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Analysis of COVID-19 Lockdown to Understand Air Pollution Processes and Their Impacts on Health: A Case Study in the Western Balkans
No full textThe effect of COVID-19 lockdown (LD) on many ambient air pollutants (NO,
NO2, PM2.5, PM10, O3 and SO2) was assessed for the first time in the Western Balkans
with an innovative approach that evaluates a variety of factors including the stringency
of the LD measures, the type of location, the pollution sources, the correlation with traffic
fluxes and the meteorology. To that end, observations from 10 urban sites were compared
with historical time series. The time window 1 February–30 May 2020 was classified in
sub-periods on the basis of the stringency of the circulation restrictions. NO2 and O3 are the
pollutants most affected by restrictions to population circulation due to lockdown during
the first phase of the COVID-19 pandemic, and are well correlated with traffic fluxes. A
reduction in fine particulate matter (PM2.5 and PM10) concentrations is observed in all sites
only during the full LD periods, while the relation between SO2 average and maximum
hourly concentrations and LD periods in industrial and traffic sites vary from site to site.
The reduction in NO2 concentrations during the LD resulted in a reduction in mortality
associated with air pollution in the largest cities, while the interpretation of the changes in
O3 and particulate matter is less clear
A Historical Overview of Methods for the Estimation of Erosion Processes on the Territory of the Republic of Serbia
No full textErosion is a significant environmental challenge in Serbia, shaped by natural
and human factors. Pronounced relief, fragile geological substrate, a developed hydrographic network, and a climate characterized by an uneven distribution of precipitation
throughout the year make this area prone to activating erosion processes and flash floods
whenever there is a significant disruption in ecological balance, whether due to the removal
of vegetation cover or inadequate land use. Researchers have recorded approximately
11,500 torrents in Serbia, most of which were activated during the 19th century, a period of
significant social and political change, as well as intensive deforestation and the irrational
exploitation of natural resources. By the mid-19th century, the effects of land degradation
were impossible to ignore. As the adequate assessment of soil erosion intensity is the
initial step in developing a prevention and protection strategy and the type and scope of
anti-erosion works and measures, this article presents the path that the anti-erosion field in
Serbia has taken from the initial observations of erosion processes through the first attempts
to create the Barren Land Cadastre and Torrent Cadastre to the creation of the Erosion
Potential Method (EPM) and its modification by Dr. Lazarevi´c that resulted in the creation
of the first Erosion Map of SR Serbia in 1971 (published in 1983). In 2020, a new Erosion
Map of Serbia was created with the application of Geographic Information System (GIS)
technologies and based on the original method by Professor Slobodan Gavrilovi´c—the
EPM—without the modifications introduced by Lazarevi´c. We compared the 1983 and 2020
erosion maps in a GIS environment, where the change in soil erosion categories was analyzed using a confusion matrix. The updated erosion maps mirror the shift in methodology
from a traditional approach (Lazarevi´c’s modification) to the modern GIS-based method
(Gavrilovi´c’s original EPM) and reflect technological improvements and changes in land
use, conservation practices, and environmental awareness
Bioecological characteristics of Iceland with reference to national parks
No full textOtrvo Island se nalazi u severnom Atlantiku blizu arktičkog kruga, sa ukupnom površinom od oko 103.000 km2 . Geografski položaj ostrva utiče na specifičnu oštru subarktičku klimu. Fitogeografski gledano, Island se nalazi u području Holarktičkog florističkog carstva i deo je njegove Arktičke provincije Cirkumborealne regije. Najveći deo zemlje nalazi se u zoni tundre. Biljni pokrivač na ostrvu je dosta redak i tek jedna četvrtina teritorije je obrasla stabilnim vegetacijskim pokrivačem, dok je na najvećem delu površine izuzetno redak. Neobradivo i neplodno zemljište (peščana polja, izlivi lave, lednici) obuhvataju 76,0% površine Islanda, pašnjaci i livade 22,7%, šume 1,2%, a obradivo je svega 0,1% površine. Na Islandu su izdvojena tri nacionalna parka: Þingvellir, Vatnajökull i Snæfellsjökull. Cilj istraživanja rada je da se opišu bioekološke karakteristike Islanda, sa posebnim osvrtom na specifičnosti nacionalnih parkov
The impact of tool height on the workpiece in wood cutting with circular saws
No full textThe tool height influences the cutting force by changing the angle at which the blade penetrates
the wood. This parameter was analyzed at two different heights. In the first set of measurements,
previously used to assess the bluntness of the tool, a sharp saw was positioned 3 mm above the
workpiece. The second set was also carried out with a sharp saw, but the height of the tool was set to
15 mm above the workpiece. In both cases, all other parameters were kept constant, so it was not
necessary to introduce the concept of specific cutting resistance.
By analyzing the average cutting forces, basic data was obtained showing that changing the saw
height changes the average fiber cutting angle. When the saw projected 3 mm beyond the workpiece,
the average cutting angle Φm was 21.25°; with a projection of 15 mm, Φm increased to 27.87°. A
significant difference is observed between these two configurations, with an average cutting angle
difference of 6.62º. The rake angle of the saw used in the analysis was 20º. This change in the average
fiber cutting angle explains the variation in the required cutting force under otherwise identical
conditions
Silicon mitigates combined pathogen and herbivore stress by affecting leaf nutritional traits and larval performance in oak
No full textThe beneficial role of silicon (Si) in enhancing plant resistance to insect herbivory and pathogen attackis well established. However, its effectiveness under simultaneous biotic stresses remains less explored.We developed a tri-trophic model system comprising pedunculate oak (Quercus robur L.), the rootpathogen Phytophthora plurivora T. Jung & T.I. Burgess, and gypsy moth (Lymantria dispar L.) larvae.Our study aimed to assess the effects of Si supplementation on leaf nutritional traits and larval feedingbehavior and performance. Silicon (+Si) was added as monosilicic acid (H4SiO4) in the amount of 100mg Si kg−1 dry soil, corresponding to a field application of about 150 kg Si ha−1. Concentrations ofphosphorus (P), boron (B), copper (Cu), iron (Fe), manganese (Mn), zinc (Zn), molybdenum (Mo),nickel (Ni), potassium (K), calcium (Ca), and magnesium (Mg) in oak leaves and larval midguts weremeasured by ICP-MS, while carbon (C), nitrogen (N), and sulfur (S) were determined via CNSelemental analysis. Larval performance was assessed using standard nutritional parameters: relativeconsumption rate (RCR), relative growth rate (RGR), approximate digestibility (AD), and efficienciesof conversion of ingested and digested food into biomass (ECI and ECD, respectively). Although theinfection by P. plurivora significantly decreased leaf concentrations of P, S, N, Mo, and Ni in −Si plants,larval performance was enhanced in this treatment, likely due to compensatory feeding and increaseddigestibility of weakened leaf tissues. Plant infection overall did not affect element concentrations(except for Ca and B) in the larval midgut. However, Si supplementation, especially under P.plurivora infection, significantly increased leaf Si accumulation, resulting in reduced leaf consumption(lower RCR), assimilation (lower AD), and conversion efficiencies (lower ECI and ECD), ultimatelysuppressing larval growth (lower RGR). In the midgut, Si treatment did not significantly affect thenutrients concentrations (apart from Ca and Ni) when larvae fed on noninfected plants, while, incontrast, it led to a general decline of nutrients (except S) when they fed on infected plants. Interestingly,this decline in midgut did not consistently reflect the induced changes in leaves. These resultsdemonstrate that soil Si application, particularly in the presence of pathogenic infection, can induce notonly the well-established antifeedant effects in leaves, but can also alter herbivore nutrient uptake,thereby affecting larval performance
Assessment of the productive potential of field elm for ex situ conservation in the protected area ”Zvezdarska šuma” (Belgrade, Serbia)
No full textIn Serbia, Ulmus minor Mill. (field elm) is categorized as a rare and endangered species, being impacted by Dutch elm disease. Within the protected area ”Zvezdarska šuma” (Belgrade, Serbia), remaining individual trees and small groups (59 georeferenced trees in total) persist in a fragmented spatial pattern, representing gene pool potentially valuable for the future species’ adaptive potential. This study aimed to assess the productive potential of field elm trees in the protected area ”Zvezdarska šuma” as a basis for ex situ conservation of the endangered gene pool. Hardwood cuttings were collected from 18 phenotypically healthy trees during FebruaryMarch 2025. The experimental setup for propagation was conducted in March 2025 under controlled glasshouse conditions, using containers (35x25x14 cm) filled with peat and perlite (1:4 ratio) as substrate and treated with rooting hormone (dry-dip method, 0.4% IBA). Following root initiation observed in May 2025, the plants were transferred to a controlled nursery environment for acclimatization. Preliminary data collected in June 2025 indicated significant variation in rooting success among 18 genotypes, with an average rooting rate of 18.44%, ranging from 10.00% to 45.31%. The productive potential of the test trees will be further assessed in a green cuttings clonal trial and a generative progeny test, both established in the nursery of the Faculty of Forestry in Belgrade. The results presented herein represent only the initial phase of ex situ conservation, which should be further expanded through the integration of in situ conservation methods and continuous monitoring of the existing gene pool
Invasive and allergenic plant species on running trails of Ada Ciganlija (Belgrade, Serbia)
No full textHigh attendance of visitors and recreational activities on running trails can affect the understory
vegetation and reduced lawn cover, further causing habitat destabilization and creating
favorable conditions for the rapid occupation by invasive plant species. Invasive plant species
represent a major problem and a hindrance to the biodiversity preservation, causing significant
and irreversible changes in the environment, primarily changes in the floristic structure and
succession of a vegetation. Running trails, from the point of users, should represent places of a
healthy environment, and the presence of allergenic plant species, especially those that cause
allergic manifestations through pollen, is not desirable.
Floristic research of lawns of Ada Ciganlija running trails are conducted whereas the total
number of 111 plant species determined, among which 15 are invasive (13,51%) and 24 are
allergenic (21,62%) plants. From the total of registered invasive plants Erigeron annuus and
Duchesnea indica stand out by their presence while Taraxacum officinale stands out among
allergenic plants. Taraxacum officinale is a plant which causes allergic contact dermatitis to a
certain number of people. Plants that cause pollen allergies dominate among the recorded
species and their synergy can have even a greater negative impact on the health of trail users.
According to the research results constant monitoring and control of invasive and allergenic
plant species is necessary. The results should provide the foundation for the development of a
strategy for monitoring of the state and planning of measures for the control or suppression of
unwanted species in the aim of protection of the autochthonous vegetation and especially the
health of the users of running trails and the entire recreational area of Ada Ciganlija. Proper
care and maintenance on time of green recreational areas are a preventive measure of
indisputable importance that will prevent the introduction and spread of invasive plant species,
i.e. the appearance and spread of pollen of allergenic plant
Hydrological regime of higrophilous forests on the islands along the Danube river
No full texthe alluvial plane of the Danube is a complex spatial-geography unit that is characterized by
specific pedological and hydrological features. Floodplain forests are ecosystems developing
along the banks of large rivers influenced by high groundwater levels and occassional flooding.
The scope of the paper is to restore the autochtonous vegetation and preserve the threatened
natural habitats of floodplain forests on the Danube islands. The most dominant species at this
area is Euroamerican poplar, which has a great market value, but its substitution by
reintroduction of autochtonous willow and poplar clones gives the advantage to ecology
compared to economics. Focus was on the analysis of the hydrological regime including both
surface water and groundwater. Water is a key ecological factor affecting development and
production of willows and poplars. Surface water in its immediate environment significantly
affects the hydrological regime of the first aquifer, while the amount of water that will reach
the aquifer zone largely depends on the pedological and vegetational characteristics. The
obtained results point to the fact that floodplain forests are a sensitive ecosystem, which means
that it is necessary to carry out permanent groundwater monitoring in order to define the amount
and level of water in the root system zone. Bearing in mind the global climate changes, which
are reflected in the alternation of extremely dry and wet years, the need for multi-year
monitoring of the hydrological regime is of a great significance in terms of implementing
adequate silviculture and management measures
Morphological and biochemical characteristics of the fruits of Malus hupehensis var. Pinyensis n.G.Jiang in Belgrade
No full textUsing an integrative approach, the morphological and biochemical characteristics of
fruits from three Malus hupehensis var. pinyensis Jiang. trees were analysed. The trees are located
in the pedestrian zone of the Stari Grad municipality, on Obilićev venac, in Belgrade. The variability
of the fruit morphometric characteristics was statistically significant and confirmed visual
observations that, with an increase in pedicel length, both fruit length and width decrease across all
trees. The second part of the research was based on the hypothesis that there are taxa with highquality fruits that provide ecosystem services. Therefore, the biochemical composition and
antioxidant capacity were determined from the fleshy parts of fresh fruits. The results highlight
ethanol as a solvent that more effectively extracts and enhances the potential of bioactive components.
In conclusion, Tea Crabapples are emphasised as valuable in landscape design due to their
ornamental appeal, ecological role and fruits with high added value
Regional variations and trends in poplar harvesting in Serbia (2013-2022)
No full textRad istražuje obim seče topole u državnim šumama Srbije za period 2013-2022. na osnovu podataka Republičkog zavoda za statistiku i Nacionalne inventure šuma. U delu materijala i metoda korišćeni su podaci o posečenom drvetu topole u različitim regionima Srbije, a na bazi toga, izvršena je deskriptivno-kvantitativna i regresiona analiza. Rezultati pokazuju da je ukupna posečena zapremina 4.386.540 m³, sa najvećim obimom u 2022. godini. Na osnovu regresione analize može se zaključiti da je linearni trend rastući, da je jačina koeficijenta determinacije, koja se odnosila na ukupnu seču topole u državnim šumama i faktor vreme, na srednjem nivou, korelaciona veza srednja, a parametri na granici signifikantnosti. Najveći procenat seče ostvaren je redovnim sečama, dok su vanredne intervencije ređe primenjivane. Zaključci ukazuju na značajnu varijaciju u obimu seče, povezanu s klimatskim uslovima, potražnjom na tržištu i primenom upravljačkih strategija