Omorika Digital repository of the Faculty of Forestry, University of Belgrad
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Natural Regeneration on Deadwood in the Primeval Forest Janj
No full textThe paper investigates the natural regeneration of downed deadwood in the Janj primeval forest. The old-growth forest is located in the southwestern part of the Republic of Srpska, which is dominated by dolomite geological base on which cambial soils were formed. The climate is perhumid and mountainous and the plantation belongs to the Piceo-Abieti-Fagetum community. The hectare contains 517 live trees with a total basal area of 53.0 m2/ha and a volume of 876 m(3)/ha. Twenty six downed deadwoods classified into three different degrees of decay were included in the study, where fir and spruce seedlings were found to be predominant and beech seedlings were rarely represented. The first degree of decay includes 7 (26.9 %), the second 8 (30.7 %), and the third 11 (42.3 %). The total volume of deadwood is 110.82 m3/ha with an average volume per tree of 4.2 m3/ha. The total number of seedlings on fallen dead trees is 836 seedlings (Abies alba - 89.59 %, Picea abies - 10.17 %, Fagus silvatica - 0.24 %).Fir seedlings are found on 25 fallen trees, spruce on 18 fallen trees, and beech on 2 fallen trees. Regarding quality, on average fir seedlings are better than spruce seedlings, but both species show a lot of senescence and very small size of current height increment. Most seedlings belong to the third quality class (fir - 46.2 %, spruce - 61.1 %), followed by second class (fir - 34.6 %, spruce -22.2 %) and third class (fir - 19.2 %, spruce - 16.7 %). The total number of seedlings was found to have a statistically significant difference in the amount of downed deadwood depending on the degree of decay, and the number of seedlings depended on the degree of tree decay. The number of seedlings increased with increasing volume and length of rotten trees
A Silhouette-Width-Induced Hierarchical Clustering for Defining Flood Estimation Regions
No full textFlood quantile estimation in ungauged basins is often performed using regional analysis. A regionalization procedure consists of two phases: the definition of homogeneous regions among gauged basins, i.e., clusters of stations, and information transfer to the ungauged sites. Due to its simplicity and widespread use, a combination of hierarchical clustering by Ward's algorithm and the index-flood method is applied in this research. While hierarchical clustering is very efficient, its shortcomings are the lack of flexibility in the definition of clusters/regions and the inability to transfer objects/stations from one cluster center to another. To overcome this, using silhouette width for induced clustering of stations in flood studies is proposed in this paper. A regionalization procedure is conducted on 53 gauging stations under a continental climate in the West Balkans. In the induced clustering, a negative silhouette width is used as an indicator for the relocation of station(s) to another cluster. The estimates of mean annual flood and 100-year flood quantiles assessed by the original and induced clustering are compared. A jackknife procedure is applied for mean annual flood estimation and 100-year flood quantiles. Both the Hosking-Wallis and Anderson-Darling bootstrap tests provide better results regarding the homogeneity of the defined regions for the induced clustering compared to the original one. The goodness-of-fit measures indicate improved clustering results by the proposed intervention, reflecting flood quantile estimation at the stations with significant overestimation by the original clustering
One-Pot Syntheses of PET-Based Plasticizer and Tetramethyl Thiuram Monosulfide (TMTS) as Vulcanization Accelerator for Rubber Production
No full textStyrene-butadiene (SBR) and acrylonitrile-butadiene (NBR) rubber blends with tetramethyl thiuram disulfide (TMTD) and tetramethyl thiuram monosulfide (TMTS) accelerators and environmentally friendly plasticizers, obtained from PET recycling and biobased resources (LA/PG/PET/EG/LA), were prepared. The mechanical properties of the obtained rubber products were tested and compared with those of commercial dioctyl terephthalate (DOTP). TMTS was prepared by simple and efficient one-pot synthesis from dimethylamine, carbon disulfide, potassium cyanide, and ammonium chloride as catalysts in recycled isopropanol/water azeotrope as solvent. In a comparative study, methoxide, ethoxide, iodide, and amide ions were also used. The two-step reaction mechanism of TMTS synthesis involves the oxidation of the amine salt of dimethyldithiocarbamic acid to TMTD by hydrogen peroxide and sulfur elimination from the TMTD disulfide bond. Potassium cyanide appears to be the most efficient nucleophile. The simplicity of operation, mild reaction conditions, solvent recycling, high yields, and applicability to the industrial level are the advantages of this process. Shore hardness, tensile strength, and compression test results of vulcanized blends before and after aging showed similar properties for both accelerators, while somewhat better results were obtained with LA/PG/PET/EG/LA plasticizer
A conceptual modelling framework for assessment multiple soil degradation: A case study in the region of Sumadija and Western Serbia
No full textSoil degradation is a global problem and researchers are facing the challenge of assessing the scale, trends, and consequences of contributing processes. With this in mind, this study implemented the new concept of multiple soil degradation indices (MSDI) for the first time in the region of Sumadija and Western Serbia (SWS). This concept enables the simultaneous integration of several environmental components that can act separately or synergistically and offers concrete answers and information on the state and distribution of physical (PSDI), chemical (CSDI) and biological (BSDI) soil degradation. Using several different geospatial-modelled approaches, results indicated that physical degradation was the greatest contributor to soil degradation in the SWS region with an impact of 55%, followed by chemical degradation at 16%, while biological degradation only had a 6% impact. The dominant indicator of physical degradation was the vegetation cover management factor with an impact of approximately 58%, while for chemical degradation it was soil organic matter, with a relative impact of almost 49%. Total microflora and total number of fungi were the most significant biological indicators with an average impact of approximately 43%. In addition, this study indicated that about 59% of the region is currently degraded, with about 44% of it classified as moderately degraded. The results of this study offer new insights into the geospatial dynamics of interactive degradation processes in Serbia and can form the basis for strengthening scientific, expert, and political support when implementing international and national policies concerned with protecting soil from degradation
Genetic Diversity and Genetic Structure of Three Sympatric Oak Species in Serbian Landscape of Outstanding Features "Kosmaj" Assessed by Nuclear Microsatellites
No full textQuercus petraea (Matt.) Liebl., Q. pubescens Willd., and Q. frainetto Ten. grow naturally in sympatry in the Landscape of Outstanding Features "Kosmaj" (Mt. Kosmaj) in Serbia, in the Western Balkans. The levels of genetic diversity and genetic structure in populations of these species (160 trees in total) was assessed by means of 14 nuclear microsatellites. The number of alleles detected in overall sample was 314, with the locus QrZAG90 being the most informative one in all three species (31, 35 and 36 alleles in Q. frainetto, Q. pubescens and Q. petraea, respectively). The levels of genetic diversity of all three species were relatively high (HE = 0.824, 0.834, and 0.794 in Q. petraea, Q. pubescens and Q. frainetto, respectively). Low but statistically significant inbreeding was detected in all three species (F = 0.100, 0.131 and 0.065 in Q. petraea, Q. pubescens and Q. frainetto, respectively), which, however, most likely reflects population substructure, which was observed in the STRUCTURE analysis. The optimal number of genetic groups revealed by Bayesian clustering analysis did not coincide with the number of analyzed species as it amounted to four (one gene pool was observed in each of the two species, Q. petraea and Q. pubescens, while two gene pools were observed in Q. pubescens). Furthermore, a higher level of hierarchical genetic structure, with six gene pools was found, with Q. frainetto being the only oak species in which population substructure was not observed. Genetic differentiation of three sympatric oak species was relatively low but statistically significant, with the highest FST value found among Q. petraea and Q. frainetto (FST = 0.047, P = 0.001), and the lowest between Q. petraea and Q. pubescens (FST = 0.032, P = 0.001). Our results reveal rather high levels of genetic diversity in all three studied oak species, which retained their genetic integrity despite sympatric distribution, indicating low levels of interspecific hybridization, and pronounced genetic structure of Q. pubescens and Q. petraea
Antifeedant activity of neemazal-t/s (biofa) on the spongy moth larvae on different three species
No full textInsecticides derived from plants have been used as pest control for centuries. Many of them,
such as Neem, a product derived from Azadirachta indica A.Juss. are used up to date, with
different efficiency against different pest species. The most significant factors affecting the
behavior of an insect exposed to Neem is the concentration of the active ingredient, and the
tree species on which it feeds. That is why we conducted a study in which we investigated the
antifeedant activity of different concentration of insecticide NEEMAZAL-T/S (BIOFA)
derived from A. indica on the larvae of the spongy moth (Lymantria dispar L, 1758), on three
different species - Turkey oak (Quercus cerris L.), Hungarian oak (Quercus frainetto Ten.)
and sweet chestnut (Castanea sativa Mill.). To test the efficiency of different concentrations
of NeemAzal we conducted choice tests in laboratory conditions. Two disks (treatment and
control) cut from the leaves of the investigated species were introduced to the second instar
spongy moth larvae in Petri dishes for the testing. Twenty-five Petri dishes were used for
each of the tested tree species at six concentrations (450 in total). The tested insecticide
showed a significant effect between the investigated species, and its efficiency increased
significantly with an increase in concentration
Uticaj abiotičkog stresa na rano razviće drvenastih vrsta
No full textBiljke su u svim fazama razvića izložene različitim abiotičkim uticajima.
Promenljivi uslovi u životnoj sredini koji su fiziološki neodgovarajući negativno utiču na
stanje biljaka i uzrokuju njihove odgovore na abiotički stres. Najizraženiji faktori stresa
su suša, ekstremne temperature, nedostatak hranljivih materija i svetlosti (EstravisBarcala et al., 2020). Promene klimatskih uslova, pored mnogobrojnih ljudskih aktivnosti
uticali su i na kvalitet supstrata uslovljavajući limitirajuće faktore za razvoj mnogih
biljaka. U područjima gde se vrši eksploatacija mineralnih sirovina ove pojave su
najizraženije
Razvoj diskoloracija i profili vlažnosti u hrastovoj rezanoj građi tokom konvencionalnog sušenja
No full textIn this study, the development of non-homogeneous color changes in oak timber during conventional drying and their relationship with the moisture gradient across the wood thickness were analyzed. The research was conducted on radial and tangential boards with a thickness of 38 mm, cut from two oak logs, one of sessile oak (Quercus petraea L.) and one of pedunculate oak (Quercus robur L.). A conventional drying schedule commonly used in enterprises was applied, and at specified time intervals samples were taken to determine the moisture content profile and monitor color changes on the cross sections of the samples. The findings reveal a complex relationship between the wood moisture content, the moisture content profile across the thickness, and the occurrence of color changes. Additionally, it was found that the wood of sessile oak dries slower and with less intense color changes compared to the wood of pedunculate oak. It was demonstrated that quarter-sawn boards dry slower compared to flat-sawn boards for both wood species. No differences in the appearan
Growth elements and stand structure of artifically established norway spruce stand at 37 and 62 years of age on dalechamps oak site at Goč
No full textNa jednoj trajnoj oglednoj površini u veštački podignutoj sastojini smrče na staništu balkanskog kitnjaka na Goču prikazani su elementi rasta i sastojinska struktura u starosti 37 i 62 godine i analizirana je njihova promena. Sastojina je podignuta sa 4500 sadnica po hektaru. U starosti 37 godina na trajnoj oglednoj površini utvrđeno je 2600 stabala po hektaru, sa temeljnicom 43,52 m2 ·ha−1 i zapreminom 319,97 m3 ·ha−1, a u starosti 62 godine utvrđeno je 878 stabala po hektaru sa temeljnicom 42,61 m2 ·ha−1 i zapreminom 454,48 m3 ·ha−1. Prva selektivna proreda, sprovedena pri srednjoj visini aspiranata (500 po hektaru) 17,6 m u starosti 37 godina je bila niska (qd = 0,88) i umerene jačine po broju stabala (28,3%) i zapremini (23,5%). Od preostalog broja stabala (1823 po hektaru) u periodu od 38. do 62. godine iz sastojine je pretežno sanitarnom sečom izlučeno 956 stabala (52,4%), sa pokazateljem niske prorede (qd = 0,68). Od početno izdvojenih aspiranata u 37. godini do 62. godine, pod uticajem biološkog diferenciranja stabala i pod uticajem nepovoljnih egzogenih faktora, a u postupku nege koji karakteriše niska proreda, u sastojini je izdvojeno 220 stabala budućnosti po hektaru. U 62. godini u sastojini su prisutni elementi nepovoljne izgrađenosti i statičke nestabilnosti jer je stepen vitkosti povećan u odnosu na stanje u 37. godini, pa se može zaključiti da je povećan i rizik za ostvarivanje njene potencijalne proizvodne i meliorativne uloge, a što je primarno posledica izostanka adekvatne nege u periodu od 38. do 62. godine
Klijanje semena vrste Cotoneaster multiflorus Bunge., nakon različitih tretmana za uklanjanje dormantnosti
No full textCotoneaster multiflorus je veliki listopadni, ukrasni žbun pogodan za korišćenje u ozelenjavanju zelenih prostora. Formira duge, lučno povijene grane, obilno cveta i cvetovi su beli, a nakon precvetavanja formira intenzivno crvene plodove koji su takođe dekorativni. To je skromna vrsta, koja nije izbirljiva prema zemljištu, raste i na glinovitim supstratima. Odlično podnosi sušu i kao takva može da se razvija u uslovima klimatskih promena. Generativno razmnožavanje ove vrste je otežano zbog kombinovane dormantnosti semenjače i embriona. Iz tog razloga, cilj ovog istraživanja je bio da se uspostavi brz i efikasan metod generativnog razmnožavanja odabranih elitnih genotipova C. multiflorus koji rastu na području Beograda. Seme je sakupljeno na javnoj zelenoj površini u parku na Petlovom brdu, u Beogradu. Nakon maceracije, ispitano je dejstvo različitih tretmana. Ovi tretmani su obuhvatili tretiranje semena 96% sumpornom kiselinom u trajanju od 60 i 90 minuta, 5 meseci hladne stratifikacije u pesku bez supstrata (tzv. gola stratifikacija) i kombinaciju pomenutih tretmana. Dobijeni rezultati su pokazali da C. multiflorus za klijanje zahteva kombinaciju tretmana sumpornom kiselinom i hladnu stratifikaciju u perlitu. Seme koje je tretirano sumpornom kiselinom a nakon toga podvrgnuto petomesečnoj goloj stratifikaciji nije klijalo. Trajanje tretmana sumpornom kiselinom je takođe uticalo na procenat klijanja i dobijeni su bolji rezultati kada je seme potapano u sumpornu kiselinu tokom 90 minuta u poređenju sa potapanjem u sumpornu kiselinu u trajanju od 60 minuta. Međutim, maksimalan procenat klijanja dobijen u ovom radu nije prelazio 40%, a apsolutna klijavost je iznosila svega 59%. Zbog toga je neophodno da se sprovedu dodatna istraživanja kojima će se ovaj metod unaprediti i time povećati procenat klijavosti semena C. multiflorus