A consistent link between drought and forest diebacks across Europe

2020 ◽  
Author(s):  
Cornelius Senf ◽  
Allan Buras ◽  
Christian Zang ◽  
Anja Rammig ◽  
Rupert Seidl
Keyword(s):  
Vapor Pressure ◽  
Large Scale ◽  
Tree Mortality ◽  
Vapor Pressure Deficit ◽  
Tree Canopy ◽  
Drought Indices ◽  
Spatially Explicit ◽  
Quantitative Evidence ◽  
Drought Conditions ◽  
Landsat Satellite

<p>Drought has been suggested as major driver of large-scale forest diebacks, but quantitative evidence covering large spatial and long temporal scales is rare for Europe. Combining spatially explicit maps of canopy mortality (i.e., partial or full loss of the dominant tree canopy) generated from Landsat satellite data for the period 1986-2016 and gridded drought indices (0.5° resolution; including vapor pressure deficit, climatic water balance, and precipitation deficit), we report a consistent link between pulses of above-average tree mortality and drought conditions as measured in all three drought indices. As such, we deliver first quantitative evidence that drought conditions can trigger large-scale forest diebacks across Europe’s forests. A future increase in the severity and intensity of droughts as predicted for Europe might thus have unforeseen consequences for Europe’s forests, with large-scale forest diebacks likely becoming more common in the future.</p>

scholarly journals Mist, Vapor Pressure Deficit, and Cutting Water Potential Influence Rooting of Stem Cuttings of Loblolly Pine

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 890D-890
Author(s):  
Anthony V. LeBude* ◽  
Barry Goldfarb ◽  
Frank A. Blazich
Keyword(s):  
Vapor Pressure ◽  
Water Potential ◽  
Pinus Taeda ◽  
Loblolly Pine ◽  
Large Scale ◽  
Vapor Pressure Deficit ◽  
Adventitious Root Formation ◽  
Silica Sand ◽  
Stem Cuttings ◽  
Range Of Values

Producing high quality rooted stem cuttings on a large scale requires precise management of the rooting environment. This study was conducted to investigate the effect of the rooting environment on adventitious root formation of stem cuttings of loblolly pine (Pinus taeda L.). Hardwood stem cuttings of loblolly pine were collected in Feb. 2002 from hedged stock plants and stored at 4 °C until setting in Apr. 2002. One hundred stem cuttings per plot in each of two replications received 45, 61, 73, 102, 147, or 310 mL·m-2 of mist delivered intermittently by a traveling gantry (boom) system. Mist frequency was similar for all treatments and was related inversely to relative humidity (RH) within the polyethylene covered greenhouse. Rooting tubs in each plot were filled with a substrate of fine silica sand, and substrate water potential was held constant using soil tensiometers that activated a subirrigation system. Cutting water potential was measured destructively on two cuttings per plot beginning at 0500 hr every 3 hh until 2300 hr (seven measurements) 7, 14, 21, or 28 days after setting. During rooting, leaf temperature and RH were recorded in each plot to calculate vapor pressure deficit (VPD). Cutting water potential and VPD were strongly related to mist application. Cutting water potential was also related to VPD. Rooting percentage had a linear and quadratic relationship with mean cutting water potential and VPD averaged between 1000 and 1800 HR. Eighty percent rooting occurred within a range of values for VPD. Data suggest that VPD can be used to manage the water deficit of stem cuttings of loblolly pine to increase rooting percentage. These results may be applicable to other species and to other rooting environments.

scholarly journals Diffusion Model for Describing the Regional Spread of Huanglongbing from First-Reported Outbreaks and Basing an Area Wide Disease Management Strategy

Plant Disease ◽  
2017 ◽  
Vol 101 (7) ◽  
pp. 1119-1127 ◽  
Author(s):  
J. L. Flores-Sánchez ◽  
G. Mora-Aguilera ◽  
E. Loeza-Kuk ◽  
J. I. López-Arroyo ◽  
M. A. Gutiérrez-Espinosa ◽  
...  
Keyword(s):  
Diffusion Model ◽  
Spatial Data ◽  
Large Scale ◽  
Disease Incidence ◽  
Management Program ◽  
Tree Canopy ◽  
Homogeneous Distribution ◽  
Diaphorina Citri ◽  
Monitoring And Control ◽  
Quantitative Evidence

Huanglongbing (HLB), a recent worldwide spreading disease on citrus, was detected in July 2009 in Yucatan State of Mexico. The objective of this study was to evaluate the fit of diffusion and classic disease gradient models to large-scale HLB spatial data originated from initial foci to improve sampling, monitoring, and control strategies for Diaphorina citri, vector of Candidatus Liberibacter asiaticus (CLas), putative agent of HLB. Four transect routes were selected: Yuc-1, Yuc-2, QRoo-1, and QRoo-2, based on the directionality of the prevailing winds and foci location of HLB infected plants. In these routes, 35 sites, 5 to 20 km apart, were selected for monthly evaluation during a 12-month period. A 10-insect sample and disease incidence and severity of HLB, further confirmed by PCR, were assessed per site. Mexican lime was more vulnerable (67.5%) than sweet orange (14%). Also, leaf symptoms were mostly found with homogeneous distribution but rarely reaching 100% of the tree canopy during the 12-month period. The diffusion model provided the best fit among the family of time-gradient curves (r2 = 0.90 to 0.99) due to the flexibility of a three-parameter model. The gradients were well conformed to the model in a 25 to 82.6 km range, having the east-west direction the longest effect. Yuc-2 and QRoo-2 transects showed 82.6 and 43.9 km gradients with a diffusion coefficient (Do) of 0.15 and 0.09, respectively. This study constitutes the first quantitative evidence of the regional spread of CLas from a single focus and the application of a flexible model that improved the fit and allowed to better compare different gradients. These results are useful to determine the size of Regional Areas of Diaphorina citri Control (ARCO), a management program currently implemented in Mexico to combat HLB.

The role of multi-sensor remote sensing for drought characterization: challenges and opportunities

2021 ◽  
Author(s):  
Lixin Wang ◽  
Wenzhe Jiao ◽  
Matthew McCabe
Keyword(s):  
Remote Sensing ◽  
Large Scale ◽  
Tree Mortality ◽  
Drought Monitoring ◽  
Drought Indices ◽  
Spatiotemporal Resolution ◽  
Continental Scale ◽  
Related Information ◽  
Challenges And Opportunities

<p>Satellite based remote sensing plays important role in studying regional to continental scale drought. One of the unique elements of remote sensing platforms is their multi-sensor capabilities, which enhance the capacity for characterizing drought from a variety of aspects. However, multi-sensor integrated drought evaluation is in its infancy. To advocate and encourage on-going exploration and integration of multi-sensor remote sensing for drought studies, we provide an overview of the role of multi-sensor remote sensing for addressing knowledge gaps and driving advances in drought studies. We first present a comprehensive summary of large-scale drought-related remote sensing datasets that can be used for multi-sensor drought studies. Then we provide a detailed review of how the integrated multi-sensor remote sensing could enhance our analysis in multiple important drought related phenomena and mechanisms such as drought-induced tree mortality, drought-related ecosystem fires, post-drought recovery and legacy effects, flash drought, and drought trends under climate change. We also provide a summary of recent modeling advances towards developing integrated multi-sensor remote sensing drought indices. We highlight that leveraging multi-sensor remote sensing provides unique benefits for regional to global drought studies, particularly in: 1) revealing the complex drought impact mechanisms on various ecosystem components; 2) providing continuous long-term drought related information at large scales; 3) presenting real-time drought information with high spatiotemporal resolution; 4) providing multiple lines of evidence of drought monitoring to improve modeling and prediction robustness; and 5) improving the accuracy of drought monitoring and assessment efforts.</p>

scholarly journals Excess forest mortality is consistently linked to drought across Europe

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Cornelius Senf ◽  
Allan Buras ◽  
Christian S. Zang ◽  
Anja Rammig ◽  
Rupert Seidl
Keyword(s):  
Large Scale ◽  
Tree Mortality ◽  
Excess Mortality ◽  
Quantitative Evidence ◽  
Forest Mortality ◽  
Continental Scale ◽  
Standard Deviations ◽  
The Relationship ◽  
Long Term Mortality

AbstractPulses of tree mortality caused by drought have been reported recently in forests around the globe, but large-scale quantitative evidence is lacking for Europe. Analyzing high-resolution annual satellite-based canopy mortality maps from 1987 to 2016 we here show that excess forest mortality (i.e., canopy mortality exceeding the long-term mortality trend) is significantly related to drought across continental Europe. The relationship between water availability and mortality showed threshold behavior, with excess mortality increasing steeply when the integrated climatic water balance from March to July fell below −1.6 standard deviations of its long-term average. For −3.0 standard deviations the probability of excess canopy mortality was 91.6% (83.8–97.5%). Overall, drought caused approximately 500,000 ha of excess forest mortality between 1987 and 2016 in Europe. We here provide evidence that drought is an important driver of tree mortality at the continental scale, and suggest that a future increase in drought could trigger widespread tree mortality in Europe.

scholarly journals Increased climate pressure on the agricultural frontier in the Eastern Amazonia–Cerrado transition zone

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
José A. Marengo ◽  
Juan C. Jimenez ◽  
Jhan-Carlo Espinoza ◽  
Ana Paula Cunha ◽  
Luiz E. O. Aragão
Keyword(s):  
Transition Zone ◽  
Large Scale ◽  
Vapor Pressure Deficit ◽  
Environmental Changes ◽  
Severe Drought ◽  
Wet Season ◽  
Agricultural Frontier ◽  
Global Food Security ◽  
Drought Conditions ◽  
Global Food

AbstractSeveral large-scale drivers of both anthropogenic and natural environmental changes are interacting nonlinearly in the transition zone between eastern Amazonia and the adjacent Cerrado, considered to be another Brazilian agricultural frontier. Land-use change for agrobusiness expansion together with climate change in the transition zone between eastern Amazonia and the adjacent Cerrado may have induced a worsening of severe drought conditions over the last decade. Here we show that the largest warming and drying trends over tropical South America during the last four decades are observed to be precisely in the eastern Amazonia–Cerrado transition region, where they induce delayed wet-season and worsen severe drought conditions over the last decade. Our results evidence an increase in temperature, vapor pressure deficit, subsidence, dry-day frequency, and a decrease in precipitation, humidity, and evaporation, plus a delay in the onset of the wet season, inducing a higher risk of fire during the dry-to-wet transition season. These findings provide observational evidence of the increasing climatic pressure in this area, which is sensitive for global food security, and the need to reconcile agricultural expansion and protection of natural tropical biomes.

scholarly journals A Model to Assess Eastern Cottonwood Water Flow Using Adjusted Vapor Pressure Deficit Associated with a Climate Change Impact Application

Climate ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 22
Author(s):  
Ying Ouyang ◽  
Theodor D. Leininger ◽  
Heidi Renninger ◽  
Emile S. Gardiner ◽  
Lisa Samuelson
Keyword(s):  
Climate Change ◽  
South Carolina ◽  
Vapor Pressure ◽  
Large Scale ◽  
Vapor Pressure Deficit ◽  
Sap Flux ◽  
Sap Flux Density ◽  
Eastern Cottonwood ◽  
Flux Data ◽  
Effective Manner

Short-rotation woody crops have maintained global prominence as biomass feedstocks for bioenergy, in part due to their fast growth and coppicing ability. However, the water usage efficiency of some woody biomass crops suggests potential adverse hydrological impacts. Monitoring tree water use in large-scale plantations would be very time-consuming and cost-prohibitive because it would typically require the installation and maintenance of sap flux sensors and dataloggers or other instruments. We developed a model to estimate the sap flux of eastern cottonwood (Populus deltoides. Bartr. ex Marsh.)) grown in bioenergy plantations. This model is based on adjusted vapor pressure deficit (VPD) using Structural Thinking and Experiential Learning Laboratory with Animation (STELLA) software (Architect Version 1.8.2), and is validated using the sap flux data collected from a 4-year-old eastern cottonwood biomass production plantation. With R2 values greater than 0.79 and Nash Sutcliffe coefficients greater than 0.69 and p values < 0.001, a strong agreement was obtained between measured and predicted diurnal sap flux patterns and annual sap flux cycles. We further validated the model using eastern cottonwood sap flux data from Aiken, South Carolina, USA with a good agreement between method predictions and field measurements. The model was able to predict a typical diurnal pattern, with sap flux density increasing during the day and decreasing at night for a 5-year-old cottonwood plantation. We found that a 10% increase in VPD due to climate change increased the sap flux of eastern cottonwood by about 5%. Our model also forecasted annual sap flux characteristics of measured cycles that increased in the spring, reached a maximum in the summer, and decreased in the fall. The model developed here can be adapted to estimate sap flux of other trees species in a time- and cost-effective manner.

Effect of Mycorrhizal Fungi on Gas Exchange of Micropropagated Guava Plantlets (Psidium guajava L.) during Acclimatization and Plant Establishment

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 501c-501
Author(s):  
Andrés A. Estrada-Luna ◽  
Jonathan N. Egilla ◽  
Fred T. Davies
Keyword(s):  
Tissue Culture ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Vapor Pressure ◽  
Mycorrhizal Fungi ◽  
Vapor Pressure Deficit ◽  
Psidium Guajava ◽  
Glomus Etunicatum ◽  
Plant Establishment ◽  
Use Efficiency

The effect of mycorrhizal fungi on gas exchange of micropropagated guava plantlets (Psidium guajava L.) during acclimatization and plant establishment was determined. Guava plantlets (Psidium guajava L. cv. `Media China') were asexually propagated through tissue culture and acclimatized in a glasshouse for eighteen weeks. Half of the plantlets were inoculated with ZAC-19, which is a mixed isolate containing Glomus etunicatum and an unknown Glomus spp. Plantlets were fertilized with modified Long Ashton nutrient solution containing 11 (g P/ml. Gas exchange measurements included photosynthetic rate (A), stomatal conductance (gs), internal CO2 concentration (Ci), transpiration rate (E), water use efficiency (WUE), and vapor pressure deficit (VPD). Measurements were taken at 2, 4, 8 and 18 weeks after inoculation using a LI-6200 portable photosynthesis system (LI-COR Inc. Lincoln, Neb., USA). Two weeks after inoculation, noninoculated plantlets had greater A compared to mycorrhizal plantlets. However, 4 and 8 weeks after inoculation, mycorrhizal plantlets had greater A, gs, Ci and WUE. At the end of the experiment gas exchange was comparable between noninoculated and mycorrhizal plantlets.

scholarly journals Documentary data and the study of past droughts: a global state of the art

2018 ◽  
Vol 14 (12) ◽  
pp. 1915-1960 ◽  
Author(s):  
Rudolf Brázdil ◽  
Andrea Kiss ◽  
Jürg Luterbacher ◽  
David J. Nash ◽  
Ladislava Řezníčková
Keyword(s):  
Large Scale ◽  
State Of The Art ◽  
Drought Indices ◽  
Documentary Evidence ◽  
Climatic Trends ◽  
Instrumental Observations ◽  
Spatio Temporal ◽  
Epigraphic Evidence ◽  
Administrative Evidence

Abstract. The use of documentary evidence to investigate past climatic trends and events has become a recognised approach in recent decades. This contribution presents the state of the art in its application to droughts. The range of documentary evidence is very wide, including general annals, chronicles, memoirs and diaries kept by missionaries, travellers and those specifically interested in the weather; records kept by administrators tasked with keeping accounts and other financial and economic records; legal-administrative evidence; religious sources; letters; songs; newspapers and journals; pictographic evidence; chronograms; epigraphic evidence; early instrumental observations; society commentaries; and compilations and books. These are available from many parts of the world. This variety of documentary information is evaluated with respect to the reconstruction of hydroclimatic conditions (precipitation, drought frequency and drought indices). Documentary-based drought reconstructions are then addressed in terms of long-term spatio-temporal fluctuations, major drought events, relationships with external forcing and large-scale climate drivers, socio-economic impacts and human responses. Documentary-based drought series are also considered from the viewpoint of spatio-temporal variability for certain continents, and their employment together with hydroclimate reconstructions from other proxies (in particular tree rings) is discussed. Finally, conclusions are drawn, and challenges for the future use of documentary evidence in the study of droughts are presented.

scholarly journals Current Wildland Fire Patterns and Challenges in Europe: A Synthesis of National Perspectives

2021 ◽  
Vol 14 ◽  
pp. 117862212110281
Author(s):  
Nieves Fernandez-Anez ◽  
Andrey Krasovskiy ◽  
Mortimer Müller ◽  
Harald Vacik ◽  
Jan Baetens ◽  
...  
Keyword(s):  
Land Use ◽  
Large Scale ◽  
Wildland Fire ◽  
Human Life ◽  
Local Analysis ◽  
Wildland Fires ◽  
Fire Statistics ◽  
Quantitative Evidence ◽  
Wide Range ◽  
Fire Patterns

Changes in climate, land use, and land management impact the occurrence and severity of wildland fires in many parts of the world. This is particularly evident in Europe, where ongoing changes in land use have strongly modified fire patterns over the last decades. Although satellite data by the European Forest Fire Information System provide large-scale wildland fire statistics across European countries, there is still a crucial need to collect and summarize in-depth local analysis and understanding of the wildland fire condition and associated challenges across Europe. This article aims to provide a general overview of the current wildland fire patterns and challenges as perceived by national representatives, supplemented by national fire statistics (2009–2018) across Europe. For each of the 31 countries included, we present a perspective authored by scientists or practitioners from each respective country, representing a wide range of disciplines and cultural backgrounds. The authors were selected from members of the COST Action “Fire and the Earth System: Science & Society” funded by the European Commission with the aim to share knowledge and improve communication about wildland fire. Where relevant, a brief overview of key studies, particular wildland fire challenges a country is facing, and an overview of notable recent fire events are also presented. Key perceived challenges included (1) the lack of consistent and detailed records for wildland fire events, within and across countries, (2) an increase in wildland fires that pose a risk to properties and human life due to high population densities and sprawl into forested regions, and (3) the view that, irrespective of changes in management, climate change is likely to increase the frequency and impact of wildland fires in the coming decades. Addressing challenge (1) will not only be valuable in advancing national and pan-European wildland fire management strategies, but also in evaluating perceptions (2) and (3) against more robust quantitative evidence.

Sign in / Sign up

Export Citation Format

Share Document