Latest Articles from Silva Balcanica Latest 55 Articles from Silva Balcanica https://silvabalcanica.pensoft.net/ Fri, 29 Mar 2024 08:32:50 +0200 Pensoft FeedCreator https://silvabalcanica.pensoft.net/i/logo.jpg Latest Articles from Silva Balcanica https://silvabalcanica.pensoft.net/ Wood identification and tree-ring chronology building of oak pillars excavated from submerged prehistoric settlement (3000 BC), Ropotamo River estuary, Black Sea https://silvabalcanica.pensoft.net/article/119972/ Silva Balcanica 25(1): 13-20

DOI: 10.3897/silvabalcanica.25.e119972

Authors: Dimitar Petrov Dimitrov

Abstract: Eighty one well-preserved wooden pillars were found аs a result of underwater archaeological excavations of a submerged prehistoric settlement in the estuary of Ropotamo River, Black Sea. That provokes a scientific interest to identify wood materials. The longest tree-ring chronologies have been used to build floating dendrochronology series. Anatomical features of xylem showed that 34 out of the 81 studied wooden pillars belong to genus Quercus. The remaining 47 pillars belong to a species of the genera Fraxinus, Acer, Ulmus and Platanus. It has been found that 8 out of 34 oak pillars have a length of tree-ring series over 30 years. This was the reason to select them for dendrochronological studies. The length of the built floating master chronology for the oaks is 84 years. The lack of strong coherent signal between 34 single oak dendrochronological series can be explained with three different types of oak forest ecosystems, in the area of the Ropotamo River estuary. These forest ecosystems are as follows: oak high stand forests in Strandzha Mountain, oak coppice forests on the Black Sea coast plains and riparian ‘Longoz’ forests of Ropotamo River. The tree-ring series of these forest types have different tree-ring signatures. Based on the tree-ring analysis it can be assumed that the timber of the above-mentioned three types of oak ecosystems was used in the construction of the prehistoric settlement.

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Research Article Mon, 12 Feb 2024 19:21:00 +0200
Identifying key quality characteristics of woody biomass for bioenergy application: an international review https://silvabalcanica.pensoft.net/article/114644/ Silva Balcanica 24(3): 77-94

DOI: 10.3897/silvabalcanica.24.e114644

Authors: Mohammad Reza Ghaffariyan

Abstract: Biomass characteristics play an important role in product classification, economic values, and types of usage. This research was initiated by the IEA Bioenergy Technology Collaboration Programme, which aimed to review and identify the top biomass characteristics as they relate to commercially viable biomaterial and bioenergy processes. An online search (in English) was conducted using the following keywords: biomass, chips, quality, characteristics, moisture content, calorific values, contamination and ash content. The search was restricted to woody biomass and raw feedstock materials. Review results were classified based on regions including Africa, America, Asia, Europe and Oceania. Each case study was described based on the study background, type of biomass and biomass attributes that were measured. The key biomass characteristic was moisture content that was consistently measured in almost all reports. Ash content and calorific value were classified as second place in terms of frequency in the biomass studies. Lower frequency belonged to the attributes such as bulk density, contamination, particle shape and nutrient (elemental) content. Detailed information of different case studies is provided in this report. It is anticipated that this literature review will assist IEA Bioenergy and its industrial and scientific network to better understand the current knowledge gaps regarding woody biomass characterisation.

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Review Article Thu, 28 Dec 2023 15:00:07 +0200
Integrated mapping of ecosystems and assessment of forest ecosystem services at river basin scale https://silvabalcanica.pensoft.net/article/115856/ Silva Balcanica 24(3): 43-60

DOI: 10.3897/silvabalcanica.24.e115856

Authors: Stoyan Nedkov, Ivaylo Ananiev, Hristina Prodanova, Vanya Stoycheva

Abstract: Ecosystems provide various goods and services to society and their valuation is among the main objectives of the concept of ecosystem services (ES). The mapping of ecosystems is the main building block of the whole process of the Mapping and Assessment of Ecosystems and their Services (MAES). The analyses of the ecosystem data produced during the implementation of the national methodology for mapping ecosystems in Bulgaria (MAES BG) reveal some problems that may cause confusion in cases of integrated assessment of all ecosystem types. In this paper, we present an approach that enables formulation of a uniform spatial dataset based on the mapping of the main ecosystem types, that can be used for mapping of ES at a river basin scale. It has been applied to the upper part of the Ogosta River basin and the result is a topologically correct uniform spatial data layer. The approach gives one possible solution to problems related to the different sources of information and the discrepancies between ecosystem types in the national mapping of ecosystems in Bulgaria. It is based on the use of a uniform spatial framework that outlines the ecosystem types and sets the initial database for further mapping. This ensures a topologically correct spatial dataset for the ecosystems and a background for further updates for each ecosystem at the different levels of MAES typology. The most appropriate spatial basis for the territory of Bulgaria is the database for the physical blocks of the Ministry of Interior. Its application to the studied river basin gives encouraging results and can be used as an example for similar areas. Further development of the approach will ensure the mapping of the forest ecosystems at level 3 of the MAES BG typology and more precise delineation of the grassland, heathland, freshwater, and sparsely vegetated ecosystems.

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Research Article Thu, 28 Dec 2023 15:00:05 +0200
Soil erosion rates based on anatomical changes in exposed roots - case study from southwest Bulgaria https://silvabalcanica.pensoft.net/article/116223/ Silva Balcanica 24(3): 27-33

DOI: 10.3897/silvabalcanica.24.e116223

Authors: Eli Pavlova-Traykova, Dimitar Dimitrov

Abstract: In recent years different methods for soil erosion assessment have been used. Because of its high accuracy in estimations, dendrogeomorphology was selected as one suitable and reliable scientific method to achieve the main goals of this study. The main goal of the study is to date denudation events using anatomical responses of the tree-rings of the roots. We analyze the histological changes that occur in the roots of two tree species, along the river banks of the Sedelska River, which is a tributary of Struma River.The significant differences between homogenous groups of measurements in pre-exposed and exposed roots was established, and it shows a remarkable response of roots to sheet erosion.

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Research Article Thu, 28 Dec 2023 15:00:03 +0200
Health status of the field protective forest belts in Dobrudzha – results from the monitoring carried out in 2022 https://silvabalcanica.pensoft.net/article/116284/ Silva Balcanica 24(3): 17-26

DOI: 10.3897/silvabalcanica.24.e116284

Authors: Yonko Dodev, Georgi Georgiev, Margarita Georgieva, Veselin Ivanov, Sevdalin Belilov, Svetozar Madzhov, Lyubomira Georgieva

Abstract: In 2022, the health status of the field protective forest belts on the territory of the State Hunting Enterprise Balchik and State Forest Enterprises General Toshevo and Dobrich was monitored. The assessment of tree crown condition covered 7069.3 ha (66% of all field protective belts in Bulgaria). The results showed that 70% of monitored belts were in good condition, 23% - in moderate condition, and 7% - in poor condition. Since 2014 the area of the protective forest belts in poor condition has increased 2.6 times, and 76% of them were situated in Dobrudzha region. Ash belts – Fraxinus excelsior (66% of all belts) and Fraxinus americana (10%) were in the worst conditon. In ash belts a process of crown dieback, premature falling of leaves and drying of whole trees were observed. In individual ash belts, drying reached up to 80% of tree crowns, regardless of their age and origin. The drying was mostly due to the biotic factors – insect pests and fungal pathogens. The protective forest belts of Quercus cerris, Q. petraea, Q., rubra and Gleditschia triacanthos stand out as sustainable tree species. It is necessary to significantly upgrade the methodology by which the monitoring of the health status of trees in the field protective forest belts is currently carried out. In the new methodology a detailed description of the type of data that need to be collected, the methods of assessments, and data reporting formats, have to be included.

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Research Article Thu, 28 Dec 2023 15:00:02 +0200
Reforestation pipeline: case for quality management of NIR-region grading of Scots pine seeds and FLR-algorithm for information processing https://silvabalcanica.pensoft.net/article/114699/ Silva Balcanica 24(3): 5-16

DOI: 10.3897/silvabalcanica.24.e114699

Authors: Tatyana P. Novikova, Evgeniy P. Petrishchev, Arthur I. Novikov

Abstract: When controlling the process of improving the quality of seeds by separating on a spectrometric basis, the primary information about the state of Scots pine seeds is carried by the wavelengths of optical fluxes and their amplitudes. The algorithm for analyzing the required characteristics of small forest seeds in the infrared range is a corresponding sequence of logical terms that provide the ability to determine the specified seed parameters by a combination of spectral frequencies and light flux amplitudes taken from the corresponding photodetectors. At ΔС = 0.5, the efficiency of the algorithm was 77.6 %, and at ΔС = 0.9, respectively, 99.5 %. In this regard, the choice of ΔС is the result of a compromise between the cost of rejection of high-quality seeds and losses when using unrecognized low-quality seeds and it is made according to the results of relevant experiments.

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Research Article Thu, 28 Dec 2023 15:00:01 +0200
Canopy influence on soil properties in Austrian pine artificial stands https://silvabalcanica.pensoft.net/article/104591/ Silva Balcanica 24(2): 91-100

DOI: 10.3897/silvabalcanica.24.e104591

Authors: Plamen Glogov, Simeon Bogdanov, Stela Gyudorova

Abstract: The aim of the present study is to track changes in the canopy (cover-abundance of the tree layer) of vegetation and cover of the forest litter, and the relationship between them and the dynamics of soil parameters in Austrian pine (Pinus nigra Arn.) plantations. The objects of study are 50-80-year-old artificial plantations of Austrian pine located in the xerothermic oak belt of five mountains in the area of Sofia. In each mountain, three test plots (SPs) were laid out, each measuring 400 m2 (Table 1). The main reason for choosing PP is the cover abundance of the first layer. Within each SP, the following metrics are measured: cover-abundance (%) of vegetation in each layer; the cover of plant litter (%). From all SPs, soil samples were taken from three depths: 0-10 cm, 10-20 cm and 20 -30 cm. An analysis of the content of soil organic matter was carried out, including: total nitrogen (N), the C/N ratio – calculation method, the reaction of the soil solution (pH) in the aqueous extract and the mechanical composition of the soil.The results show that the properties of the studied soils change to a significant extent in accordance with the cover abundance, especially in the first floor of the vegetation. Soil organic matter content, C/N ratio and mechanical composition are the indicators that most clearly reflect the relationship between the canopy and the cover of plant litter on the one hand, and soil properties. The proven, statistically significant differences in the values of these indicators emphasize the role of vegetation in soil-forming processes, the formation and change of soil fertility.

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Research Article Tue, 21 Nov 2023 17:54:00 +0200
Influence of spring and autumn frosts on Impatiens glandulifera populations in the Sofia region (Bulgaria) https://silvabalcanica.pensoft.net/article/103325/ Silva Balcanica 24(2): 83-90

DOI: 10.3897/silvabalcanica.24.e103325

Authors: Plamen Glogov, Despina Poupaki

Abstract: The present study aims to analyze and determine to what extent spring and autumn frosts affect the population size and life cycle of this invasive alien species (IAS). The study area is located in the immediate vicinity of the capital Sofia and covers the Iskar River stream and its tributaries in the gorge between Plana and Lozenska Mountains (Southwestern Bulgaria). The study was carried out in the period 2020-2022. Six permanent sample plots (PSP), each measuring 10 m2, were established in characteristic localities of I. glandulifera populations along the Iskar River and its tributaries (Table 1). Each year, during the spring and autumn frosts, the percentage of dead individuals of I. glandulifera relative to the total number of individuals of this species in the PSP was recorded. During the autumn frosts, the number of alive individuals in the following phenological stages was also recorded: flowering; fruiting; dispersal of fruits and seeds; end of growing season. The results show that frosts in the study area did not significantly affect the population size and life cycle of I. glandulifera. The death of the whole population оccurs only in permanent periods of negative daytime temperatures, however a significant part of the individuals at that time are in a generative stage of development. The temperature conditions in the area favor the invasiveness of I. glandulifera, extending the vegetation period of this species and the possibilities for its reproduction and spread.

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Research Article Fri, 10 Nov 2023 09:18:00 +0200
Operational properties of forestry mulchers for cleaning field protection forest belts after sanitary cuttings https://silvabalcanica.pensoft.net/article/109161/ Silva Balcanica 24(2): 59-81

DOI: 10.3897/silvabalcanica.24.e109161

Authors: Konstantin Marinov, Konstantin Kostov, Dimitar Peev

Abstract: Experimental studies were conducted with forestry mulchers in field protection forest belts and clearings in the North-Eastern region of Bulgaria. Regression models were elaborated to determine the operating performance and fuel consumption of forestry mulchers with a rated power of 70 kW to 245 kW for site preparation of clearings with the amount of wood residues, shoots and bushes from 15 t/ha to 48 t/ha. The mode of influence of the mulcher rotor speed , the concentration of comminuted biomass and the mulching unit power on the performance and fuel consumption were established. When treating clearings with small biomass concentration of 15 t/ha, the productivity of the mulching units with a greater power of 245 kW is 0.392 ha/h, and of those with a smaller power of 70 kW it is 0.086 ha/h. This difference is even greater in clearings with a biomass concentration of 48 t/ha, where the operating productivity of 245 kW mulchers is 0.304 ha/h and that of 70 kW mulchers is 0.021 ha/h. Mulching units with greater power also have a lower relative fuel consumption per unit area. This fact is more pronounced in clearings with a larger amount of wood residues of 48 t/ha, where the fuel consumption of bigger units with a power of 245 kW is 155 l/ha, of units with a medium power of 160 kW it is 217 l /ha, and of units with a smaller power of 70 kW it is 335 l/ha. For treating clearings with relatively less wood residues and shrubs of 15 t/ha, depending on the rated power of mulching units, these fuel costs are respectively 86 l/ha, 122 l/ha and 214 l/ha. The optimal power and rotor revolutions of forestry mulchers when processing cuttings with different concentrations of woody biomass were determined.

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Research Article Fri, 10 Nov 2023 08:00:00 +0200
Assessment and cultural ecosystem service mapping in mountain protected areas – “Pirin” National park https://silvabalcanica.pensoft.net/article/106658/ Silva Balcanica 24(2): 45-57

DOI: 10.3897/silvabalcanica.24.e106658

Authors: Maria Glushkova, Miglena Zhiyanski, Rositsa Yaneva

Abstract: The assessment and mapping of ecosystems and their services is considered an important action that effectively contributes to proper understanding of how ecosystems support human well-being, and furthermore – to promote the sustainable use of natural resources. The diversity of cultural landscapes, especially in mountain areas, is a significant prerequisite for a variety of cultural ecosystem services that are valuable for the society. This evaluation is the basis for environmental management practices and policymaking. The study presents an approach for assessment and mapping of cultural ecosystem service (CES) “Cultural heritage” that is recognised as important and is provided by mountain protected areas (PAs) in “Pirin” National Park. The data from the Management Plan of “Pirin” NP were used for characterization and biophysical assessment of the condition of forest ecosystems and their potential to provide CESs. The analysis of the results revealed that the conservation regime allowed the territories to preserve a high degree of naturalness and a very good ecological condition as 94.80% of forest ecosystems are assessed with score 4 –“good” condition and 0.44% are with “very good” condition – score 5. The majority of forest ecosystems with “very good” ecological condition are Pinus peuce forests, located mainly on the territory of the reserves “Bayuvi Dupki- Dzhindzhiritsa” and “Yulen”, proving the importance of the protective regime of the territories. Forest ecosystems with average and high capacity to provide ES "Cultural heritage" prevailed, which is consistent with well-preserved and unique nature, the diversity of landscapes, and species richness. Considerable areas were assessed with score 5 – very high capacity, mostly on the territory of the reserves “Bayuvi Dupki- Dzhindzhiritsa” and “Yulen”, and at the foothill of the huts.

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Research Article Tue, 29 Aug 2023 08:36:00 +0300
Local taper functions for natural black pine forests  in the Northwestern Rhodopes in Bulgaria Local taper functions for black pine https://silvabalcanica.pensoft.net/article/103848/ Silva Balcanica 24(2): 37-43

DOI: 10.3897/silvabalcanica.22.e103848

Authors: Filip Ustabashiev

Abstract: Unlike the heavily deforested Eastern or Low Rhodopes, the Western or High Rhodopes are one of Bulgaria’s main forestry areas, where black pine is widespread and economically important. Based on stem analyzes, an average taper curve for black pine stems in the Northwestern Rhodopes was determined. The method of relative taper curves (echte Ausbauchungsreihen) was used. Taper models based on spline functions and power functions were fitted. A comparison with the official assortment table of Nedyalkov was made. The systematic deviation of the sample stems from the long-used assortment table justifies the development of a local black pine table.

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Research Article Tue, 4 Jul 2023 18:47:00 +0300
4D monitoring of mountain areas using the UAV-PPK workflow https://silvabalcanica.pensoft.net/article/104499/ Silva Balcanica 24(2): 13-35

DOI: 10.3897/silvabalcanica.22.e104499

Authors: Davis Dinkov Dinkov

Abstract: The mapping and three-dimensional modeling of mountain areas and the study of land cover change dynamics are current tasks in preserving and maintaining protected natural parks and forests. In this context, recent developments in digital photogrammetry using the SfM-MVS method to process captured imagery and the development of unmanned aerial systems (UAS) allow for reducing the costs, time, and the use of human resources and obtaining and repeatable 3D topographic data for moun-tainous regions. We will call this acquired 3D high-resolution topographic data (HRTD) 4D data in the context of an additional temporal component. The main objective of this study is to evaluate the applicability of PPK (Post-Processing Kinematic) direct georeferencing of images captured by UAVs and processed through the SfM-MVS method to obtain HRTDs for 4D land cover analysis. We analyze a 3D HRTD with an acquisition interval of two years for a mountain test area in Plana Mountain near Sofia. The test area has a diverse vegetation cover, including coniferous forest, grassland, hay meadows, shrubs, and single deciduous trees. We conducted multiple surveys of the test area with a budget PPK-UAV configuration (DJI Phantom 4 Pro with a single-frequency PPK-GNSS kit installed) from March 2020 to October 2022. Two autumn surveys from September 2020 and October 2022 were se-lected, which possess the most-good performance on numerical data accuracy. We performed 3D data analysis on 1) Assessment of the accuracy of PPK-SfM-MVS photogrammetry generated topographic data (3D clouds and DSM); 2) Investigation of the errors in the individual specific surfaces (for the individual isolated sections) using the M3C2 tool for comparing and evaluating dense point clouds; 3) Determining land cover changes in the demarcated areas using a surface of differences (DoD).Accuracy analysis showed that the PPK solution provides comparable accuracy (about RMSE3D = 0.067 m for the 2020 data, georeferencing (PPK+1GCP) and RMSE3D about 0.13 m for the 2022 data, georeferencing (PPK only)) like the GCP method.The multi-temporal topographic reconstructions based on UAV- PPK-SfM allowed us to quantify and qualitatively determine the land cover changes that occurred. The UAV-PPK-SfM workflow in the context of 4D land surface monitoring and the results suggested that even low-cost UAV-PPK systems can provide data suitable for measuring geomorphic change at the scale of the acquired data. The multi-temporal topographic reconstructions based on UAV- PPK-SfM allowed us to quantify and qualitatively determine the land cover changes that occurred. The UAV-PPK-SfM workflow in the context of 4D land surface monitoring and the results suggested that even low-cost UAV-PPK systems can provide data suitable for measuring geomorphic change at the scale of the acquired data.

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Research Article Tue, 4 Jul 2023 08:46:00 +0300
Green spaces in Sofia – analyses of spatial distribution https://silvabalcanica.pensoft.net/article/101911/ Silva Balcanica 24(1): 69-80

DOI: 10.3897/silvabalcanica.22.e101911

Authors: Elena Todorova

Abstract: Green spaces in urban ecosystems is the main provider of a variety of ecosystem services. It is important for a city that undergoes dynamic changes in size, structure and number of inhabitants to manage bal-anced urban green spaces. Using the geographical information systems, this research investigates the green spaces within the building boundary of Sofia by administrative regions and confirms and demon-strates the spatial deficiencies in their distribution. The proportion of parks and gardens and open green spaces by region is taken into consideration and supplemented with analysis of the density of the tree coverage in the park. The green area per capita is calculated to demonstrate how the coverage with green spaces relates to the population. The results outline some main issues that urban development is facing towards sustainability. If considered by the planning and management of the city this could help respond to the contemporary challenges and adopt policies for a vital, healthy, and attractive environment for the capital’s residents.

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Research Article Thu, 23 Mar 2023 07:44:23 +0200
Short review of collecting technologies and methods in forest harvesting residues recovery https://silvabalcanica.pensoft.net/article/97620/ Silva Balcanica 24(1): 55-68

DOI: 10.3897/silvabalcanica.24.e97620

Authors: Mohammad Reza Ghaffariyan

Abstract: Tree felling and processing can create harvesting residues including leaves and twigs (needles), cones, barks, and branches. Collecting forest harvesting residues requires application of suitable machines and working methods. This article is aimed at reviewing the published reports to identify new harvesting machines and working methods for recovering harvesting residues and the current gaps. The scope of review included published research reports/articles from 2017 to 2022 (last five years). This global review results showed that popular methods for residue collection are chipping residues at roadside/landing and integrated biomass recovery. Forwarder, cable yarder and in-field chipper are predominantly applied within various recovery methods depending on ground and stand conditions. Harvesting residues are one of the promising sources for bioenergy production which requires developing efficient and low-cost harvesting systems. Latest research findings indicate that piling harvesting residues by a harvester-pro-cessor can improve the collecting productivity by the forwarder within cut-to-length harvesting opera-tions. Integrating residue biomass recovery with conventional timber supply can reduce the total supply chain cost by 2%. Researchers also recommend applying more climate-friendly technologies and focus-ing on developing new machines with lower fuel consumption and subsequent emissions. Future studies can focus on the following subjects; a) to determine the productivity and cost rates of various residue recovery systems, b) to develop and test technologies with lower fuel consumption rates and c) to find in-novative solutions to utilize thinning materials and best practices to store and process biomass materials.

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Review Article Wed, 22 Mar 2023 11:51:00 +0200
Outcrossing rates in two seed orchards of Pinus nigra Arn. in Bulgaria https://silvabalcanica.pensoft.net/article/101560/ Silva Balcanica 24(1): 47-54

DOI: 10.3897/silvabalcanica.24.e101560

Authors: Stanimira Shuleva, Velichko Gagov, Petar Zhelev

Abstract: Seed orchards are an important source of seeds with improved genetic quality. Here we present results of a study on the genetic composition of seed orchards crop of Austrian black pine (Pinus nigra Arn.). Two seed orchards were included in the study – a clonal seed orchard established near Sliven, and a seedling seed orchard, established in the region of Simitli. The outcrossing rates were higher in the clonal seed orchard (Sliven), 0.873 and 0.806 multi-locus (tm) and single-locus (ts) estimates, respectively. The same values were 0.623 and 0.530, respectively, in the seedling seed orchard (Simitli). The inbreeding coefficient was positive in both cases, but was significantly different from zero in the clonal seed orchard only (0.101 vs. 0.032). Thus, the two studied seed orchards demonstrate different genetic efficiency. The results are discussed in relation to seed orchard management and efficiency.

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Research Article Tue, 28 Feb 2023 08:00:03 +0200
Studies on Manna ash (Fraxinus ornus L.) In Bulgaria https://silvabalcanica.pensoft.net/article/101459/ Silva Balcanica 24(1): 35-45

DOI: 10.3897/silvabalcanica.24.e101459

Authors: Stela Gyudorova

Abstract: The purpose of this publication is to review and analyze the main studies of Manna ash in Bulgaria in order to present summarized information and acquire an objective view of the possibilities for proper perception of the importance of this local tree species and its use in various aspects of science and practice in our country. The study covers the period from the second half of the 1940s, when the first specialized journals in the field of forest science were published, until 2022. The focus of the study is on publications related directly or indirectly to various aspects of research on manna ash. The tracking of the chronology of forestry studies in Bulgaria shows trends towards a change in the perception of Manna ash as an inferior species and the search for its benefits for forestry practice, including rethinking its role from one of a weed species into an adjustable competitor, stimulating the regeneration of oaks and others indigenous species in plantations.The role of phytocoenological studies, which in relation to the Manna ash communities, both in natural and artificial forest plantations, with its participation have increased in recent years. With their help, it is possible to trace the stages of successions and fluctuations and behavior of Manna ash in xerothermic oak forests and austian pine crops – its ecological-coenotic strategy towards the main tree species.The studies of Manna ash in Bulgaria in the field of special uses are close to their European analogues and in a number of cases overtake them with new data and discoveries, mostly in terms of biologically active products and antiallergic agents obtained from this plant species, among which we have world patents.

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Research Article Tue, 28 Feb 2023 08:00:02 +0200
Using high precision climate data for wildfire risk assessment https://silvabalcanica.pensoft.net/article/101192/ Silva Balcanica 24(1): 5-16

DOI: 10.3897/silvabalcanica.24.e101192

Authors: Elena Todorova, Miglena Zhiyanski, Leonid Todorov

Abstract: The present study is focused on examining the changes of key weather parameters using detailed daily data for the period 1985-2021 in an area of interest situated in Rila mountain in Bulgaria which is a territory that is prone to wildfires. Using this long-term horizon, the research defines the main climate factor trends and relates them with real events of wildfires by using the Angström index and statistical methods with focus on outlining specific weather conditions that indicate fire risk. As a result, the Angström index was proven to be a reliable source for determining the potential weather conditions for fire occurrence in the area of interest, part of protected area BG0000496 Rilski manastir. Low relative humidity was identified as the main factor influencing fire occurrence in the reviewed real wildfire events. Specific range and behavior of the key weather parameters, influencing wildfire occurrence were detected. These findings could be a good source of information when elaborating a forest fire prevention system and may help for appropriate prioritization of factors and management of resources.

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Research Article Fri, 24 Feb 2023 17:47:00 +0200
Microbial cellulose: an alternate source for plant cellulose https://silvabalcanica.pensoft.net/article/84213/ Silva Balcanica 23(2): 69-81

DOI: 10.3897/silvabalcanica.23.e84213

Authors: L. Sarvananda, P.R.M.K. Fernando, P.A.D.S. Palihaderu, Amal D. Premarathna

Abstract: In the contemporary generation, rapid urbanization, industrialization, and declining woodland lead to global weather modifications. The massive scale of deforestation for firewood, constructions, paper products, textile, and plenty of different packages are steadily enforcing a critical poor impact on the surroundings. Inherently, plant cellulose has restrained utility because of the presence of hemicellulose and lignin. Consequently, studies in the discipline of microbial cellulose display many benefits over plant cellulose. It possesses numerous crucial and unique properties compared to plant cellulose, including high purity, better absorptivity, excellent polymerization, crystallization, in-situ mold potential, biodegradability, biocompatibility, and plenty of others. This assessment looks into a potent cellulose producer to develop an economically feasible manner for huge-scale production of microbial cellulose therefore, it may replace some of the requirements where plant cellulose has been currently in use.

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Review Article Tue, 20 Dec 2022 17:15:00 +0200
Work productivity assessment of small forwarders in forest operations: An international review https://silvabalcanica.pensoft.net/article/91143/ Silva Balcanica 23(2): 55-68

DOI: 10.3897/silvabalcanica.23.e91143

Authors: Mohammad Reza Ghaffariyan

Abstract: There are two types of forwarders available in the practice including conventional forestry forwarders and farm tractors equipped with a trailer/grapple loader that operate as a forwarder. Forwarders loading capacity can vary depending on the machine size. This paper aimed to review the work productivity of small size forwarders (payload

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Review Article Tue, 20 Dec 2022 17:14:00 +0200
Survival and growth of Common beech (Fagus sylvatica L.) provenances in North-Eastern Bulgaria https://silvabalcanica.pensoft.net/article/95109/ Silva Balcanica 23(2): 5-17

DOI: 10.3897/silvabalcanica.22.e95109

Authors: Krasimira Petkova, Emil Molle, Aysel Mustafova

Abstract: Two provenance tests in North-Eastern Bulgaria have been studied, whose purpose is to test the response of beech provenances from Southern Germany to the drier and warmer climatic conditions in Bulgaria, in order to predict how they would perform in a warming and drying climate. The provenance tests were established in the spring of 2010 in the area of the Varbitza and Kipilovo Forest Services with 2-year-old seedlings in a 2 x 1 m scheme in 3 replications. Four provenances of common beech were studied - 2 German (Silberbach and Ebersdorf) and 2 Bulgarian (Petrohan and Berkovitza). On the 12th year after afforestation, an inventory and measurements of the height and root collar diameter were carried out. The results were processed statistically by applying one and two-factor analysis of variance, as well as Tukey’s test for multiple comparisons. A higher survival rate was found in the provenance test in Kipilovo. The Bulgarian provenances Petrohan and Berkovitza were characterized by better growth in height in both provenance tests, and in root collar diameter - provenance Petrohan. Provenance Ebersdorf could be recommended for use in drier and warmer places in Southern Germany.

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Research Article Tue, 20 Dec 2022 17:13:00 +0200
Using the EPM method for the estimation of soil erosion in forest territories in the upper part of Dzherman River https://silvabalcanica.pensoft.net/article/96504/ Silva Balcanica 23(2): 19-25

DOI: 10.3897/silvabalcanica.22.e96504

Authors: Eli Pavlova-Traykova

Abstract: One of the most vulnerable to soil erosion parts in Bulgaria is the Struma river watershed. In the past, a lot of erosion control activities have been carried out in this catchment, but the topographic condition and easily prone to soil erosion soils are still redounding to erosion processes. As a global problem with severe effects on the environment, soil erosion is on the agenda of scientific community. Because of difficult recognition on time, various methods for erosion risk and sediment loss assessment were applied. For mountainous watersheds one of the most appropriate approach is Erosion Potential Model (EPM). The study aims to evaluate soil erosion and investigate its spatial distribution by applying EPM, also known as Gavrilovic method. The object of investigation is the upper part of the Dzherman river, which is tributary of Struma river. The method was implemented only for forest territories to determine the most vulnerable part of the forest. The results showed that for the forest territories the average value of the coefficient Z is 0.19, which defines erosion as “low” and the average soil loss only for forest areas is 15.28 m3/km2/year. Nevertheless there are territories with more than 100 m3/km2/year.

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Research Article Tue, 20 Dec 2022 17:12:00 +0200
Study on the level of operational reliability of diesel engines for backhoe loaders https://silvabalcanica.pensoft.net/article/96802/ Silva Balcanica 23(2): 47-54

DOI: 10.3897/silvabalcanica.23.e96802

Authors: Svetozar Madzhov

Abstract: In the present study the main numerical characteristics of the reliability indicators for the Komatsu SAA4D104E-1 engines of the KOMATSU WB93R-5 backhoe loader have been determined, and the laws of resource allocation have been established.To study the level of reliability of machines, a methodology for experimental research has been developed, where the complex, comparative and formal methods, as well as the systematic, cybernetic and statistical approach have been used. It has been found that increasing the level of reliability of the engine elements can be improved by increasing the quality and timeliness of the repair and maintenance activities and compliance with the rules of operation.This study is a continuation of a study conducted by the author.

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Research Article Tue, 20 Dec 2022 17:10:00 +0200
Integrated approach for health status assessment of urban forests in the municipalities of Etropole  and Pravets, Bulgaria https://silvabalcanica.pensoft.net/article/91220/ Silva Balcanica 23(1): 89-102

DOI: 10.3897/silvabalcanica.23.e91220

Authors: Margarita Georgieva, Georgi Georgiev, Miroslav Ivanov, Konstantin Tyufekchiev, Sevdalin Belilov, Yonko Dodev, Plamen Glogov, Mira L. Georgieva, Grud Popov, Svetozar Madzhov

Abstract: In 2020, the health status of urban forests in Etropole and Pravets municipalities was monitored based on remote sensing data and field assessment. The study provides information for early detection and identification of pests and pathogens causing damage in different forest types. Three forest stands were assessed: Scots pine (Pinus sylvestris) plantation near the town of Etropole, European beech (Fagus sylvatica) natural stand near Etropole Monastery, and Quercus spp. coppice stands in ‘Nebesnite Pasbishta’ forest park near Osikovitsa village. In two sample plots (town of Etropole and Osikovitsa village), remote sensing data were obtained by a ‘Parrot Sequoia’ multispectral camera integrated with a specialized professional system eBee ‘Flying Wing’. Normalised difference vegetation index (NDVI) was assessed by digital mixing of imagery, captured in the red and near-infrared range. It was established that the Scots pine plantations were weakened, with NDVI values between 0.66 and 0.75. The oak stands in the area of Osikovitsa village were in better health condition (NDVI mainly 0.79-0.98). Symptoms of diseases and pest damage were found during the field verifications. Severe deterioration caused by the invasive fungal pathogen Dothistroma septosporum had destroyed the pine plantation near Etropole. The pathogen caused premature needle defoliation, resulting in loss of timber yield and, in severe cases, tree death. In oak stands, damage was caused mainly by the invasive insect pest – oak lace bug (Corythucha arcuata). In Fagus sylvatica forests damage was caused mainly by abiotic factors (snow and wind), and wood destroying fungus Fomes fomentarius.

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Research Article Wed, 17 Aug 2022 12:26:00 +0300
Effect of tree shelters on the survival and growth of coniferous tree species in Central South Bulgaria https://silvabalcanica.pensoft.net/article/84286/ Silva Balcanica 23(1): 67-78

DOI: 10.3897/silvabalcanica.23.e84286

Authors: Krasimira Petkova, Nasko Iliev, Martin Borisov, Martin Sattler

Abstract: The effects of tree shelters on the survival, height and diameter growth of three coniferous tree species – Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and Silver fir (Abies alba Mill.) were observed. The study was conducted in two experimental plantations, established in the spring of 2016 in the Training and Experimental Forest Range Jundola (Central South Bulgaria). Three experimental variants with tree shelters – Tubex Ventex Classic, Layflat Shelterguard, Layflat Treeguard and a control one (without tree shelters) were used. Twenty to twenty-five seedlings in three replications of each variant and tree species were planted. The experimental plantation 1 included Scots pine and Norway spruce and was established on a south east-facing terrain at an altitude of 1400 m. The soil is Cambisols (FAO) mixture of clay and sandy, medium stony, medium deep to deep. The habitat is medium rich, slightly moist. The experimental plantation 2 is of Silver fir and was located on an east-facing terrain at an altitude of 1400 m. The soil is Cambisols (FAO) mixture of clay and sandy, medium stony, medium deep to deep. The habitat is medium rich, slightly moist to moist.In the autumn of the fifth year after the establishment, inventories and measurements of heights, height increment and groundline diameter of the seedlings were made. The survival in both experimental plantations was higher in the variants with tree shelter. The height growth of all tree species was better in tree shelter variants, with the highest average height in the variant with Tubex Ventex Classic. The biggest height increment was established in the variant with Layflat Shelterguard for Norway spruce and Silver fir and in variant without tree shelters for Scots pine. The ground line diameter was highest in control variant for Scots pine and Norway spruce and in the variant with Layflat Treegard for the Silver fir.

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Research Article Wed, 10 Aug 2022 08:21:00 +0300
Silvicultural aspects of the sycamore (Acer pseudoplatanus L.) propagation – Overview https://silvabalcanica.pensoft.net/article/82756/ Silva Balcanica 23(1): 37-55

DOI: 10.3897/silvabalcanica.22.e82756

Authors: Nasko Iliev, Lyubka Varbeva, Neno Alexandrov

Abstract: The purpose of this study is to analyze existing silvicultural experience related to the sycamore using literary data in order to optimize future work with the species. The discussion looks into matters related to: ecological requirements, seed propagation, vegetative propagation via rooting of stem cuttings and grafting, natural regeneration specifications, creating and cultivation of forest plantations, growth and productivity of the stands, and silviculture activities dedicated to the production of high-quality timber.

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Review Article Fri, 20 May 2022 18:01:00 +0300
An overview of work productivity evaluation of farm tractors in timber skidding operations https://silvabalcanica.pensoft.net/article/82383/ Silva Balcanica 23(1): 21-36

DOI: 10.3897/silvabalcanica.23.e82383

Authors: Mohammad Reza Ghaffariyan

Abstract: Farm tractors have been applied in forest operations to carry out several tasks such as tree/felling/process-ing, forwarding, loading, skidding and cable yarding. Farm tractors can be equipped with special logging equipment that allows for their safe and efficient work in the harvesting of forest stands. This research is aimed to collect and review available literary sources on the productivity of farm tractors during skidding operations. The study results showed that work productivity of farm tractors for timber skidding has been studied by several researchers around the world. According to the results, the reported work productivity of skidding with farm tractors varied from 1.2 m3/PMH0 to 15.8 m3/PMH0 among international studies. Main variables impacting the work productivity of skidding included skidding distance, load volume, number of pieces per turn, tree diameter, tree length, slope of skid trails and engine power. Proper skid trail planning, applying suitable skidding equipment (e.g. winches, sulkies etc.), considering suitable engine size and prop-er safety standards can all help improving the work efficiency of the farm tractors during timber extracting. The information provided in this research can help the forest industry users and researchers gain proper knowledge on the work productivity of farm tractors applied for timber skidding. The study results can be also useful for planning and development purposes within small-scale forest operations.

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Review Article Thu, 21 Apr 2022 17:31:00 +0300
Dendrochronological analysis of the influence of climate on autochthonous and introduced coniferous tree species in the city park “Prostor”, Kardzhali https://silvabalcanica.pensoft.net/article/79249/ Silva Balcanica 23(1): 11-19

DOI: 10.3897/silvabalcanica.23.e79249

Authors: Dimitar Petrov Dimitrov, Miglena Zhiyanski

Abstract: The study focuses on the response to climate change of indigenous and introduced coniferous tree species – Austrian black pine (Pinus nigra Arn.) and Colorado spruce (Picea pungens Engelm.) situated in the urban city park “Prostor” in the town of Kardzhali. A multifactor regression analysis was used in the frame of the dendrochronological studies to establish the functional dependence “climate – radial growth”. The model was tested in a climate window with a segment of 16 years – from 2005 to 2020. The data for air temperature and monthly precipitation amounts for Hydro-meteorological station (HMS) Kardzhali were used as predictors for the radial growth. = Both species’s indifference to the temperatures and rainfalls during the months August and September, crucial for the ring formation, leads to the absence of significant growth depressions in tree-rings chronologies and justifies the good condition of the studied trees.

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Research Article Fri, 18 Mar 2022 17:46:00 +0200
Assessing the carbon stock changes in forest soils in Bulgaria https://silvabalcanica.pensoft.net/article/76252/ Silva Balcanica 22(3): 69-78

DOI: 10.3897/silvabalcanica.22.e76252

Authors: Lora Stoeva, Lora Kirova

Abstract: Forest soils are a key element of the forest ecosystems which could contribute to carbon storage and climate change mitigation. The carbon sequestration and storage potential of the forest soils, however, depends to a great extent on the forestry operations and forest management activities carried out in the forest. There is a widely accepted assumption that under a set of climate and management conditions the carbon content in the forest soils is at equilibrium. However, different factors like management activities, productivity, decay rates and/or natural disturbances could alter the carbon dynamics of forest soils. The aim of the current study was to assess the carbon stock and the carbon stock changes in mineral forest soils in Bulgaria based on the forest soil monitoring information gathered under the ICP Forest Programme. For that purpose, a dataset from the programme on mineral forest soils from 1998 was processed and analysed. The carbon stock for each sample plot was estimated for the 0-30 cm layer. The carbon stock change was calculated for all the sample plots with repeated measurements over the study period. The results were further analysed with parametric and non-parametric statistical tests to assess whether the carbon stock changes are significant. However, the lack of other relevant observations within the monitoring implementation such as litter decomposition, turnover rates, climatic conditions, etc., hinder the application of dynamic soil carbon models in assessing and predicting the current and the future rate of the soil carbon in forests in Bulgaria.

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Research Article Fri, 31 Dec 2021 15:41:00 +0200
Spassimir Tonkov (2021): The Postglacial Vegetation History in Southwestern Bulgaria. A Paleoecological Approach https://silvabalcanica.pensoft.net/article/80737/ Silva Balcanica 22(3): 79-79

DOI: 10.3897/silvabalcanica.22.e80737

Authors: Spassimir Tonkov

Abstract: Book Review

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Book Review Fri, 31 Dec 2021 12:25:00 +0200
Acute toxicity of Galium odoratum to the freshwater cladoceran Moina macrocopa https://silvabalcanica.pensoft.net/article/77816/ Silva Balcanica 22(3): 49-55

DOI: 10.3897/silvabalcanica.22.e77816

Authors: Mariam Bozhilova

Abstract: Galium odoratum (L.) is a medicinal plant with a number of health benefits, used in traditional and modern medicine. The toxicity of the coumarin in Galium odoratum is classified as high, however, no experimental data or data on toxic effects in humans following intake of Galium odoratum are available. The potential toxic effect can be estimated based on the content of coumarin and knowledge of its toxicity.The aim of the current study is to evaluate the acute toxicity effects of a range of concentrations of Galium odoratum water extract on Moina macrocopa and calculate the LC50 within 24 hours. In order to compare the toxicity with those of other, well-known and widely used medicinal plants, extracts of Matricaria chamomilla and Tribulus terrestris are also tested. The results show that LC50 value of Galium odoratum is comparable with those of Matricaria chamomilla and Tribulus terrestris, and Galium odoratum has intermediate toxicity between the two other studied species.

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Research Article Wed, 29 Dec 2021 08:43:00 +0200
Green roofs – good regulatory practices with potential to be applied in Bulgaria and North Macedonia https://silvabalcanica.pensoft.net/article/75511/ Silva Balcanica 22(3): 29-39

DOI: 10.3897/silvabalcanica.22.e75511

Authors: Mariam Bozhilova, Miglena Zhiyanski, Biljana Stojanova, Plamen Glogov

Abstract: Green roofs are used worldwide to mitigate the impacts of extensive urbanization, bringing benefits on social, economic, and environmental levels. In order to promote and facilitate the construction of green roofs by private investors, many countries have developed specific legislative requirements and incentives. However, there still are countries where the construction of green roofs is not properly addressed in the legislation, and where no incentive mechanisms are developed. The good practices in three European countries, leaders in regards to the implementation of green roofs – the Netherlands, Belgium, and Germany, are analyzed in this article. A variety of incentives is introduced to accelerate the construction of green roofs. Different requirements are also set to ensure that the roofs will be designed and maintained to provide the desired benefits. The existing local regulations in Bulgaria and North Macedonia were analyzed as well. The only incentive in Bulgaria is the possibility of reducing the legally required green area by compensating it with a green roof. In North Macedonia, no legislative documents or incentives related to green roofs were found.The regulations, applied in the Netherlands, Belgium, Germany, and other countries can be used as good practice examples, modified, and applied from the authorities of countries that still have not developed their own, in order to motivate the investors and facilitate the construction of green roofs.

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Research Article Thu, 16 Dec 2021 09:57:00 +0200
Predicting productivity of timber loading operations: a literature review https://silvabalcanica.pensoft.net/article/69240/ Silva Balcanica 22(2): 81-90

DOI: 10.3897/silvabalcanica.22.e69240

Authors: Mohammad Reza Ghaffariyan

Abstract: Loading is considered a bottleneck of the forest harvesting system as it acts as a connection between primary transport and secondary transport (from roadside/ landing to mills or central yards). Any delay during the loading component can cause delay in the primary wood extraction and/ or secondary transportation. This article reviewed the current knowledge on loading productivity studies. Based on the results, the main variables impacting the loading productivity include log size, log lengths, load volume per truck, number of logs (or pieces) per truck and number of safety straps. The productivity of loading operations ranged from 3.4 m3/PMH0 in a manual loading to 168.9 m3/PMH0 using mechanised loaders. The results of this review can assist the academic and industrial users for predicting, controlling and managing the productivity of loading operations.

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Research Article Wed, 20 Oct 2021 11:53:00 +0300
Challenges of assessment and mapping of ecosystem services in Bulgarian (Rhodope) and Russian (Altai) mountain protected areas in the context of post-socialist transformations and new conservation paradigms https://silvabalcanica.pensoft.net/article/69861/ Silva Balcanica 22(2): 43-68

DOI: 10.3897/silvabalcanica.22.e69861

Authors: Dmitry V. Chernykh, Maria Glushkova, Dmitry K. Pershin, Miglena Zhiyanski, Alina E. Zinovieva, Dmitry V. Zolotov, Lilia F. Lubenets, Roman Yu. Biryukov

Abstract: The overarching goal of this survey was to identify the challenges of ecosystem services assessment and mapping in Russian and Bulgarian mountain protected areas in the context of post-socialist transformations, new conservation paradigms and climate change. The Altai Mountains in Russia and the Rhodope Mountains in Bulgaria were selected as key mountain territories for comparison due to their similar characteristics: agriculture, forest exploitation, tourism activities, etc. Both in Bulgaria and in Russia, perceptions of the protected areas functioning have been changing, facilitated by global shifts. Thus, the concept of ecosystem services has now been actively introduced in nature and biodiversity conservation policies. Based on WDPA data the emergence of different types of protected areas in Russia and Bulgaria was determined. Key problems of assessment and mapping of ecosystem services in Russian and Bulgarian mountain protected areas were recognised, mainly related to the shortage and quality of baseline data. At the same time, there were also some specifics for the two countries due to their size and national legislation. Like many other mountainous regions in the world, the Rhodopes in Bulgaria and the Altai Mountains in Russia are flagships in the improvement of nature conservation strategies. These regions often participate in a variety of international conservation programmes and are constantly expanding the range of protected areas. It is generally accepted that the Altai Mountains and the Rhodopes are not only centres of biodiversity richness in their countries, but also hotspots of a variety of ecosystem services.

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Research Article Wed, 20 Oct 2021 07:23:00 +0300
Insect pests and their role as biocontrol agents on populations of Impatiens glandulifera in Bulgaria – a case study https://silvabalcanica.pensoft.net/article/72662/ Silva Balcanica 22(2): 33-41

DOI: 10.3897/silvabalcanica.22.e72662

Authors: Gergana Zaemdzhikova, Plamen Glogov

Abstract: Based on data from available scientific publications, a review of the insects, trophically related to Impatiens glandulifera in its European invasion zone has been made. As a result, nine insect species (Pristerognatha fuligana, Deilephila elpenor, Xanthorhoe biriviata, Chrysolina herbacea, Siobla sturmi, Impatientinum asiaticum, Aphis fabae, Aphis nasturtii, Phytoliriomyza melampyga) were found on the invasive plant. Of the identified insects, seven species (D. elpenor, X. biriviata, A. fabae, A. nasturtii, C. herbacea, P. fuligana, P. melampyga) are widespread in the country, of which only two – C. herbacea and P. fuligana are associated with I. glandulifera. The remaining two (I. asiaticum and S. sturmi) are not pre-sented in the Bulgarian entomofauna. Тhe potential role of these insects as agents of biological control of populations of I. glandulifera in Bulgaria has been assessed.

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Research Article Fri, 8 Oct 2021 07:13:00 +0300
A short review on studies on work productivity of mechanical tree planting https://silvabalcanica.pensoft.net/article/64233/ Silva Balcanica 22(2): 25-32

DOI: 10.3897/silvabalcanica.22.e64233

Authors: Mohammad Reza Ghaffariyan

Abstract: Reforestation can be carried out using natural regeneration or artificial regeneration. There are vari-ous methods for the artificial regeneration, including manual planting, mechanical planting and aerial/or ground seeding. This article aimed to review the current reports on the productivity of mechanical planting to provide a summary of productivity rates for the planting machines. According to the review’s results, mechanical planting productivity may vary from 143 to 475 seedlings per productive machine hours depending on the machine type, environment (such as surfaces obstacles and stoniness) and the operator experience. Employing skilled operators and selecting suitable worksites can help increasing the work productivity. Integrating and optimising the whole planting chain, from the nursery to the plant-ing phase, can assist also with reducing the cost and improving the productivity. As mechanical planting machines get more widely adopted in different countries, their overall efficiency will improve over time.

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Research Article Tue, 5 Oct 2021 08:35:00 +0300
Possible benefits from greening of public transport stops in Sofia, Bulgaria https://silvabalcanica.pensoft.net/article/69245/ Silva Balcanica 22(2): 17-24

DOI: 10.3897/silvabalcanica.22.e69245

Authors: Mariam Bozhilova, Miglena Zhiyanski

Abstract: Public transport shelters provide an unused surface that can be utilized in various ways, including for unconventional landscaping. The benefits from greening of public transport shelters are insufficiently studied and unutilized. The article evaluates some of the benefits which may result from the construction of green public transport shelters in the central part of Sofia.There are a total of 2780 aboveground public transport stops in Sofia. In the surveyed area are located 257 stops, 150 of which currently have shelters. The potential of greened shelters to remove PM10 and CO2 from the ambient air is estimated for several different scenarios. If 250 public transport shelters are entirely greened (roof and 3 walls) with Festuca sp., the removed PM10 will be about 20 kg/yr, or 0.01% of the yearly emissions of PM10 from transport in the surveyed area. The sequestered CO2 will be 17047.3 kg /yr., or approximately the CO2 emitted by 40 diesel cars with an average daily mileage of 10 km per day for a year. The reduction of PM10 and CO2 is not significant, however, in a big city with intensive construction and a constantly increasing population, every possibility for greening needs to be explored. Green stops may be used in combination with other measures. Proper selection of plant species and design solutions maximizing the green surface will increase the benefits.

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Research Article Tue, 27 Jul 2021 10:25:00 +0300
Review of studies on motor-manual felling productivity in eucalypt stands https://silvabalcanica.pensoft.net/article/58750/ Silva Balcanica 22(1): 77-87

DOI: 10.3897/silvabalcanica.22.e58750

Authors: Mohammad Reza Ghaffariyan

Abstract: Globally, about 20 million ha of land area is occupied by plantations of Eucalyptus. Motor-manual tree harvest-ing techniques (using chainsaws) are still applied in eucalypt plantations, especially in difficult terrains or for large- sized trees where mechanised felling may not be an effective and safe possible option to apply. There is little information available on motor-manual felling in eucalypt stands. This article reviewed available literature on the productivity of motor-manual felling. The results were classified into four regions, including Africa, Asia/Oceania, America and Europe. Results of international studies indicate that the main factors impacting the productivity of motor-manual felling include diameter at the breast height (DBH), travelling distance to trees, understory density and terrain slope. Operator experience also plays a key role in felling operations. The range of reported productivity varied from 0.6 m3/PMH0 to 48.9 m3/PMH0 in different regions. This article provides key recommendations on improving motor-manual felling productivity, which can provide a guide for sustainable harvesting planning purposes.

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Review Article Fri, 19 Mar 2021 10:00:07 +0200
Effect of wastewater sludge treatment on early growth and physiological responses of willow (Salix spp.) and poplar (Populus spp.) pot-grown plants https://silvabalcanica.pensoft.net/article/58528/ Silva Balcanica 22(1): 57-65

DOI: 10.3897/silvabalcanica.22.e58528

Authors: Ivaylo Tsvetkov, Nikolina Tzvetkova, Svetla Marinova

Abstract: Combining biomass production from fast-growing woody species with wastewater treatment is an attractive concept from the economic, energy and environmental points of view. A pilot experiment on study-ing the effect of wastewater treatment on the early growth and initial physiological responses of willow and poplar plants was carried out in greenhouse conditions. The survival, height growth, net photosyn-thesis, stomatal conductance and transpiration of two hybrid clones of black poplar (Populus x euroameri-cana (Dode) Guinier) (I-214 and I-45/51) and white willow (S. alba L.) pot-grown plants treated with different doses of agrochemically characterised wastewater sludge were studied during the establishment year. The height growth and number of resprouted willow shoots were also measured during the second year after cutting, at the end of the vegetation season. While the early growth height of poplar clones was markedly affected by the clone origin and wastewater sludge treatment, the latter did not considerably influence the height of the willow plants either during the establishment and the following year, but essentially increased the number of resprouted shoots during the second vegetation season. The rate of CO2 assimilation of willow plants was significantly influenced by the wastewater sludge treatment, with plants grown at the higher doses displaying higher photosynthetic performance. The application of wastewater sludge had no essential impact on the values of the physiological parameters of the poplar plants, but particular responses were found among the clones.

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Research Article Fri, 19 Mar 2021 10:00:05 +0200
Economics of forest biomass for bioenergy: potential site preparation savings from coarse woody harvesting residue removal in a short-rotation Eucalyptus globulus (Labill.) plantation https://silvabalcanica.pensoft.net/article/58636/ Silva Balcanica 22(1): 45-55

DOI: 10.3897/silvabalcanica.22.e58636

Authors: Martin Strandgard, Mathieu Béland

Abstract: The study used time studies and cost analysis to assess potential economic benefits from site preparation cost reductions resulting from producing coarse woody harvesting residue (CWHR) for bioenergy. In contrast, previous studies have predominantly used anecdotal estimates of site preparation costs.The study was performed in a recently clearfelled 15-year-old plantation of Eucalyptus globulus (Labill) in Tasmania, Australia. The study area consisted of the control area (0.51 ha), containing ~35 m3 ha-1 of CWHR and the CWHR harvest area (2.47 ha), containing ≤12 m3 ha-1 of CWHR. The control area had been harvested with a harvester – forwarder system, which left all harvesting residue (HR) onsite, where-as the CWHR harvest area had been harvested with a feller-buncher – skidder – processor system which removed most of the HR. The latter site was used to simulate an area where CWHR had been harvested. The study examined productivities and costs of machines performing site preparation in each area. The preparation of the control area site was performed with an excavator that windrowed CWHR, fol-lowed by a skidder-mounted plough constructing planting furrows. Residual CWHR post-windrowing was <1 m3 ha-1. Productivities and costs were 0.53 ha PMH0-1 and AUD$319 ha-1 for the excavator and 1.1 ha PMH0-1 and AUD$139 PMH0-1 for the skidder-mounted plough. The excavator was not required in the CWHR harvest area. In this area, skidder-mounted plough productivity and cost were 1.16 ha PMH0-1 and AUD$109 ha-1 suggesting CWHR reduction to ≤12 m3 ha-1 could reduce site preparation costs by AUD$319 ha-1. Further studies on costs and revenues associated with CWHR removal and sale are required to determine net economic benefits and determine excavator cost and productivity for a range of CWHR quantities.

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Research Article Fri, 19 Mar 2021 10:00:04 +0200
Comparison of tree diameter distributions in managed and unmanaged Kazdağı fir forests https://silvabalcanica.pensoft.net/article/58020/ Silva Balcanica 22(1): 31-43

DOI: 10.3897/silvabalcanica.22.e58020

Authors: Ferhat Kara

Abstract: Forest structural complexity affects tree growth, species diversity, understory seedling density, wildlife habitat and fire behaviour. Thus, defining the structural complexity of forest ecosystems would play a crucial role in their management. The vertical structure in stands of shade-tolerant tree species can be described by using the distribution of tree diameters. In this study, the main objective was to determine and compare the diameter distribution patterns of managed and unmanaged Kazdağı fir (Abies nordmanniana subsp. equi-trojani) forests in northern Turkey. Hierarchical clustering analysis was used to define the diameter distribution patterns. Three main diameter distribution patterns were examined in both managed and unmanaged forests. Two of the patterns in the managed forest did not possess the expected diameter structure of selection silviculture (i.e. reverse J-shape). The observed patterns in the unmanaged forest were mostly representative of the diameter structure of old-growth forests. Given the initial findings, it is likely that the small-scale disturbances created by selection methods may not be adequate to establish and recruit sufficient number of trees into small- diameter sizes in Kazdağı fir forests. The assessment of patterns of tree diameter distribution in these forests would create a basis for future research, aiming to enhance the structural complexity.

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Research Article Fri, 19 Mar 2021 10:00:03 +0200
Biofertlizer Lumbrical improves the growth and ex vitro acclimatization of micropropagated pear plants https://silvabalcanica.pensoft.net/article/57661/ Silva Balcanica 22(1): 17-30

DOI: 10.3897/silvabalcanica.22.e57661

Authors: Nataliya Dimitrova, Lilyana Nacheva, Małgorzata Berova, Danuta Kulpa

Abstract: In vitro micropropagation of plants is highly useful for obtaining large quantities of planting material with valuable economic qualities. However, plantlets grow in vitro in a specific environment and the adaptation after the transfer to ex vitro conditions is difficult. Therefore, the acclimatization is a key step, which mostly determines the success of micropropagation. The aim of this investigation was to study the effect of the biofertlizer Lumbrical on ex vitro acclimatization of micropropagated pear rootstock OHF 333 (Pyrus communis L.). Micropropagated and rooted plantlets were potted in peat and perlite (2:1) mixture with or without Lumbrical. They were grown in a growth chamber at a temperature of 22±2 °C and photoperiod of 16/8 hours supplied by cool-white fluorescent lamps (150 µmol m-2 s-1 Photosynthetic Photon Flux Density, PPFD). The plants were covered with transparent foil to maintain the high humidity, and ten days later, the humidity was gradually decreased. Biometric parameters, anatomic-morphological analyses, net photosynthetic rate and chlorophyll a fluorescence (JIP test) were measured 21 days after transplanting the plants to ex vitro conditions. The obtained results showed that the plants, acclimatized ex vitro in the substrate with Lumbrical, presented better growth (stem length, number of leaves, leaf area and fresh mass) and photosynthetic characteristics as compared to the control plants. This biostimulator could also be used to improve acclimatization in other woody species

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Research Article Fri, 19 Mar 2021 10:00:02 +0200
First records of a potentially new plant community from the ruderal vegetation in the Black Sea Coast, Bulgaria https://silvabalcanica.pensoft.net/article/56860/ Silva Balcanica 22(1): 5-15

DOI: 10.3897/silvabalcanica.22.e56860

Authors: Plamen Glogov, Mira L. Georgievа

Abstract: The paper presents the first data of an unreported plant community dominated by Hordeum leporinum Link and Bituminaria bituminosa (L.) Stirt. (class Stellarietea mediae R. Tx., Lohmeyer et Preising in R.Tx. 1950). It is currently established in four localities in the region of the Black Sea coast, between the town of Ravda and the town of Nessebar, Bulgaria. Among the characteristic features of the community are: (i) it occupies places with an active human presence near the beach; (ii) preferences for shallow san-dy or rocky soils; (iii) Bituminaria bituminosa (L.) Stirt. as a dominant, diagnostic and constant species for the community. Other diagnostic species for the association are Anchusa officinalis L., Malva sylves-tris L., Sonchus arvensis L. and Avena fatua L. (iv) annual and perennial species have an equal participa-tion in the community; (v) increased presence of diagnostic species for the class Artemisietea vulgaris Lohmeyer et al. ex von Rochow 1951. Phytogeographically, the species composition of the community has a strong Mediterranean influence. In close proximity to its reléves there are always communities of xerophytic shrubs or low trees (in many cases alien species, such as Amorpha fruticosa L., Ziziphus jujuba Mill. and Robinia pseudoacacia L.) that participate in the association without forming a full second layer (their cover abundance is less than 30%).

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Research Article Fri, 19 Mar 2021 10:00:01 +0200
Legislative requirements related to substrate depth as a barrier to the construction of green roofs in Bulgaria https://silvabalcanica.pensoft.net/article/56917/ Silva Balcanica 21(2): 99-104

DOI: 10.3897/silvabalcanica.21.e56917

Authors: Mariam Bozhilova, Miglena Zhiyanski, Plamen Glogov

Abstract: There are 265 municipalities in Bulgaria. According to the national legislation, each Municipal Coun-cil adopts an Ordinance for the construction and protection of the green system. Most of the mu-nicipalities have such ordinances, however, only 75 of them stipulate regulative requirements, under which a green roof can be considered a green area. These requirements refer to the substrate depth and are unreasonably high. While positive impacts are reported in green roofs with a substrate layer thickness of 4 – 5 cm, green roofs with substrate depth under 10 cm are not considered a green area in any of the reviewed ordinances. One municipality considers green roofs with substrate 10-30 cm as a green area, under specific conditions. This paper provides a review of the stipulations of the Bulgarian local legislation against the existing data for the effects of green roofs with different substrate depths and outlines the need for amendment of the legislation and future research.

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Research Article Tue, 6 Oct 2020 17:15:00 +0300
Reviewing productivity studies of skidders working in coniferous forests and plantations https://silvabalcanica.pensoft.net/article/56071/ Silva Balcanica 21(2): 83-98

DOI: 10.3897/silvabalcanica.21.e56071

Authors: Mohammad Reza Ghaffariyan

Abstract: Skidding is an important element of harvesting operations, which contributes to the extraction of wood. A skidder can be used in different types of harvesting operations, such as thinning, clear fell, native forest thinning or salvage work. The main goal of this article was to review the available stud-ies on productivity of skidding operations in coniferous forests/ plantations. Information on skid-der productivity was collected from publications and then was classified in three regions, including North America, Europe and the Southern Hemisphere. The parameters affecting machine productivity included machine type/ size, tree volume/ log volume/ load volume, average skidding distance and slope of the ground for each reported productivity. The average productivity reported in the published reports ranged from 9.3 m3/PMH to 78.0 m3/PMH. Detailed information and conclusions collected from various studies can be of use to forest academic and industry users to gain knowledge about vari-ations of skidder productivity in different regions and site/ operation conditions, which can be helpful for predicting, controlling and improving current levels of productivity.

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Review Article Tue, 6 Oct 2020 17:15:00 +0300
General regularities of height-diameter curves in Hungarian oak, sessile oak and Turkey oak high forests https://silvabalcanica.pensoft.net/article/56074/ Silva Balcanica 21(2): 71-82

DOI: 10.3897/silvabalcanica.21.e56074

Authors: Roumen Petrin

Abstract: The height-diameter curves of natural even-aged Hungarian oak, sessile oak and Turkey oak forests in the regions of Staro Oryahovo, Sherba, Tsonevo and Aytos Forestry Districts have been studied. In order to explore the shape of the curves and, in particular, their steepness, the steepness index SI of Douhovnikov (“the method of natural indicators”) was applied. The curves were divided into three groups according to it: flat curves, medium steep curves and steep curves. Both the traditional height-diameter curves and the corresponding relative curves of Tyurin were studied. Consideration of the traditional height-diameter curves gives a certain ground for investigating to-gether the height-diameter curves of Hungarian oak and sessile oak, disregarding the tree species. This inference was confirmed by comparing the relative height-diameter curves for Hungarian oak, sessile oak and Turkey oak with Tyurin’s uniform curve of relative heights. For these comparisons we used the Willcoxon test. A statistically significant great proximity in their shapes was found. As a uniform average curve of relative heights has been established for all tree species, this proximity indicates a possibility of creating a single fan of height-diameter curves for high Hungarian, sessile and Turkey oak.

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Research Article Tue, 6 Oct 2020 17:15:00 +0300
A methodological approach for monitoring of riparian forests in protected areas on Danube islands https://silvabalcanica.pensoft.net/article/54963/ Silva Balcanica 21(2): 53-69

DOI: 10.3897/silvabalcanica.21.e54963

Authors: Georgi Hinkov, Plamen Glogov, Vania Kachova, Mira L. Georgieva, Cristian Anghelus, Аlexandru Liviu Ciuvat

Abstract: In the last decades, invasive plant species have rapidly settled on the islands in the Danube River. This process is closely related to anthropogenic activities, such as felling and cultivation of soil for affor-estation of Euro-American poplar trees throughout the Danube River basin. In this regard, it is im-portant to: (i) determine the speed and scope of invasive vegetation establishment and (ii) determine more precisely the ongoing successional dynamics. Monitoring in permanent plots is needed to track the changes and assist in decision-making processes for the management of protected areas on the islands in the Danube River. The aim of the study is to describe and justify an innovative approach to analyse the dynamic of the invasion species occurrence and development as related to site conditions and management across the islands in the Danube River. The following methodological approach was considered: (1) selection of islands with well-preserved and sufficient in area covered by natural forest vegetation; (2) differentiation of strata by forest type, age and canopy cover; (3) setting up permanent sample plots for long-term monitoring in natural riparian forests.

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Research Article Tue, 6 Oct 2020 17:15:00 +0300
Green roofs and green walls – legislative framework in Bulgaria https://silvabalcanica.pensoft.net/article/56916/ Silva Balcanica 21(2): 45-51

DOI: 10.3897/silvabalcanica.21.e56916

Authors: Mariam Bozhilova, Miglena Zhyanski, Plamen Glogov

Abstract: In Bulgaria, public relations associated with spatial planning, investment design and construction are regu-lated by the Spatial Development Act (2001). According to article 62 (10) of this act, each Municipal Coun-cil adopts an Ordinance for the construction and protection of the green system on the territory of the municipality. There are 265 municipalities in Bulgaria and they are free to customise this ordinance as long as the goals and framework of the Spatial Development Act (2001) are maintained. The aim of this article is to review all Ordinances for the construction and protection of the green system available in Bulgaria and to analyse the included information and regulations regarding the construction of green roofs and green walls. The review of the ordinances showed that the construction of green roofs and green walls is not suf-ficiently addressed in the Bulgarian legislation at the municipal level. About 30.2% of the municipalities in the country do not have an Ordinance for development, maintenance and protection of the green system, 33.6% of the municipalities have such an ordinance but it does not mention green roofs and green walls and only 30.9% have an ordinance and it regulates the construction of green roofs and/or green walls.

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Research Article Tue, 6 Oct 2020 17:15:00 +0300
New records of longhorn beetles (Coleoptera: Cerambycidae) in Bulgaria https://silvabalcanica.pensoft.net/article/54609/ Silva Balcanica 21(1): 91-112

DOI: 10.3897/silvabalcanica.21.e54609

Authors: Denis Gradinarov, Ognyan Sivilov, Victor Gashtarov, Enrico Migliaccio, Vladimir Sakalian, Georgi Georgiev

Abstract: During the period 1969-2019, longhorn beetles (Coleoptera: Cerambycidae) were studied in Bulgaria. In different regions of the country, 144 cerambycid taxa from six subfamilies were established: Prioninae (five species), Lepturinae (37 species and subspecies), Necydalinae (one species), Spondylidinae (nine species and subspecies), Cerambycinae (46 species and subspecies) and Lamiinae (46 species and subspecies). New localities of 14 rare cerambycid taxa were established (Pedostrangalia revestita, Alocerus moesiacus, Anisarthron barbipes, Icosium tomentosum atticum, Paraclytus sexguttatus, Aegomorphus krueperi, Agapanthia frivaldszkyi, Deroplia genei genei, Dorcadion equestre transsilvanicum, Phytoecia albovittigera, Phytoecia praetextata praetextata, Pogonocherus hispidus, Niphona picticornis and Saperda perforata). New longhorn beetles were also found in the West Balkan Range, the Eastern and Western Rhodopes, Maleshevska Planina Mt. and North-eastern Bulgaria. These new records enlarged the knowledge about the regional distribution of longhorn beetles in Bulgaria.

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Research Article Tue, 30 Jun 2020 16:00:00 +0300
Spread of the invasive pathogen Lecanosticta acicola on species of Pinus in Bulgaria https://silvabalcanica.pensoft.net/article/54610/ Silva Balcanica 21(1): 83-90

DOI: 10.3897/silvabalcanica.21.e54610

Authors: Margarita Georgieva

Abstract: The brown spot needle blight, caused by the fungal pathogen Lecanosticta acicola, has been the most serious and damaging disease on needles of Pinus spp. in recent years. In Bulgaria, the pathogen was reported for the first time in 2017 in a generative plantation of Pinus sylvestris in the region of the State Forestry Ardino, the Eastern Rhodopes. The newly- established invasive pathogen is considered highly adaptable to new hosts and environmental conditions. The life cycle and symptoms of the disease strongly suggest that the new emerging pathogen has the potential to cause severe damages and is a serious threat to naturally distributed species of Pinus in the country. In the period 2018-2019, a spread of L. acicola from the initial outbreak was established throughout stands of P. sylvestris and P. nigra on the territory of Kardzhali District.

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Research Article Tue, 30 Jun 2020 16:00:00 +0300
Dynamics of populations of pine processionary moth (Thaumetopoea pityocampa) in the Republic of North Macedonia during the period 2007-2017 https://silvabalcanica.pensoft.net/article/54605/ Silva Balcanica 21(1): 77-82

DOI: 10.3897/silvabalcanica.21.e54605

Authors: Sterja Nacheski, Irena Papazova-Anakieva, Stanislava Lazarevska, Blagoj Shurbevski

Abstract: This study presents results for the dynamic of the populations of the pine processionary moth (Thaumetopoea pityocampa) during the period 2007-2017 and the impact of reducing factors in the Repub-lic of North Macedonia. The population density was determined by the number of larval nests both per tree and per hectare that varied during the research period. The number of individuals went up between 2007 and 2010, while during the following years it rapidly decreased. Since 2011, an overall prograding trend has been recorded in the several subsequent years. This could be explained by the huge number of individuals from the previous years that were in a diapause. The abundance of pest populations continued to grow in 2016 as no measures were taken. During the winter of 2016/2017, the impact of the extremely low temperatures on pest mortality was monitored in 2016-2017 generation. The density of the populations came to latency due to the very large number of dead larvae of second and third larval stages. We recorded a 100% mortality of larvae in plantations of Pinus nigra in the regions near Prilep, Sveti Nikole, Shtip, Kochani and Negotino Villages.

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Research Article Tue, 30 Jun 2020 16:00:00 +0300
Assessment of Public Awareness of the Forestry Sector: Biodiversity, Certification and Ecosystem Services in Velingrad Municipality https://silvabalcanica.pensoft.net/article/54698/ Silva Balcanica 21(1): 69-76

DOI: 10.3897/silvabalcanica.21.e54698

Authors: Ivan Tsvetkov, Ivan Atanassov, Krasimir Rusanov

Abstract: The purpose of this study was to survey the current public awareness in Velingrad Municipality in terms of biodiversity preservation, certification and ecosystem services in the regional forestry sector. The answers to the questions related to the biodiversity and ecosystem services showed good aware- ness and a very positive attitude of respondents regarding the need for conservation and sustainable use of biodiversity as well as the improvement of ecosystem services. According to the conducted surveys, the awareness concerning the certification and standards in the local forestry sector as well as the regional NATURA 2000 protected sites was still weak or lacking.

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Research Article Tue, 30 Jun 2020 16:00:00 +0300
Ecosystem services from mountain forest ecosystems: conceptual framework, approach and challenges https://silvabalcanica.pensoft.net/article/54628/ Silva Balcanica 21(1): 47-68

DOI: 10.3897/silvabalcanica.21.e54628

Authors: Maria Glushkova, Miglena Zhiyanski, Stoyan Nedkov, Rositsa Yaneva, Lora Stoeva

Abstract: Mountain ecosystems play an essential role in sustainable mountain development, providing benefits and values to humanity not only for the rich biodiversity they contain, but also because of their important role in climate regulation, water cycle, provisioning of recreation, tourism, cultural or spiritual values. The high biodiversity of the mountain areas allow the provision of a wide range of ecosystem services. However, different impacts to the environment threaten the delivery of these services and, consequently, the quality of life of people, both living in the mountains and outside the mountains. Recognizing, demonstrating and capturing the value of ecosystem services can play an important role in setting policy directions for ecosystem management and conservation and, thus, in increasing the provision of ecosystem services and their contributions to human well-being. Quantifying and mapping of these benefits can also help managers and decision makers to realize the importance of these sites for conservation and to allow the proper understandings of the impacts of mountain forest ecosystems on territorial development and welfare of local populations.The paper aims to outline the relevance and applicability of the ecosystem services approach for the assessment of the condition of mountain ecosystems and the services, they provide, for better understanding by the scientific community and to support decision makers in sustainable management of mountain regions.

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Review Article Tue, 30 Jun 2020 16:00:00 +0300
Sequence-related amplified polymorphism (SRAP) markers, an efficient and affordable tool for evaluation genetic diversity in forest areas https://silvabalcanica.pensoft.net/article/54699/ Silva Balcanica 21(1): 41-46

DOI: 10.3897/silvabalcanica.21.e54699

Authors: Tzvetelina Zagorcheva, Krasimir Rusanov, Eirini Bosmali, Panagiotis Madesis, Ivan Tsvetkov, Ivan Atanasov

Abstract: This article describes testing the application of SRAP (sequence-related amplified polymorphism) markers for characterisation of a small set of plants of Quercus coccifera L and samples from 25 other forest tree species. The results suggest that SRAP markers could be used as an affordable and efficient tool for the characterisation of the genetic diversity in populations of tree species as a part of the characterisation of forest biodiversity and the related decision making and management.

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Research Article Tue, 30 Jun 2020 16:00:00 +0300
Application of Nelder wheel experimental design in forestry research https://silvabalcanica.pensoft.net/article/54425/ Silva Balcanica 21(1): 29-40

DOI: 10.3897/silvabalcanica.21.e54425

Authors: Tatiana Stankova

Abstract: This article presents a concise review on the forestry research, which involves application of a Nelder wheel experimental design, a type of systematic design for spacing trials. Short presentation of the design is included, practical applications of various objectives and methodological approaches to data analysis are outlined and the pros and cons of the design are discussed.

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Review Article Tue, 30 Jun 2020 16:00:00 +0300
Study on the relict flora of Lozenska Mountain https://silvabalcanica.pensoft.net/article/54625/ Silva Balcanica 21(1): 5-28

DOI: 10.3897/silvabalcanica.21.e54625

Authors: Plamen Glogov

Abstract: The purpose of this study is to make an inventory of the relicts in the flora of Lozenska Mt., to clarify their origin, taxonomical, ecological and phytogeographical structure and to evaluate their role for the formation of the contemporary flora and vegetation, economic uses and measures for their con- servation. The study was conducted in the period 2017-2019. In order to cover the maximum area and different ecological niches, the sampling was conducted using the transect method. The surveyed territory and its two geographic regions, north-west and south-east, were divided into four sub re- gions (parts) and 19 transects were used for possible comparisons. The biology and ecology of the relict plants was made, thus allowing to group the species in biological and ecological groups, based on life forms, floristic and phytogeographical elements, synanthropy and economic uses. As a result, 61 species and three subspecies, belonging to 48 genera and 35 families, were identified as relict taxa. These number represent 7.4% of the whole flora of Lozenska Mt. (823 species) and 17.6% of the relict species in Bulgarian flora. Tertiary were 93.4% of the mountain’s relicts. The families with the richest number of relict species were Salicaceae (9 species) and Ranunculaceae (4 species). The genera with the largest number of relict species were Salix (5 species) and Populus (4 species). The most relicts (73.7% from their total number on the territory of the mountain) were registered in the south-west part of the mountain, while the smallest number (52.5%) was found in its north-east and south-east parts. The phanerophytes (dominated by the threes) prevailed with more than 60%, followed by the hemicryptophytes (16.4%) and geophytes (13.1%). Most of the relicts on the territory of the Lozenska Mt. have Euroasiatic (17.7%) and sub-Mediterranean (17.7%) origin. The established relicts are pre- dominantly heliophytes (61.3%), mesotherms (86.9%) and mesophytes (59.0%). Each of the studied species is a plant with economic benefits: forestry (36.1%), non-wood resources (88.5%) or ornamental uses (54.1%). Salix caprea and Polygonatum odoratum are included in the Bulgarian Biodiversity Act (2002). The other relict species fall under provisions of different laws, such as the Medicinal plants Act, Forestry Act, Biodiversity Act, including NATuRA 2000 legislative base.

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Research Article Tue, 30 Jun 2020 16:00:00 +0300