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Plant species as indicators of site conditions after clearcutting in natural and artificially established stands within beech sites in the TImok forest area
No full texthe research was conducted in the Timok Forest Area after a natural disaster in winter 2015,
causing ice breaks and uproots and leading to extensive clear-cutting. To assess ecological
changes five years after, sample plots were established in areas where natural beech stands and
artificially established conifer stands within beech sites (Fagetum moesiace submontanum
(Rudski 1949) B. Jovanović 1976) existed before clear-cutting. Based on the inventory of
vascular flora, plants were distributed by plant indicator values. A total of 176 plant species were
recorded on the sample plots. Although submesophytes and mesophytes predominated on the
clearings (70%), there was a noticeable increase in subxerophytes and xerophytes, suggesting
moderate site xerothermization. The substantial occurrence of mesotrophic and transitional
groups between oligotrophic and mesotrophic plants (77%) implied that soil fertility was not
significantly diminished. Moreover, the relatively high share of transitional groups between
hemi-sciophytes and heliophytes (29%) indicated the ecosystem openness, whereas the share of
typical sciophytes decreased (< 2%). These species were notably more abundant in natural beech
forests, particularly in artificially established conifer stands within beech sites. Limited typical
heliophytes (<1%) could be attributed to vigorous colonization by spontaneous shrub vegetation,
which restricted light penetration to herbaceous heliophytes. The occurrence of extremely
frigophilic and thermophilic species underscores the climatic extremes of eastern Serbia.
Transitional groups between frigophilic and mesothermic plants (65%) were more prevalent than
typical mesothermic representatives of South European beech forests (30%) indicating stronger
cold manifestation in open forest ecosystems. These findings confirm plants role as bioindicators
of site conditions
Dendroecological research in the sessile oak stands on the warmer site conditions of the Đerdap national park, Serbia
No full textU radu su prezentovani rezultati dendroekoloških istraživanja u dvema sastojinama hrasta kitnjaka
na toplijim staništima na području Nacionalnog parka „Đerdap”. Za sagledavanje uticaja temperature i padavina na prirast (radijalni prirast – RW, prirast kasnog drveta – LW i prirast ranog drveta
– EW) ove vrste drveća korišćena su četiri metodološka pristupa: korelacije između tromesečnih
(sezonskih) veličina temperature i padavina i rezidualne hronologije, korelacije između mesečnih
temperatura i padavina i rezidualne hronologije, tzv. odzivne funkcije i korelacije između SPEI indeksa suše i rezidualne hronologije. Rezultati su pokazali veliku senzitivnost hrasta kitnjaka prema
padavinama u letnjim mesecima, na taj način da veće količine padavina u leto, naročito u julu,
prouzrokuju statistički značajno veće iznose prirasta. Variranje prirasta mnogo je manje uslovljeno
varijacijama temperature, pri čemu je registrovan slabiji negativan uticaj viših julskih i avgustovskih
temperatura na veličinu prirasta. Konstatovano je da je u ukupnoj veličini radijalnog prirasta i u
prirastu kasnog drveta detektovan jači klimatski signal nego u prirastu ranog drveta. Utvrđena reakcija hrasta kitnjaka u ovde analiziranim toplijim stanišnim uslovima u pogledu prirasta i njegove
zavisnosti od klime slična je reakciji kitnjaka iz sastojina u neposrednom okruženju NP „Đerdap” i iz
drugih okolnih zemalja koje se karakterišu srodnim klimatskim uslovim
Methodology of stability calculation when the influential parameters are stochastic quantities
No full textWhen using the calculation of stability (regardless of the methodology that is being used), there are two approaches: deterministic and stochastic. The first prerequisite for any calculations is that there are enough data that can be processed statistically to satisfy the student classification. When using the deterministic method, the main value to be taken into account in the calculations is the mean value, whereas when using stochastic calculations, all the results obtained by laboratory or field examinations are equally represented. Thanks to this, non-homogeneity of the rock mass has been introduced to the calculations. This paper presents the methodology of stochastic calculations, and shows one example of comparative analysis of the results of stochastic and deterministic calculations
The Influence of Printing Orientation on the Flexural Strength of PA 12 Specimens Produced by SLS
No full textThis article aims to investigate the mechanical characteristics of specimens fabricated using Selective Laser Sintering technology. The research covers flexural specimens, produced by PA12 materials. CAD model dimensions were selected according to the ISO 178 standard, and the chosen specimen geometry is 96 x 8 x 4 [mm] in bulk. All specimens were produced using a specialized machine Fuse 1 (FormLabs, Summerville, MA). Four specimen batches were produced, each with a different printing orientation (i.e. vertical and horizontal) and location on the printing plate (i.e. in the middle and on the edge of the powder bed). The specimens are tested using a Shimadzu universal machine for testing the mechanical characteristics of materials, AGS-X 100 kN, with a unique additional tool for testing 3-point bending specimens
Soil conservation measures in the context of climate change
No full textZemljište, kao krucijalan prirodni resurs, danas je u velikoj meri degradiran
i uništen. Dejstvom agresivnih klimatskih promena, prvenstveno padavina i
temperatura, taj proces je intenziviran i permanentan. Glavni zadatak je prilagoditi se
takvim uslovima primenom konzervacionih mera, koje će ublažiti klimatske promene,
očuvati resurs i obezbediti ekonomsku korist. Uz povećnje svesti o klimatskim
promenama i važnosti očuvanja zemljišnog resursa, moguće je obezbediti održivost i
čoveka i resursa.Soil, as a crucial natural resource, is currently significantly degraded and destroyed.
The impact of aggressive climate changes, primarily precipitation and temperature, has intensified
and perpetuated this process. The main task is to adapt to such conditions by applying
conservation measures that will mitigate climate changes, preserve the resource, and ensure
economic benefits. By increasing awareness of climate change and the importance of preserving
soil resources, we ensure the sustainability of both humans and resources
Harmonised statistics and maps of forest biomass and increment in Europe
No full textForest biomass is an essential resource in relation to the green transition and its assessment
is key for the sustainable management of forest resources. Here, we present a forest biomass
dataset for Europe based on the best available inventory and satellite data, with a higher
level of harmonisation and spatial resolution than other existing data. This database provides
statistics and maps of the forest area, biomass stock and their share available for wood
supply in the year 2020, and statistics on gross and net volume increment in 2010–2020, for
38 European countries. The statistics of most countries are available at a sub-national scale
and are derived from National Forest Inventory data, harmonised using common reference
defnitions and estimation methodology, and updated to a common year using a modelling
approach. For those counties without harmonised statistics, data were derived from the
State of Europe’s Forest 2020 Report at the national scale. The maps are coherent with the
statistics and depict the spatial distribution of the forest variables at 100m resolution
Biljne vrste kao indikatori staništa bukovih šuma nakon čiste seče
No full textIn the winter of 2015, extensive damage affected forest ecosystems in
eastern Serbia due to severe ice-induced tree breakage and falls. As a result, clearcutting
was necessary in certain forest stands. This study evaluates the ecological characteristics of
plant species that emerged on clearcut sites five years after clearcutting. The research was
conducted within the Timok Forest Region, encompassing both natural beech stands and
artificially established conifer plantations on beech sites (Helleboro odori-Fagetum
moesiacae Soó & Borhidi 1960). This investigation focuses only on the stocked areas within
the Timok Forest Region (natural forests and artificially established stands) managed by the
state-owned company "Srbijašume" in Belgrade. Vascular flora was categorised based on
their affiliation with specific ecological plant groups according to the following key
environmental parameters: soil moisture (V), soil acidity (K), nitrogen availability (N), light
(S), and temperature (T). Spontaneously colonised plants, serving as bioindicators, reflect
changes in ecological (particularly microclimatic and edaphic) conditions. Additionally,
these bioindicators reveal the degradation of forest habitats post-clearcutting, which
manifests as increased light penetration, xerothermic microclimatic shifts, surface soil
acidification, and diminished nutrient availability
Environmental protection, public interest, sustainable development
No full textMinistarstvo rudarstva i energetike Republike Srbije izdalo je oko 200 istražnih prava za
različite mineralne resurse, na prostoru od oko 6% nacionalne teritorije, čime je obuhvaćeno 536.000
hektara. Istražna prava se odnose, dominantno, na rezerve zlata, litijuma, bora, srebra, bakra, nikla i
antimona. Tražioci istražnih prava su, uglavnom, privatne rudarske kompanije, registrovane u Srbiji,
kao firme-ćerke globalnih rudarskih korporacija, ili domaće kompanije. Istražni prostori u pojedinim regionima Srbije zahvataju od 50 do 150 km2
, i locirani su u stabilnim poljoprivrednim i
šumskim predelima (dolina Jadra i Rađevina; Levač; Šumadija; Homolje). Eventualno izdavanje
eksploatacionih prava na iskopavanje i preradu ruda, podrazumeva primenu složenih hemijskotehnoloških procesa, sa upotrebom velikih količina agresivnih i veoma toksičnih materija (sumporna,
fosforna i hlorovodonična kiselina, natrijum-cijanid), koje nose veliki rizik i od zagađenja zemljišta,
voda, vazduha, ugrožavanja živog sveta i pogoršavanja pokazatelja javnog zdravlja lokalnog stanovništva.
Pored fizičkog uništenja nekoliko desetina hiljada hektara obradivog zemljišta i šumskih površina,
bila bi značajno kompromitovana mogućnost intenzivne poljoprivredne proizvodnje, opstanka lokalnih
zajednica, a time identitetskih i kulturnih vrednosti pojedinih delova Srbije. Istovremeno, zanemaruje
se neiskorišćen potencijal srpske poljoprivrede, koji pored materijalne koristi, može da donese
potpunu sigurnost u proizvodnji kvalitetne hrane, prosperitet seoskih sredina i opšti rast svih
pokazatelja ekonomskog razvoja. Neophodno je strateško, strukturno preispitivanje privrednog modela
Srbije u cilju objektivne procene dostignutih rezultata i definisanje ciljeva ekonomskog suvereniteta,
na bazi održivosti i punog poštovanja javnog interes
No Future Growth Enhancement Expected at the Northern Edge for European Beech due to Continued Water Limitation
No full textWith ongoing global warming, increasing water deficits promote physiological stress on forest ecosystems with negative impacts on tree growth, vitality, and survival. How individual tree species will react to increased drought stress is therefore a key research question to address for carbon accounting and the development of climate change mitigation strategies. Recent tree-ring studies have shown that trees at higher latitudes will benefit from warmer temperatures, yet this is likely highly species-dependent and less well-known for more temperate tree species. Using a unique pan-European tree-ring network of 26,430 European beech (Fagus sylvatica L.) trees from 2118 sites, we applied a linear mixed-effects modeling framework to (i) explain variation in climate-dependent growth and (ii) project growth for the near future (2021–2050) across the entire distribution of beech. We modeled the spatial pattern of radial growth responses to annually varying climate as a function of mean climate conditions (mean annual temperature, mean annual climatic water balance, and continentality). Over the calibration period (1952–2011), the model yielded high regional explanatory power (R2 = 0.38–0.72). Considering a moderate climate change scenario (CMIP6 SSP2-4.5), beech growth is projected to decrease in the future across most of its distribution range. In particular, projected growth decreases by 12%–18% (interquartile range) in northwestern Central Europe and by 11%–21% in the Mediterranean region. In contrast, climate-driven growth increases are limited to around 13% of the current occurrence, where the historical mean annual temperature was below ~6°C. More specifically, the model predicts a 3%–24% growth increase in the high-elevation clusters of the Alps and Carpathian Arc. Notably, we find little potential for future growth increases (−10 to +2%) at the poleward leading edge in southern Scandinavia. Because in this region beech growth is found to be primarily water-limited, a northward shift in its distributional range will be constrained by water availability
Structural Integrity Assessment of Spherical Tanks for Propane Butane Gas Storage
No full textStructural integrity analysis of spherical tank is presented based on use of experimental results, together with the analytical and numerical ones. Analytical calculation of stresses in the scope of design process is shortly presented. Numerical analysis was performed by using the Finite Element Method (FEM) to identify areas with high stress concentration, indicating that stress values near supports reach the yield stress. FEM results were verified by the experiment, indicating that it was not necessary to reinforce the spherical tank supports, since its integrity was not jeopardized in normal working conditions. This was also proved by repeating the experiment after 8 months of exploitation