scholarly journals Effects of extremely high temperatures on some growth parameters of sessile oak (Quercus petraea/Matt./Liebl.) seedlings in northeastern Serbia

2018 ◽  
Vol 70 (3) ◽  
pp. 521-529 ◽  
Author(s):  
Milun Krstic ◽  
Branko Kanjevac ◽  
Violeta Babic

This paper presents research results on the effects of the extremely high temperatures during the heat wave of August 2017 on the growth and development of injury symptoms in sessile oak (Quercus petraea /Matt./Liebl.) seedlings of different age in the area of the Majdanpek municipality in northeastern Serbia. The starting hypotheses of this study is that the resistance of sessile oak seedlings to extremely high temperatures changes with age and that the stand canopy has a significant protective role in situations where sessile oak seedlings are endangered by extremely high temperatures. The extreme weather conditions at the beginning of August manifested themselves in extremely high temperatures and prolonged absence of precipitation. The average temperature at the beginning of August 2017 was 5.0 to 5.1o? (depending on the altitude) higher compared to the period of seedling growth (2010-2016). During the heat wave, the recorded precipitation was in the range from 0 to 1 mm. These climate conditions significantly affected the development of young seedlings, causing wilting of smaller or larger parts of the leaf surface and sometimes leading to plant death. Using analysis of variance, differences in the intensity of seedling damage were found to depend on age, height, and the protection provided by the mature stand canopy. The obtained results point to the very important role of mature trees in the protection of seedlings from the dangers of extremely high temperatures.

2020 ◽  
Vol 40 (12) ◽  
pp. 1648-1667
Author(s):  
Leila Arab ◽  
Stefan Seegmueller ◽  
Michael Dannenmann ◽  
Monika Eiblmeier ◽  
Ghada Albasher ◽  
...  

Abstract Due to climate change, sessile oak (Quercus petraea) seedlings experience an increasing risk of drought during regeneration of forest stands by management practices. The present study was aimed at elucidating the potential of sessile oak seedlings originating from sites with different aridity and nitrogen (N) supply to acclimate to contrasting water availability. For this purpose, a free-air cross-exchange experiment was conducted between a dry and a humid forest stand with high and low soil N contents, respectively, during two consecutive years differing in aridity before harvest. Almost all structural and physiological foliar traits analyzed did not differ consistently between seed origins during both years, when cultivated at the same site. As an exception, the arid provenance upregulated foliar ascorbate contents under drought, whereas the humid provenance accumulated the phenolic antioxidants vescalagin and castalagin (VC) under favorable weather conditions and consumed VC upon drought. Apparently, differences in long-term aridity at the forest sites resulted in only few genetically fixed differences in foliar traits between the provenances. However, structural and physiological traits strongly responded to soil N contents and weather conditions before harvest. Foliar N contents and their partitioning were mostly determined by the differences in soil N availability at the sites, but still were modulated by weather conditions before harvest. In the first year, differences in aridity before harvest resulted in differences between most foliar traits. In the second year, when weather conditions at both sites were considerably similar and more arid compared to the first year, differences in foliar traits were almost negligible. This pattern was observed irrespective of seed origin. These results support the view that leaves of sessile oak seedlings generally possess a high plasticity to cope with extreme differences in aridity by immediate acclimation responses that are even better developed in plants of arid origin.


2006 ◽  
Vol 26 (6) ◽  
pp. 759-766 ◽  
Author(s):  
H. Folzer ◽  
J. F. Dat ◽  
N. Capelli ◽  
D. Rieffel ◽  
P.-M. Badot

Trees ◽  
2021 ◽  
Author(s):  
Leila Arab ◽  
Stefan Seegmueller ◽  
Jürgen Kreuzwieser ◽  
Monika Eiblmeier ◽  
Michael Dannenmann ◽  
...  

Abstract Key message Sessile oak leaves showed a high degree of plasticity to atmospheric and pedospheric conditions. Abstract The aim of the present study was to elucidate the significance of current weather conditions for foliar traits of adult sessile oak (Quercus petraea), one of the most valuable forest tree species in Central Europe. For this purpose, structural and functional traits were analysed in fully expanded, sun exposed leaves collected in south-west Germany from five old-growth forest stands, representing the meteorological and pedospheric conditions in the growing region, but differing in aridity during the 12 days before harvest in two consecutive years. Across the forest stands, most foliar traits differed significantly between wet and dry weather conditions before harvest as indicated by partial least square discriminant analysis (PLS-DA). These traits included fresh weight/dry weight ratio, leaf hydration, leaf-C content, leaf-C/N ratio, structural N, soluble protein-N, total amino acid-N, cell wall composition, numerous specific amino acids as well as soluble sugar content. Structural biomass, δ13C signature, total N and total C as well as H2O2 contents were not affected by the weather before harvest. These results indicate a high plasticity of the foliar metabolism of drought-tolerant sessile oak to current weather conditions. They also suggest that sessile oak is characterized by a high potential to cope with the growth conditions expected as a consequence of future climate change.


2021 ◽  
Vol 72 (1) ◽  
pp. 79-87
Author(s):  
Nenad Radaković ◽  
Branko Stajić

In this article, the dependence of the sessile oak (Quercus petraea (Matt.) Liebl.) radial growth (tree-ring, earlywood, and latewood widths) on climate (the mean monthly temperature and precipitation totals) was studied in the Majdanpek area, north-eastern Serbia. The growth response of the oak trees to the prevailing climate conditions was dendroecologically investigated, by applying the correlation and response function, as well as by pointer years analysis. The site chronology covered 159 years (1855-2013). We found that latewood and total tree-ring width contain the imprinted positive response to the amount of precipitation in summer months (June and July) of the current growing season. The earlywood width showed no direct dependence on climate data, but it was significantly affected by the previous-year latewood width. Moreover, 40 % of the variation in the latewood width is explained by the earlywood variation in the same season. The temperature was not found to have any significant effect on the growth of oak at the study site. The use of pointer years, determined by applying several calculation procedures, has highlighted previous results, indicating that the precipitation in summer months was the deciding climate factor leading to the occurrence of the years with exceptionally wide or narrow tree-rings and latewood. To enhance our understanding of the response of the sessile oak growth at south-oriented sites with a shallow soil profile to precipitation and temperature variations, and expand the current database and knowledge, future studies should be undertaken.


2020 ◽  
pp. 28-33
Author(s):  
Valery Genadievich Popov ◽  
Andrey Vladimirovich Panfilov ◽  
Yuriy Vyacheslavovich Bondarenko ◽  
Konstantin Mikhailovich Doronin ◽  
Evgeny Nikolaevih Martynov ◽  
...  

The article analyzes the experience of the impact of the system of forest belts and mineral fertilizers on the yield of spring wheat, including on irrigated lands. Vegetation irrigation is designed to maintain the humidity of the active soil layer from germination to maturation at the lower level of the optimum-70-75%, and in the phases of tubulation-earing - flowering - 75-80% NV. However, due to the large differences in zones and microzones of soil and climate conditions and due to the weather conditions of individual years, wheat irrigation regimes require a clear differentiation. In the Volga region in the dry autumn rainfalls give the norm of 800-1000 m3/ha, and in saline soils – 1000-1300 and 3-4 vegetation irrigation at tillering, phases of booting, earing and grain formation the norm 600-650 m3/ha. the impact of the system of forest belts, mineral fertilizers on the yield of spring wheat is closely tied to the formation of microclimate at different distances from forest edges.


Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3030
Author(s):  
Simon Liebermann ◽  
Jung-Sup Um ◽  
YoungSeok Hwang ◽  
Stephan Schlüter

Due to the globally increasing share of renewable energy sources like wind and solar power, precise forecasts for weather data are becoming more and more important. To compute such forecasts numerous authors apply neural networks (NN), whereby models became ever more complex recently. Using solar irradiation as an example, we verify if this additional complexity is required in terms of forecasting precision. Different NN models, namely the long-short term (LSTM) neural network, a convolutional neural network (CNN), and combinations of both are benchmarked against each other. The naive forecast is included as a baseline. Various locations across Europe are tested to analyze the models’ performance under different climate conditions. Forecasts up to 24 h in advance are generated and compared using different goodness of fit (GoF) measures. Besides, errors are analyzed in the time domain. As expected, the error of all models increases with rising forecasting horizon. Over all test stations it shows that combining an LSTM network with a CNN yields the best performance. However, regarding the chosen GoF measures, differences to the alternative approaches are fairly small. The hybrid model’s advantage lies not in the improved GoF but in its versatility: contrary to an LSTM or a CNN, it produces good results under all tested weather conditions.


2017 ◽  
Vol 77 (1) ◽  
pp. 22-28 ◽  
Author(s):  
E. Foelkel ◽  
M. Voss ◽  
L. B. Monteiro ◽  
G. Nishimura

Abstract Entomopathogenic nematodes (EPNs) are a promising alternative to integrated control in many fruit pests. Few studies were made on the relationship of Anastrepha fraterculus natural population with native EPNs population and other biotic and abiotic factors. The aim of this work was to verify the occurrence of endemic nematodes in an apple orchard, concerning environmental conditions and technical procedure, and access isolates virulence to A. fraterculus larvae. The experiment was conducted during a year taking monthly soil samples from an apple orchard, with and without fallen fruits just above the soil. Samples were baited with Tenebrium molitor and A. fraterculus larvae in laboratory. Canopy and fallen fruits were sampled to access the pest infestation. Seventy three EPN isolates were captured, in 23.2% soil samples, more with T. molitor than with A. fraterculus baits. From the 20 isolates tested against A. fraterculus, only five were pathogenic, and they were identified as Oscheius sp. The nematodes were captured during all seasons in a similar frequency. Soil and weather conditions, presence of fruit over the orchard soil, and A. fraterculus pupae in the fruits had no significant influence on the capture. As a conclusion, nematodes of the genera Oscheius are found in an apple orchard of Porto Amazonas constantly along the year, independently of fluctuations in A. fraterculus population, climate conditions and presence of fruit over the soil. Some of the isolates are pathogenic to A. fraterculus.


2000 ◽  
Vol 78 (12) ◽  
pp. 1531-1544 ◽  
Author(s):  
Eric Nicolini ◽  
Daniel Barthélémy ◽  
Patrick Heuret

The growth and branching patterns of the main axis of 6-year-old sessile oak, growing in a natural regeneration in the north of France, were analysed each year retrospectively according to three increasing canopy density conditions: large gap, small gap, and dense canopy. Increasing gap size is associated with an increase in the total height, basal diameter, branching probability, and global polycyclism rate of the trees. At the growth unit or annual shoot level, from dense canopy to large gaps these botanical entities also show an increase in their total length, number of nodes, polycyclism, and branching rate as well as mean number of branches and mean internode length. A discussion of our results revealed some endogenous features of growth and branching patterns in young sessile oak trees. It is also shown that increasing canopy density generally tends to reduce the expression of the endogenous architectural sequence of differentiation of young sessile oak trees. Young trees growing below dense canopy thus seem to be "delayed" in their sequence of differentiation and appear to be in a "waiting" status, whereas young trees growing in large gaps exhibit an architecture very similar to trees growing in nurseries under nonlimiting growth conditions.Key words: architecture, Quercus petraea, growth, morphology, canopy density.


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