scholarly journals The Impact of Drought Stress on the Height Growth of Young Norway Spruce Full-Sib and Half-Sib Clonal Trials in Sweden and Finland

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 498
Author(s):  
Haleh Hayatgheibi ◽  
Matti Haapanen ◽  
Jenny Lundströmer ◽  
Mats Berlin ◽  
Katri Kärkkäinen ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Additive Genetic Variance ◽  
Height Growth ◽  
Severe Drought ◽  
Summer Drought ◽  
Good Growth ◽  
Genotype By Environment ◽  
Genetic And Phenotypic Correlations ◽  
The Impact ◽  
Selection Of

The summer drought of 2018 was one of the most climatically severe events in Europe that led to record-breaking temperatures and wildfires in many parts of Europe. The main objective of this study was to assess the impact of the 2018 drought on the phenotypic and genetic response of Norway spruce height growth using the Standardized Precipitation-Evapotranspiration Index (SPEI). To achieve this, the total cumulative height growth of about 6000 clones from 2016 to 2019 in four full-sib trials in Sweden, aged 6–7 years, and from 2017 to 2019 in two half-sib trials in Finland, aged 8–9 years, were measured. The results indicate that the 2018 drought caused reductions in the increment of trees. Although heritability estimates were similar to other reports for Norway spruce, the additive genetic variance was highly inflated in one of the visibly drought-damaged trials in Southern Sweden. Similarly, the genotype by environment (G × E) interaction was highly significant in the drought-damaged Southern Swedish trials. Both additive genetic and phenotypic correlations obtained between height increments in 2019 and final heights were the weakest in all studied trials, implying that the drought legacies might have influenced the recovery of trees in 2019. We may conclude that the severe drought can be an underlying factor for a strong G × E interaction and changes in the ranking of genotypes. Therefore, a selection of drought-resistant genotypes with a good growth capacity tested in variables sites should be considered as an important criterion for future breeding of Norway spruce.

scholarly journals The impact of drought on total ozone flux in a mountain Norway spruce forest

2020 ◽  
Vol 66 (No. 7) ◽  
pp. 280-278 ◽  
Author(s):  
Thomas Agyei ◽  
Stanislav Juráň ◽  
Kojo Kwakye Ofori-Amanfo ◽  
Ladislav Šigut ◽  
Otmar Urban ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Stomatal Closure ◽  
Severe Drought ◽  
Summer Drought ◽  
Spruce Forest ◽  
Soil Humidity ◽  
Drought Period ◽  
The Impact ◽  
Mild Drought ◽  
Norway Spruce Forest

In order to understand the impact of summer drought on dry deposition of tropospheric ozone (O<sub>3</sub>), we compared severe and mild drought periods of summer 2018 in a mountain Norway spruce forest at Bílý Kříž, Beskydy Mts. An eddy covariance technique was applied to measure diurnal courses of the ecosystem O<sub>3</sub> and CO<sub>2</sub> fluxes. Low O<sub>3</sub> deposition was recorded in the morning and evening, while the highest CO<sub>2</sub> and O<sub><sup>3</sup></sub> fluxes were recorded during the central hours of the day. Total O<sub>3</sub> deposition during severe drought (soil humidity 13%) was significantly higher than the deposition during the mild drought period (soil humidity 19%). Our data indicate that high vapour pressure deficit and low soil humidity during severe drought led to the stomatal closure, while non-stomatal O<sub>3</sub> deposition, associated with chemical reactions of O<sub>3</sub> with NO and volatile organic compounds, are responsible for higher total O<sub>3</sub> deposition during the severe drought period. Therefore, we assume that under severe drought stomatal O<sub>3</sub> uptake decreases but non-stomatal depositions to forest ecosystems substantially increase.

scholarly journals Standardized Drought Indices for Pre-Summer Drought Assessment in Tropical Areas

Atmosphere ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1209
Author(s):  
David Romero ◽  
Eric Alfaro ◽  
Roger Orellana ◽  
Maria-Engracia Hernandez Cerda
Keyword(s):  
Vegetation Index ◽  
Temporal Variations ◽  
Climatic Conditions ◽  
Drought Indices ◽  
Drought Severity ◽  
Severe Drought ◽  
Summer Drought ◽  
Tropical Zone ◽  
Drought Assessment ◽  
The Impact

The main climatic indices used for the determination of pre-summer drought severity were developed for temperate zones with very different climatic conditions from those found in the tropical climate zones, particularly with respect to seasonal rainfall variations. The temporal evolution of pre-summer drought leads the authors to compute the indices for each year over a defined period according to the climatic normals of each meteorological station and to consider the months inside the dry episode differently, according to the law of emptying the water reserves. As a function of this, standardized drought indices are proposed for the evaluation of the pre-summer drought in tropical zone. Two new indices were tested: one developed from precipitation and the other also considering temperature. These indices were validated by correlation with Advanced very-high-resolution radiometer (AVHRR) normalized difference vegetation index (NDVI) time series and used to identify the most severe drought conditions in the Yucatan Peninsula. The comparison between the indices and their temporal variations highlighted the importance of temperature in the most critical events and left indications of the impact of global warming on the phenomenon.

scholarly journals Impacts of extreme summers on European ecosystems: a comparative analysis of 2003, 2010 and 2018

2020 ◽  
Vol 375 (1810) ◽  
pp. 20190507 ◽  
Author(s):  
A. Bastos ◽  
Z. Fu ◽  
P. Ciais ◽  
P. Friedlingstein ◽  
S. Sitch ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Gross Primary Production ◽  
Severe Drought ◽  
Summer Drought ◽  
Climate Anomalies ◽  
Continental Scale ◽  
Vegetation Models ◽  
Global Vegetation ◽  
Autumn And Winter ◽  
The Impact

In Europe, three widespread extreme summer drought and heat (DH) events have occurred in 2003, 2010 and 2018. These events were comparable in magnitude but varied in their geographical distribution and biomes affected. In this study, we perform a comparative analysis of the impact of the DH events on ecosystem CO 2 fluxes over Europe based on an ensemble of 11 dynamic global vegetation models (DGVMs), and the observation-based FLUXCOM product. We find that all DH events were associated with decreases in net ecosystem productivity (NEP), but the gross summer flux anomalies differ between DGVMs and FLUXCOM. At the annual scale, FLUXCOM and DGVMs indicate close to neutral or above-average land CO 2 uptake in DH2003 and DH2018, due to increased productivity in spring and reduced respiration in autumn and winter compensating for less photosynthetic uptake in summer. Most DGVMs estimate lower gross primary production (GPP) sensitivity to soil moisture during extreme summers than FLUXCOM. Finally, we show that the different impacts of the DH events at continental-scale GPP are in part related to differences in vegetation composition of the regions affected and to regional compensating or offsetting effects from climate anomalies beyond the DH centres. This article is part of the theme issue ‘Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale’.

scholarly journals Impact of the European Russia drought in 2010 on the Caspian Sea level

2011 ◽  
Vol 8 (4) ◽  
pp. 7781-7803
Author(s):  
K. Arpe ◽  
S. A. G. Leroy ◽  
H. Lahijani ◽  
V. Khan
Keyword(s):  
Sea Level ◽  
Caspian Sea ◽  
Analysis Data ◽  
Volga Basin ◽  
European Russia ◽  
Severe Drought ◽  
Summer Drought ◽  
The Caspian Sea ◽  
Volga River ◽  
The Impact

Abstract. The hydrological budgets of the Volga basin (VB) and the Caspian Sea (CS) have been established. The components of the water balance for the CS were calculated for the period 1993 to 2010 with emphasis on summer 2010 when a severe drought developed over European Russia. A drop in precipitation over the VB in July 2010 occurs simultaneously with a decrease in evaporation for the same area, an increase of evaporation over the CS itself and a drop of the Caspian Sea Level (CSL). The drop in the precipitation over the VB cannot have led to an instantaneous drop of the CSL because the precipitated water needs some months to reach the CS. The delay is estimated to be 1 to 3 months for excessive precipitation in summer, longer for other cases. However, the evaporation over the CS itself is considered to be responsible for a simultaneous drop of the CSL from July to September 2010. The impact on the CSL from the precipitation deficit over the VB occurs in the months following the drought. The water deficit from July to September 2010 calculated from the anomalous precipitation minus evaporation over the VB would decrease the CSL by 22 cm, of which only 2 cm had been observed until end of September (observed Volga River discharge anomaly), 7 cm from October to the end of 2010 and another 5 cm to the end of May 2011. From October 2010 to February 2011 excessive precipitation occurred over the Volga basin, equivalent to an increase of the CSL of 7 cm which might just compensate the 7 cm of the remaining deficit from the summer drought. A deficit of water took however already place in the months before July 2010. In previous studies the precipitation over the VB has been identified as the main cause for CSL changes, but here from a 10 cm drop from beginning of July to end of September, 6 cm can be directly assigned to the enhanced evaporation over the CS itself and 2 cm due to reduced precipitation over the CS. Further periods with strong changes of the CSL are investigated as well which provide some estimates concerning the accuracy of the analysis data. The investigation was possible due to the new ECMWF interim reanalysis data which are used to provide data also for sensitive quantities like surface evaporation and precipitation. The comparison with independent data and the consistency between such data for calculating the water budget over the CS gives a high confidence in the quality of the data used. This investigation provides some scope for making forecasts of the CSL few months ahead to allow for mitigating societal impacts.

scholarly journals The Mesoamerican mid-summer drought: the impact of its definition on occurrences and recent changes

2021 ◽  
Author(s):  
Edwin P. Maurer ◽  
Iris T. Stewart ◽  
Kenneth Joseph ◽  
Hugo G. Hidalgo
Keyword(s):  
Historical Record ◽  
Climate Projections ◽  
Summer Drought ◽  
Seasonal Forecasts ◽  
Drought Pattern ◽  
The Caribbean ◽  
The Impact ◽  
Minimum Intensity ◽  
Selection Of

Abstract. The mid-summer drought, veranillo or canícula, is a phenomenon experienced in many areas, including Mexico, Central America, and the Caribbean. It generally is experienced as reduced rainfall in July–August, in the middle of the typical rainy season (May–September). Many past studies have attempted to quantify changes in mid-summer drought characteristics during the recent past or for future climate projections. To do this, objective definitions of a mid-summer drought’s occurrence, strength and duration have been developed by many researchers. In this effort we adopt a recent set of definitions and examine the impact of varying these on the characterization of mid-summer droughts and the detected changes over the past four decades. We find the selection of a minimum intensity threshold has a dramatic effect on the results of both the area considered as experiencing a mid-summer drought and the changes detected in the recent historical record. The intensity chosen can affect both the magnitude and direction of changes reported in the recent observed record. Further, we find that the typical mid-summer drought pattern may not be occurring during the time it has historically; whether examining past or future changes or developing improved seasonal forecasts, the non-stationarity of its timing should be accommodated.

scholarly journals The impact of occasional drought periods on vegetation spread and greenhouse gas exchange in rewetted fens

2020 ◽  
Vol 375 (1810) ◽  
pp. 20190685
Author(s):  
Franziska Koebsch ◽  
Pia Gottschalk ◽  
Florian Beyer ◽  
Christian Wille ◽  
Gerald Jurasinski ◽  
...  
Keyword(s):  
Carbon Sink ◽  
Severe Drought ◽  
Summer Drought ◽  
Theme Issue ◽  
Vegetation Development ◽  
Continental Scale ◽  
Rapid Spread ◽  
Carry Over ◽  
The Impact

Peatland rewetting aims at stopping the emissions of carbon dioxide (CO 2 ) and establishing net carbon sinks. However, in times of global warming, restoration projects must increasingly deal with extreme events such as drought periods. Here, we evaluate the effect of the European summer drought 2018 on vegetation development and the exchange of methane (CH 4 ) and CO 2 in two rewetted minerotrophic fens (Hütelmoor—Hte and Zarnekow—Zrk) including potential carry-over effects in the post-drought year. Drought was a major stress factor for the established vegetation but also promoted the rapid spread of new vegetation, which will likely gain a lasting foothold in Zrk. Accordingly, drought increased not only respiratory CO 2 losses but also photosynthetic CO 2 uptake. Altogether, the drought reduced the net CO 2 sink in Hte, while it stopped the persistent net CO 2 emissions of Zrk. In addition, the drought reduced CH 4 emissions in both fens, though this became most apparent in the post-drought year and suggests a lasting shift towards non-methanogenic organic matter decomposition. Occasional droughts can be beneficial for the restoration of the peatland carbon sink function if the newly grown vegetation increases CO 2 sequestration in the long term. Nonetheless, care must be taken to prevent extensive peat decay. This article is part of the theme issue ‘Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.

scholarly journals Variability of Norway spruce morphometric characteristics in progeny tests in Bosnia and Herzegovina

2016 ◽  
pp. 11-34 ◽  
Author(s):  
Branislav Cvjetkovic ◽  
Milan Mataruga ◽  
Mirjana Sijacic-Nikolic ◽  
Vojislav Dukic ◽  
Vladan Popovic
Keyword(s):  
Norway Spruce ◽  
Bosnia And Herzegovina ◽  
Natural Populations ◽  
Height Growth ◽  
Progeny Test ◽  
Morphometric Characteristics ◽  
Progeny Tests ◽  
The Impact ◽  
Root Collar ◽  
Growth Of Seedlings

The paper presents the results of an analysis of morphometric characteristics of Norway spruce seedlings in the progeny tests in Bosnia and Herzegovina, localities: Drinic and Srebrenica. Progeny tests were established by using seedlings originating from six natural populations from Bosnia and Herzegovina. Seedling height, root collar and whorl distance from the ground, which represents seedling heights in 2011, 2012 and 2013 were measured. The results indicate statistically significant differences between the analyzed characteristics of the observed population. Especially interesting are the populations Potoci and Olovo, which showed the highest growth during the observed period in both progeny tests. The impact of the drought in 2013 can be seen in the progeny test in Srebrenica where height growth in 2013 was lower by more than 50% in comparison to 2012. The impact of drought in the progeny test in Drinic was not observed. The research provides the baseline when selecting the starting population, where the rapid growth of seedlings is set as the main goal.

scholarly journals Importance of light conditions for the height growth of underplatings in Norway spruce stands in the Oravské Beskydy Mts.

Beskydy ◽  
2013 ◽  
Vol 6 (1) ◽  
pp. 53-58 ◽  
Author(s):  
P. Jaloviar ◽  
M. Saniga ◽  
S. Kucbel
Keyword(s):  
Norway Spruce ◽  
Natural Regeneration ◽  
Basal Area ◽  
Height Growth ◽  
Crown Architecture ◽  
Stem Number ◽  
Site Factor ◽  
Spruce Stands ◽  
Main Component ◽  
The Impact

The study analyses the relationships between the components of relative irradiance and density of parent Norway spruce stand as well as the impact of light on height growth and crown architecture of beech and fir underplantings and natural regeneration of spruce. We observed three variants of regeneration: fir underplanting, beech underplanting and spruce natural regeneration. For each variant three circular research plots with the size 500 m2 were established. To determine the intensity of relative irradiance 15 hemispherical photographs in the height of 1.5 m were taken for each variant. The analysis confirmed a significant relationship only between indirect site factor (ISF) and basal area and partly stem number of parent stand. There is almost no influence of spruce overstorey density (within the observed range of basal area and stem number) on the values of total site factor (TSF) and its main component direct site factor (DSF). The relevant predictor for the height increments of underplanted saplings is ISF. Relationship between TSF and height increment is weak. Apical dominance ratio (ADR) that was used to characterize crown architecture is significantly correlated with ISF only for beech and fir. In the case of spruce, increase of light intensity in the observed range does not lead to a significant change of saplings crown architecture.

Methods for Restricting Maximum Exposure Rate in Computerized Adaptative Testing

Methodology ◽  
2007 ◽  
Vol 3 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Juan Ramon Barrada ◽  
Julio Olea ◽  
Vicente Ponsoda
Keyword(s):  
Measurement Accuracy ◽  
Computerized Adaptive Testing ◽  
Computation Time ◽  
Adaptive Testing ◽  
Exposure Rate ◽  
Control Parameters ◽  
The Impact ◽  
Two Alternatives ◽  
Selection Of ◽  
Maximum Exposure

Abstract. The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method ( Revuelta & Ponsoda, 1998 ), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy.

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