Experimental Watershed Study Site “Bazenishki dol” is established since 1965 and extends on an area of 321 ha and is a part of the Experimental Area (773.8 ha). The principal designation of the experimental area is conducting of long-term hydrological, ecological and forestry investigations. In fact, the area of the entire Training and Experimental Forestry Enterprise is a subject of a variety of forestry studies since the establishment of the enterprise till the present.

The Training and Experimental Forest “Yundola” is a center for long-term complex ecological, hydrological and forestry related studies in the mixed coniferous forests. The experimental watershed, the sites for two-store forest management, the permanent sample and experimental plots, the experimental plantations and provenance trials and other experimental sites are used in studies on ecology and management of mixed coniferous forest ecosystems.

According to the climatic division in regions the area of the station falls entirely under the medium-mountainous part of the mountain climatic region of the transition continental sub-region of the European continental climatic region.


  • Available data

 The Training and Experimental Forestry Enterprise “Yundola” and Experimental Watershed Study Site (EWSS) forests have been subject of different ecological studies. Among them are the studies on: site conditions and site classification; accumulation and decomposition of the forest litter; forest growth and development; floristic classification of the forests of TEFE; interaction between mineral fertilizers and forest ecosystems and assessment of the risk for environmental pollution as a result of nitrogen fertilizer application, and intensive monitoring of forest ecosystems.

The studies of the parameters of the physical environment in the Experimental Area have been made and published immediately after its establishment (Florov and Donov, 1965). This investigation covers the morphology and major water-related physical and chemical properties of the soil, as well as the main climatic parameters within the boundaries of the EA. The data from this study supplement the information about the site conditions under which mixed coniferous forests in this country emerge, grow and develop.

Systematization of the available hydrological information at Yundola station was performed in a specially set up information database for almost 40 years, which contains data about the daily water quantities and precipitation, air temperature and annual sediment run-off.

Beside the main purpose of the station – the study of the processes of liquid and solid run-off formation with a special emphasis on the role of forest ecosystems and the factors of coniferous forest management, many other investigations, experiments, student training and group study of all components of the forest ecosystems are carried out there. For example, studies were carried out on: the characteristics of soil and litter forest cover, the forest stands and their regeneration, the understanding of run-off chemistry and leaf mass biochemistry, fertilizing, the influence of logging technology on water supply, soil protection, growth functions of the forests, the precipitation.

The results from the hydrological studies have been analysed and summarized by Kitin (1988), Rafailov & Kitin (1995) and Rafailova (2004). Some very important results and conclusions from this very important study have been made, as: the quantity and distribution of precipitation and the runoff (runoff module and coefficient) in the watersheds with southern and northern exposure component; the runoff dynamics depending on the precipitation regimes during the current year and previous years; the runoff parameters depending on the hydrographic characteristics of the partial watersheds; the water-retaining effect of soil floor.

Since the beginning of 1997 intensive monitoring of forest ecosystems has been implemented on Experimental Area. The study is in the framework of the International Co-operation Program for “Assessment and monitoring of forest ecosystems” – level II (Intensive monitoring) under international methodology (ICP Manual, 1998). The study covers the meteorological parameters, air pollutants, depositions, soils, plant communities, foliar analysis, species indicators and defoliation of trees.

  • Facilities

 Experimental Watershed Study Site “Bazenishki Dol” , with Experimental station “Prof. Boyan Biolchev ”,exits for 40 years. It has laboratories and basic laboratory facilities.

  • Main references
  1. Biolchev, As., P. Pimpirev, B. Kitin. 1970. Hydrological investigations at the test section of the G. St. Avramov Training Experimental Forest Enterprise, Research Works of the Bulgarian Forestry Engineering Institute, Volume 18.
  2. Gergov, G., E. Rafailova. 2003. Formation and regularity of the river flow in a forested mountain region. In Proceedings of Workshop on Mountain Hydrology. Bucharest, September 2003.
  3. Gergov, G., E Rafailova. 2004. Hydrological investigations on experimental watershed basins. In Proc. of International Symposium on Earth System Sciences 2004, Istanbul, Turkey
  4. Kitin, B. 1988. Investigations on hydrological and antierosivon role of coniferous forests. Dissertation
  5. Kitin B. E. Rafailova 2000. Precipitation and runoff in stationary investigation in forested catchments. Proceedings of scientific conference “75 years Higher Forestry Education in Bulgaria“ Sofia. pp. 347-349.
  6. Rafailov G. Kitin, B., 1995. 30 years investigations in ecological station in Yundola Training Experimental Forest Enterprise. Proceedings of scientific conference “75 years Higher Forestry Education in Bulgaria. “Sofia. Volume III, 423-429
  7. Rafailova E., 2004. The impact of silvicultural activities on hidrological characteristics of mixed coniferous forests. PhD Dissertation
  8. Rafailova, E. 2003. Experimental hydrological stations in Bulgaria. In Proceedings of International year of mountainous conference: Natural and Socio-economic Effects of Erosion Control in Mountain Regions. Belgrade, 2003.
  9. Rafailova, E. 2005. 40 Years of Ecological and Forestry Studies at the Experimental Area of Training and Experimental Forestry Enterprise “Yundola” In Proc. of International conference – Forest Impact on Hydrological Processes and Soil Erosion, Yundola 5-8 Oct. 2005
  10. Rafailova, E. 2005. Impact of Forestry Activities on Hydrological Processes. In Proc. of International conference – Forest Impact on Hydrological Processes and Soil Erosion, Yundola 5-8 Oct. 2005


Responsible Institution:

University of Forestry

Address: 10 Kl. Ohridsky Blv., 1797 Sofia, BULGARIA

Phone: +359 2 91907/ 350

Fax: +359 2 8622830



Site coordinator:

Elena Rafailova, PhD