Silva Balcanica, 19(1)/2018 DENDROLOGICAL DIVERSITY IN SANTA MARINA HOLIDAY VILLAGE - SOZOPOL AS AN EXAMPLE OF CONTEMPORARY LANDSCAPE DESIGN TRENDS IN BULGARIA Svetlana Anisimova Faculty of Ecology and Landscape Architecture, University of Forestry – Sofia Abstract The paper presents dendrofloral characteristics of Santa Marina Holiday Village, situated on the Southern Bulgarian Black Sea coast. The systematic structure and species composition of woody ornamentals, the absolute and relative quantitative participation of each species were analyzed. A total number of 227 woody species, 315 species and intraspecific taxa, respectively of 110 genera, belonging to 54 families, were recorded. Furthermore, 44.4% of the families were represented by only one species. The results indicate a significant tree and shrub diversity, competitive with the one displayed in some Bulgarian historical parks famous for their dendrological collections. Some of them have been rarely cultivated in the green spaces in Bulgaria so far. A trend of a large scale use of alien species and cultivars was established. Consequently, the participation of autochthonous species is insignificant (5.9%). A relatively high percentage of coniferous and evergreen woody species provides the constant ornamental effect of the holiday village green spaces. Key words: urban green spaces, alien species, woody ornamentals, landscape planning INTRODUCTION The ornamental tree and shrub vegetation plays a leading role in the landscape design, creating the volume-spatial composition and enhancing environmental aesthetics and expressiveness. All ecosystem services provided by woody species depend on their adaptability to extreme environmental conditions (Chen, Jim 2008). In recent years, the diversity of ornamental tree and shrub species and cultivated varieties has grown considerably (Knapp, 2010; Chalker-Scott 2015; Sjöman et al., 2016.). The periodic inventory of public green spaces, accompanied by quantitative and qualitative dendrological analysis, provides valuable guidelines for landscape planning, construction and management of green spaces with specific environmental conditions. Dendrological analysis of public green spaces was conducted for the following Bulgarian cities: General Toshevo – Arboretum (Dimitrov, 1973, Alexandrov et al., 1996); Blagoevgrad, Kyustendil, Sandanski (Vakarelov, Delkov, 1988b); Plovdiv (Zhelev, Yurukov, 1995); Nessebar (Vakarelov, Delkov, 1996); Sofia (Vakarelov, Delkov, 1988; Delkov, Gateva, 2004, Dimitrov et al., 2005); Silistra (Tsavkov, 2000); Pernik (Anisimova, 2013). Object of study was also the dendroflora of some resorts and architectural-and-park complexes along Bulgarian Black Sea coast: Golden Sands (Delkov, Vakarelov, 1976), St. 5 Constantine and Elena, Albena (Vakarelov et al., 1973), Sunny Beach (Gateva, Kozarev, 2001), as well as Botanical garden in Balchik (Kitanova, 2005) and Euxinograd residence (Metodieva et al., 2001). Many of these inventory results have completely lost their relevance. The purpose of the present study was to analyse the dendrological diversity in the green spaces of a Sozopol’s holiday village and to assess its expediency to the environmental factors. OBJECT AND METHODS The study object was the dendroflora of Santa Marina Holiday Village (42°24’32.7”N 27°40’40.2”E). The settlement is located on the Southern Black Sea coast, 2 km north of the ancient town of Sozopol and 34 km south of Burgas. It is situated amphitheatrically on a bay facing northwest towards the Black Sea. The holiday village covers 16 ha, about 2/3 of the area are green spaces. It consists of 80 three- or four-storey villa units. The altitude range is from 9 to 50 m a. s. l. Landscaping activities started in 2007. Light and regular standard trees have been planted not following landscape master plan. The holiday village was built on a terrain with an experimental 50-year-old Austrian black pine plantation in Saint Marina locality. The studied area is bordered to the east by the municipal forest park Saint Marina. The dendrological inventory was conducted in 2014-2016. Species composition was determined by applying the route method, inventorying the woody specimens along the whole alley network and in the depth of the groups and massifs. All woody species, apart from those applied as hedges and groundcovers, were presented as absolute and relative specimen quantities. Due to the different dendrometric characteristics, species were devided by their biological type into three groups – trees, shrubs (incl. lianas) and subshrubs. Still, the number of individuals of each species is not indicative of its real presence in the green spaces. The number of specimens used for hedges, green screens, borders, ground cover, as cascading plants and climbers, corresponds rather to the number of designs in which they are encountered. The sources used as referece books in plant identification are Krüssmann (1960, 1972) and Auders, Spicer (2012). The names of the species and cultivated varieties are consistent with the IPNI (http://www.ipni.org) and the RHS (https://www.rhs.org.uk/ plants) database. RESULTS AND DISCUSSION Climate. The climate analysis of the site is based on the data of Hydrological and Meteorological Service of Sozopol (meteorological station 9 m a. s. l.) (BCRB, 1983; CRB, 1990). According to the climatic division of Bulgaria, Sozopol falls within the Continental-Mediterranean climate zone, Black Sea climate subzone, Southern Black Sea coast, climatic region of Burgas valley (Sabev et al., 1963). 6 Th e climate is characterized by a mild winter with a positive January mean temperature - + 3°C, and a long and hot summer (July and August average temperatures, respectively + 23.7°C and + 23.5°C). Th e mean annual temperature for Sozopol is 13.3°C. Since the town is located on the Black Sea coast, the weather rarely becomes extremely hot due to the infl uence of breeze circulation. However, it increases the soil dryness. Winter is relatively warm but windy. Northwest and southwest winds prevail, with an almost double the country’s average speed value. Th e adjoining sea basin determines year-round high humidity rate. Th e mean annual precipitation is very low - 494 mm, most of it being concentrated in the winter months. Snow is infrequent and melts soon thereafter. Th e Walter (1963) diagram (Fig. 1) shows moisture defi cit during the major part of the growing season – lasting from mid-June to the last decade of September. Th erefore, the accurate irrigation system design and schedule during the drought period are vitally important. Fig. 1. Climatic diagram of Sozopol Th e general characteristics of the climate due to the lack of extreme values of the main climatic elements is favourable for the development of diverse ornamental species. However, species composition should include mainly moderately hardy woody ornamentals because of the adverse wind regime, combined with high atmospheric humidity during winter months and low precipitation in summer. Soils. Th e regional soil type is Chromic Luvisols (Lc). Th ese soils are characterised by high bulk density, low aeration and water supply. Th ey alternate in depth (0.5 ÷ 1 m). In some places the soil profi le is very shallow. Th e soil reaction is slightly acidic. Th ey are poor in humus and very low in total nitrogen and assimilable phosphorus. Th e main problems of the site related to the landscaping are highly fragmented terrain with steep slopes up to 60% in some places and poor soil conditions. 7 The natural climatic and soil conditions of the site have been partially modified in relation to: the microclimate between the buildings, the intensive maintenance of the green areas in the complex in terms of irrigation, pruning, fertilizing. Woody vegetation. The oldest trees on the site that existed before the holiday village construction were: Pinus nigra J.F.Arnold, Cupressus sempervirens L., Acer campestre L., Cornus sanguinea L., Fraxinus ornus L., Quercus cerris L., Quercus pubescens Willd., Robinia pseudoacacia L., Ruscus aculeatus L., Ulmus minor Mill., Viburnum lantana L. The investigation of Saint Marina municipal forest park dendroflora, which borders the village to the east, represented the species diversity in the region prior its establishment. The inventory results showed almost equal participation of coniferous and broadleaved species. P. nigra was the main coniferous species (89%), while the most widely spread deciduous species were U. minor, F. ornus, C. orientalis. According to the habitat classification in Bulgaria (CFHB, 2011) the recommendable species for such growth conditions – flat to hilly terrain, lower slopes, sunny places on dry Chromic Luvisols (Lc) – are xerothermic oak communities of Q. cerris, Q. pubescens, Quercus frainnetto Ten., mixed with C. orientalis as a satellite broadleaved species. On the territory of the villa settlement Austrian black pine specimens have been entirely preserved everywhere outside the constructions perimeter. A total of 227 woody species, 315 species and intraspecific taxa, respectively, of 110 genera, belonging to 54 families were recorded in the green spaces of Santa Marina Holiday Village (Table 1). Probably, the list of the varieties is non-exhaustive. The results indicate that ratio of gymnosperm to angiosperm species is 1:3.1. Out of 227 woody species, 16.7% of them were found to be Gymnosperms, represented by 4 families: Cupressaceae – 20 species, Pinaceae – 16, Ginkgoaceae and Taxaceae – 1 each. Out of 38 coniferous species,