1
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Song Y, Sapes G, Chang S, Chowdhry R, Mejia T, Hampton A, Kucharski S, Sazzad TMS, Zhang Y, Tillman BL, Resende MFR, Koppal S, Wilson C, Gerber S, Zare A, Hammond WM. Hyperspectral signals in the soil: Plant-soil hydraulic connection and disequilibrium as mechanisms of drought tolerance and rapid recovery. PLANT, CELL & ENVIRONMENT 2024; 47:4171-4187. [PMID: 38924477 DOI: 10.1111/pce.15011] [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: 01/19/2024] [Revised: 04/12/2024] [Accepted: 06/10/2024] [Indexed: 06/28/2024]
Abstract
Predicting soil water status remotely is appealing due to its low cost and large-scale application. During drought, plants can disconnect from the soil, causing disequilibrium between soil and plant water potentials at pre-dawn. The impact of this disequilibrium on plant drought response and recovery is not well understood, potentially complicating soil water status predictions from plant spectral reflectance. This study aimed to quantify drought-induced disequilibrium, evaluate plant responses and recovery, and determine the potential for predicting soil water status from plant spectral reflectance. Two species were tested: sweet corn (Zea mays), which disconnected from the soil during intense drought, and peanut (Arachis hypogaea), which did not. Sweet corn's hydraulic disconnection led to an extended 'hydrated' phase, but its recovery was slower than peanut's, which remained connected to the soil even at lower water potentials (-5 MPa). Leaf hyperspectral reflectance successfully predicted the soil water status of peanut consistently, but only until disequilibrium occurred in sweet corn. Our results reveal different hydraulic strategies for plants coping with extreme drought and provide the first example of using spectral reflectance to quantify rhizosphere water status, emphasizing the need for species-specific considerations in soil water status predictions from canopy reflectance.
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Affiliation(s)
- Yangyang Song
- Agronomy Department, University of Florida, Gainesville, Florida, USA
| | - Gerard Sapes
- Agronomy Department, University of Florida, Gainesville, Florida, USA
| | - Spencer Chang
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida, USA
| | - Ritesh Chowdhry
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida, USA
| | - Tomas Mejia
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida, USA
| | - Anna Hampton
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida, USA
| | - Shelby Kucharski
- School of Natural Resources and Environment, University of Florida, Gainesville, Florida, USA
| | - T M Shahiar Sazzad
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida, USA
| | - Yuxuan Zhang
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida, USA
| | - Barry L Tillman
- North Florida Research and Education Center, University of Florida, Marianna, Florida, USA
| | - Márcio F R Resende
- Horticultural Sciences Department, University of Florida, Gainesville, Florida, USA
| | - Sanjeev Koppal
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida, USA
| | - Chris Wilson
- Agronomy Department, University of Florida, Gainesville, Florida, USA
| | - Stefan Gerber
- Soil, Water and Ecosystem Sciences Department, University of Florida, Gainesville, Florida, USA
| | - Alina Zare
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida, USA
| | - William M Hammond
- Agronomy Department, University of Florida, Gainesville, Florida, USA
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2
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Dickman LT, Jonko AK, Linn RR, Altintas I, Atchley AL, Bär A, Collins AD, Dupuy J, Gallagher MR, Hiers JK, Hoffman CM, Hood SM, Hurteau MD, Jolly WM, Josephson A, Loudermilk EL, Ma W, Michaletz ST, Nolan RH, O'Brien JJ, Parsons RA, Partelli‐Feltrin R, Pimont F, Resco de Dios V, Restaino J, Robbins ZJ, Sartor KA, Schultz‐Fellenz E, Serbin SP, Sevanto S, Shuman JK, Sieg CH, Skowronski NS, Weise DR, Wright M, Xu C, Yebra M, Younes N. Integrating plant physiology into simulation of fire behavior and effects. THE NEW PHYTOLOGIST 2023; 238:952-970. [PMID: 36694296 PMCID: PMC10952334 DOI: 10.1111/nph.18770] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
Wildfires are a global crisis, but current fire models fail to capture vegetation response to changing climate. With drought and elevated temperature increasing the importance of vegetation dynamics to fire behavior, and the advent of next generation models capable of capturing increasingly complex physical processes, we provide a renewed focus on representation of woody vegetation in fire models. Currently, the most advanced representations of fire behavior and biophysical fire effects are found in distinct classes of fine-scale models and do not capture variation in live fuel (i.e. living plant) properties. We demonstrate that plant water and carbon dynamics, which influence combustion and heat transfer into the plant and often dictate plant survival, provide the mechanistic linkage between fire behavior and effects. Our conceptual framework linking remotely sensed estimates of plant water and carbon to fine-scale models of fire behavior and effects could be a critical first step toward improving the fidelity of the coarse scale models that are now relied upon for global fire forecasting. This process-based approach will be essential to capturing the influence of physiological responses to drought and warming on live fuel conditions, strengthening the science needed to guide fire managers in an uncertain future.
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Affiliation(s)
- L. Turin Dickman
- Earth & Environmental Sciences DivisionLos Alamos National LaboratoryLos AlamosNM87545USA
| | - Alexandra K. Jonko
- Earth & Environmental Sciences DivisionLos Alamos National LaboratoryLos AlamosNM87545USA
| | - Rodman R. Linn
- Earth & Environmental Sciences DivisionLos Alamos National LaboratoryLos AlamosNM87545USA
| | - Ilkay Altintas
- San Diego Supercomputer Center and Halicioglu Data Science InstituteUniversity of California San DiegoLa JollaCA92093USA
| | - Adam L. Atchley
- Earth & Environmental Sciences DivisionLos Alamos National LaboratoryLos AlamosNM87545USA
| | - Andreas Bär
- Department of BotanyUniversity of Innsbruck6020InnsbruckAustria
| | - Adam D. Collins
- Earth & Environmental Sciences DivisionLos Alamos National LaboratoryLos AlamosNM87545USA
| | - Jean‐Luc Dupuy
- Ecologie des Forêts Méditerranéennes (URFM)INRAe84914AvignonFrance
| | | | | | - Chad M. Hoffman
- Department of Forest and Rangeland StewardshipColorado State UniversityFort CollinsCO80523USA
| | - Sharon M. Hood
- Rocky Mountain Research StationUSDA Forest ServiceMissoulaMT59801USA
| | | | - W. Matt Jolly
- Rocky Mountain Research StationUSDA Forest ServiceMissoulaMT59801USA
| | - Alexander Josephson
- Earth & Environmental Sciences DivisionLos Alamos National LaboratoryLos AlamosNM87545USA
| | | | - Wu Ma
- Earth & Environmental Sciences DivisionLos Alamos National LaboratoryLos AlamosNM87545USA
| | - Sean T. Michaletz
- Department of Botany and Biodiversity Research CentreThe University of British ColumbiaVancouverBCV6T 1Z4Canada
| | - Rachael H. Nolan
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityPenrithNSW2753Australia
- NSW Bushfire Risk Management Research HubWollongongNSW2522Australia
| | | | | | - Raquel Partelli‐Feltrin
- Department of Botany and Biodiversity Research CentreThe University of British ColumbiaVancouverBCV6T 1Z4Canada
| | - François Pimont
- Ecologie des Forêts Méditerranéennes (URFM)INRAe84914AvignonFrance
| | - Víctor Resco de Dios
- School of Life Sciences and EngineeringSouthwest University of Science and TechnologyMianyang621010China
- Department of Crop and Forest Sciences and JRU CTFC‐AGROTECNIOUniversitat de LleidaLleida25198Spain
| | - Joseph Restaino
- Fire and Resource Assessment ProgramCalifornia Department of Forestry and Fire ProtectionSouth Lake TahoeCA96155USA
| | - Zachary J. Robbins
- Earth & Environmental Sciences DivisionLos Alamos National LaboratoryLos AlamosNM87545USA
| | - Karla A. Sartor
- Environmental Protection and Compliance DivisionLos Alamos National LaboratoryLos AlamosNM87545USA
| | - Emily Schultz‐Fellenz
- Earth & Environmental Sciences DivisionLos Alamos National LaboratoryLos AlamosNM87545USA
| | - Shawn P. Serbin
- Environmental and Climate Sciences DepartmentBrookhaven National LaboratoryUptonNY11973USA
| | - Sanna Sevanto
- Earth & Environmental Sciences DivisionLos Alamos National LaboratoryLos AlamosNM87545USA
| | - Jacquelyn K. Shuman
- Climate and Global Dynamics Laboratory, Terrestrial Sciences SectionNational Center for Atmospheric ResearchBoulderCO80305USA
| | - Carolyn H. Sieg
- Rocky Mountain Research StationUSDA Forest ServiceFlagstaffAZ86001USA
| | | | - David R. Weise
- Pacific Southwest Research StationUSDA Forest ServiceRiversideCA92507USA
| | - Molly Wright
- Cibola National ForestUSDA Forest ServiceAlbuquerqueNM87113USA
| | - Chonggang Xu
- Earth & Environmental Sciences DivisionLos Alamos National LaboratoryLos AlamosNM87545USA
| | - Marta Yebra
- Fenner School of Environment and SocietyAustralian National UniversityCanberraACT2601Australia
- School of EngineeringAustralian National UniversityCanberraACT2601Australia
| | - Nicolas Younes
- Fenner School of Environment and SocietyAustralian National UniversityCanberraACT2601Australia
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Bison NN, Partelli-Feltrin R, Michaletz ST. Trait phenology and fire seasonality co-drive seasonal variation in fire effects on tree crowns. THE NEW PHYTOLOGIST 2022; 234:1654-1663. [PMID: 35181920 DOI: 10.1111/nph.18047] [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: 09/30/2021] [Accepted: 02/06/2022] [Indexed: 06/14/2023]
Abstract
The plume of hot gases rising above a wildfire can heat and kill the buds in tree crowns. This can reduce leaf area and rates of photosynthesis, growth, and reproduction, and may ultimately lead to mortality. These effects vary seasonally, but the mechanisms governing this seasonality are not well understood. A trait-based physical model combining buoyant plume and energy budget theories shows the seasonality of bud necrosis height may originate from temporal variation in climate, fire behaviour, and/or bud functional traits. To assess the relative importance of these drivers, we parameterized the model with time-series data for air temperature, fireline intensity, and bud traits from Pinus contorta, Picea glauca, and Populus tremuloides. Air temperature, fireline intensity, and bud traits all varied significantly through time, causing significant seasonal variation in predicted necrosis height. Bud traits and fireline intensity explained almost all the variation in necrosis height, with air temperature explaining relatively minor amounts of variation. The seasonality of fire effects on tree crowns appears to originate from seasonal variation in functional traits and fire behaviour. Our approach and results provide needed insight into the physical mechanisms linking environmental variation to plant performance via functional traits.
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Affiliation(s)
- Nicole N Bison
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Raquel Partelli-Feltrin
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Sean T Michaletz
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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4
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Hoffmann WA, Rodrigues AC, Uncles N, Rossi L. Hydraulic segmentation does not protect stems from acute water loss during fire. TREE PHYSIOLOGY 2021; 41:1785-1793. [PMID: 33929545 DOI: 10.1093/treephys/tpab057] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 04/22/2021] [Indexed: 06/12/2023]
Abstract
The heat plume associated with fire has been hypothesized to cause sufficient water loss from trees to induce embolism and hydraulic failure. However, it is unclear whether the water transport path remains sufficiently intact during scorching or burning of foliage to sustain high water loss. We measured water uptake by branches of Magnolia grandiflora while exposing them to a range of fire intensities and examined factors influencing continued water uptake after fire. Burning caused a 22-fold mean increase in water uptake, with greatest rates of water loss observed at burn intensities that caused complete consumption of leaves. Such rapid uptake is possible only with steep gradients in water potential, which would likely result in substantial cavitation of xylem and loss of conductivity in intact stems. Water uptake continued after burning was complete and was greatest following burn intensities that killed leaves but did not consume them. This post-fire uptake was mostly driven by rehydration of the remaining tissues, rather than evaporation from the tissues. Our results indicate that the fire plume hypothesis can be expanded to include a wide range of burning conditions experienced by plants. High rates of water loss are sustained during burning, even when leaves are killed or completely consumed.
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Affiliation(s)
- William A Hoffmann
- Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695, USA
| | - Amanda C Rodrigues
- Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695, USA
- University Studies and Educational Technology, Johnston Community College, Smithfield, NC 27577, USA
| | - Nicholas Uncles
- Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695, USA
| | - Lorenzo Rossi
- Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695, USA
- Horticultural Sciences Department, University of Florida, Institute of Food and Agricultural Science, Indian River Research and Education Center, Fort Pierce, FL 34945, USA
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5
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Zylstra P, Liow LH. Linking fire behaviour and its ecological effects to plant traits, using FRaME in R. Methods Ecol Evol 2021. [DOI: 10.1111/2041-210x.13615] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Philip Zylstra
- Centre for Sustainable Ecosystem Solutions University of Wollongong Wollongong NSW Australia
| | - Lee Hsiang Liow
- Centre for Sustainable Ecosystem Solutions University of Wollongong Wollongong NSW Australia
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6
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Brunori E, Maesano M, Moresi FV, Antolini A, Bellincontro A, Forniti R, Biasi R, Mencarelli F. Using UAV-based remote sensing to assess grapevine canopy damage due to fire smoke. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2020; 100:4531-4539. [PMID: 32406515 DOI: 10.1002/jsfa.10494] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 05/03/2020] [Accepted: 05/14/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Bushfires are becoming an increasing issue for the wine sector due to grape and vine losses and smoke taint in wine. Smoke affects vine physiology and the smoke's volatile phenols are absorbed by plants and berries, contaminating the wine. Our hypothesis was that, for the first time, unmanned aerial vehicle (UAV)-based visible images can be used to study the physiology of smoke-affected vines and to assess compromised vines. RESULTS Procanico vines were exposed to two smoke treatments, a week apart. Gas exchanges and leaf biochemical traits were measured in the short term (30 min after smoke exposure) and in the long term (24 h after smoke exposure). Canopy damage was assessed with conventional vegetation indices (VIs) and by an innovative index derived by UAV-based visible images, the Canopy Area Health Index (CAHI). Gas exchange showed a reduction after the first smoke exposure, but the vines recovered within 24 h. The second smoke exposure led to an irreversible reduction in functional parameters. The VIs exhibited significant differences and CAHI presented a damage gradient related to bushfire nearby. CONCLUSION The vineyard damage assessment by UAV-based visible images may represent a tool to study the physiological activity of smoke-affected vines and to quantify the loss of destroyed or damaged vines. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Elena Brunori
- Department for Innovation in Biological, Agro-Food and Forestry Systems (DIBAF) University of Tuscia, via San Camillo De Lellis snc, Viterbo, Italy
| | - Mauro Maesano
- Department for Innovation in Biological, Agro-Food and Forestry Systems (DIBAF) University of Tuscia, via San Camillo De Lellis snc, Viterbo, Italy
- University Consortium for Socioeconomic and Environmental Research (CURSA), Rome, Italy
| | - Federico V Moresi
- University Consortium for Socioeconomic and Environmental Research (CURSA), Rome, Italy
| | - Adriano Antolini
- Department for Innovation in Biological, Agro-Food and Forestry Systems (DIBAF) University of Tuscia, via San Camillo De Lellis snc, Viterbo, Italy
| | - Andrea Bellincontro
- Department for Innovation in Biological, Agro-Food and Forestry Systems (DIBAF) University of Tuscia, via San Camillo De Lellis snc, Viterbo, Italy
| | - Roberto Forniti
- Department for Innovation in Biological, Agro-Food and Forestry Systems (DIBAF) University of Tuscia, via San Camillo De Lellis snc, Viterbo, Italy
| | - Rita Biasi
- Department for Innovation in Biological, Agro-Food and Forestry Systems (DIBAF) University of Tuscia, via San Camillo De Lellis snc, Viterbo, Italy
| | - Fabio Mencarelli
- Department for Innovation in Biological, Agro-Food and Forestry Systems (DIBAF) University of Tuscia, via San Camillo De Lellis snc, Viterbo, Italy
- DAFE, University of Pisa, Via del Borghetto 39, Pisa, Italy
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7
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Gričar J, Hafner P, Lavrič M, Ferlan M, Ogrinc N, Krajnc B, Eler K, Vodnik D. Post-fire effects on development of leaves and secondary vascular tissues in Quercus pubescens. TREE PHYSIOLOGY 2020; 40:796-809. [PMID: 32175576 DOI: 10.1093/treephys/tpaa030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 01/22/2020] [Accepted: 03/06/2020] [Indexed: 06/10/2023]
Abstract
An increased frequency of fire events on the Slovenian Karst is in line with future climate change scenarios for drought-prone environments worldwide. It is therefore of the utmost importance to better understand tree-fire-climate interactions for predicting the impact of changing environment on tree functioning. To this purpose, we studied the post-fire effects on leaf development, leaf carbon isotope composition (δ13C), radial growth patterns and the xylem and phloem anatomy in undamaged (H-trees) and fire-damaged trees (F-trees) of Quercus pubescens Willd. with good resprouting ability in spring 2017, the growing season after a rangeland fire in August 2016. We found that the fully developed canopy of F-trees reached only half of the leaf area index values measured in H-trees. Throughout the season, F-trees were characterized by higher water potential and stomatal conductivity and achieved higher photosynthetic rates compared to unburnt H-trees. The foliage of F-trees had more negative δ13C values than those of H-trees. This reflects that F-trees less frequently meet stomatal limitations due to reduced transpirational area and more favourable leaf-to-root ratio. In addition, the growth of leaves in F-trees relied more on the recent photosynthates than on reserves due to the fire disturbed starch accumulation in the previous season. Cambial production stopped 3 weeks later in F-trees, resulting in 60 and 22% wider xylem and phloem increments, respectively. A novel approach by including phloem anatomy in the analyses revealed that fire caused changes in conduit dimensions in the early phloem but not in the earlywood. However, premature formation of the tyloses in the earlywood vessels of the youngest two xylem increments in F-trees implies that xylem hydraulic integrity was also affected by heat. Analyses of secondary tissues showed that although xylem and phloem tissues are interlinked changes in their transport systems due to heat damage are not necessarily coordinated.
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Affiliation(s)
- Jožica Gričar
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana, Slovenia
| | - Polona Hafner
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana, Slovenia
| | - Martina Lavrič
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana, Slovenia
| | - Mitja Ferlan
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana, Slovenia
| | - Nives Ogrinc
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Bor Krajnc
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Klemen Eler
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana, Slovenia
- Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia
| | - Dominik Vodnik
- Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia
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Gea-Izquierdo G, Férriz M, García-Garrido S, Aguín O, Elvira-Recuenco M, Hernandez-Escribano L, Martin-Benito D, Raposo R. Synergistic abiotic and biotic stressors explain widespread decline of Pinus pinaster in a mixed forest. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 685:963-975. [PMID: 31247442 DOI: 10.1016/j.scitotenv.2019.05.378] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/20/2019] [Accepted: 05/24/2019] [Indexed: 06/09/2023]
Abstract
Global change potentially increases forest vulnerability. Different abiotic and biotic factors may interact to cause forest decline and accelerated tree mortality. We studied a mixed Mediterranean continental forest where Pinus pinaster Ait. (maritime pine) shows widespread decline to analyse the role of different abiotic and biotic factors on health status and growth dynamics both at the individual and plot levels. We also analysed stand composition and regeneration of tree species to check whether there is a change in species dominance. Fungal pathogens were seldom present and we detected no pervasive fungi or insect infestation and no presence of pathogens like Heterobasidion or Phytophthora. Infection of hemiparasite plants like Viscum album L. (mistletoe) can reduce leaf area and its abundance is generally considered an expression of host decline. Yet, the existence among declining trees of high defoliation levels without mistletoe, but not vice versa, suggests that defoliation in response to some abiotic stressor could be a predisposing factor preceding mistletoe infection. Compared to healthy trees, declining and dead trees exhibited higher defoliation rates, smaller needles and lower recent growth with steeper negative trends. Dead and declining trees showed similar negative growth trends since the early 1990s droughts, which we interpreted as early warning signals anticipating mortality of currently declining trees in the near future. Mortality of maritime pine extending across all size classes, the lower presence of this species in the smallest size classes and its lack of regeneration suggest it is potentially losing its current dominance and being replaced by other co-occurring, more drought-tolerant species. Our results unravelled that maritime pine decline seems to be mainly driven by a combination of predisposing and inciting abiotic factors (microenvironment and drought stress) and biotic factors (mistletoe). The absence of widespread fungal pathogens suggests that they may have a minor role on pine decline acting only eventually as contributing factors. Although there could be other interrelations among factors or other biotic agents at play, our results strongly suggest that water stress plays a major role in the decline process of the dominant species on an ecosystem with strong land-use legacies.
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Affiliation(s)
| | | | | | - Olga Aguín
- Estación Fitopatolóxica do Areeiro, Subida a la Robleda s/n, 36153 Pontevedra, Spain
| | | | | | | | - Rosa Raposo
- INIA-CIFOR, Ctra. La Coruña km. 7.5, 28040 Madrid, Spain
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9
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Bär A, Michaletz ST, Mayr S. Fire effects on tree physiology. THE NEW PHYTOLOGIST 2019; 223:1728-1741. [PMID: 31032970 DOI: 10.1111/nph.15871] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 04/07/2019] [Indexed: 05/02/2023]
Abstract
Heat injuries sustained in a fire can initiate a cascade of complex mechanisms that affect the physiology of trees after fires. Uncovering the exact physiological mechanisms and relating specific injuries to whole-plant and ecosystem functioning is the focus of intense current research. Recent studies have made critical steps forward in our understanding of tree physiological processes after fires, and have suggested mechanisms by which fire injuries may interact with disturbances such as drought, insects and pathogens. We outline a conceptual framework that unifies the involved processes, their interconnections, and possible feedbacks, and contextualizes these responses with existing hypotheses for disturbance effects on plants and ecosystems. By focusing on carbon and water as currencies of plant functioning, we demonstrate fire-induced cambium/phloem necrosis and xylem damage to be main disturbance effects. The resulting carbon starvation and hydraulic dysfunction are linked with drought and insect impacts. Evaluating the precise process relationships will be crucial for fully understanding how fires can affect tree functionality, and will help improve fire risk assessment and mortality model predictions. Especially considering future climate-driven increases in fire frequency and intensity, knowledge of the physiological tree responses is important to better estimate postfire ecosystem dynamics and interactions with climate disturbances.
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Affiliation(s)
- Andreas Bär
- Department of Botany, University of Innsbruck, Sternwartestraße 15, Innsbruck, 6020, Austria
| | - Sean T Michaletz
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, Innsbruck, 6020, Austria
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