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Waite PA, Kumar M, Link RM, Schuldt B. Coordinated hydraulic traits influence the two phases of time to hydraulic failure in five temperate tree species differing in stomatal stringency. TREE PHYSIOLOGY 2024; 44:tpae038. [PMID: 38606678 DOI: 10.1093/treephys/tpae038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 03/08/2024] [Accepted: 03/28/2024] [Indexed: 04/13/2024]
Abstract
Worldwide, forests are increasingly exposed to extreme droughts causing tree mortality. Because of the complex nature of the mechanisms involved, various traits have been linked to tree drought responses with contrasting results. This may be due to species-specific strategies in regulating water potential, a process that unfolds in two distinct phases: a first phase until stomatal closure, and a second phase until reaching lethal xylem hydraulic thresholds. We conducted dry-down experiments with five broadleaved temperate tree species differing in their degree of isohydry to estimate the time to stomatal closure (tsc) and subsequent time to critical hydraulic failure (tcrit). We measured various traits linked to tree drought responses, such as the water potentials at turgor loss point (Ptlp), stomatal closure (Pgs90), and 12%, 50% and 88% loss of xylem hydraulic conductance (P12, P50, P88), hydraulic capacitance (C), minimum leaf conductance (gmin), hydroscape area (HSA) and hydraulic safety margins (HSM). We found that Pgs90 followed previously recorded patterns of isohydry and was associated with HSA. Species ranked from more to less isohydric in the sequence Acer pseudoplatanus < Betula pendula < Tilia cordata < Sorbus aucuparia < Fagus sylvatica. Their degree of isohydry was associated with leaf safety (Ptlp and gmin), drought avoidance (C) and tsc, but decoupled from xylem safety (HSM and P88) and tcrit. Regardless of their stomatal stringency, species with wider HSM and lower P88 reached critical hydraulic failure later. We conclude that the duration of the first phase is determined by stomatal regulation, while the duration of the second phase is associated with xylem safety. Isohydry is thus linked to water use rather than to drought survival strategies, confirming the proposed use of HSA as a complement to HSM for describing plant drought responses before and after stomatal closure.
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Affiliation(s)
- Pierre-André Waite
- Julius-von-Sachs-Institute of Biological Sciences, Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Platz 3, 97082 Würzburg, Germany
- Forest Botany, TUD Dresden University of Technology, Pienner Straße 7, 01737, Tharandt, Germany
- CIRAD, UPR AIDA, 34398 Montpellier, France
| | - Manish Kumar
- Julius-von-Sachs-Institute of Biological Sciences, Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Platz 3, 97082 Würzburg, Germany
- ICAR - Central Soil Salinity Research Institute (CSSRI), Karnal, 132001, India
| | - Roman M Link
- Julius-von-Sachs-Institute of Biological Sciences, Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Platz 3, 97082 Würzburg, Germany
- Forest Botany, TUD Dresden University of Technology, Pienner Straße 7, 01737, Tharandt, Germany
| | - Bernhard Schuldt
- Julius-von-Sachs-Institute of Biological Sciences, Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Platz 3, 97082 Würzburg, Germany
- Forest Botany, TUD Dresden University of Technology, Pienner Straße 7, 01737, Tharandt, Germany
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2
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Depardieu C, Lenz P, Marion J, Nadeau S, Girardin MP, Marchand W, Bégin C, Treydte K, Gessler A, Bousquet J, Savard MM, Isabel N. Contrasting physiological strategies explain heterogeneous responses to severe drought conditions within local populations of a widespread conifer. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 923:171174. [PMID: 38402972 DOI: 10.1016/j.scitotenv.2024.171174] [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: 10/23/2023] [Revised: 01/12/2024] [Accepted: 02/20/2024] [Indexed: 02/27/2024]
Abstract
Understanding how trees prioritize carbon gain at the cost of drought vulnerability under severe drought conditions is crucial for predicting which genetic groups and individuals will be resilient to future climate conditions. In this study, we investigated variations in growth, tree-ring anatomy as well as carbon and oxygen isotope ratios to assess the sensitivity and the xylem formation process in response to an episode of severe drought in 29 mature white spruce (Picea glauca [Moench] Voss) families grown in a common garden trial. During the drought episode, the majority of families displayed decreased growth and exhibited either sustained or increased intrinsic water-use efficiency (iWUE), which was largely influenced by reduced stomatal conductance as revealed by the dual carbon‑oxygen isotope approach. Different water-use strategies were detected within white spruce populations in response to drought conditions. Our results revealed intraspecific variation in the prevailing physiological mechanisms underlying drought response within and among populations of Picea glauca. The presence of different genetic groups reflecting diverse water-use strategies within this largely-distributed conifer is likely to lessen the negative effects of drought and decrease the overall forest ecosystems' sensitivity to it.
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Affiliation(s)
- Claire Depardieu
- Canada Research Chair in Forest Genomics, Institute for Systems and Integrative Biology, Université Laval, Québec, QC G1V 0A6, Canada; Forest Research Centre, Département des sciences du bois et de la forêt, Université Laval, Québec, QC G1V 0A6, Canada; Natural Ressources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 rue du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada.
| | - Patrick Lenz
- Canada Research Chair in Forest Genomics, Institute for Systems and Integrative Biology, Université Laval, Québec, QC G1V 0A6, Canada; Natural Resources Canada, Canadian Forest Service, Canadian Wood Fibre Centre, 1055 rue du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada
| | - Joelle Marion
- Geological Survey of Canada, Natural Resources Canada, 490 rue de la Couronne, Québec, QC G1K 9A9, Canada
| | - Simon Nadeau
- Canada Research Chair in Forest Genomics, Institute for Systems and Integrative Biology, Université Laval, Québec, QC G1V 0A6, Canada; Natural Resources Canada, Canadian Forest Service, Canadian Wood Fibre Centre, 1055 rue du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada
| | - Martin P Girardin
- Natural Ressources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 rue du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada; Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, Succ. Centre-ville, Montréal, QC H3C 3P8, Canada; Forest Research Institute, Université du Québec en Abitibi-Témiscamingue, 445 boul. de l'Université, Rouyn-Noranda, QC J9X 5E4, Canada
| | - William Marchand
- Natural Ressources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 rue du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada; Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, Succ. Centre-ville, Montréal, QC H3C 3P8, Canada; Forest Research Institute, Université du Québec en Abitibi-Témiscamingue, 445 boul. de l'Université, Rouyn-Noranda, QC J9X 5E4, Canada
| | - Christian Bégin
- Geological Survey of Canada, Natural Resources Canada, 490 rue de la Couronne, Québec, QC G1K 9A9, Canada
| | - Kerstin Treydte
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Arthur Gessler
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland; Institute of Terrestrial Ecosystems, ETH Zurich, Zurich, Switzerland
| | - Jean Bousquet
- Canada Research Chair in Forest Genomics, Institute for Systems and Integrative Biology, Université Laval, Québec, QC G1V 0A6, Canada; Forest Research Centre, Département des sciences du bois et de la forêt, Université Laval, Québec, QC G1V 0A6, Canada
| | - Martine M Savard
- Geological Survey of Canada, Natural Resources Canada, 490 rue de la Couronne, Québec, QC G1K 9A9, Canada
| | - Nathalie Isabel
- Canada Research Chair in Forest Genomics, Institute for Systems and Integrative Biology, Université Laval, Québec, QC G1V 0A6, Canada; Natural Ressources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 rue du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada
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3
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Tonet V, Brodribb T, Bourbia I. Variation in xylem vulnerability to cavitation shapes the photosynthetic legacy of drought. PLANT, CELL & ENVIRONMENT 2024; 47:1160-1170. [PMID: 38108586 DOI: 10.1111/pce.14788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 11/08/2023] [Accepted: 12/01/2023] [Indexed: 12/19/2023]
Abstract
Increased drought conditions impact tree health, negatively disrupting plant water transport which, in turn, affects plant growth and survival. Persistent drought legacy effects have been documented in many diverse ecosystems, yet we still lack a mechanistic understanding of the physiological processes limiting tree recovery after drought. Tackling this question, we exposed saplings of a common Australian evergreen tree (Eucalyptus viminalis) to a cycle of drought and rewatering, seeking evidence for a link between the spread of xylem cavitation within the crown and the degree of photosynthetic recovery postdrought. Individual leaves experiencing >35% vein cavitation quickly died but this did not translate to a rapid overall canopy damage. Rather, whole canopies showed a gradual decline in mean postdrought gas exchange rates as water stress increased. This gradual loss of canopy function postdrought was due to a significant variation in cavitation vulnerability of leaves within canopies leading to diversity in the capacity of leaves within a single crown to recover function after drought. These results from the evergreen E. viminalis emphasise the importance of within-crown variation in xylem vulnerability as a central character regulating the dynamics of canopy death and the severity of drought legacy through time.
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Affiliation(s)
- Vanessa Tonet
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Australia
- School of Forestry & Environmental Studies, Yale University, New Haven, Connecticut, USA
| | - Timothy Brodribb
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Australia
| | - Ibrahim Bourbia
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Australia
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4
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Lv H, Gangwisch M, Saha S. Crown die-back of peri-urban forests after combined heatwave and drought was species-specific, size-dependent, and also related to tree neighbourhood characteristics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 913:169716. [PMID: 38159755 DOI: 10.1016/j.scitotenv.2023.169716] [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: 10/26/2023] [Revised: 12/17/2023] [Accepted: 12/25/2023] [Indexed: 01/03/2024]
Abstract
The Rhine River valley of Germany has been facing recurrent and intense spells of drought and heatwaves threatening the health of trees in peri-urban forests. Crown damage intensified by climate change accelerates tree mortality, threatening its ecological, economic, and social benefits; however, the pattern of crown die-back in peri-urban forests remained unclear. We performed a field inventory to estimate the crown die-back of 2578 trees of 51 species from 68 randomly selected peri-urban forest plots in Karlsruhe region on the right bank of the Rhine, after the catastrophic summer heatwave and drought of 2018. We related crown die-back to species-specific drought tolerance, wood anatomical traits, tree size, canopy surface temperature, tree density, Shannon's diversity and Gini coefficient for tree height. Regression results indicate that small-size trees were found to be more susceptible to canopy damage than large trees, with a 1-meter increase in tree height associated with a 0.8 % reduction in crown die-back. This size-dependent process is also species-specific. Among the 12 species with significant (p < 0.05) linear relationship between height and die-back, 9 species demonstrated negative correlations and 3 species showed positive relationships. Species tolerant to drought or cavitation (e.g., trees with diffuse porous xylem, 21 species) had significantly lower crown dieback. For example, with a 1-point-scale increase in drought tolerance crown die-back declined 14.35 %. Trees that experienced high canopy surface temperature and grew with high tree density and species diversity (Shannon's diversity) had more crown die-back. However, high structural diversity (Gini coefficient) was related to lower crown die-back. Our results suggested that future research should focus more on tree species-specific hydraulic and thermal traits and tree density and structure management to improve tree health and species selection in peri-urban forests under future climate change.
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Affiliation(s)
- Hailiang Lv
- Heilongjiang Bayi Agricultural University, Xinfeng Road 5, 163316 Daqing, China; Institute for Technology Assessment and Systems Analysis (ITAS), Karlsruhe Institute of Technology, Karlstr. 11, 76133 Karlsruhe, Germany.
| | - Marcel Gangwisch
- Institute of Earth and Environmental Sciences, Faculty of Environment and Natural Resources, University of Freiburg, Werthmannstr. 10, D-79085 Freiburg, Germany
| | - Somidh Saha
- Institute for Technology Assessment and Systems Analysis (ITAS), Karlsruhe Institute of Technology, Karlstr. 11, 76133 Karlsruhe, Germany; Institute of Geography and Geoecology (IfGG), Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany
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5
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Li Y, Xin Z, Yao B, Duan R, Dong X, Bao Y, Li X, Ma Y, Huang Y, Luo F, Li X, Wei X, Jiang ZR, Lozada-Gobilard S, Zhu J. Density affects plant size in the Gobi Desert. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169401. [PMID: 38114032 DOI: 10.1016/j.scitotenv.2023.169401] [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: 07/16/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 12/21/2023]
Abstract
Plant size is a crucial functional trait with substantial implications in agronomy and forestry. Understanding the factors influencing plant size is essential for ecosystem management and restoration efforts. Various environmental factors and plant density play significant roles in plant size. However, how plant size responds to mean annual precipitation (MAP), mean annual temperature (MAT), and density in the arid areas remains incomplete. To address this knowledge gap, we conducted comprehensive vegetation surveys in the Gobi Desert in northwestern China with a MAP below 250 mm. We also collected climate data to disentangle the respective influences of climate and density on the community-weighted plant height, crown length, and crown width. Our observations revealed that the community-weighted mean plant height, crown length, and width demonstrated a positive association with MAT but negative relationships with both MAP and density. These patterns can be attributed to the predominance of shrubs over herbs in arid regions, as shrubs tend to be larger in size. The proportion of shrubs increases with MAT, while it decreases with MAP and density, resulting in higher plant height and larger crown dimensions. Although both MAP and MAT affect plant size in the Gobi Desert, our findings highlight the stronger role of plant density in regulating plant size, indicating that the surrounding plant community and competition among individuals are crucial drivers of plant size patterns. Our findings provide valuable guidance for nature-based solutions for vegetation restoration and ecosystem management, highlighting the importance of considering plant density as a key factor when designing and implementing restoration strategies in arid areas.
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Affiliation(s)
- Yonghua Li
- Institute of Ecological Conservation and Restoration, Chinese Academy of Forestry, Beijing 100091, China; Gansu Dunhuang Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China; Kumtag Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China
| | - Zhiming Xin
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Bin Yao
- Institute of Ecological Conservation and Restoration, Chinese Academy of Forestry, Beijing 100091, China; Gansu Dunhuang Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China; Kumtag Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China
| | - Ruibing Duan
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Xue Dong
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Yanfeng Bao
- Institute of Ecological Conservation and Restoration, Chinese Academy of Forestry, Beijing 100091, China; Gansu Dunhuang Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China; Kumtag Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China
| | - Xinle Li
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Yuan Ma
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Yaru Huang
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Fengmin Luo
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Xing Li
- Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou County, Inner Mongolia 015200, China; Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, Dengkou 015200, China
| | - Xu Wei
- School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Zi-Ru Jiang
- Laboratory of Forest Protection, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 4648601, Japan
| | | | - Jinlei Zhu
- Institute of Ecological Conservation and Restoration, Chinese Academy of Forestry, Beijing 100091, China; Gansu Dunhuang Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China; Kumtag Desert Ecosystem National Observation and Research Station, Dunhuang 736200, China.
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6
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Cao J, Liu H, Zhao B, Li Z, Liang B, Shi L, Song Z, Wu L, Wang Q, Cressey EL, Zhu Y, Li S. Nitrogen addition enhances tree radial growth but weakens its recovery from drought impact in a temperate forest in northern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166884. [PMID: 37696401 DOI: 10.1016/j.scitotenv.2023.166884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 09/04/2023] [Accepted: 09/04/2023] [Indexed: 09/13/2023]
Abstract
Forest growth in the majority of northern China is currently limited by drought and low nitrogen (N) availability. Drought events with increasing intensity have threatened multiple ecosystem services provided by forests. Whether N addition will have a detrimental or beneficial moderation effect on forest resistance and recovery to drought events was unclear. Here, our study focuses on Pinus tabulaeformis, which is the main plantation forest species in northern China. We investigated the role of climate change and N addition in driving multi-year tree growth with an 8-year soil nitrogen fertilization experiment and analyzing 184 tree ring series. A moderate drought event occurred during the experiment, providing an opportunity for us to explore the effects of drought and N addition on tree resistance and recovery. We found that N addition was beneficial for increasing the resistance of middle-aged trees, but had no effect on mature trees. The recovery of trees weakened significantly with increasing N addition, and the reduction in fine root biomass caused by multiyear N addition was a key influencing factor limiting recovery after moderate drought. Our study implies that the combined effect of increasing drought and N deposition might increase the risk of pine forest mortality in northern China.
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Affiliation(s)
- Jing Cao
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Regional Eco-process and Function Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Hongyan Liu
- College of Urban and Environmental Science and MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, China
| | - Bo Zhao
- Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
| | - Zongshan Li
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing, China
| | - Boyi Liang
- College of Forestry, Beijing Key Laboratory of Precise Forestry, Institute of GIS, RS & GPS, Beijing Forestry University, Beijing 100083, China
| | - Liang Shi
- Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhaopeng Song
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Regional Eco-process and Function Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Lu Wu
- China Meteorological Administration Training Center, Beijing 100081, China
| | - Qiuming Wang
- College of Urban and Environmental Science and MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, China
| | - Elizabeth L Cressey
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter EX4 4RJ, UK
| | - Yanpeng Zhu
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Regional Eco-process and Function Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Shuang Li
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory of Regional Eco-process and Function Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
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7
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Smith-Martin CM, Muscarella R, Hammond WM, Jansen S, Brodribb TJ, Choat B, Johnson DM, Vargas-G G, Uriarte M. Hydraulic variability of tropical forests is largely independent of water availability. Ecol Lett 2023; 26:1829-1839. [PMID: 37807917 DOI: 10.1111/ele.14314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 07/06/2023] [Accepted: 08/08/2023] [Indexed: 10/10/2023]
Abstract
Tropical rainforest woody plants have been thought to have uniformly low resistance to hydraulic failure and to function near the edge of their hydraulic safety margin (HSM), making these ecosystems vulnerable to drought; however, this may not be the case. Using data collected at 30 tropical forest sites for three key traits associated with drought tolerance, we show that site-level hydraulic diversity of leaf turgor loss point, resistance to embolism (P50 ), and HSMs is high across tropical forests and largely independent of water availability. Species with high HSMs (>1 MPa) and low P50 values (< -2 MPa) are common across the wet and dry tropics. This high site-level hydraulic diversity, largely decoupled from water stress, could influence which species are favoured and become dominant under a drying climate. High hydraulic diversity could also make these ecosystems more resilient to variable rainfall regimes.
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Affiliation(s)
- Chris M Smith-Martin
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota, USA
- Department of Ecology Evolution and Environmental Biology, Columbia University, New York City, New York, USA
| | - Robert Muscarella
- Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - William M Hammond
- Agronomy Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, USA
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, USA
| | - German Vargas-G
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - María Uriarte
- Department of Ecology Evolution and Environmental Biology, Columbia University, New York City, New York, USA
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8
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Chen L, Li M, Li C, Zheng W, Liu R. Different Physiological Responses to Continuous Drought between Seedlings and Younger Individuals of Haloxylon ammodendron. PLANTS (BASEL, SWITZERLAND) 2023; 12:3683. [PMID: 37960040 PMCID: PMC10647405 DOI: 10.3390/plants12213683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/18/2023] [Accepted: 10/18/2023] [Indexed: 11/15/2023]
Abstract
Drought is an important environmental factor that influences physiological processes in plants; however, few studies have examined the physiological mechanisms underlying plants' responses to continuous drought. In this study, the seedlings and younger individuals of Haloxylon ammodendron were experimentally planted in the southern part of the Gurbantunggut Desert. We measured their photosynthetic traits, functional traits and non-structural carbohydrate contents (NSCs) in order to assess the effects of continuous drought (at 15-day and 30-day drought points) on the plants' physiological responses. The results showed that at the 15-day (15 d) drought point, the leaf light-saturated net photosynthetic rate (An) values of both the seedlings and the younger individuals were decreased (by -68.9% and -45.2%, respectively). The intrinsic water use efficiency (iWUE) of the seedlings was significantly lower than that of the control group (-52.2%), but there was no diffenrence of iWUE observed in younger individuals. At the 30-day (30 d) drought point, a decrease in the An (-129.8%) of the seedlings was induced via biochemical inhibition, with a lower potential maximum photochemical rate (Fv/Fm, 0.42) compared with the control group, while a decrease in the An (-52.3%) of the younger individuals was induced due to lower stomatal conductance (gs, -50.5%). Our results indicated that prolonged drought induced a greater risk of seedling mortality as the relatively limited ability of stomatal regulation may increase the possibility of massive embolism, resulting in hydraulic failure.
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Affiliation(s)
- Lidan Chen
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; (L.C.); (M.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
- Fukang National Station of Observation and Research for Desert Ecosystem, Fukang 831505, China
| | - Minqing Li
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; (L.C.); (M.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
- Fukang National Station of Observation and Research for Desert Ecosystem, Fukang 831505, China
| | - Congjuan Li
- National Engineering Technology Research Center for Desert-Oasis Ecological Construction, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China;
| | - Weihua Zheng
- Institute of Agricultural Quality Standards and Testing Technology, Xinjiang Academy of Agricultural Sciecnes, Urumuqi 830091, China;
| | - Ran Liu
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; (L.C.); (M.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
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9
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Blackman CJ, Billon LM, Cartailler J, Torres-Ruiz JM, Cochard H. Key hydraulic traits control the dynamics of plant dehydration in four contrasting tree species during drought. TREE PHYSIOLOGY 2023; 43:1772-1783. [PMID: 37318310 PMCID: PMC10652334 DOI: 10.1093/treephys/tpad075] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/07/2023] [Accepted: 06/08/2023] [Indexed: 06/16/2023]
Abstract
Trees are at risk of mortality during extreme drought, yet our understanding of the traits that govern the timing of drought-induced hydraulic failure remains limited. To address this, we tested SurEau, a trait-based soil-plant-atmosphere model designed to predict the dynamics of plant dehydration as represented by the changes in water potential against those observed in potted trees of four contrasting species (Pinus halepensis Mill., Populus nigra L., Quercus ilex L. and Cedrus atlantica (Endl.) Manetti ex Carriére) exposed to drought. SurEau was parameterized with a range of plant hydraulic and allometric traits, soil and climatic variables. We found a close correspondence between the predicted and observed plant water potential (in MPa) dynamics during the early phase drought, leading to stomatal closure, as well as during the latter phase of drought, leading to hydraulic failure in all four species. A global model's sensitivity analysis revealed that, for a common plant size (leaf area) and soil volume, dehydration time from full hydration to stomatal closure (Tclose) was most strongly controlled by the leaf osmotic potential (Pi0) and its influence on stomatal closure, in all four species, while the maximum stomatal conductance (gsmax) also contributed to Tclose in Q. ilex and C. atlantica. Dehydration times from stomatal closure to hydraulic failure (Tcav) was most strongly controlled by Pi0, the branch residual conductance (gres) and Q10a sensitivity of gres in the three evergreen species, while xylem embolism resistance (P50) was most influential in the deciduous species P. nigra. Our findings point to SurEau as a highly useful model for predicting changes in plant water status during drought and suggest that adjustments made in key hydraulic traits are potentially beneficial to delaying the onset of drought-induced hydraulic failure in trees.
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Affiliation(s)
- Chris J Blackman
- ARC Centre of Excellence for Plant Success in Nature and Agriculture, School of Natural Sciences, University of Tasmania, Hobart 7001, Australia
- Université Clermont-Auvergne, INRAE, PIAF, Clermont-Ferrand 63100, France
| | - Lise-Marie Billon
- Université Clermont-Auvergne, INRAE, PIAF, Clermont-Ferrand 63100, France
| | - Julien Cartailler
- Université Clermont-Auvergne, INRAE, PIAF, Clermont-Ferrand 63100, France
| | - José M Torres-Ruiz
- Université Clermont-Auvergne, INRAE, PIAF, Clermont-Ferrand 63100, France
| | - Hervé Cochard
- Université Clermont-Auvergne, INRAE, PIAF, Clermont-Ferrand 63100, France
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10
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Losso A, Gauthey A, Choat B, Mayr S. Seasonal variation in the xylem sap composition of six Australian trees and shrubs. AOB PLANTS 2023; 15:plad064. [PMID: 37899974 PMCID: PMC10601387 DOI: 10.1093/aobpla/plad064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 09/11/2023] [Indexed: 10/31/2023]
Abstract
In recent years, xylem sap composition has been shown to affect xylem hydraulics. However, information on how much xylem sap composition can vary across seasons and specifically under drought stress is still limited. We measured xylem sap chemical composition ([Ca2+], [K+], [Na+], electrical conductivity EC and pH) and surface tension (γ) of six Australian angiosperm trees and shrubs over 1 year, which comprised of exceptional dry and wet periods. Percentage losses of hydraulic conductivity and predawn leaf water potential were also monitored. In all species, measured parameters changed considerably over the annual time course. Ions and pH tended to decrease during winter months whereas γ showed a slight increase. No clear correlation was found between sap and hydraulic parameters, except for pH that was higher when plants suffered higher drought stress levels. Results indicate xylem sap composition to be complex and dynamic, where most variation in its composition seems to be dictated by season, even under severe dry conditions. However, pH might play a role as signals of drought stress.
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Affiliation(s)
- Adriano Losso
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797 Penrith, 2751 New South Wales, Australia
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797 Penrith, 2751 New South Wales, Australia
- Plant Ecology Research Laboratory PERL, Ecole Polytechnique Fédérale de Lausanne EPFL, 1015 Lausanne, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797 Penrith, 2751 New South Wales, Australia
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
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11
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Au J, Bloom AA, Parazoo NC, Deans RM, Wong CYS, Houlton BZ, Magney TS. Forest productivity recovery or collapse? Model-data integration insights on drought-induced tipping points. GLOBAL CHANGE BIOLOGY 2023; 29:5652-5665. [PMID: 37497614 DOI: 10.1111/gcb.16867] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 04/03/2023] [Indexed: 07/28/2023]
Abstract
More frequent and severe droughts are driving increased forest mortality around the globe. We urgently need to describe and predict how drought affects forest carbon cycling and identify thresholds of environmental stress that trigger ecosystem collapse. Quantifying the effects of drought at an ecosystem level is complex because dynamic climate-plant relationships can cause rapid and/or prolonged shifts in carbon balance. We employ the CARbon DAta MOdel fraMework (CARDAMOM) to investigate legacy effects of drought on forest carbon pools and fluxes. Our Bayesian model-data fusion approach uses tower observed meteorological forcing and carbon fluxes to determine the response and sensitivity of aboveground and belowground ecological processes associated with the 2012-2015 California drought. Our study area is a mid-montane mixed conifer forest in the Southern Sierras. CARDAMOM constrained with gross primary productivity (GPP) estimates covering 2011-2017 show a ~75% reduction in GPP, compared to negligible GPP change when constrained with 2011 only. Precipitation across 2012-2015 was 45% (474 mm) lower than the historical average and drove a cascading depletion in soil moisture and carbon pools (foliar, labile, roots, and litter). Adding 157 mm during an especially stressful year (2014, annual rainfall = 293 mm) led to a smaller depletion of water and carbon pools, steering the ecosystem away from a state of GPP tipping-point collapse to recovery. We present novel process-driven insights that demonstrate the sensitivity of GPP collapse to ecosystem foliar carbon and soil moisture states-showing that the full extent of GPP response takes several years to arise. Thus, long-term changes in soil moisture and carbon pools can provide a mechanistic link between drought and forest mortality. Our study provides an example for how key precipitation threshold ranges can influence forest productivity, making them useful for monitoring and predicting forest mortality events.
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Affiliation(s)
- J Au
- Department of Plant Sciences, University of California Davis, Davis, California, USA
| | - A A Bloom
- Jet Propulsion Laboratory California Institute of Technology, Pasadena, California, USA
| | - N C Parazoo
- Jet Propulsion Laboratory California Institute of Technology, Pasadena, California, USA
| | - R M Deans
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
| | - C Y S Wong
- Department of Plant Sciences, University of California Davis, Davis, California, USA
| | - B Z Houlton
- Department of Ecology and Evolutionary Biology and Department of Global Development, Cornell University, Ithaca, New York, USA
| | - T S Magney
- Department of Plant Sciences, University of California Davis, Davis, California, USA
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12
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Noleto-Dias C, Picoli EADT, Porzel A, Wessjohann LA, Tavares JF, Farag MA. Metabolomics characterizes early metabolic changes and markers of tolerant Eucalyptus ssp. clones against drought stress. PHYTOCHEMISTRY 2023; 212:113715. [PMID: 37156433 DOI: 10.1016/j.phytochem.2023.113715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 05/05/2023] [Accepted: 05/05/2023] [Indexed: 05/10/2023]
Abstract
EUCALYPTUS L'Hér. (Myrtaceae) is one of the economically most important and widely cultivated trees for wood crop purposes worldwide. Climatic changes together with the constant need to expand plantations to areas that do not always provide optimal conditions for plant growth highlight the need to assess the impact of abiotic stresses on eucalypt trees. We aimed to unveil the drought effect on the leaf metabolome of commercial clones with differential phenotypic response to this stress. For this, seedlings of 13 clones were grown at well-watered (WW) and water-deficit (WD) conditions and their leaf extracts were subjected to comparative analysis using ultra-high performance liquid chromatography coupled to mass spectrometry (UPLC-MS) and nuclear magnetic resonance spectroscopy (NMR). UPLC-MS and NMR analyses led to the annotation of over 100 molecular features of classes such as cyclitols, phenolics, flavonoids, formylated phloroglucinol compounds (FPCs) and fatty acids. Multivariate data analysis was employed for specimens' classifications and markers identification from both platforms. The results obtained in this work allowed us to classify clones differing in drought tolerance. Classification models were validated using an extra subset of samples. Tolerant plants exposed to water deficit accumulated arginine, gallic acid derivatives, caffeic acid and tannins at higher levels. In contrast, stressed drought-sensitive clones were characterised by a significant reduction in glucose, inositol and shikimic acid levels. These changes in contrasting drought response eucalypt pave ways for differential outcomes of tolerant and susceptible phenotypes. Under optimal growth conditions, all clones were rich in FPCs. These results can be used for early screening of tolerant clones and to improve our understanding of the role of these biomarkers in Eucalyptus tolerance to drought stress.
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Affiliation(s)
- Clarice Noleto-Dias
- Natural and Synthetic Bioactive Products Graduate Program, Federal University of Paraíba, João Pessoa, PB, 58051-900, Brazil; Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Halle (Saale), 06120, Germany
| | - Edgard A de T Picoli
- Plant Biology Department, Federal University of Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Andrea Porzel
- Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Halle (Saale), 06120, Germany
| | - Ludger A Wessjohann
- Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Halle (Saale), 06120, Germany.
| | - Josean F Tavares
- Natural and Synthetic Bioactive Products Graduate Program, Federal University of Paraíba, João Pessoa, PB, 58051-900, Brazil
| | - Mohamed A Farag
- Pharmacognosy Department, College of Pharmacy, Cairo University, Cairo, 11562, Egypt.
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13
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Wright BR, Nipper M, Nipper N, Merson SD, Guest T. Mortality rates of desert vegetation during high‐intensity drought at
Uluru‐Kata
Tjuta National Park, Central Australia. AUSTRAL ECOL 2023. [DOI: 10.1111/aec.13290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Affiliation(s)
- Boyd R. Wright
- Uluru‐Kata Tjuta National Park Yulara Northwest Territories Australia
- School of Agriculture and Food Science University of Queensland Brisbane Queensland Australia
- Botany, School of Environmental and Rural Science University of New England Armidale New South Wales Australia
| | - Martin Nipper
- Mutitjulu Community Ranger Program, Mutitjulu Community Yulara Northwest Territories Australia
| | - Nathan Nipper
- Mutitjulu Community Ranger Program, Mutitjulu Community Yulara Northwest Territories Australia
| | | | - Tracey Guest
- Uluru‐Kata Tjuta National Park Yulara Northwest Territories Australia
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14
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Guan X, Wen Y, Zhang Y, Chen Z, Cao KF. Stem hydraulic conductivity and embolism resistance of Quercus species are associated with their climatic niche. TREE PHYSIOLOGY 2023; 43:234-247. [PMID: 36209451 DOI: 10.1093/treephys/tpac119] [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: 01/24/2022] [Accepted: 10/01/2022] [Indexed: 06/16/2023]
Abstract
The hydraulic traits of a plant species may reflect its climate adaptations. Southwest China is considered as a biodiversity hotpot of the genus Quercus (oak). However, the hydraulic adaptations of Asian oaks to their climate niches remain unclear. Ten common garden-grown oak species with distinct natural distributions in eastern Asia were used to determine their stem xylem embolism resistance (water potential at 50% loss of hydraulic conductivity, P50), stem hydraulic efficiency (vessel anatomy and sapwood specific hydraulic conductivity (Ks)) and leaf anatomical traits. We also compiled four key functional traits: wood density, hydraulic-weighted vessel diameter, Ks and P50 data for 31 oak species from previous literature. We analyzed the relationship between hydraulic traits and climatic factors over the native ranges of 41 oak species. Our results revealed that the 10 Asian oak species, which are mainly distributed in humid subtropical habitats, possessed a stem xylem with low embolism resistance and moderate hydraulic efficiency. The deciduous and evergreen species of the 10 Asian oaks differed in the stem and leaf traits related to hydraulic efficiency. Ks differed significantly between the two phenological groups (deciduous and evergreens) in the 41-oak dataset. No significant difference in P50 between the two groups was found for the 10 Asian oaks or the 41-oak dataset. The oak species that can distribute in arid habitats possessed a stem xylem with high embolism resistance. Ks negatively related to the humidity of the native range of the 10 Asian oaks, but showed no trend when assessing the entire global oak dataset. Our study suggests that stem hydraulic conductivity and embolism resistance in Quercus species are shaped by their climate niche. Our findings assist predictions of oak drought resistance with future climate changes for oak forest management.
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Affiliation(s)
- Xinyi Guan
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilisation of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi 530004, China
| | - Yin Wen
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilisation of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi 530004, China
| | - Ya Zhang
- Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Zhao Chen
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilisation of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi 530004, China
| | - Kun-Fang Cao
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilisation of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi 530004, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi 530004, China
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15
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Losso A, Challis A, Gauthey A, Nolan RH, Hislop S, Roff A, Boer MM, Jiang M, Medlyn BE, Choat B. Canopy dieback and recovery in Australian native forests following extreme drought. Sci Rep 2022; 12:21608. [PMID: 36517498 PMCID: PMC9751299 DOI: 10.1038/s41598-022-24833-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 11/21/2022] [Indexed: 12/15/2022] Open
Abstract
In 2019, south-eastern Australia experienced its driest and hottest year on record, resulting in massive canopy dieback events in eucalypt dominated forests. A subsequent period of high precipitation in 2020 provided a rare opportunity to quantify the impacts of extreme drought and consequent recovery. We quantified canopy health and hydraulic impairment (native percent loss of hydraulic conductivity, PLC) of 18 native tree species growing at 15 sites that were heavily impacted by the drought both during and 8-10 months after the drought. Most species exhibited high PLC during drought (PLC:65.1 ± 3.3%), with no clear patterns across sites or species. Heavily impaired trees (PLC > 70%) showed extensive canopy browning. In the post-drought period, most surviving trees exhibited hydraulic recovery (PLC:26.1 ± 5.1%), although PLC remained high in some trees (50-70%). Regained hydraulic function (PLC < 50%) corresponded to decreased canopy browning indicating improved tree health. Similar drought (37.1 ± 4.2%) and post-drought (35.1 ± 4.4%) percentages of basal area with dead canopy suggested that trees with severely compromised canopies immediately after drought were not able to recover. This dataset provides insights into the impacts of severe natural drought on the health of mature trees, where hydraulic failure is a major contributor in canopy dieback and tree mortality during extreme drought events.
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Affiliation(s)
- Adriano Losso
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia.
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria.
| | - Anthea Challis
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- Plant Ecology Research Laboratory PERL, Ecole Polytechnique Fédérale de Lausanne EPFL, 1015, Lausanne, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | - Rachael H Nolan
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- NSW Bushfire Risk Management Research Hub, Wollongong, NSW, Australia
| | - Samuel Hislop
- Forest Science, NSW Department of Primary Industries, Parramatta, NSW, 2150, Australia
| | - Adam Roff
- Department of Planning, Industry and Environment, Remote Sensing and Landscape Science, 26 Honeysuckle Drive, Newcastle, NSW, 2302, Australia
| | - Matthias M Boer
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- NSW Bushfire Risk Management Research Hub, Wollongong, NSW, Australia
| | - Mingkai Jiang
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- College of Life Sciences, Zhejiang University, 866 Yuhangtang Rd, Hangzhou, Zhejiang, China
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia.
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16
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Kahmen A, Basler D, Hoch G, Link RM, Schuldt B, Zahnd C, Arend M. Root water uptake depth determines the hydraulic vulnerability of temperate European tree species during the extreme 2018 drought. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:1224-1239. [PMID: 36219537 DOI: 10.1111/plb.13476] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
We took advantage of the European 2018 drought and assessed the mechanisms causing differences in drought vulnerability among mature individuals of nine co-occurring tree species at the Swiss Canopy Crane II site in Switzerland. Throughout the drought we monitored leaf water status and determined native embolism formation in the canopy of the trees as indicators of drought vulnerability. We also determined hydraulic vulnerability thresholds (Ψ12 -, Ψ50 - and Ψ88 -values), corresponding hydraulic safety margins (HSMs) and carbohydrate reserves for all species as well as total average leaf area per tree, and used stable isotopes to assess differences in root water uptake depth among the nine species as variables predicting differences in drought vulnerability among species. Marked differences in drought vulnerability were observed among the nine tree species. Six species maintained their water potentials above hydraulic thresholds, while three species, Fagus sylvatica, Carpinus betulus and Picea abies, were pushed beyond their hydraulic thresholds and showed loss of hydraulic conductivity in their canopies at the end of the drought. Embolism resistance thresholds and associated HSMs did not explain why the co-existing species differed in their drought vulnerability, neither did their degree of isohydry, nor their regulation of carbohydrate reserves. Instead, differences in structural-morphological traits, in particular root water uptake depth, were associated with the risk of reaching hydraulic vulnerability thresholds and embolism formation among the nine species. Our study shows that structural-morphological traits, such as root water uptake depth, determine how quickly different species approach hydraulic vulnerability thresholds during a drought event and can thus explain species differences in drought vulnerability among mature field-grown trees.
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Affiliation(s)
- A Kahmen
- Department of Environmental Sciences - Botany, University of Basel, Basel, Switzerland
| | - D Basler
- Department of Environmental Sciences - Botany, University of Basel, Basel, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - G Hoch
- Department of Environmental Sciences - Botany, University of Basel, Basel, Switzerland
| | - R M Link
- Ecophysiology and Vegetation Ecology, Universität Würzburg, Würzburg, Germany
| | - B Schuldt
- Ecophysiology and Vegetation Ecology, Universität Würzburg, Würzburg, Germany
| | - C Zahnd
- Department of Environmental Sciences - Botany, University of Basel, Basel, Switzerland
| | - M Arend
- Department of Environmental Sciences - Botany, University of Basel, Basel, Switzerland
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17
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Marchin RM, Esperon-Rodriguez M, Tjoelker MG, Ellsworth DS. Crown dieback and mortality of urban trees linked to heatwaves during extreme drought. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 850:157915. [PMID: 35944640 DOI: 10.1016/j.scitotenv.2022.157915] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/02/2022] [Accepted: 08/04/2022] [Indexed: 06/15/2023]
Abstract
Cities have been described as 'heat islands' and 'dry islands' due to hotter, drier air in urban areas, relative to the surrounding landscape. As climate change intensifies, the health of urban trees will be increasingly impacted. Here, we posed the question: Is it possible to predict urban tree species mortality using (1) species climate envelopes and (2) plant functional traits? To answer these, we tracked patterns of crown dieback and recovery for 23 common urban tree and shrub species in Sydney, Australia during the record-breaking austral 2019-2020 summer. We identified 10 heat-tolerant species including five native and five exotic species, which represent climate-resilient options for urban plantings that are likely to continue to thrive for decades. Thirteen species were considered vulnerable to adverse conditions due to their mortality, poor health leading to tree removal, and/or extensive crown dieback. Crown dieback increased with increasing precipitation of the driest month of species climate of origin, suggesting that species from dry climates may be better suited for urban forests in future climates. We effectively grouped species according to their drought strategy (i.e., tolerance versus avoidance) using a simple trait-based framework that was directly linked with species mortality. The seven most climate-vulnerable species used a drought-avoidance strategy, having low wood density and high turgor loss points along with large, thin leaves with low heat tolerance. Overall, plant functional traits were better than species climate envelopes at explaining crown dieback. Recovery after stress required two mild, wet years for most species, resulting in prolonged loss of cooling benefits as well as economic losses due to replacement of dead/damaged trees. Hotter, longer, and more frequent heatwaves will require selection of more climate-resilient species in urban forests, and our results suggest that future research should focus on plant thermal traits to improve prediction models and species selection.
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Affiliation(s)
- Renée M Marchin
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2751, Australia.
| | - Manuel Esperon-Rodriguez
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2751, Australia
| | - Mark G Tjoelker
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2751, Australia
| | - David S Ellsworth
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2751, Australia
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18
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Frei ER, Gossner MM, Vitasse Y, Queloz V, Dubach V, Gessler A, Ginzler C, Hagedorn F, Meusburger K, Moor M, Samblás Vives E, Rigling A, Uitentuis I, von Arx G, Wohlgemuth T. European beech dieback after premature leaf senescence during the 2018 drought in northern Switzerland. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:1132-1145. [PMID: 36103113 PMCID: PMC10092601 DOI: 10.1111/plb.13467] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 09/04/2022] [Indexed: 06/15/2023]
Abstract
During the particularly severe hot summer drought in 2018, widespread premature leaf senescence was observed in several broadleaved tree species in Central Europe, particularly in European beech (Fagus sylvatica L.). For beech, it is yet unknown whether the drought evoked a decline towards tree mortality or whether trees can recover in the longer term. In this study, we monitored crown dieback, tree mortality and secondary drought damage symptoms in 963 initially live beech trees that exhibited either premature or normal leaf senescence in 2018 in three regions in northern Switzerland from 2018 to 2021. We related the observed damage to multiple climate- and stand-related parameters. Cumulative tree mortality continuously increased up to 7.2% and 1.3% in 2021 for trees with premature and normal leaf senescence in 2018, respectively. Mean crown dieback in surviving trees peaked at 29.2% in 2020 and 8.1% in 2019 for trees with premature and normal leaf senescence, respectively. Thereafter, trees showed first signs of recovery. Crown damage was more pronounced and recovery was slower for trees that showed premature leaf senescence in 2018, for trees growing on drier sites, and for larger trees. The presence of bleeding cankers peaked at 24.6% in 2019 and 10.7% in 2020 for trees with premature and normal leaf senescence, respectively. The presence of bark beetle holes peaked at 22.8% and 14.8% in 2021 for trees with premature and normal leaf senescence, respectively. Both secondary damage symptoms occurred more frequently in trees that had higher proportions of crown dieback and/or showed premature senescence in 2018. Our findings demonstrate context-specific differences in beech mortality and recovery reflecting the importance of regional and local climate and soil conditions. Adapting management to increase forest resilience is gaining importance, given the expected further beech decline on dry sites in northern Switzerland.
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Affiliation(s)
- E. R. Frei
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- WSL Institute for Snow and Avalanche Research SLFDavos DorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
- Climate Change and Extremes in Alpine Regions Research Centre CERCDavos DorfSwitzerland
| | - M. M. Gossner
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
- Department of Environmental Systems ScienceETH ZurichZurichSwitzerland
| | - Y. Vitasse
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
| | - V. Queloz
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
| | - V. Dubach
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
| | - A. Gessler
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
- Department of Environmental Systems ScienceETH ZurichZurichSwitzerland
| | - C. Ginzler
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
| | - F. Hagedorn
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
| | - K. Meusburger
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
| | - M. Moor
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
| | - E. Samblás Vives
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- Autonomous University of Barcelona (UAB)Cerdanyola del VallesSpain
| | - A. Rigling
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
- Department of Environmental Systems ScienceETH ZurichZurichSwitzerland
| | - I. Uitentuis
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
| | - G. von Arx
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
- Oeschger Centre for Climate Change ResearchUniversity of BernBernSwitzerland
| | - T. Wohlgemuth
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorfSwitzerland
- SwissForestLabBirmensdorfSwitzerland
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19
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Guan X, Werner J, Cao KF, Pereira L, Kaack L, McAdam SAM, Jansen S. Stem and leaf xylem of angiosperm trees experiences minimal embolism in temperate forests during two consecutive summers with moderate drought. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:1208-1223. [PMID: 34990084 DOI: 10.1111/plb.13384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
Drought events may increase the likelihood that the plant water transport system becomes interrupted by embolism. Yet our knowledge about the temporal frequency of xylem embolism in the field is frequently lacking, as it requires detailed, long-term measurements. We measured xylem embolism resistance and midday xylem water potentials during the consecutive summers of 2019 and 2020 to estimate maximum levels of embolism in leaf and stem xylem of ten temperate angiosperm tree species. We also studied vessel and pit membrane characteristics based on light and electron microscopy to corroborate potential differences in embolism resistance between leaves and stems. Apart from A. pseudoplatanus and Q. petraea, eight species experienced minimum xylem water potentials that were close to or below those required to initiate embolism. Water potentials corresponding to ca. 12% loss of hydraulic conductivity (PLC) could occur in six species, while considerable levels of embolism around 50% PLC were limited to B. pendula and C. avellana. There was a general agreement in embolism resistance between stems and leaves, with leaves being equally or more resistant than stems. Also, xylem embolism resistance was significantly correlated to intervessel pit membrane thickness (TPM ) for stems, but not to vessel diameter and total intervessel pit membrane surface area of a vessel. Our data indicate that low amounts of embolism occur in most species during moderate summer drought, and that considerable levels of embolism are uncommon. Moreover, our experimental and TPM data show that leaf xylem is generally no more vulnerable than stem xylem.
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Affiliation(s)
- X Guan
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - J Werner
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - K-F Cao
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilisation of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
| | - L Pereira
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - L Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - S A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
| | - S Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
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20
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Knüver T, Bär A, Ganthaler A, Gebhardt T, Grams TEE, Häberle K, Hesse BD, Losso A, Tomedi I, Mayr S, Beikircher B. Recovery after long-term summer drought: Hydraulic measurements reveal legacy effects in trunks of Picea abies but not in Fagus sylvatica. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:1240-1253. [PMID: 35611757 PMCID: PMC10084041 DOI: 10.1111/plb.13444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Climate change is expected to increase the frequency and intensity of summer droughts. Sufficient drought resistance, the ability to acclimate to and/or recover after drought, is thus crucial for forest tree species. However, studies on the hydraulics of mature trees during and after drought in natura are scarce. In this study, we analysed trunk water content (electrical resistivity: ER) and further hydraulic (water potential, sap flow density, specific hydraulic conductivity, vulnerability to embolism) as well as wood anatomical traits (tree ring width, conduit diameter, conduit wall reinforcement) of drought-stressed (artificially induced summer drought via throughfall-exclusion) and unstressed Picea abies and Fagus sylvatica trees. In P. abies, ER indicated a strong reduction in trunk water content after 5 years of summer drought, corresponding to significantly lower pre-dawn leaf water potential and xylem sap flow density. Vulnerability to embolism tended to be higher in drought-stressed trees. In F. sylvatica, only small differences between drought-stressed and control trees were observed. Re-watering led to a rapid increase in water potentials and xylem sap flow of both drought-stressed trees, and to increased growth rates in the next growing season. ER analyses revealed lower trunk water content in P. abies trees growing on throughfall-exclusion plots even 1 year after re-watering, indicating a limited capacity to restore internal water reserves. Results demonstrated that P. abies is more susceptible to recurrent summer drought than F. sylvatica, and can exhibit long-lasting and pronounced legacy effects in trunk water reserves.
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Affiliation(s)
- T. Knüver
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - A. Bär
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - A. Ganthaler
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - T. Gebhardt
- Technical University of MunichSchool of Life SciencesProfessorship for Land Surface‐Atmosphere Interactions AG Ecophysiology of PlantsFreisingGermany
| | - T. E. E. Grams
- Technical University of MunichSchool of Life SciencesProfessorship for Land Surface‐Atmosphere Interactions AG Ecophysiology of PlantsFreisingGermany
| | - K.‐H. Häberle
- Technical University of MunichSchool of Life SciencesChair of Restoration EcologyFreisingGermany
| | - B. D. Hesse
- Technical University of MunichSchool of Life SciencesProfessorship for Land Surface‐Atmosphere Interactions AG Ecophysiology of PlantsFreisingGermany
| | - A. Losso
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityRichmondAustralia
| | - I. Tomedi
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - S. Mayr
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - B. Beikircher
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
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21
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Jia H, Guan C, Zhang J, He C, Yin C, Meng P. Drought effects on tree growth, water use efficiency, vulnerability and canopy health of Quercus variabilis-Robinia pseudoacacia mixed plantation. FRONTIERS IN PLANT SCIENCE 2022; 13:1018405. [PMID: 36311079 PMCID: PMC9597382 DOI: 10.3389/fpls.2022.1018405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 09/22/2022] [Indexed: 06/16/2023]
Abstract
Drought-induced forest canopy die-back and tree mortality have been commonly recorded in the lithoid mountainous regions of northern China. However, the capacity of trees to regulate their carbon and water balance in response to drought remains inadequately understood. We measured tree growth, intrinsic water use efficiency (iWUE), vulnerability, and canopy health during drought events using dendrochronology, C isotope measurements, and a tree canopy health survey in a mixed plantation of Quercus variabilis and Robinia pseudoacacia. Resistance (Rt), recovery (Rc), resilience (Rs), and increased amplitude in iWUE compared to the indices 3 years before drought (iWUEr) were calculated for each species across the dominant tree (D), co-dominant tree (CD), and suppressed tree (S). Our results revealed that D and CD showed lower Rt, higher Rc, and higher iWUEr than S. After exposure to multiple sequential drought events, Q. variabilis showed an increasing trend in Rt, and R. pseudoacacia showed a decreasing trend in Rc. R. pseudoacacia exhibited a more conservative strategy towards drought, resulting in a negative SRt-iWUEr (slope of the linear model fitted to capture the trend between Rt and iWUEr) during drought events than Q. variabilis. For individual trees, lower Rc or positive SRt-iWUEr Q. variabilis and negative SRt-iWUEr R. pseudoacacia were more susceptible to canopy die-back. In conclusion, our study offers a new perspective for improved management practices in the design of silvicultural actions for forestry plantations in lithoid mountainous areas with increasing drought risk.
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Affiliation(s)
- HanSen Jia
- Key Laboratory of Tree Breeding and Cultivation, National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
- Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forest University, Nanjing, China
- Henan Xiaolangdi Earth Critical Zone National Research Station on the Middle Yellow River, Jiyuan, China
| | - ChongFan Guan
- Key Laboratory of Tree Breeding and Cultivation, National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
- Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forest University, Nanjing, China
- Henan Xiaolangdi Earth Critical Zone National Research Station on the Middle Yellow River, Jiyuan, China
| | - JinSong Zhang
- Key Laboratory of Tree Breeding and Cultivation, National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
- Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forest University, Nanjing, China
- Henan Xiaolangdi Earth Critical Zone National Research Station on the Middle Yellow River, Jiyuan, China
| | - ChunXia He
- Key Laboratory of Tree Breeding and Cultivation, National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
- Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forest University, Nanjing, China
- Henan Xiaolangdi Earth Critical Zone National Research Station on the Middle Yellow River, Jiyuan, China
| | - ChangJun Yin
- Key Laboratory of Tree Breeding and Cultivation, National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
- Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forest University, Nanjing, China
- Henan Xiaolangdi Earth Critical Zone National Research Station on the Middle Yellow River, Jiyuan, China
| | - Ping Meng
- Key Laboratory of Tree Breeding and Cultivation, National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
- Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forest University, Nanjing, China
- Henan Xiaolangdi Earth Critical Zone National Research Station on the Middle Yellow River, Jiyuan, China
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22
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Pritzkow C, Brown MJM, Carins-Murphy MR, Bourbia I, Mitchell PJ, Brodersen C, Choat B, Brodribb TJ. Conduit position and connectivity affect the likelihood of xylem embolism during natural drought in evergreen woodland species. ANNALS OF BOTANY 2022; 130:431-444. [PMID: 35420657 PMCID: PMC9486930 DOI: 10.1093/aob/mcac053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND AIMS Hydraulic failure is considered a main cause of drought-induced forest mortality. Yet, we have a limited understanding of how the varying intensities and long time scales of natural droughts induce and propagate embolism within the xylem. METHODS X-ray computed tomography (microCT) images were obtained from different aged branch xylem to study the number, size and spatial distribution of in situ embolized conduits among three dominant tree species growing in a woodland community. KEY RESULTS Among the three studied tree species, those with a higher xylem vulnerability to embolism (higher water potential at 50 % loss of hydraulic conductance; P50) were more embolized than species with lower P50. Within individual stems, the probability of embolism was independent of conduit diameter but associated with conduit position. Rather than the occurrence of random or radial embolism, we observed circumferential clustering of high and low embolism density, suggesting that embolism spreads preferentially among conduits of the same age. Older xylem also appeared more likely to accumulate embolisms than young xylem, but there was no pattern suggesting that branch tips were more vulnerable to cavitation than basal regions. CONCLUSIONS The spatial analysis of embolism occurrence in field-grown trees suggests that embolism under natural drought probably propagates by air spreading from embolized into neighbouring conduits in a circumferential pattern. This pattern offers the possibility to understand the temporal aspects of embolism occurrence by examining stem cross-sections.
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Affiliation(s)
- Carola Pritzkow
- School of Biology, University of Tasmania, Hobart, TAS, 7005, Australia
| | - Matilda J M Brown
- School of Biology, University of Tasmania, Hobart, TAS, 7005, Australia
| | | | - Ibrahim Bourbia
- School of Biology, University of Tasmania, Hobart, TAS, 7005, Australia
| | | | - Craig Brodersen
- School of the Environment, Yale University, New Haven, CT 06511, USA
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2750, Australia
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23
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Crates R, Watson DM, Albery GF, Bonnet T, Murphy L, Rayner L, Stojanovic D, Timewell C, Meney B, Roderick M, Ingwersen D, Heinsohn R. Mistletoes could moderate drought impacts on birds, but are themselves susceptible to drought-induced dieback. Proc Biol Sci 2022; 289:20220358. [PMID: 35858071 PMCID: PMC9277258 DOI: 10.1098/rspb.2022.0358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Mistletoes are hemiparasitic plants and keystone species in many ecosystems globally. Given predicted increases in drought frequency and intensity, mistletoes may be crucial for moderating drought impacts on community structure. Dependent on host vascular flows, mistletoes can succumb to stress when water availability falls, making them susceptible to mortality during drought. We counted mistletoe across greater than 350 000 km2 of southeastern Australia and conducted standardized bird surveys between 2016 and 2021, spanning a major drought event in 2018-2019. We aimed to identify predictors of mistletoe abundance and mortality and determine whether mistletoes might moderate drought impacts on woodland birds. Live mistletoe abundance varied with tree species composition, land use and presence of mistletoebirds. Mistletoe mortality was widespread, consistent with high 2018/2019 summer temperatures, low 2019/2020 summer rainfall and the interaction between summer temperatures and rainfall in 2019/2020. The positive association between surviving mistletoes and woodland birds was greatest in the peak drought breeding seasons of 2018/2019 and 2019/2020, particularly for small residents and insectivores. Paradoxically, mistletoes could moderate drought impacts on birds, but are themselves vulnerable to drought-induced mortality. An improved understanding of the drivers and dynamics of mistletoe mortality is needed to address potential cascading trophic impacts associated with mistletoe die-off.
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Affiliation(s)
- Ross Crates
- Fenner School of Environment and Society, Australian National University, Linnaeus Way, Acton, Canberra 2601, Australia
| | - David M. Watson
- School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Albury, New South Wales, Australia
| | | | - Timothée Bonnet
- Research School of Biology, Australian National University, Linnaeus Way, Acton, Canberra 2601, Australia
| | - Liam Murphy
- Fenner School of Environment and Society, Australian National University, Linnaeus Way, Acton, Canberra 2601, Australia
| | - Laura Rayner
- Fenner School of Environment and Society, Australian National University, Linnaeus Way, Acton, Canberra 2601, Australia
| | - Dejan Stojanovic
- Fenner School of Environment and Society, Australian National University, Linnaeus Way, Acton, Canberra 2601, Australia
| | | | - Beau Meney
- BirdLife Australia, Carlton, Melbourne, Australia
| | | | | | - Robert Heinsohn
- Fenner School of Environment and Society, Australian National University, Linnaeus Way, Acton, Canberra 2601, Australia
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24
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De Kauwe MG, Sabot MEB, Medlyn BE, Pitman AJ, Meir P, Cernusak LA, Gallagher RV, Ukkola AM, Rifai SW, Choat B. Towards species-level forecasts of drought-induced tree mortality risk. THE NEW PHYTOLOGIST 2022; 235:94-110. [PMID: 35363880 PMCID: PMC9321630 DOI: 10.1111/nph.18129] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/28/2022] [Indexed: 05/14/2023]
Abstract
Predicting species-level responses to drought at the landscape scale is critical to reducing uncertainty in future terrestrial carbon and water cycle projections. We embedded a stomatal optimisation model in the Community Atmosphere Biosphere Land Exchange (CABLE) land surface model and parameterised the model for 15 canopy dominant eucalypt tree species across South-Eastern Australia (mean annual precipitation range: 344-1424 mm yr-1 ). We conducted three experiments: applying CABLE to the 2017-2019 drought; a 20% drier drought; and a 20% drier drought with a doubling of atmospheric carbon dioxide (CO2 ). The severity of the drought was highlighted as for at least 25% of their distribution ranges, 60% of species experienced leaf water potentials beyond the water potential at which 50% of hydraulic conductivity is lost due to embolism. We identified areas of severe hydraulic stress within-species' ranges, but we also pinpointed resilience in species found in predominantly semiarid areas. The importance of the role of CO2 in ameliorating drought stress was consistent across species. Our results represent an important advance in our capacity to forecast the resilience of individual tree species, providing an evidence base for decision-making around the resilience of restoration plantings or net-zero emission strategies.
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Affiliation(s)
| | - Manon E. B. Sabot
- ARC Centre of Excellence for Climate ExtremesSydneyNSW2052Australia
- Climate Change Research CentreUniversity of New South WalesSydneyNSW2052Australia
| | - Belinda E. Medlyn
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityLocked Bag 1797PenrithNSW2751Australia
| | - Andrew J. Pitman
- ARC Centre of Excellence for Climate ExtremesSydneyNSW2052Australia
- Climate Change Research CentreUniversity of New South WalesSydneyNSW2052Australia
| | - Patrick Meir
- School of GeosciencesThe University of EdinburghEdinburghEH9 3FFUK
| | - Lucas A. Cernusak
- College of Science and EngineeringJames Cook UniversityCairnsQld4878Australia
| | - Rachael V. Gallagher
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityLocked Bag 1797PenrithNSW2751Australia
| | - Anna M. Ukkola
- ARC Centre of Excellence for Climate ExtremesSydneyNSW2052Australia
- Climate Change Research CentreUniversity of New South WalesSydneyNSW2052Australia
| | - Sami W. Rifai
- ARC Centre of Excellence for Climate ExtremesSydneyNSW2052Australia
- Climate Change Research CentreUniversity of New South WalesSydneyNSW2052Australia
| | - Brendan Choat
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityLocked Bag 1797PenrithNSW2751Australia
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25
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Influence of Juvenile Growth on Xylem Safety and Efficiency in Three Temperate Tree Species. FORESTS 2022. [DOI: 10.3390/f13060909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The evolution of the internal water transport system was a prerequisite for high plant productivity. In times of climate change, understanding the dependency of juvenile growth on xylem hydraulic physiology is therefore of high importance. Here, we explored various wood anatomical, hydraulic, and leaf morphological traits related to hydraulic safety and efficiency in three temperate broadleaved tree species (Acer pseudoplatanus, Betula pendula, and Sorbus aucuparia). We took advantage of a severe natural heat wave that resulted in different climatic growing conditions for even-aged plants from the same seed source growing inside a greenhouse and outside. Inside the greenhouse, the daily maximum vapour pressure deficit was on average 36% higher than outside during the growing seasons. Because of the higher atmospheric moisture stress, the biomass production differed up to 5.6-fold between both groups. Except for one species, a high productivity was associated with a high hydraulic efficiency caused by large xylem vessels and a large, supported leaf area. Although no safety-efficiency trade-off was observed, productivity was significantly related to P50 in two of the tree species but without revealing any clear pattern. A considerable plasticity in given traits was observed between both groups, with safety-related traits being more static while efficiency-related traits revealed a higher intra-specific plasticity. This was associated with other wood anatomical and leaf morphological adjustments. We confirm that a high hydraulic efficiency seems to be a prerequisite for a high biomass production, while our controversial results on the growth–xylem safety relationship confirm that safety-efficiency traits are decoupled and that their relationship with juvenile growth and water regime is species-specific.
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26
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Han H, Xi B, Wang Y, Feng J, Li X, Tissue DT. Lack of phenotypic plasticity in leaf hydraulics for 10 woody species common to urban forests of North China. TREE PHYSIOLOGY 2022; 42:1203-1215. [PMID: 35038332 DOI: 10.1093/treephys/tpac003] [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: 09/28/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
The survival and performance of urban forests are increasingly challenged by urban drought, consequently compromising the sustainability and functionality of urban vegetation. Plant-water relations largely determine species drought tolerance, yet little is known about the hydraulics of urban forest species. Here, we report the leaf hydraulic and carbon traits that govern plant growth and drought resistance, including vulnerability to embolism, hydraulic conductivity and leaf gas exchange characteristics, as well as morphological traits that are potentially linked with these physiological attributes, with the aim of guiding species selection and management in urban forests. Plant materials were collected from mature shrubs and trees on our university campus in Beijing, representing 10 woody species common to urban forests in north China. We found that the leaf embolism resistance, represented by the water potential inducing 50% loss of hydraulic conductivity (P50), as well as the hydraulic safety margin (HSM) defined by P50 and the water potential threshold at the inception of embolism (P12), varied remarkably across species, but was unrelated to growth form. Likewise, stem and leaf-specific hydraulic conductivity (Kstem and kl) was also highly species-specific. Leaf P50 was positively correlated with hydraulic conductivity. However, neither P50 nor hydraulic conductivity was correlated with leaf gas exchange traits, including maximum photosynthetic rate (Amax) and stomatal conductance (gs). Plant morphological and physiological traits were not related, except for specific leaf area, which showed a negative relationship with HSM. Traits influencing plant-water transport were primarily correlated with the mean annual precipitation of species climatic niche. Overall, current common woody species in urban forest environments differed widely in their drought resistance and did not have the capacity to modify these characteristics in response to a changing climate. Species morphology provides limited information regarding physiological drought resistance. Thus, screening urban forest species based on plant physiology is essential to sustain the ecological services of urban forests.
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Affiliation(s)
- Hang Han
- College of Life and Environmental Science, Minzu University of China, 27 Zhongguancun South Avenue, Haidian District, Beijing 100081, People's Republic of China
| | - Benye Xi
- Ministry of Education Key Laboratory of Silviculture and Conservation, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, People's Republic of China
| | - Ye Wang
- Beijing Academy of Forestry and Pomology Sciences, 12 A Rui Wang Fen, Fragrance Hills, Haidian District, Beijing 100093, People's Republic of China
| | - Jinchao Feng
- College of Life and Environmental Science, Minzu University of China, 27 Zhongguancun South Avenue, Haidian District, Beijing 100081, People's Republic of China
| | - Ximeng Li
- College of Life and Environmental Science, Minzu University of China, 27 Zhongguancun South Avenue, Haidian District, Beijing 100081, People's Republic of China
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
- Global Centre for Land-based Innovation, Western Sydney University, Hawkesbury Campus, Richmond, NSW 2753, Australia
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27
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Hajek P, Link RM, Nock CA, Bauhus J, Gebauer T, Gessler A, Kovach K, Messier C, Paquette A, Saurer M, Scherer-Lorenzen M, Rose L, Schuldt B. Mutually inclusive mechanisms of drought-induced tree mortality. GLOBAL CHANGE BIOLOGY 2022; 28:3365-3378. [PMID: 35246895 DOI: 10.1111/gcb.16146] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/16/2021] [Indexed: 06/14/2023]
Abstract
Unprecedented tree dieback across Central Europe caused by recent global change-type drought events highlights the need for a better mechanistic understanding of drought-induced tree mortality. Although numerous physiological risk factors have been identified, the importance of two principal mechanisms, hydraulic failure and carbon starvation, is still debated. It further remains largely unresolved how the local neighborhood composition affects individual mortality risk. We studied 9435 young trees of 12 temperate species planted in a diversity experiment in 2013 to assess how hydraulic traits, carbon dynamics, pest infestation, tree height and neighborhood competition influence individual mortality risk. Following the most extreme global change-type drought since record in 2018, one third of these trees died. Across species, hydraulic safety margins (HSMs) were negatively and a shift towards a higher sugar fraction in the non-structural carbohydrate (NSC) pool positively associated with mortality risk. Moreover, trees infested by bark beetles had a higher mortality risk, and taller trees a lower mortality risk. Most neighborhood interactions were beneficial, although neighborhood effects were highly species-specific. Species that suffered more from drought, especially Larix spp. and Betula spp., tended to increase the survival probability of their neighbors and vice versa. While severe tissue dehydration marks the final stage of drought-induced tree mortality, we show that hydraulic failure is interrelated with a series of other, mutually inclusive processes. These include shifts in NSC pools driven by osmotic adjustment and/or starch depletion as well as pest infestation and are modulated by the size and species identity of a tree and its neighbors. A more holistic view that accounts for multiple causes of drought-induced tree mortality is required to improve predictions of trends in global forest dynamics and to identify mutually beneficial species combinations.
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Affiliation(s)
- Peter Hajek
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Roman M Link
- Chair of Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Institute of Biological Sciences, Würzburg, Germany
| | - Charles A Nock
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Jürgen Bauhus
- Chair of Silviculture, University of Freiburg, Freiburg, Germany
| | - Tobias Gebauer
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Arthur Gessler
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
- ETH Zurich, Institute of Terrestrial Ecosystems, Zurich, Switzerland
| | - Kyle Kovach
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Christian Messier
- Center for Forest Research, Université du Québec à Montréal, Montréal, Quebec, Canada
- University of Quebec in Outaouais (UQO), Institut des Sciences de la Forêt Tempérée (ISFORT), Gatineau, Quebec, Canada
| | - Alain Paquette
- Center for Forest Research, Université du Québec à Montréal, Montréal, Quebec, Canada
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland
| | | | - Laura Rose
- Geobotany, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Bernhard Schuldt
- Chair of Ecophysiology and Vegetation Ecology, University of Würzburg, Julius-von-Sachs-Institute of Biological Sciences, Würzburg, Germany
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Arend M, Link RM, Zahnd C, Hoch G, Schuldt B, Kahmen A. Lack of hydraulic recovery as a cause of post-drought foliage reduction and canopy decline in European beech. THE NEW PHYTOLOGIST 2022; 234:1195-1205. [PMID: 35238410 PMCID: PMC9310744 DOI: 10.1111/nph.18065] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/19/2022] [Indexed: 05/06/2023]
Abstract
European beech (Fagus sylvatica) was among the most affected tree species during the severe 2018 European drought. It not only suffered from instant physiological stress but also showed severe symptoms of defoliation and canopy decline in the following year. To explore the underlying mechanisms, we used the Swiss-Canopy-Crane II site and studied in branches of healthy and symptomatic trees the repair of hydraulic function and concentration of carbohydrates during the 2018 drought and in 2019. We found loss of hydraulic conductance in 2018, which did not recover in 2019 in trees that developed defoliation symptoms in the year after drought. Reduced branch foliation in symptomatic trees was associated with a gradual decline in wood starch concentration throughout summer 2019. Visualization of water transport in healthy and symptomatic branches in the year after the drought confirmed the close relationship between xylem functionality and supported branch leaf area. Our findings showed that embolized xylem does not regain function in the season following a drought and that sustained branch hydraulic dysfunction is counterbalanced by the reduction in supported leaf area. It suggests acclimation of leaf development after drought to mitigate disturbances in canopy hydraulic function.
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Affiliation(s)
- Matthias Arend
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
| | - Roman Mathias Link
- Ecophysiology and Vegetation EcologyUniversität Würzburg97082WürzburgGermany
| | - Cedric Zahnd
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
| | - Günter Hoch
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
| | - Bernhard Schuldt
- Ecophysiology and Vegetation EcologyUniversität Würzburg97082WürzburgGermany
| | - Ansgar Kahmen
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
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Challis A, Blackman C, Ahrens C, Medlyn B, Rymer P, Tissue D. Adaptive plasticity in plant traits increases time to hydraulic failure under drought in a foundation tree. TREE PHYSIOLOGY 2022; 42:708-721. [PMID: 34312674 DOI: 10.1093/treephys/tpab096] [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: 10/30/2020] [Accepted: 07/07/2021] [Indexed: 06/13/2023]
Abstract
The viability of forest trees, in response to climate change-associated drought, will depend on their capacity to survive through genetic adaptation and phenotypic plasticity in drought tolerance traits. Genotypes with enhanced plasticity for drought tolerance (adaptive plasticity) will have a greater ability to persist and delay the onset of hydraulic failure. By examining populations from different climate-origins grown under contrasting soil water availability, we tested for genotype (G), environment (E) and genotype-by-environment (G × E) effects on traits that determine the time it takes for saplings to desiccate from stomatal closure to 88% loss of stem hydraulic conductance (time to hydraulic failure, THF). Specifically, we hypothesized that: (i) THF is dependent on a G × E interaction, with longer THF for warm, dry climate populations in response to chronic water deficit treatment compared with cool, wet populations, and (ii) hydraulic and allometric traits explain the observed patterns in THF. Corymbia calophylla saplings from two populations originating from contrasting climates (warm-dry or cool-wet) were grown under well-watered and chronic soil water deficit treatments in large containers. Hydraulic and allometric traits were measured and then saplings were dried-down to critical levels of drought stress to estimate THF. Significant plasticity was detected in the warm-dry population in response to water-deficit, with enhanced drought tolerance compared with the cool-wet population. Projected leaf area and total plant water storage showed treatment variation, and minimum conductance showed significant population differences driving longer THF in trees from warm-dry origins grown in water-limited conditions. Our findings contribute information on intraspecific variation in key drought traits, including hydraulic and allometric determinants of THF. It highlights the need to quantify adaptive capacity in populations of forest trees in climate change-type drought to improve predictions of forest die-back.
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Affiliation(s)
- Anthea Challis
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Chris Blackman
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
- School of Biological Sciences, University of Tasmania, Hobart, TAS 7001, Australia
| | - Collin Ahrens
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Belinda Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Paul Rymer
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - David Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
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30
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Klein T, Torres-Ruiz JM, Albers JJ. Conifer desiccation in the 2021 NW heatwave confirms the role of hydraulic damage. TREE PHYSIOLOGY 2022; 42:722-726. [PMID: 35084498 DOI: 10.1093/treephys/tpac007] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
The unprecedented heatwave which hit the Pacific northwest of North America in late June-early July 2021 impacted ecosystems and communities, yet evidence for and analysis of this impact are still missing. Here we bring a unique dataset quantifying the impact on conifer trees, which are keystone species of many northwest ecosystems. Moreover, we take advantage of this exceptional event as a broad, extreme, 'field experiment' to test a fundamental theory in plant physiology and prepare our forests for a harsher future. Overall, the data collected confirm the role of hydraulic vulnerability in drought-induced injury to trees.
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Affiliation(s)
- Tamir Klein
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Jose M Torres-Ruiz
- Université Clermont-Auvergne, INRAE, PIAF, Clermont-Ferrand 63000, France
| | - John J Albers
- Albers Marcovina Vista Gardens, Bremerton, WA 98310-2150, USA
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
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31
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Li X, Xi B, Wu X, Choat B, Feng J, Jiang M, Tissue D. Unlocking Drought-Induced Tree Mortality: Physiological Mechanisms to Modeling. FRONTIERS IN PLANT SCIENCE 2022; 13:835921. [PMID: 35444681 PMCID: PMC9015645 DOI: 10.3389/fpls.2022.835921] [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: 12/15/2021] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Drought-related tree mortality has become a major concern worldwide due to its pronounced negative impacts on the functioning and sustainability of forest ecosystems. However, our ability to identify the species that are most vulnerable to drought, and to pinpoint the spatial and temporal patterns of mortality events, is still limited. Model is useful tools to capture the dynamics of vegetation at spatiotemporal scales, yet contemporary land surface models (LSMs) are often incapable of predicting the response of vegetation to environmental perturbations with sufficient accuracy, especially under stressful conditions such as drought. Significant progress has been made regarding the physiological mechanisms underpinning plant drought response in the past decade, and plant hydraulic dysfunction has emerged as a key determinant for tree death due to water shortage. The identification of pivotal physiological events and relevant plant traits may facilitate forecasting tree mortality through a mechanistic approach, with improved precision. In this review, we (1) summarize current understanding of physiological mechanisms leading to tree death, (2) describe the functionality of key hydraulic traits that are involved in the process of hydraulic dysfunction, and (3) outline their roles in improving the representation of hydraulic function in LSMs. We urge potential future research on detailed hydraulic processes under drought, pinpointing corresponding functional traits, as well as understanding traits variation across and within species, for a better representation of drought-induced tree mortality in models.
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Affiliation(s)
- Ximeng Li
- College of Life and Environmental Science, Minzu University of China, Beijing, China
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Benye Xi
- Ministry of Education Key Laboratory of Silviculture and Conservation, Beijing Forestry University, Beijing, China
| | - Xiuchen Wu
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Jinchao Feng
- College of Life and Environmental Science, Minzu University of China, Beijing, China
| | - Mingkai Jiang
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - David Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- Global Centre for Land-based Innovation, Western Sydney University, Richmond, NSW, Australia
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32
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Gauthey A, Peters JMR, Lòpez R, Carins-Murphy MR, Rodriguez-Dominguez CM, Tissue DT, Medlyn BE, Brodribb TJ, Choat B. Mechanisms of xylem hydraulic recovery after drought in Eucalyptus saligna. PLANT, CELL & ENVIRONMENT 2022; 45:1216-1228. [PMID: 35119114 DOI: 10.1111/pce.14265] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 12/06/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
The mechanisms by which woody plants recover xylem hydraulic capacity after drought stress are not well understood, particularly with regard to the role of embolism refilling. We evaluated the recovery of xylem hydraulic capacity in young Eucalyptus saligna plants exposed to cycles of drought stress and rewatering. Plants were exposed to moderate and severe drought stress treatments, with recovery monitored at time intervals from 24 h to 6 months after rewatering. The percentage loss of xylem vessels due to embolism (PLV) was quantified at each time point using microcomputed tomography with stem water potential (Ψx ) and canopy transpiration (Ec ) measured before scans. Plants exposed to severe drought stress suffered high levels of embolism (47.38% ± 10.97% PLV) and almost complete canopy loss. No evidence of embolism refilling was observed at 24 h, 1 week, or 3 weeks after rewatering despite rapid recovery in Ψx . Recovery of hydraulic capacity was achieved over a 6-month period by growth of new xylem tissue, with canopy leaf area and Ec recovering over the same period. These findings indicate that E. saligna recovers slowly from severe drought stress, with potential for embolism to persist in the xylem for many months after rainfall events.
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Affiliation(s)
- Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - Jennifer M R Peters
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
- Environmental Sciences Division, Oak Ridge National Laboratory, Climate Change Science Institute, Oak Ridge, Tennessee, USA
| | - Rosana Lòpez
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
- Departamento de Sistemas y Recursos Naturales, Universidad Politécnica de Madrid, Madrid, Spain
| | | | - Celia M Rodriguez-Dominguez
- Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Sevilla, Spain
- Laboratory of Plant Molecular Ecophysiology, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Sevilla, Spain
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
- Global Centre for Land Based Innovation, Western Syndey University, Richmond, New South Wales, Australia
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - Tim J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
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Guillemot J, Martin-StPaul NK, Bulascoschi L, Poorter L, Morin X, Pinho BX, le Maire G, R L Bittencourt P, Oliveira RS, Bongers F, Brouwer R, Pereira L, Gonzalez Melo GA, Boonman CCF, Brown KA, Cerabolini BEL, Niinemets Ü, Onoda Y, Schneider JV, Sheremetiev S, Brancalion PHS. Small and slow is safe: On the drought tolerance of tropical tree species. GLOBAL CHANGE BIOLOGY 2022; 28:2622-2638. [PMID: 35007364 DOI: 10.1111/gcb.16082] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 12/09/2021] [Accepted: 12/09/2021] [Indexed: 06/14/2023]
Abstract
Understanding how evolutionary history and the coordination between trait trade-off axes shape the drought tolerance of trees is crucial to predict forest dynamics under climate change. Here, we compiled traits related to drought tolerance and the fast-slow and stature-recruitment trade-off axes in 601 tropical woody species to explore their covariations and phylogenetic signals. We found that xylem resistance to embolism (P50) determines the risk of hydraulic failure, while the functional significance of leaf turgor loss point (TLP) relies on its coordination with water use strategies. P50 and TLP exhibit weak phylogenetic signals and substantial variation within genera. TLP is closely associated with the fast-slow trait axis: slow species maintain leaf functioning under higher water stress. P50 is associated with both the fast-slow and stature-recruitment trait axes: slow and small species exhibit more resistant xylem. Lower leaf phosphorus concentration is associated with more resistant xylem, which suggests a (nutrient and drought) stress-tolerance syndrome in the tropics. Overall, our results imply that (1) drought tolerance is under strong selective pressure in tropical forests, and TLP and P50 result from the repeated evolutionary adaptation of closely related taxa, and (2) drought tolerance is coordinated with the ecological strategies governing tropical forest demography. These findings provide a physiological basis to interpret the drought-induced shift toward slow-growing, smaller, denser-wooded trees observed in the tropics, with implications for forest restoration programmes.
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Affiliation(s)
- Joannès Guillemot
- CIRAD, UMR Eco&Sols, Piracicaba, São Paulo, Brazil
- Eco&Sols, Univ. Montpellier, CIRAD, INRAe, Institut Agro, IRD, Montpellier, France
- Department of Forest Sciences, ESALQ, University of São Paulo, Piracicaba, São Paulo, Brazil
| | | | - Leticia Bulascoschi
- Department of Forest Sciences, ESALQ, University of São Paulo, Piracicaba, São Paulo, Brazil
| | - Lourens Poorter
- Forest Ecology and Forest Management Group, Wageningen University, Wageningen, The Netherlands
| | - Xavier Morin
- CEFE, CNRS, Univ. Montpellier, EPHE, IRD, Univ. Paul Valéry Montpellier 3, Montpellier, France
| | - Bruno X Pinho
- AMAP, Univ Montpellier, INRAe, CIRAD, CNRS, IRD, Montpellier, France
- Departamento de Botânica, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Guerric le Maire
- CIRAD, UMR Eco&Sols, Piracicaba, São Paulo, Brazil
- Eco&Sols, Univ. Montpellier, CIRAD, INRAe, Institut Agro, IRD, Montpellier, France
| | | | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, Campinas, São Paulo, Brazil
| | - Frans Bongers
- Forest Ecology and Forest Management Group, Wageningen University, Wageningen, The Netherlands
| | - Rens Brouwer
- Forest Ecology and Forest Management Group, Wageningen University, Wageningen, The Netherlands
| | - Luciano Pereira
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, Campinas, São Paulo, Brazil
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | | | - Coline C F Boonman
- Department of Aquatic Ecology and Environmental Biology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
| | - Kerry A Brown
- Department of Geography, Geology and the Environment, Kingston University London, Kingston Upon Thames, UK
| | - Bruno E L Cerabolini
- Department of Biotechnologies and Life Sciences (DBSV), University of Insubria, Varese, Italy
| | - Ülo Niinemets
- Estonian University of Life Sciences, Tartu, Estonia
| | - Yusuke Onoda
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Julio V Schneider
- Department of Botany and Molecular Evolution, Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt, Germany
- Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt, Germany
| | | | - Pedro H S Brancalion
- Department of Forest Sciences, ESALQ, University of São Paulo, Piracicaba, São Paulo, Brazil
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Abstract
Forest research and professional workforces continue to be dominated by men, particularly at senior and management levels. In this review, we identify some of the historical and ongoing barriers to improved gender inclusion and suggest some solutions. We showcase a selection of women in forestry from different disciplines and parts of the globe to highlight a range of research being conducted by women in forests. Boosting gender equity in forest disciplines requires a variety of approaches across local, regional and global scales. It is also important to include intersectional analyses when identifying barriers for women in forestry, but enhanced equity, diversity and inclusion will improve outcomes for forest ecosystems and social values of forests, with potential additional economic benefits.
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35
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Britton TG, Brodribb TJ, Richards SA, Ridley C, Hovenden MJ. Canopy damage during a natural drought depends on species identity, physiology and stand composition. THE NEW PHYTOLOGIST 2022; 233:2058-2070. [PMID: 34850394 DOI: 10.1111/nph.17888] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/21/2021] [Indexed: 06/13/2023]
Abstract
Vulnerability to xylem cavitation is a strong predictor of drought-induced damage in forest communities. However, biotic features of the community itself can influence water availability at the individual tree-level, thereby modifying patterns of drought damage. Using an experimental forest in Tasmania, Australia, we determined the vulnerability to cavitation (leaf P50 ) of four tree species and assessed the drought-induced canopy damage of 2944 6-yr-old trees after an extreme natural drought episode. We examined how individual damage was related to their size and the density and species identity of neighbouring trees. The two co-occurring dominant tree species, Eucalyptus delegatensis and Eucalyptus regnans, were the most vulnerable to drought-induced xylem cavitation and both species suffered significantly greater damage than neighbouring, subdominant species Pomaderris apetala and Acacia dealbata. While the two eucalypts had similar leaf P50 values, E. delegatensis suffered significantly greater damage, which was strongly related to the density of neighbouring P. apetala. Damage in E. regnans was less impacted by neighbouring plants and smaller trees of both eucalypts sustained significantly more damage than larger trees. Our findings demonstrate that natural drought damage is influenced by individual plant physiology as well as the composition, physiology and density of the surrounding stand.
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Affiliation(s)
- Travis G Britton
- Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Tas., 7001, Australia
- ARC Training Centre for Forest Value, University of Tasmania, Hobart, Tas., 7001, Australia
| | - Timothy J Brodribb
- Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Tas., 7001, Australia
| | - Shane A Richards
- School of Natural Sciences, University of Tasmania, Hobart, Tas., 7001, Australia
| | - Chantelle Ridley
- Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Tas., 7001, Australia
| | - Mark J Hovenden
- Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Tas., 7001, Australia
- ARC Training Centre for Forest Value, University of Tasmania, Hobart, Tas., 7001, Australia
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Nolan RH, Collins L, Leigh A, Ooi MKJ, Curran TJ, Fairman TA, Resco de Dios V, Bradstock R. Limits to post-fire vegetation recovery under climate change. PLANT, CELL & ENVIRONMENT 2021; 44:3471-3489. [PMID: 34453442 DOI: 10.1111/pce.14176] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 08/09/2021] [Accepted: 08/13/2021] [Indexed: 06/13/2023]
Abstract
Record-breaking fire seasons in many regions across the globe raise important questions about plant community responses to shifting fire regimes (i.e., changing fire frequency, severity and seasonality). Here, we examine the impacts of climate-driven shifts in fire regimes on vegetation communities, and likely responses to fire coinciding with severe drought, heatwaves and/or insect outbreaks. We present scenario-based conceptual models on how overlapping disturbance events and shifting fire regimes interact differently to limit post-fire resprouting and recruitment capacity. We demonstrate that, although many communities will remain resilient to changing fire regimes in the short-term, longer-term changes to vegetation structure, demography and species composition are likely, with a range of subsequent effects on ecosystem function. Resprouting species are likely to be most resilient to changing fire regimes. However, even these species are susceptible if exposed to repeated short-interval fire in combination with other stressors. Post-fire recruitment is highly vulnerable to increased fire frequency, particularly as climatic limitations on propagule availability intensify. Prediction of community responses to fire under climate change will be greatly improved by addressing knowledge gaps on how overlapping disturbances and climate change-induced shifts in fire regime affect post-fire resprouting, recruitment, growth rates, and species-level adaptation capacity.
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Affiliation(s)
- Rachael H Nolan
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia
- NSW Bushfire Risk Management Research Hub, Wollongong, New South Wales, Australia
| | - Luke Collins
- School of Ecosystem and Forest Sciences, University of Melbourne, Creswick, Victoria, Australia
- Department of Ecology, Environment & Evolution, La Trobe University, Bundoora, Victoria, Australia
- Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, Canada
| | - Andy Leigh
- School of Life Sciences, University of Technology Sydney, Broadway, New South Wales, Australia
| | - Mark K J Ooi
- NSW Bushfire Risk Management Research Hub, Wollongong, New South Wales, Australia
- School of Biological, Earth and Environmental Sciences, University of New South Wales UNSW, Sydney, New South Wales, Australia
| | - Timothy J Curran
- Department of Pest-management and Conservation, Lincoln University, Lincoln, New Zealand
| | - Thomas A Fairman
- School of Ecosystem and Forest Sciences, University of Melbourne, Creswick, Victoria, Australia
| | - Víctor Resco de Dios
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, China
- Joint Research Unit CTFC-AGROTECNIO, University of Lleida, Lleida, Spain
- Department of Crop and Forest Sciences, University of Lleida, Lleida, Spain
| | - Ross Bradstock
- NSW Bushfire Risk Management Research Hub, Wollongong, New South Wales, Australia
- Centre for Environmental Risk Management of Bushfires, University of Wollongong, Wollongong, New South Wales, Australia
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37
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Compound climate extremes driving recent sub-continental tree mortality in northern Australia have no precedent in recent centuries. Sci Rep 2021; 11:18337. [PMID: 34526586 PMCID: PMC8443737 DOI: 10.1038/s41598-021-97762-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/17/2021] [Indexed: 12/03/2022] Open
Abstract
Compound climate extremes (CCEs) can have significant and persistent environmental impacts on ecosystems. However, knowledge of the occurrence of CCEs beyond the past ~ 50 years, and hence their ecological impacts, is limited. Here, we place the widespread 2015–16 mangrove dieback and the more recent 2020 inland native forest dieback events in northern Australia into a longer historical context using locally relevant palaeoclimate records. Over recent centuries, multiple occurrences of analogous antecedent and coincident climate conditions associated with the mangrove dieback event were identified in this compilation. However, rising sea level—a key antecedent condition—over the three decades prior to the mangrove dieback is unprecedented in the past 220 years. Similarly, dieback in inland forests and savannas was associated with a multi-decadal wetting trend followed by the longest and most intense drought conditions of the past 250 years, coupled with rising temperatures. While many ecological communities may have experienced CCEs in past centuries, the addition of new environmental stressors associated with varying aspects of global change may exceed their thresholds of resilience. Palaeoclimate compilations provide the much-needed longer term context to better assess frequency and changes in some types of CCEs and their environmental impacts.
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38
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Fuchs S, Leuschner C, Mathias Link R, Schuldt B. Hydraulic variability of three temperate broadleaf tree species along a water availability gradient in central Europe. THE NEW PHYTOLOGIST 2021; 231:1387-1400. [PMID: 33964029 DOI: 10.1111/nph.17448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 05/01/2021] [Indexed: 06/12/2023]
Abstract
Plant hydraulic traits are key for understanding and predicting tree drought responses. Information about the degree of the traits' intra-specific variability may guide the selection of drought-resistant genotypes and is crucial for trait-based modelling approaches. For the three temperate minor broadleaf tree species Acer platanoides, Carpinus betulus and Tilia cordata, we measured xylem embolism resistance (P50 ), leaf turgor loss point (PTLP ), specific hydraulic conductivity (KS ), Huber values (HVs), and hydraulic safety margins in adult trees across a precipitation gradient. We further quantified trait variability on different organizational levels (inter-specific to within-canopy variation), and analysed its relationship to climatic and soil water availability. Although we observed a certain intra-specific trait variability (ITV) in safety-related traits (P50 , PTLP ) with higher within-tree and between-tree than between populations variability, the magnitude was small compared to inter-specific differences, which explained 78.4% and 58.3% of the variance in P50 and PTLP , respectively. In contrast, efficiency-related traits (KS , HV) showed a high ITV both within populations and within the crowns of single trees. Surprisingly, the observed ITV of all traits was neither driven by climatic nor soil water availability. In conclusion, the high degree of conservatism in safety-related traits highlights their potential for trait-based modelling approaches.
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Affiliation(s)
- Sebastian Fuchs
- Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, Goettingen, 37073, Germany
| | - Christoph Leuschner
- Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, Goettingen, 37073, Germany
- Centre for Biodiversity and Sustainable Land Use (CBL), University of Goettingen, Goettingen, 37075, Germany
| | - Roman Mathias Link
- Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, Goettingen, 37073, Germany
| | - Bernhard Schuldt
- Plant Ecology, Albrecht von Haller Institute for Plant Sciences, University of Goettingen, Untere Karspüle 2, Goettingen, 37073, Germany
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39
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Peters JMR, López R, Nolf M, Hutley LB, Wardlaw T, Cernusak LA, Choat B. Living on the edge: A continental-scale assessment of forest vulnerability to drought. GLOBAL CHANGE BIOLOGY 2021; 27:3620-3641. [PMID: 33852767 DOI: 10.1111/gcb.15641] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
Globally, forests are facing an increasing risk of mass tree mortality events associated with extreme droughts and higher temperatures. Hydraulic dysfunction is considered a key mechanism of drought-triggered dieback. By leveraging the climate breadth of the Australian landscape and a national network of research sites (Terrestrial Ecosystem Research Network), we conducted a continental-scale study of physiological and hydraulic traits of 33 native tree species from contrasting environments to disentangle the complexities of plant response to drought across communities. We found strong relationships between key plant hydraulic traits and site aridity. Leaf turgor loss point and xylem embolism resistance were correlated with minimum water potential experienced by each species. Across the data set, there was a strong coordination between hydraulic traits, including those linked to hydraulic safety, stomatal regulation and the cost of carbon investment into woody tissue. These results illustrate that aridity has acted as a strong selective pressure, shaping hydraulic traits of tree species across the Australian landscape. Hydraulic safety margins were constrained across sites, with species from wetter sites tending to have smaller safety margin compared with species at drier sites, suggesting trees are operating close to their hydraulic thresholds and forest biomes across the spectrum may be susceptible to shifts in climate that result in the intensification of drought.
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Affiliation(s)
- Jennifer M R Peters
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Rosana López
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Markus Nolf
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Lindsay B Hutley
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, NT, Australia
| | - Tim Wardlaw
- ARC Centre for Forest Value, University of Tasmania, Hobart, Tas, Australia
| | - Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, Qld, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
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