | | | | - Fernanda V Barros
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
| | - Joao A S Junior
- Instituto de Biologia, University of Campinas (UNICAMP), Campinas, Brazil
| | | | | | - Patrick Meir
- Research School of Biology, Australian National University, Canberra, ACT, Australia
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
| | - Lucy Rowland
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
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15
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Kiorapostolou N, Camarero JJ, Carrer M, Sterck F, Brigita B, Sangüesa-Barreda G, Petit G. Scots pine trees react to drought by increasing xylem and phloem conductivities. TREE PHYSIOLOGY 2020; 40:774-781. [PMID: 32186730 DOI: 10.1093/treephys/tpaa033] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 02/29/2020] [Accepted: 03/12/2020] [Indexed: 06/10/2023]
Abstract
Drought limits the long-distance transport of water in the xylem due to the reduced leaf-to-soil water potential difference and possible embolism-related losses of conductance and of sugars in the phloem due to the higher viscosity of the dehydrated sugary solution. This condition can have cascading effects in water and carbon (C) fluxes that may ultimately cause tree death. We hypothesize that the maintenance of xylem and phloem conductances is fundamental for survival also under reduced resource availability, when trees may produce effective and low C cost anatomical adjustments in the xylem and phloem close to the treetop where most of the hydraulic resistance is concentrated. We analyzed the treetop xylem and phloem anatomical characteristics in coexisting Scots pine trees, symptomatic and non-symptomatic of drought-induced dieback. We selected the topmost 55 cm of the main stem and selected several sampling positions at different distances from the stem apex to test for differences in the axial patterns between the two groups of trees. We measured the annual ring area, the tracheid hydraulic diameter (Dh) and cell wall thickness (CWT), the conductive phloem area and the average lumen diameter of the 20 largest phloem sieve cells (Dph). Declining trees grew less than the non-declining ones, and despite the similar axial scaling of anatomical traits, had larger Dh and lower CWT. Moreover, declining trees had wider Dph. Our results demonstrate that even under drought stress, maintenance of xylem and phloem efficiencies is of primary importance for survival, even if producing fewer larger tracheids may lead to a xylem more vulnerable to embolism formation.
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Affiliation(s)
- Natasa Kiorapostolou
- Dip. Territorio e Sistemi Agro-Forestali, Università di Padova, Viale dell'Università 16, Legnaro, PD 35020, Italy
| | - J Julio Camarero
- Depto. Conservación de Ecosistemas, Instituto Pirenaico de Ecologia (IPE-CSIC), Avda Montanana 1005, Zaragoza 50059, Spain
| | - Marco Carrer
- Dip. Territorio e Sistemi Agro-Forestali, Università di Padova, Viale dell'Università 16, Legnaro, PD 35020, Italy
| | - Frank Sterck
- Department of Environmental Sciences, Wageningen University, Droevendaalsesteeg 3, NL 6700 AA Wageningen, The Netherlands
| | - Brigita Brigita
- Department of Environmental Sciences, Wageningen University, Droevendaalsesteeg 3, NL 6700 AA Wageningen, The Netherlands
| | - Gabriel Sangüesa-Barreda
- Depto. Conservación de Ecosistemas, Instituto Pirenaico de Ecologia (IPE-CSIC), Avda Montanana 1005, Zaragoza 50059, Spain
- Depto Ciencias Agroforestales, iuFOR-EiFAB, University of Valladolid, Campus Duques de Soria s/n, Soria E-42004, Spain
| | - Giai Petit
- Dip. Territorio e Sistemi Agro-Forestali, Università di Padova, Viale dell'Università 16, Legnaro, PD 35020, Italy
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16
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Zhao S, Erbilgin N. Larger Resin Ducts Are Linked to the Survival of Lodgepole Pine Trees During Mountain Pine Beetle Outbreak. FRONTIERS IN PLANT SCIENCE 2019; 10:1459. [PMID: 31850006 PMCID: PMC6888816 DOI: 10.3389/fpls.2019.01459] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 10/21/2019] [Indexed: 05/29/2023]
Abstract
Periodic mountain pine beetle outbreaks have killed millions of hectares of lodgepole pine forests in western North America. Within these forests some pine trees often remain alive. It has been rarely documented whether anatomical defenses differ between beetle-killed and remaining live pine trees, especially at the northern latitudinal range of beetles in North America. In this study, we compared the resin duct-based anatomical defenses and radial growth between beetle-killed and live residual lodgepole pine trees, and we characterized the resin ducts and the growth of the residual trees before and after outbreak. We found that tree radial growth was not associated with tree survival. The best two predictors of tree survival were resin duct size and production (number per year). Trees having larger but fewer resin ducts showed higher survival probability compared to those with smaller but more abundant resin ducts annually. Residual trees had larger resin ducts prior to the outbreak and continued having so after the outbreak. We further categorized residual trees as healthy (having no signs or symptoms of insect or pathogen attacks), declining (with signs or symptoms of biotic attacks), and survived (from mountain pine beetle attacks during the outbreak) to investigate resin duct-based anatomical defenses among them. Healthy trees had consistently larger resin ducts than declining trees in the past 20 years in post-outbreak stands. Survival trees ranked between healthy and declining trees. Overall, these results demonstrate that resin duct size of lodgepole pine trees can be an important component of tree defenses against mountain pine beetle attacks and suggest that lodgepole pine trees with large resin ducts are likely to show resistance to future bark beetle attacks.
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17
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Gea-Izquierdo G, Férriz M, García-Garrido S, Aguín O, Elvira-Recuenco M, Hernandez-Escribano L, Martin-Benito D, Raposo R. Synergistic abiotic and biotic stressors explain widespread decline of Pinus pinaster in a mixed forest. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 685:963-975. [PMID: 31247442 DOI: 10.1016/j.scitotenv.2019.05.378] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/20/2019] [Accepted: 05/24/2019] [Indexed: 06/09/2023]
Abstract
Global change potentially increases forest vulnerability. Different abiotic and biotic factors may interact to cause forest decline and accelerated tree mortality. We studied a mixed Mediterranean continental forest where Pinus pinaster Ait. (maritime pine) shows widespread decline to analyse the role of different abiotic and biotic factors on health status and growth dynamics both at the individual and plot levels. We also analysed stand composition and regeneration of tree species to check whether there is a change in species dominance. Fungal pathogens were seldom present and we detected no pervasive fungi or insect infestation and no presence of pathogens like Heterobasidion or Phytophthora. Infection of hemiparasite plants like Viscum album L. (mistletoe) can reduce leaf area and its abundance is generally considered an expression of host decline. Yet, the existence among declining trees of high defoliation levels without mistletoe, but not vice versa, suggests that defoliation in response to some abiotic stressor could be a predisposing factor preceding mistletoe infection. Compared to healthy trees, declining and dead trees exhibited higher defoliation rates, smaller needles and lower recent growth with steeper negative trends. Dead and declining trees showed similar negative growth trends since the early 1990s droughts, which we interpreted as early warning signals anticipating mortality of currently declining trees in the near future. Mortality of maritime pine extending across all size classes, the lower presence of this species in the smallest size classes and its lack of regeneration suggest it is potentially losing its current dominance and being replaced by other co-occurring, more drought-tolerant species. Our results unravelled that maritime pine decline seems to be mainly driven by a combination of predisposing and inciting abiotic factors (microenvironment and drought stress) and biotic factors (mistletoe). The absence of widespread fungal pathogens suggests that they may have a minor role on pine decline acting only eventually as contributing factors. Although there could be other interrelations among factors or other biotic agents at play, our results strongly suggest that water stress plays a major role in the decline process of the dominant species on an ecosystem with strong land-use legacies.
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Affiliation(s)
| | | | | | - Olga Aguín
- Estación Fitopatolóxica do Areeiro, Subida a la Robleda s/n, 36153 Pontevedra, Spain
| | | | | | | | - Rosa Raposo
- INIA-CIFOR, Ctra. La Coruña km. 7.5, 28040 Madrid, Spain
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18
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Conflicting functional effects of xylem pit structure relate to the growth-longevity trade-off in a conifer species. Proc Natl Acad Sci U S A 2019; 116:15282-15287. [PMID: 31209057 DOI: 10.1073/pnas.1900734116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Consistent with a ubiquitous life history trade-off, trees exhibit a negative relationship between growth and longevity both among and within species. However, the mechanistic basis of this life history trade-off is not well understood. In addition to resource allocation conflicts among multiple traits, functional conflicts arising from individual morphological traits may also contribute to life history trade-offs. We hypothesized that conflicting functional effects of xylem structural traits contribute to the growth-longevity trade-off in trees. We tested this hypothesis by examining the extent to which xylem morphological traits (i.e., wood density, tracheid diameters, and pit structure) relate to growth rates and longevity in two natural populations of the conifer species Pinus ponderosa Hydraulic constraints arise as trees grow larger and xylem anatomical traits adjust to compensate. We disentangled the effects of size through ontogeny in individual trees and growth rates among trees on xylem traits by sampling each tree at multiple trunk diameters. We found that the oldest trees had slower lifetime growth rates compared with younger trees in the studied populations, indicating a growth-longevity trade-off. We further provide evidence that a single xylem trait, pit structure, with conflicting effects on xylem function (hydraulic safety and efficiency) relates to the growth-longevity trade-off in a conifer species. This study highlights that, in addition to trade-offs among multiple traits, functional constraints based on individual morphological traits like that of pit structure provide mechanistic insight into how and when life history trade-offs arise.
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19
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Michelot-Antalik A, Granda E, Fresneau C, Damesin C. Evidence of a seasonal trade-off between growth and starch storage in declining beeches: assessment through stem radial increment, non-structural carbohydrates and intra-ring δ13C. TREE PHYSIOLOGY 2019; 39:831-844. [PMID: 30824921 DOI: 10.1093/treephys/tpz008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 01/08/2019] [Indexed: 06/09/2023]
Abstract
Forest decline is reported in recent decades all over the world. However, developing a clear vision of the associated tree dysfunctioning is still a challenge for plant physiologists. In this study, our aim was to examine the seasonal carbon adjustments of beech trees in the case of a long-term drought-induced decline. We compared healthy and declining trees in terms of stem radial growth, phloem sugar content and δ13C, together with xylem carbohydrates and intra-ring δ13C patterns. The radial growth of declining trees was clearly reduced by lower growth rates and shorter growing season length (44 days compared with healthy trees). The soluble sugar content was higher in the xylem of declining trees compared with the healthy ones, but similar in the phloem except at the end of their growth. Declining trees increased their levels of xylem starch content from budburst until the date of maximal growth rate. These reserve dynamics revealed an early trade-off between radial growth and starch storage that might be the result of an active or passive process. For declining trees, the slight decrease of intra-ring cellulose δ13C pattern during the early growing season was attributed to the synthesis of 13C enriched starch. For healthy trees, δ13C patterns were characterized by a progressive 13C increase along the ring, attributed to increased water-use efficiency (WUE) in response to decreased water availability. Individual variations of the crown area were negatively correlated to the intra-ring δ13C amplitude, which was ascribed to variations in canopy WUE and resource competition for healthy trees and partly to variations in the amount of reserves accumulated during spring for declining ones. Our study highlights the carbon physiological adjustment of declining trees towards reducing spring growth while storing starch, which can be reflected in the individual intra-ring cellulose δ13C patterns.
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Affiliation(s)
- Alice Michelot-Antalik
- Université de Lorraine, Inra, LAE, Nancy, France
- Laboratoire Ecologie Systématique et Evolution, UMR 8079, Université Paris-Sud, CNRS, AgroParisTech, Orsay, France
| | - Elena Granda
- Laboratoire Ecologie Systématique et Evolution, UMR 8079, Université Paris-Sud, CNRS, AgroParisTech, Orsay, France
- Department of Crop and Forest Sciences - AGROTECNIO Center, Universitat de Lleida, Lleida, Spain
| | - Chantal Fresneau
- Laboratoire Ecologie Systématique et Evolution, UMR 8079, Université Paris-Sud, CNRS, AgroParisTech, Orsay, France
| | - Claire Damesin
- Laboratoire Ecologie Systématique et Evolution, UMR 8079, Université Paris-Sud, CNRS, AgroParisTech, Orsay, France
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20
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Flake SW, Weisberg PJ. Fine-scale stand structure mediates drought-induced tree mortality in pinyon-juniper woodlands. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01831. [PMID: 30548934 DOI: 10.1002/eap.1831] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/24/2018] [Accepted: 08/30/2018] [Indexed: 05/25/2023]
Abstract
Severe drought has resulted in widespread tree die-off events in forests and woodlands globally and is forecast to become more frequent in coming decades. Tree mortality is a complex process influenced by climate, soils, characteristics of individual trees, interactions between trees, and the dynamics of pests and pathogens. The role of stand structure and stand density in mediating the resistance of trees to drought remains poorly understood, especially in semiarid woodlands, which are expected to be highly susceptible to future severe drought. We sampled permanent plots in central Nevada woodlands dominated by single-leaf pinyon pine and Utah juniper before and after a severe multi-year drought (2013-2015) to investigate the importance of climate, tree attributes, and local-neighborhood stand structure on tree mortality and canopy dieback at the level of individual trees and 0.1-ha plots. We observed widespread tree mortality of pinyon at approximately eight times the reported background mortality rate, and substantial canopy dieback in both pinyon and juniper. Both species were more prone to mortality and dieback in hotter, drier sites. Canopy dieback was associated with both long-term average climate and the severity of recent drought, with elevated mortality on sites with higher water deficits, average summer temperatures, and vapor pressure deficits. Soils also played a role in tree dieback, with greater mortality on deeper soils. While mortality was driven largely by climate at coarse scales, fine-scale stand structure interacted with climate to mediate mortality and dieback. Neighborhood statistics showed that trees were susceptible to competitive influence, and pinyon trees were especially sensitive to neighborhood density on drier sites. Mortality and dieback were associated with diverse, co-occurring insect and parasitic plant mortality agents. Canopy dieback prior to the drought was strongly associated with tree mortality during the drought, implying that current widespread defoliation caused by these agents may foreshadow future elevated woodland decline. Fine-scale influences such as stand structure and soil characteristics play a key role in the long-term dynamics of semiarid woodlands, and these factors should be considered in predictive models of forest and woodland susceptibility to drought.
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Affiliation(s)
- Samuel W Flake
- Department of Natural Resources and Environmental Science, University of Nevada Reno, Reno, Nevada, 89557, USA
| | - Peter J Weisberg
- Department of Natural Resources and Environmental Science, University of Nevada Reno, Reno, Nevada, 89557, USA
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21
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Vázquez-González C, López-Goldar X, Zas R, Sampedro L. Neutral and Climate-Driven Adaptive Processes Contribute to Explain Population Variation in Resin Duct Traits in a Mediterranean Pine Species. FRONTIERS IN PLANT SCIENCE 2019; 10:1613. [PMID: 31921257 PMCID: PMC6923275 DOI: 10.3389/fpls.2019.01613] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 11/15/2019] [Indexed: 05/20/2023]
Abstract
Resin ducts are important anatomical defensive traits related to biotic resistance in conifers. Previous studies have reported intraspecific genetic variation in resin duct characteristics. However, little is currently known about the micro-evolutionary patterns and adaptive value of these defensive structures. Here, we quantified inter-population genetic variation in resin duct features and their inducibility in Pinus pinaster and assessed whether such variation was associated with climate gradients. To that end, we characterized the resin duct system of 2-year-old saplings from 10 populations across the species' distribution range. We measured axial resin duct features (density, mean size, and percentage conductive area of resin ducts) and their inducibility in response to methyl jasmonate. Genotyping of single nucleotide polymorphisms allowed to account for the population genetic structure in our models in order to avoid spurious correlations between resin duct characteristics and climate. We found large inter-population variation in resin duct density and conductive area, but not in their inducibility. Our results suggest that population variation in the percentage conductive area of resin ducts likely arise from adaptation to local climate conditions. This study highlights the adaptive relevance of resin ducts and helps to shed light on the micro-evolutionary patterns of resin-based defenses in conifers.
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22
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McBranch NA, Grossiord C, Adams H, Borrego I, Collins AD, Dickman T, Ryan M, Sevanto S, McDowell NG. Lack of acclimation of leaf area:sapwood area ratios in piñon pine and juniper in response to precipitation reduction and warming. TREE PHYSIOLOGY 2019; 39:135-142. [PMID: 30272223 DOI: 10.1093/treephys/tpy066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Indexed: 05/16/2023]
Abstract
The leaf area to sapwood area ratios of trees (Al: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.
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Affiliation(s)
- Natalie A McBranch
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM , USA
| | - Charlotte Grossiord
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM , USA
| | - Henry Adams
- Department of Plant Biology, Ecology, and Evolution, Oklahoma State University, Stillwater, OK, USA
| | - Isaac Borrego
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM , USA
| | - Adam D Collins
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM , USA
| | - Turin Dickman
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM , USA
| | - Max Ryan
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM , USA
| | - Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM , USA
| | - Nate G McDowell
- Earth Systems Science Division, Pacific Northwest National Laboratory, Richland, WA, USA
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23
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Trugman AT, Detto M, Bartlett MK, Medvigy D, Anderegg WRL, Schwalm C, Schaffer B, Pacala SW. Tree carbon allocation explains forest drought-kill and recovery patterns. Ecol Lett 2018; 21:1552-1560. [DOI: 10.1111/ele.13136] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 05/29/2018] [Accepted: 07/12/2018] [Indexed: 12/18/2022]
Affiliation(s)
- A. T. Trugman
- Department of Biology; University of Utah; Salt Lake City UT 84112 USA
| | - M. Detto
- Department of Ecology and Evolutionary Biology; Princeton University; Princeton NJ 08544 USA
| | - M. K. Bartlett
- Department of Ecology and Evolutionary Biology; Princeton University; Princeton NJ 08544 USA
| | - D. Medvigy
- Department of Biological Sciences; University of Notre Dame; Notre Dame IN 46556 USA
| | - W. R. L. Anderegg
- Department of Biology; University of Utah; Salt Lake City UT 84112 USA
| | - C. Schwalm
- Center for Ecosystem Science and Society; Northern Arizona University; Flagstaff AZ 86001 USA
- Woods Hole Research Center; Falmouth MA 02540 USA
| | - B. Schaffer
- Department of Civil and Environmental Engineering; Princeton University; Princeton NJ 08544 USA
| | - S. W. Pacala
- Department of Ecology and Evolutionary Biology; Princeton University; Princeton NJ 08544 USA
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24
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McDowell N, Allen CD, Anderson-Teixeira K, Brando P, Brienen R, Chambers J, Christoffersen B, Davies S, Doughty C, Duque A, Espirito-Santo F, Fisher R, Fontes CG, Galbraith D, Goodsman D, Grossiord C, Hartmann H, Holm J, Johnson DJ, Kassim AR, Keller M, Koven C, Kueppers L, Kumagai T, Malhi Y, McMahon SM, Mencuccini M, Meir P, Moorcroft P, Muller-Landau HC, Phillips OL, Powell T, Sierra CA, Sperry J, Warren J, Xu C, Xu X. Drivers and mechanisms of tree mortality in moist tropical forests. THE NEW PHYTOLOGIST 2018; 219:851-869. [PMID: 29451313 DOI: 10.1111/nph.15027] [Citation(s) in RCA: 169] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/19/2017] [Indexed: 05/22/2023]
Abstract
Tree mortality rates appear to be increasing in moist tropical forests (MTFs) with significant carbon cycle consequences. Here, we review the state of knowledge regarding MTF tree mortality, create a conceptual framework with testable hypotheses regarding the drivers, mechanisms and interactions that may underlie increasing MTF mortality rates, and identify the next steps for improved understanding and reduced prediction. Increasing mortality rates are associated with rising temperature and vapor pressure deficit, liana abundance, drought, wind events, fire and, possibly, CO2 fertilization-induced increases in stand thinning or acceleration of trees reaching larger, more vulnerable heights. The majority of these mortality drivers may kill trees in part through carbon starvation and hydraulic failure. The relative importance of each driver is unknown. High species diversity may buffer MTFs against large-scale mortality events, but recent and expected trends in mortality drivers give reason for concern regarding increasing mortality within MTFs. Models of tropical tree mortality are advancing the representation of hydraulics, carbon and demography, but require more empirical knowledge regarding the most common drivers and their subsequent mechanisms. We outline critical datasets and model developments required to test hypotheses regarding the underlying causes of increasing MTF mortality rates, and improve prediction of future mortality under climate change.
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Affiliation(s)
- Nate McDowell
- Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Craig D Allen
- US Geological Survey, Fort Collins Science Center, New Mexico Landscapes Field Station, Los Alamos, NM, 87544, USA
| | - Kristina Anderson-Teixeira
- Center for Tropical Forest Science-Forest Global Earth Observatory, Smithsonian Tropical Research Institute, Washington, DC, 20036, USA
- Conservation Ecology Center, Smithsonian Conservation Biology Institute, National Zoological Park, Front Royal, VA, 22630, USA
| | - Paulo Brando
- Woods Hole Research Center, 149 Woods Hole Road, Falmouth, MA, 02450, USA
- Instituto de Pesquisa Ambiental de Amazonia, Lago Norte, Brasilia, Brazil
| | - Roel Brienen
- School of Geography, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Jeff Chambers
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Brad Christoffersen
- Department of Biology and School of Earth, Environmental and Marine Sciences, University of Texas Rio Grande Valley, Edinburg, TX, 78539, USA
| | - Stuart Davies
- Center for Tropical Forest Science-Forest Global Earth Observatory, Smithsonian Tropical Research Institute, Washington, DC, 20036, USA
| | - Chris Doughty
- SICCS, Northern Arizona University, Flagstaff, AZ, 86001, USA
| | - Alvaro Duque
- Departmento de Ciencias Forestales, Universidad Nacional de Columbia, Medellín, Columbia
| | | | - Rosie Fisher
- National Center for Atmospheric Research, Boulder, CO, 80305, USA
| | - Clarissa G Fontes
- Department of Integrative Biology, University of California at Berkeley, Berkeley, CA, 94720, USA
| | - David Galbraith
- School of Geography, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Devin Goodsman
- Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | | | - Henrik Hartmann
- Department of Biogeochemical Processes, Max Plank Institute for Biogeochemistry, 07745, Jena, Germany
| | - Jennifer Holm
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | | | - Abd Rahman Kassim
- Geoinformation Programme, Forestry and Environment Division, Forest Research Institute Malaysia, Selangor, Malaysia
| | - Michael Keller
- International Institute of Tropical Forestry, USDA Jardin Botanico Sur, 1201 Calle Ceiba, San Juan, 00926, Puerto Rico
- Embrapa Agricultural Informatics, Parque Estacao Biologica, Brasilia DF, 70770, Brazil
- Jet Propulsion Laboratory, Pasadena, CA, 91109, USA
| | - Charlie Koven
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Lara Kueppers
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Energy and Resources Group, University of California, Berkeley, CA, 94720, USA
| | - Tomo'omi Kumagai
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 7 Chome-3-1 Hongo, Bunkyo, Tokyo, 113-8654, Japan
| | - Yadvinder Malhi
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, OX1 2JD, UK
| | - Sean M McMahon
- Center for Tropical Forest Science-Forest Global Earth Observatory, Smithsonian Tropical Research Institute, Washington, DC, 20036, USA
| | - Maurizio Mencuccini
- ICREA, CREAF, University of Barcelona, Gran Via de les Corts Catalenes, 585 08007, Barcelona, Spain
| | - Patrick Meir
- Australian National University, Acton, Canberra, ACT, 2601, Australia
- School of Geosciences, University of Edinburgh, Old College, South Bridge, Edinburgh, EH8 9YL, UK
| | | | - Helene C Muller-Landau
- Smithsonian Tropical Research Institute, Apartado Postal, 0843-03092, Panamá, República de Panamá
| | - Oliver L Phillips
- School of Geography, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Thomas Powell
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Carlos A Sierra
- Department of Biogeochemical Processes, Max Plank Institute for Biogeochemistry, 07745, Jena, Germany
| | - John Sperry
- University of Utah, Salt Lake City, UT, 84112, USA
| | - Jeff Warren
- Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Chonggang Xu
- Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Xiangtao Xu
- Department of Geosciences, Princeton University, Princeton, NJ, 08544, USA
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25
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Drought Decreases Growth and Increases Mortality of Coexisting Native and Introduced Tree Species in a Temperate Floodplain Forest. FORESTS 2018. [DOI: 10.3390/f9040205] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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26
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Dai Y, Wang L, Wan X. Relative contributions of hydraulic dysfunction and carbohydrate depletion during tree mortality caused by drought. AOB PLANTS 2018; 10:plx069. [PMID: 29367873 PMCID: PMC5774510 DOI: 10.1093/aobpla/plx069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 11/30/2017] [Indexed: 05/29/2023]
Abstract
Drought-induced tree mortality has been observed worldwide. Nevertheless, the physiological mechanisms underlying this phenomenon are still being debated. Potted Robinia pseudoacacia and Platycladus orientalis saplings were subjected to drought and their hydraulic failure and carbon starvation responses were studied. They underwent simulated fast drought (FD) and slow drought (SD) until death. The dynamics of their growth, photosynthesis, water relations and carbohydrate concentration were measured. The results showed that during drought, growth and photosynthesis of all saplings were significantly reduced in both species. The predawn water potential in both species was ~ -8 MPa at mortality. The percentage loss of conductivity (PLC) was at a maximum at mortality under both FD and SD. For R. pseudoacacia and P. orientalis, they were >95 and ~45 %, respectively. At complete defoliation, the PLC of R. pseudoacacia was ~90 % but the trees continued to survive for around 46 days. The non-structural carbohydrate (NSC) concentrations in the stems and roots of both FD and SD R. pseudoacacia declined to a very low level near death. In contrast, the NSC concentrations in the needles, stems and roots of P. orientalis at mortality under FD did not significantly differ from those of the control, whereas the NSC concentrations in SD P. orientalis stems and roots at death were significantly lower than those of the control. These results suggest that the duration of the drought affected NSC at mortality in P. orientalis. In addition, the differences in NSC between FD and SD P. orientalis did not alter mortality thresholds associated with hydraulic failure. The drought-induced death of R. pseudoacacia occurred at 95 % PLC for both FD and SD, indicating that hydraulic failure played an important role in mortality. Nevertheless, the consistent decline in NSC in R. pseudoacacia saplings following drought-induced defoliation may have also contributed to its mortality.
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Affiliation(s)
- Yongxin Dai
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, P.R. China
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, P.R. China
| | - Lin Wang
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, P.R. China
| | - Xianchong Wan
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, P.R. China
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27
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Hudson PJ, Limousin JM, Krofcheck DJ, Boutz AL, Pangle RE, Gehres N, McDowell NG, Pockman WT. Impacts of long-term precipitation manipulation on hydraulic architecture and xylem anatomy of piñon and juniper in Southwest USA. PLANT, CELL & ENVIRONMENT 2018; 41:421-435. [PMID: 29215745 DOI: 10.1111/pce.13109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 11/09/2017] [Accepted: 11/14/2017] [Indexed: 06/07/2023]
Abstract
Hydraulic architecture imposes a fundamental control on water transport, underpinning plant productivity, and survival. The extent to which hydraulic architecture of mature trees acclimates to chronic drought is poorly understood, limiting accuracy in predictions of forest responses to future droughts. We measured seasonal shoot hydraulic performance for multiple years to assess xylem acclimation in mature piñon (Pinus edulis) and juniper (Juniperus monosperma) after 3+ years of precipitation manipulation. Our treatments consisted of water addition (+20% ambient precipitation), partial precipitation-exclusion (-45% ambient precipitation), and exclusion-structure control. Supplemental watering elevated leaf water potential, sapwood-area specific hydraulic conductivity, and leaf-area specific hydraulic conductivity relative to precipitation exclusion. Shifts in allocation of leaf area to sapwood area enhanced differences between irrigated and droughted KL in piñon but not juniper. Piñon and juniper achieved similar KL under ambient conditions, but juniper matched or outperformed piñon in all physiological measurements under both increased and decreased precipitation treatments. Embolism vulnerability and xylem anatomy were unaffected by treatments in either species. Absence of significant acclimation combined with inferior performance for both hydraulic transport and safety suggests piñon has greater risk of local extirpation if aridity increases as predicted in the southwestern USA.
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Affiliation(s)
- P J Hudson
- Department of Biology, MSC03 2020, University of New Mexico, Albuquerque, NM, 87131-0001, USA
| | - J M Limousin
- Centre d'Ecologie Fonctionnelle et Evolutive CEFE, UMR5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, Montpellier, 34293, France
| | - D J Krofcheck
- Department of Biology, MSC03 2020, University of New Mexico, Albuquerque, NM, 87131-0001, USA
| | - A L Boutz
- Department of Biology, MSC03 2020, University of New Mexico, Albuquerque, NM, 87131-0001, USA
| | - R E Pangle
- Department of Biology, MSC03 2020, University of New Mexico, Albuquerque, NM, 87131-0001, USA
| | - N Gehres
- Department of Biology, MSC03 2020, University of New Mexico, Albuquerque, NM, 87131-0001, USA
| | - N G McDowell
- Earth Systems Analysis and Modeling, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - W T Pockman
- Department of Biology, MSC03 2020, University of New Mexico, Albuquerque, NM, 87131-0001, USA
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28
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Wu X, Liu H, Li X, Ciais P, Babst F, Guo W, Zhang C, Magliulo V, Pavelka M, Liu S, Huang Y, Wang P, Shi C, Ma Y. Differentiating drought legacy effects on vegetation growth over the temperate Northern Hemisphere. GLOBAL CHANGE BIOLOGY 2018; 24:504-516. [PMID: 28973825 DOI: 10.1111/gcb.13920] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 08/15/2017] [Accepted: 09/21/2017] [Indexed: 05/04/2023]
Abstract
In view of future changes in climate, it is important to better understand how different plant functional groups (PFGs) respond to warmer and drier conditions, particularly in temperate regions where an increase in both the frequency and severity of drought is expected. The patterns and mechanisms of immediate and delayed impacts of extreme drought on vegetation growth remain poorly quantified. Using satellite measurements of vegetation greenness, in-situ tree-ring records, eddy-covariance CO2 and water flux measurements, and meta-analyses of source water of plant use among PFGs, we show that drought legacy effects on vegetation growth differ markedly between forests, shrubs and grass across diverse bioclimatic conditions over the temperate Northern Hemisphere. Deep-rooted forests exhibit a drought legacy response with reduced growth during up to 4 years after an extreme drought, whereas shrubs and grass have drought legacy effects of approximately 2 years and 1 year, respectively. Statistical analyses partly attribute the differences in drought legacy effects among PFGs to plant eco-hydrological properties (related to traits), including plant water use and hydraulic responses. These results can be used to improve the representation of drought response of different PFGs in land surface models, and assess their biogeochemical and biophysical feedbacks in response to a warmer and drier climate.
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Affiliation(s)
- Xiuchen Wu
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China
- Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Hongyan Liu
- College of Urban and Environmental Science, Peking University, Beijing, China
| | - Xiaoyan Li
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China
- Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Philippe Ciais
- CEA-CNRS-UVSQ, UMR8212-Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Gif-Sur-Yvette, France
| | - Flurin Babst
- Dendro Sciences, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
- W. Szafer Institute of Botany, Polish Academy of Sciences, Krakow, Poland
| | - Weichao Guo
- College of Urban and Environmental Science, Peking University, Beijing, China
| | - Cicheng Zhang
- Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Vincenzo Magliulo
- National Research Council of Italy, Institute for Mediterranean Agriculture and Forest Systems (CNR-ISAFoM), Ercolano, Italy
| | - Marian Pavelka
- CzechGlobe-Global Change Research Institute CAS, Brno, Czech Republic
| | - Shaomin Liu
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China
- Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Yongmei Huang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China
- Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Pei Wang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China
- Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Chunming Shi
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China
- College of Global Change and Earth System Science, Beijing Normal University, Beijing, China
| | - Yujun Ma
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China
- Faculty of Geographical Science, Beijing Normal University, Beijing, China
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29
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del-Val E, Sáenz-Romero C. INSECTOS DESCORTEZADORES (COLEOPTERA: CURCULIONIDAE) Y CAMBIO CLIMÁTICO: PROBLEMÁTICA ACTUAL Y PERSPECTIVAS EN LOS BOSQUES TEMPLADOS. TIP REVISTA ESPECIALIZADA EN CIENCIAS QUÍMICO-BIOLÓGICAS 2017. [DOI: 10.1016/j.recqb.2017.04.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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30
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Wong CM, Daniels LD. Novel forest decline triggered by multiple interactions among climate, an introduced pathogen and bark beetles. GLOBAL CHANGE BIOLOGY 2017; 23:1926-1941. [PMID: 27901296 DOI: 10.1111/gcb.13554] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 10/14/2016] [Accepted: 10/18/2016] [Indexed: 06/06/2023]
Abstract
Novel forest decline is increasing due to global environmental change, yet the causal factors and their interactions remain poorly understood. Using tree ring analyses, we show how climate and multiple biotic factors caused the decline of whitebark pine (Pinus albicaulis) in 16 stands in the southern Canadian Rockies. In our study area, 72% of whitebark pines were dead and 18% had partially dead crowns. Tree mortality peaked in the 1970s; however, the annual basal area increment of disturbed trees began to decline significantly in the late 1940s. Growth decline persisted up to 30 years before trees died from mountain pine beetle (Dendroctonus ponderosae), Ips spp. bark beetles or non-native blister rust pathogen (Cronartium ribicola). Climate-growth relations varied over time and differed among the healthy and disturbed subpopulations of whitebark pine. Prior to the 1940s, cool temperatures limited the growth of all subpopulations. Growth of live, healthy trees became limited by drought during the cool phase (1947 -1976) of the Pacific Decadal Oscillation (PDO) and then reverted to positive correlations with temperature during the subsequent warm PDO phase. In the 1940s, the climate-growth relations of the disturbed subpopulations diverged from the live, healthy trees with trees ultimately killed by mountain pine beetle diverging the most. We propose that multiple factors interacted over several decades to cause unprecedented rates of whitebark pine mortality. Climatic variation during the cool PDO phase caused drought stress that may have predisposed trees to blister rust. Subsequent decline in snowpack and warming temperatures likely incited further climatic stress and with blister rust reduced tree resistance to bark beetles. Ultimately, bark beetles and blister rust contributed to tree death. Our findings suggest the complexity of whitebark pine decline and the importance of considering multiway drought-disease-insect interactions over various timescales when interpreting forest decline.
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Affiliation(s)
- Carmen M Wong
- Department of Geography, University of British Columbia, Vancouver, BC, V6T 1Z2, Canada
| | - Lori D Daniels
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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31
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Bentz BJ, Hood SM, Hansen EM, Vandygriff JC, Mock KE. Defense traits in the long-lived Great Basin bristlecone pine and resistance to the native herbivore mountain pine beetle. THE NEW PHYTOLOGIST 2017; 213:611-624. [PMID: 27612209 PMCID: PMC5213150 DOI: 10.1111/nph.14191] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Accepted: 08/05/2016] [Indexed: 05/11/2023]
Abstract
Mountain pine beetle (MPB, Dendroctonus ponderosae) is a significant mortality agent of Pinus, and climate-driven range expansion is occurring. Pinus defenses in recently invaded areas, including high elevations, are predicted to be lower than in areas with longer term MPB presence. MPB was recently observed in high-elevation forests of the Great Basin (GB) region, North America. Defense and susceptibility in two long-lived species, GB bristlecone pine (Pinus longaeva) and foxtail pine (P. balfouriana), are unclear, although they are sympatric with a common MPB host, limber pine (P. flexilis). We surveyed stands with sympatric GB bristlecone-limber pine and foxtail-limber pine to determine relative MPB attack susceptibility and constitutive defenses. MPB-caused mortality was extensive in limber, low in foxtail and absent in GB bristlecone pine. Defense traits, including constitutive monoterpenes, resin ducts and wood density, were higher in GB bristlecone and foxtail than in limber pine. GB bristlecone and foxtail pines have relatively high levels of constitutive defenses which make them less vulnerable to climate-driven MPB range expansion relative to other high-elevation pines. Long-term selective herbivore pressure and exaptation of traits for tree longevity are potential explanations, highlighting the complexity of predicting plant-insect interactions under climate change.
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Affiliation(s)
- Barbara J. Bentz
- USDA Forest Service Rocky Mountain Research StationLoganUT84321USA
| | - Sharon M. Hood
- USDA Forest Service Rocky Mountain Research StationMissoulaMT59808USA
| | | | | | - Karen E. Mock
- Department of Wildland Resources and Ecology CenterUtah State UniversityLoganUT84321USA
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32
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Petit G, Savi T, Consolini M, Anfodillo T, Nardini A. Interplay of growth rate and xylem plasticity for optimal coordination of carbon and hydraulic economies in Fraxinus ornus trees. TREE PHYSIOLOGY 2016; 36:1310-1319. [PMID: 27587483 DOI: 10.1093/treephys/tpw069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 06/17/2016] [Accepted: 07/02/2016] [Indexed: 05/22/2023]
Abstract
Efficient leaf water supply is fundamental for assimilation processes and tree growth. Renovating the architecture of the xylem transport system requires an increasing carbon investment while growing taller, and any deficiency of carbon availability may result in increasing hydraulic constraints to water flow. Therefore, plants need to coordinate carbon assimilation and biomass allocation to guarantee an efficient and safe long-distance transport system. We tested the hypothesis that reduced branch elongation rates together with carbon-saving adjustments of xylem anatomy hydraulically compensate for the reduction in biomass allocation to xylem. We measured leaf biomass, hydraulic and anatomical properties of wood segments along the main axis of branches in 10 slow growing (SG) and 10 fast growing (FG) Fraxinus ornus L. trees. Branches of SG trees had five times slower branch elongation rate (7 vs 35 cm year-1), and produced a higher leaf biomass (P < 0.0001) and thinner xylem rings with fewer but larger vessels (P < 0.0001). On the contrary, we found no differences between SG and FG trees in terms of leaf-specific conductivity (P > 0.05) and xylem safety (Ψ50 ≈ -3.2 MPa). Slower elongation rate coupled with thinner annual rings and larger vessels allows the reduction of carbon costs associated with growth, while maintaining similar leaf-specific conductivity and xylem safety.
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Affiliation(s)
- Giai Petit
- Dipartimento Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, Viale dell'Università 16, I-35020 Legnaro (PD), Italy
| | - Tadeja Savi
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
| | - Martina Consolini
- Dipartimento Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, Viale dell'Università 16, I-35020 Legnaro (PD), Italy
| | - Tommaso Anfodillo
- Dipartimento Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, Viale dell'Università 16, I-35020 Legnaro (PD), Italy
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
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33
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Ziaco E, Biondi F, Rossi S, Deslauriers A. Environmental drivers of cambial phenology in Great Basin bristlecone pine. TREE PHYSIOLOGY 2016; 36:818-831. [PMID: 26917705 DOI: 10.1093/treephys/tpw006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 01/16/2016] [Indexed: 06/05/2023]
Abstract
The timing of wood formation is crucial to determine how environmental factors affect tree growth. The long-lived bristlecone pine (Pinus longaeva D. K. Bailey) is a foundation treeline species in the Great Basin of North America reaching stem ages of about 5000 years. We investigated stem cambial phenology and radial size variability to quantify the relative influence of environmental variables on bristlecone pine growth. Repeated cellular measurements and half-hourly dendrometer records were obtained during 2013 and 2014 for two high-elevation stands included in the Nevada Climate-ecohydrological Assessment Network. Daily time series of stem radial variations showed rehydration and expansion starting in late April-early May, prior to the onset of wood formation at breast height. Formation of new xylem started in June and lasted until mid-September. There were no differences in phenological timing between the two stands, or in the air and soil temperature thresholds for the onset of xylogenesis. A multiple logistic regression model highlighted a separate effect of air and soil temperature on xylogenesis, the relevance of which was modulated by the interaction with vapor pressure and soil water content. While air temperature plays a key role in cambial resumption after winter dormancy, soil thermal conditions coupled with snowpack dynamics also influence the onset of wood formation by regulating plant-soil water exchanges. Our results help build a physiological understanding of climate-growth relationships in P. longaeva, the importance of which for dendroclimatic reconstructions can hardly be overstated. In addition, environmental drivers of xylogenesis at the treeline ecotone, by controlling the growth of dominant species, ultimately determine ecosystem responses to climatic change.
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Affiliation(s)
| | - Franco Biondi
- DendroLab, University of Nevada, Reno, NV 89557, USA
| | - Sergio Rossi
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Chicoutimi, QC G7H2B1, Canada Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Provincial Key Laboratories of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Annie Deslauriers
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Chicoutimi, QC G7H2B1, Canada
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34
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Hood S, Sala A. Ponderosa pine resin defenses and growth: metrics matter. TREE PHYSIOLOGY 2015; 35:1223-35. [PMID: 26433021 DOI: 10.1093/treephys/tpv098] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 08/26/2015] [Indexed: 05/20/2023]
Abstract
Bark beetles (Coleoptera: Curculionidae, Scolytinae) cause widespread tree mortality in coniferous forests worldwide. Constitutive and induced host defenses are important factors in an individual tree's ability to survive an attack and in bottom-up regulation of bark beetle population dynamics, yet quantifying defense levels is often difficult. For example, in Pinus spp., resin flow is important for resistance to bark beetles but is extremely variable among individuals and within a season. While resin is produced and stored in resin ducts, the specific resin duct metrics that best correlate with resin flow remain unclear. The ability and timing of some pine species to produce induced resin is also not well understood. We investigated (i) the relationships between ponderosa pine (Pinus ponderosa Lawson & C. Lawson) resin flow and axial resin duct characteristics, tree growth and physiological variables, and (ii) if mechanical wounding induces ponderosa pine resin flow and resin ducts in the absence of bark beetles. Resin flow increased later in the growing season under moderate water stress and was highest in faster growing trees. The best predictors of resin flow were nonstandardized measures of resin ducts, resin duct size and total resin duct area, both of which increased with tree growth. However, while faster growing trees tended to produce more resin, models of resin flow using only tree growth were not statistically significant. Further, the standardized measures of resin ducts, density and duct area relative to xylem area, decreased with tree growth rate, indicating that slower growing trees invested more in resin duct defenses per unit area of radial growth, despite a tendency to produce less resin overall. We also found that mechanical wounding induced ponderosa pine defenses, but this response was slow. Resin flow increased after 28 days, and resin duct production did not increase until the following year. These slow induced responses may allow unsuccessfully attacked or wounded trees to resist future bark beetle attacks. Forest management that encourages healthy, vigorously growing trees will also favor larger resin ducts, thereby conferring increased constitutive resistance to bark beetle attacks.
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Affiliation(s)
- Sharon Hood
- Division of Biological Sciences, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT 59808, USA
| | - Anna Sala
- Division of Biological Sciences, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA
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