Issues

Abstract

The study bases on pellet analyses of Barn owl (Tyto alba (Scopoli, 1769)) in 27 breeding localities with total 18,314 preyed small mammals in the Kazanlak valley. Five species: Sorex araneus (Linnaeus, 1758), Sorex minutus (Linnaeus, 1766), Suncus etruscus (Savi, 1822), Muscardinus avellanarius (Linnaeus, 1758), and Myodes glareolus (Schreber, 1780) were found for the first time in the study area. The distribution of Microtus subterraneus (de Selys-Longchamps, 1836) was found to be much wider than reported. Suncus etruscus was the only Mediterranean and typical lowland inhabitant among them and the new localities mark the northern border of its distribution in Bulgaria. The other five species are common mountainous inhabitants with single localities in lowlands. The adjacent high mountains favor their distribution in the Kazanlak valley but they were rare preys of Barn owls between 0.01 % and 0.68 % among the small mammals.

Abstract

Beech forests are among the most widely spread forests in Bulgaria. They have a significant economic importance for the country and for that reason they are an object of a great number of studies. The aim of the present study was to analyse the growth and the increment of beech communities in five permanent sample plots and to quantify the distribution of aboveground phytomass of the trees together with the annual increment for two beech communities. The studied phytocoenoses are related to the associations Festuco drymejae-Fagetum sylvaticae and Asperulo odoratae-Fagetum sylvaticae (habitat Asperulo-Fagetum - 9130) and to the association Luzulo luzuloidis-Fagetum sylvaticae (habitat Luzulo-Fagetum - 9110) in the region of Petrohan (the West Balkan Mountains, Bulgaria). The results for the phytomass stores (between 488 t·ha^-1 and 612 t·ha^-1) and for the annual biomass increment (correspondingly between 12 t·ha^-1 and 23 t·ha^-1) were obtained using the method of the average tree model. These values allow us to relate the phytocoenosis of the first plot to the middle productive plant communities while the second phytocoenosis can be assigned to the high productive plant communities.

Abstract

The article illustrates the deteriorated condition of wood-bush formations of the park “Vrana” and the reduction of their high artistic value as a building material for well-scaled in the past parks, which were created with excellent knowledge of the biological characteristics and artistic effect of the vegetation. All archival materials and documents about the composition of the park spaces in different periods of its construction and development are systemised. Mapping is performed and forest taxation of bush-tree arrays is made, as the species structure and their other forest features (established in 2008) are defined. Photo archive is also complied documenting their condition at this time (2009). The significance of the forest stand and the seedlings for the aesthetic qualities of the park spaces is substantiated. The conclusions made on this basis underline the need for urgent measures to improve their health and aesthetic condition. The characteristics and the main criteria, which those forest stands should meet, are defined and there is a proof for the need of timely forestry and landscaping intervention to improve the artistic aspect with a view to the future exposition of the park to the citizens and the guests of the Bulgarian capital. Concrete proposals have been made and possible present solutions to the issue have been formulated as a basis for planning the major events for the recovery and preservation of the authentic spatial composition in the park. The idea is this to serve to specify the biological, ecological and aesthetic aspects of a common strategy for the conservation, development and socialization of park “Vrana” according to the accepted principles of conservation of cultural and historical heritage.

Abstract

In this paper, results of investigation of root systems of containerized and bare root seedlings and trees in stands of Austrian black pine in the R. of Macedonia are presented. The aim of the investigation was to analyze root morphology and deformations of 1+0 Austrian black pine (Pinus nigra Arn.) seedlings and trees grown in containers 'Paperpot' and 'Yucosad', compared with bare root seedlings. Presence and deformations of lateral and vertical roots of the seedlings were analyzed. Investigated stands were raised by the same seedling stock types and developing in different ecological conditions. On each stand trees were excavated with root ball, cleaned, measured and analyzed. Deformities of roots and irregularities of lateral roots spreading were recorded. Indexes R, HV and A were calculated. Root systems of seedlings of both container types are modified and deformed by the container. Morphology and deformities of root systems of young trees of both container types are similar and the influence of primal container is still perceptible. Root systems of older trees gradually overcome this disposition and develop according to site conditions ensuring functionality and stability. Secondary deformations take part in root morphology modification of all seedling stock types. There is no significant difference between Paperpot and Yucosad seedlings and trees features, roots morphology and field performance. Container and bare root stands' growth and vitality depend mostly on site conditions and planting technique.

Abstract

The purpose of this study was to determine some of the environmental factors affecting the population of Blackbirds (Turdus merula) in the area of the West Park in Sofia. The study was conducted in 2008 and 2009. The number of blackbirds during the breeding (12.5 pair per 100 ha) and non-breeding (5.3 ind. per 100 ha) season was determined. It was found that the density of Blackbird in the area surveyed is defined by the availability of suitable nesting sites, the quantity of food and the soil moisture. The human presence also impacts the number of reported blackbirds.

Abstract

In the1950s, the interest of the professional public was drawn by Taxodium distichum Rich., as an allochthonous coniferous species in Serbia. It can be considered a fast-growing species, one of rare coniferous species that can be favourable for the afforestation of lowlands, and especially flooded sites, on which it can achieve high productivity. There is only one registered Taxodium seed stand in Serbia, located near Backa Palanka, within FMU 'Palanacke Ade - Cipski Poloj', Compartment 11, Section a, area 0.22 ha, with 111 trees. The stand is about 70 years old, d_s=51.7 cm, h_s=26.5 m. The effect of four different pre-sawing treatments on Taxodium seed germination percentage was studied on five trees originating from the seed stand. Germination percentage was researched on a standard sample (4 x 100 seeds per tree), during 28 days. The study data were processed using the software 'Statgraph 6.0'. The summary statistics was presented, the two-way analysis of variance for treatment and tree, and LSD-test. The study results show that seed immersion in citric acid (100 or 500 ppm) during 48 hours stimulates the germination percentage in laboratory conditions. Based on the two-way analysis of variance, it was confirmed that the differences in the number of germinated seeds was the result of the applied treatments, and not of the seed origin. Taking into account that this treatment is simple, inexpensive and harmless to human health and environment, it can be more widely applied in the production of Taxodium seedlings.

Abstract

The paper presents results from investigation on soil texture changes caused by forest fires. Cinnamonic Forest soils (Chromic Luvisols, FAO) and Gray Forest soils (Gray Luvisols, FAO) have been investigated. The sample plots were set up in burned and unburned control areas. They were situated in the Lower forestry zone (0-700 m a.s.l.) of the Tracian forest area and the Lower forestry zone (0-600 m a.s.l.) of the Moesian forest area, respectively. Soil samples have been taken three times in a course of nine years. The fractions of sand, silt and clay have been determined by pipette method. A relationship was established between soil texture and soil type, and the type and intensity of fires.

Abstract

The purpose of this work was to present the necessity of definition and categorization of State Forest Enterprises (SFE) and State Hunting Enterprises (SHE) in Bulgaria as separate economic units, based on some major groups of features. Feature classification was based on the natural territorial characteristics, quantitative and qualitative indices, production restrictions according to the active regulations, as well as the public functions performed by the forestry. Forestry categorization makes possible to determine the economic elements that form the incomes from wood production taking into account objective factors. This work applies to three forest enterprises within the territorial range of the Regional Forest Directorate of Plovdiv. The methods used to determine groups and different features were applied in the forestry science for qualitative and quantitative assessment, as well as for definition of the priority and share of each feature in the group. The outcomes of present work could make possible the differential determination of expense rates of wood production, the more objective definition of income share, including fees of the State Forest Fund, according to the legislately determined forestry category.

Abstract

The Wild trout density and biomass in Bunayska River, Aegean catchment area, was estimated on the basis of electrofishing. The mean population size in the Bunayska River was 630 individuals per hectare and the trout biomass 21.73 kg·ha^-1 was well below the established average values for the other rivers in Bulgaria. The number of individuals allowed for fishing according to the Law for Fisheries and Aquaculture is very low too. We recommend a restocking of 6000 young fish per year (with weight 3-5 g per individuals). The fish used for restocking should be bred from trout inhabiting the river in the area.

Abstract

An individual’s profession is much more than simply earning money and indeed of paramount importance for his or her sense of identity and consequently to his or her self-esteem. The aim of this paper is to discover how the students of the Department of Forestry and Management of the Environment and Natural Resources of the Democritus University of Thrace, see the profession of the forester, which values they expect to satisfy through their profession in the future and in which job position they wish to work. The paper also attempts to connect values with job positions. The methodology used in this paper, including the questionnaire, may be used to investigate the expectations and problems of students in other disciplines, in other university departments.

Abstract

Phenotypic and allozyme variation of Silver Birch (Betula pendula Roth) was studied in three sub-populations in the locality near Ardino, which is one of the largest in Bulgaria. The 14 leaf traits studied were highly variable with coefficients of variation ranging from 14 to 33 %. Genetic variation, studied at 11 polymorphic allozyme loci, was well within the range reported for species with similar life-history characteristics; however, at the lower tail. Mean number of alleles per locus ranged from 1.8 to 2.2, and effective allele number - from 1.11 to 1.47. Expected and observed heterozygosities had similar values (0.137 and 0.135, respectively) and the inbreeding coefficient was not significantly different from zero. The overall differentiation was low (F_ST = 0.022). The results could be used for designing of management and gene conservation strategies.

Abstract

The forest cover of Bulgaria is characterized by great diversity. Both conifers and broadleaves show reduced vitality. Among all tree species, Pines, Silver fir and deciduous Oaks are the most damaged. Our research was based on the hypothesis that forest decline is caused by multiple stresses affecting the ecosystem. With such stress-caused diseases, a distinction was done between predisposing, inciting and accompanying stress factors. Dendrochronology was used for extracting ecological information from dated tree rings. No single factor has been clearly identified as the cause of the forest decline. Among the important predisposing factors was the drought. However, other factors such as fungal diseases, insect damages and mistletoes played part in the forest decline. Studies into these aspects show­ed that air pollution also plays a part in the deterioration of forest health.