Omorika Digital repository of the Faculty of Forestry, University of Belgrad
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The water-vapour permeability of the coated medium density fiberboard
No full textThe use of foil-faced medium density fiberboard (MDF) in wood surface finishing enables a
reduction in surface finishing time and an enhancement of specific properties of coated surfaces. The
objective of this study was to evaluate the differences in water-vapour permeability between foil-faced
MDF and standard MDF panels (without foil), coated with polyurethane (PU) coating. Both types of
coated MDF were exposed to water-vapour for a period of 14 days, during which differences in water- vapour absorption and subsequent desorption (for the next 14 days) were examined. The results show
that facing the wider face of MDF panels with foil reduced the water-vapour absorption of the coated
samples. Considering the results of water-vapour permeability results, the use of MDF double-faced
with ground foil prior to finishing show the advantages for the use of furniture components in indoor
environments with elevated moisture levels
REMOTE SENSING–BASED ASSESSMENT OF SOIL EROSION AND THE EFFECTIVENESS OF BIOLOGICAL CONTROL MEASURES IN GRDELICA GORGE AND VRANJSKA VALLEY WATERSHED
No full textSoil erosion represents one of the most widespread and severe forms of soil degradation in Serbia, which significantly affects the disruption of the natural functions of the soil. The most long-lasting and effective measure in preventing soil degradation is the application of biological works (most often afforestation). The success of the performed biological works cannot be determined immediately after afforestation, but it is necessary to study a longer period of time, because the vegetation cover requires a longer period to establish a structure that could resist erosion processes. For the purposes of analyzing the effects of these works, the traditional method through field research represents a long-term and often too expensive solution. The application of remote sensing provides an efficient and economical solution for the analysis and detection of soil erosion, as well as the assessment of the long-term effects of the biological works carried out on the degraded area.
The availability of multispectral satellite images since 1972 (Landsat 1 ERTS-1) enables long-term monitoring of the state of vegetation and the effects of biological works. By applying vegetation indices such as the Normalized Difference Vegetation Index (NDVI) multi-decade quantification of changes in vegetation cover is possible. The most modern satellite images such as (Sentinel-2, PlanetScope, WorldView-3) enable even more precise detection of spatial and temporal changes in the vegetation cover. In this way, it is possible to identify more accurate erosion zones and evaluate the effectiveness of biological measures.
This study, using Landsat, shows the multi-decade change in soil erosion, as well as the change in the vegetation cover after the biological works carried out in the middle of the last century in the southern part of the Republic of Serbia (Grdelica Gorge and Vranjska Valley). A gradual increase in vegetation areas has been recorded from the late 1980s onwards, with vegetation cover becoming larger over time. By the end of the 2010s, areas under excessive erosion had generally decreased, giving way to predominantly well-developed vegetation.
The results of this study indicate the importance of remote sensing in assessing the long-term impact of biological works and monitoring erosion processes. This approach enables researchers and decision makers to detect critical zones of soil degradation and assess the spatial impact of biological works. Also, by using this method, it is possible to plan future measures within the framework of integrated watershed management, as well as adaptive planning of biological works
POTENTIAL OF SESSILE OAK FROM THE AREA OF THE NATIONAL PARK ‘ĐERDAP’ FOR VARYING DENDROCHRONOLOGICAL RESEARCH
No full textThis study aims to present part of the results from ongoing efforts to develop a comprehensive network of tree-ring chronologies for sessile oak (Quercus petraea L.) within the National Park "Đerdap" in Eastern Serbia and to evaluate its potential for dendrochronological and dendroclimatological applications. As a valuable, climate-sensitive species, understanding its growth patterns is crucial for effective protection and forest management planning. A detailed dendrochronological analysis was conducted across five distinct sites in the park, representing varied ecological conditions. From visually dominant and healthy trees, a total of 100 cores were extracted at breast height. Following standard preparation procedures, the tree-ring widths were measured with high precision. The cross-dating of the series was rigorously performed using both visual and statistical methods in specialised software (TSAP and dplR in R) to ensure accurate dating. The development of residual site chronologies involved detrending to remove non-climatic trends and autoregressive modelling to eliminate persistence. The strength of the common signal within each site chronology was robustly confirmed by high values of the Expressed Population Signal (EPS) and the Gleichläufigkeit coefficient. Тhe temporal stability of this common signal was verified using a moving-window analysis. To explore inter-site relationships, Principal Component Analysis (PCA) and hierarchical clustering were employed. The PCA revealed a very high common variance, with the first two components explaining 84% of the total variance, allowing for the grouping of the five site chronologies into three coherent regional clusters. The results unequivocally demonstrate that sessile oak from the NP "Đerdap" exhibits a strong common growth signal, making the developed chronologies highly suitable as proxies in future dendroclimatological studies, particularly for climate reconstruction. For even more robust and spatially extensive research, additional sampling of older trees and an expansion of the site network are recommended
EARLY MORPHOLOGICAL VARIATION OF SALIX ALBA CLONES IN A CONSERVATION-ORIENTED PROGENY TEST
No full textWhite willow (Salix alba L.) conservation is tightly linked to riparian habitat condition and hydrological regimes. These habitats are faced with fragmentation, human disturbances and degradation of ecosystems in general. All this alteration affects white willow populations in a negative way. Remaining forest stands can function as dynamic metapopulations but may depend on site history and within-population genetic diversity. To secure reproductive material and genetic resources national/regional programs combine in situ measures with ex situ actions. With the aim of conserving the white willow on Great War Island (Belgrade), a clonal (vegetative) progeny test was established in the nursery. The test consists of 25 clones whose ortets—parent trees—were selected from the species’ gene pool on the territory of Great War Island. The selection of ortets was carried out in the spring of 2024. The selected trees were georeferenced and mapped. Each tree in the field was marked with a number. The branches were cut with a telescopic pruner, and the cuttings were formed immediately afterward on-site. The cuttings varied in diameter but were uniform in length, approximately 20 cm long with 3–4 dormant buds. A total of 1,611 cuttings were produced, with the number of planted cuttings per clone ranging from 51 to 94. Sprouting of the cuttings was uneven, and the final rooting/survival percentage was determined on May 23, 2024. In total, 999 cuttings rooted and 859 survived first growing season. The morphological characteristics of the plants were analyzed at the end of the first growing period. The overall mean height for all seedlings was 7500.96 ± 1682.01 mm, with a total coefficient of variation of 22.42%. The average ground-level diameter was 5.09 ± 1.06 mm, with a coefficient of variation of 20.82%. Heights were considerably more variable than diameters. Thus, according to descriptive statistical parameters, clones BV_09 and BV_19 stand out. Clone BV_09 shows the lowest average values for both height and diameter, whereas clone BV_19 has the highest average height values, but not the highest diameter values. Based on the analyses conducted during the first growing season, the established clonal test of white willow from Great War Island demonstrates substantial variability in seedling height and diameter across the 25 examined clones. The early identification of distinctive clones, such as BV_09 and BV_19, further highlights the value of this collection for ongoing conservation and breeding efforts. Overall, the clonal test provides a good basis for conservation and improvement of the genetic resources of white willow in this ecologically important riparian habitat
Modeliranje protoka podzemnih voda korišćenjem kriging interpolacije u okviru ArcGIS paketa
No full textGroundwater is the main factor that affects the development and existence of forest sites
in lowland areas. A continuous layer of water that fills all soil pores and has a positive
pressure value is referred to as groundwater. This layer is located in the deeper parts of
the soil or in the rock, and its upper limit represents the level of the groundwater. The
water present in the soil plays a major role in the existence of oak forests, which are the
most dominant association at investigated area. The significant impact of groundwater
on the features of lowland sites is reflected in the fact that they lead to an increase in soil
moisture to an extent that cannot be compensated directly by rainfalls. Numerous
negative human activities have led to the disruption of the natural watering regime
(increased oscillations in the level of flood water and groundwater), which has reflected
on the stability and vitality of forest ecosystems in lowland areas. Due to global warming
and long dry periods, there is an increasingly present trend of groundwater level decline,
which has a very negative impact on the development and production characteristics of
forest associations in alluviums, especially bearing in mind that pedunculate oak, as a
dominant species, is primarily supplied with water from groundwater. Based on the
aforementioned facts, it should be noted that knowing of groundwater trend is of a huge
practical significance in terms of forest management. For that reason, it is necessary to
carry out the monitoring of groundwater fluctuations on piezometric stations, not only to
have an insight in current state, but also in order to predict their behaviour in the future.
In the paper was used Kriging method, which is one of the geostatistical methods with a
great significance for groundwater monitoring. Kriging includes geostatistical techniques
which serve to determine the unknown value of some variable based on available data
related to so-called control points, and based on structural characteristics of variogram,
as well. Kriging assessment is based on the use of existing measurements, whose impact
is expressed through appropriate weighting coefficients. The aforementioned
assessment must be as accurate as possible, and this is achieved by making the
variance of the difference between the real and estimated values at the selected points
as small as possible. This value is called the Kriging variance and us designated as an
interpolation quality control element. ArcGIS enables spatial analysis of hydrological
elements, creation of maps and modelling of groundwater flows. It is important to conduct
groundwater modelling in order to determine the proportion of available water between
groundwater and rainfalls, which is essential for the management of lowland forests. The
recommendation for some future research that will deal with the monitoring of
groundwater level fluctuations in forest ecosystems is to include, in addition to Kriging,
multi-criteria analysis methods, such as AHP, which are before all based on the
determination of weight criteria on the principle of defined prioritie
Children’s perception of the street in front of their school
No full textUnderstanding how children perceive and experience urban environments, particularly streets near
schools, has become a growing interdisciplinary concern that bridges urban design, public health, environmental psychology, and child studies. While the “school street” model has gained global traction
as a tool to improve safety, mobility, and well-being, few studies have integrated children’s subjective
spatial knowledge into early stage planning. This research examines how young children perceive the
street in front of their school in Belgrade and how these insights can inform more inclusive, safe,
and joyful urban design strategies. The study involved 16 second-grade pupils (eight years old) from
Vladislav Ribnikar Elementary School in Belgrade. Using a child-centred participatory methodology
grounded in the Urban500 initiative and inspired by the GDCI’s international toolkit, students engaged
with four large-format poster boards that focused on emotions, mobility habits, desired activities, and
preferred urban elements. In addition, the students conducted a photo-documentation task during their
daily commute, capturing images of street elements that they liked and disliked. The resulting visual,
verbal, and tactile data were interpreted using the SCORELINE framework, which evaluates public spaces across six hierarchical criteria: safety, accessibility, legibility, comfort, inspiration, attractiveness,
and liveability. Children’s responses revealed a layered understanding of their urban surroundings.
Positive feedback clustered around green infrastructure, playspaces, legible and clean walking paths,
and culturally resonant landmarks. Negative impressions focused on unsafe crossings, obstructed
sidewalks, graffi ti and poorly maintained buildings. Despite their age, the children demonstrated spatial literacy and emotional nuances when assessing their environment. Most participants walked to
school, but many reported feelings of discomfort and insecurity in doing so. The fi ndings illustrate the
value of integrating children’s perspectives into urban planning processes, not only as users, but also
as capable evaluators and co-designers of space. Their feedback aligns closely with International
School Street principles, highlighting a broader vision of child-friendly and joyful cities. This study
offers timely evidence for embedding participatory, child-centred methods into local planning frameworks in the Serbian context. The results also serve as input for the reconstruction of the Vladislav
Ribnikar school and the surrounding public space, following the tragic events of 2023. Ultimately,
streets shaped by children’s needs and imaginations hold the potential to improve not only safety and
function but also emotional well-being and community cohesion
Beech forests of Kosmaj as a natural resource of medicinal plants
No full textThis paper presents the results of research on wild-growing medicinal
plants in the beech forests of the protected area of Kosmaj. Beech forests in this region are
widely distributed and occur either as pure stands (Helleboro odori–Fagetum moesiacae Soo
& Borhidi 1960) or as mixed stands with sessile oak (Querco petraeae–Fagetum moesiacae
Glišić 1971). The floristic composition of these forests was analyzed using 22
phytosociological relevés. Out of a total of 100 recorded plant taxa, 60 medicinal species
belonging to 50 genera and 36 families were identified. The taxonomic analysis showed that
the most represented medicinal plants belong to the families Rosaceae (15%) and Lamiaceae
(13%), followed by Fagaceae (7%) and Liliaceae (5%). Species of the Central European
distribution type were the most common (36%), while the analysis of life forms indicated a
predominance of phanerophytes (48.4%) and hemicryptophytes (23.3%), with a notable
share of geophytes (18%
Effect of ultrasound pretreatment on spring-back and moisture behavior in densified poplar wood
No full textThis study explores the effects of ultrasound pretreatment on the densification behavior of poplar
wood (Populus × euramericana, cv. "Robusta"). Matched sample pairs were used to form two groups:
one underwent ultrasound pretreatment, while the other served as control. The ultrasound pretreatment was conducted in a water bath at a frequency of 28 kHz, temperature of 30 °C, and duration
of 45 minutes. Densification was carried out at a pressing temperature of 200 °C, followed by cooling
under pressure to 60 °C to stabilize the compressed structure. The target compression was 50%,
reducing the sample thickness from 20 mm to 10 mm. The average compression rate was 49% in the
control group and 51% in the ultrasound-pretreated group. After densification, the samples were
evaluated for spring-back effect, moisture content after compression, and relative moisture content
loss. A statistically significant difference in spring-back was observed between the groups, with the
ultrasound pre-treated group showing a mean value of -1.55% compared to 1.4% in the control group,
indicating enhanced thickness stabilization. In contrast, no statistically significant differences were
found between the groups in post-densification moisture content or relative moisture content loss.
These results suggest that ultrasound pretreatment can improve the compressibility and shape retention
of poplar wood during densification, likely through cavitation effect which improves moisture flow, without substantially affecting moisture content of densified wood
The influence of light and air temperature on the visual perception of Photinia × fraseri 'Red Robin' in the parterre composition of Savski Square in Belgrade
No full textThis research is dedicated to analysing the linear structure of Photinia × fraseri 'Red
Robin' as one of the visual elements of Savski Square in Belgrade. Using an integrative approach to
phenological and climatic factors over two consecutive, climatologically distinct years, the influence
of light and air temperature on the phenology and morphometric characteristics of the inflorescence
in early spring was assessed. Descriptive statistics, the Spearman Rank correlation, Tukey’s test, and
one-way ANOVA were used to quantify the investigated parameters. The results confirm that Photinia
'Red Robin' is both adaptive and sustainable, and that during the period of shoot growth and
flowering it contributes significantly to the visual identity of the space. Seasonal changes in its linear
structure within the parterre design of the square reflect periodicity, flexibility, and diversity, along
with a high adaptability to contemporary trends and the physical environmen
Green invaders: understanding and addressing the opportunities and challenges of predominant wooden plant species in Serbian urban landscapes
No full textAs urbanization continues to reshape landscapes, the prevalence of invasive species in cities
has become a growing concern. However, a shift in perspective is emerging, recognizing the
ecosystem services of harnessing these invasive species for various urban applications. This
study aims to analyze the dual impact of invasive plant species, considering both their
ecosystem disservices and potential ecosystem services in urban landscapes, and suggest
innovative approaches that enable ecosystem services to prevail over ecosystem disservices.
Invasive species, known for their adaptability, can contribute to urban tree canopies and
provide shade, thereby aiding in the mitigation of the urban heat island effect. One of the most
present in Serbia‘s urban landscapes are false indigo and black locust which have nitrogenfixing capabilities that may benefit soil quality, making it a potential candidate for sustainable
urban farming. Boxelder maple and tree of heaven are highly spread in Serbia and considered
of the top 40 invasive species in the world, known for their tolerance to various soil
conditions, can be utilized to absorb pollutants and improve soil quality in areas where other
species aren‘t an option. This application helps address soil degradation and stabilizes land in
urban areas undergoing redevelopment or facing environmental challenges not only in Serbia.
While the repurposing of invasive species in cities presents promising opportunities, it is
crucial to acknowledge and address associated challenges and ecosystem disservices. As
invasive species establish themselves, they can alter ecosystem structure and disrupt the
balance of native plant and animal communities, potentially leading to the extinction or
decline of indigenous species. Nevertheless, with innovative and sustainable planning, urban
ecologists can explore ways to harness these species for environmental benefit. In addition to
physical ecosystem functions, many invasive species also possess significant biochemical
potential. In this study, the antioxidant capacity of A. fruticosa, R. pseudoacacia, A. altissima,
and A. negundo was assessed using the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical
scavenging assay. Plant material (leaves and bark) was collected from urban areas in Novi
Sad, air-dried, ground, and extracted with 70% methanol. Extracts at concentrations of 0.5–5
mg/mL were mixed with DPPH solution and incubated in the dark for 30 minutes.
Absorbance was measured at 517 nm. DPPH inhibition was calculated and expressed as a
percentage. The results showed strong antioxidant potential: A. fruticosa exhibited 60–85%
inhibition, R. pseudoacacia 50–80%, while A. altissima and A. negundo showed inhibition in
the range of 45–75%, depending on concentration and plant part. These findings suggest that
invasive species, when properly managed, could offer added value in urban bioremediation,
green infrastructure, and even phytochemical applications. By embracing a proactive and
sustainable mindset, urban planners, ecologists, and policymakers can explore ways to
harness the strengths of invasive species for the betterment of urban environments while
safeguarding native ecosystems