It is located on the land of the villages of Bulgari and Kosti, Tsarevo municipality, 2 km north of Kosti. The junction on the main road 99 (Tsarevo - Malko Tarnovo), leading to the village of Kosti, goes through the middle of the reserve.
Coordinates: 42°05’21.46” N, 27°45’09.27” E, 289 m above sea level
SILKOSIA (Code in the register: 1)
Size: 389.6 hectares
Location: District: Burgas, Municipality: Tzarevo, Town/Village: the village of Bulgari and the village of Kosti
Documents declaring it a reserve: Order №1046 of 23.07.1931
Documents for changes:
1. Order №8455 of 29.04.1933
2. Decree of the Council of Ministers №13188 of 20.09.1934
Purposes for declaring it a reserve:
1. Mixed deciduous forest of oak and Oriental beech and plants unique only to Strandja mountain plants.
Mode of activities:
All activities are prohibited in the reserve except: 1. safeguarding the reserve; 2. visits for scientific purposes; 3. passage of people along the marked trails, including those visiting it for educational purposes; 4. collection of seeds, wild plants and animals for scientific purposes or to grow or breed them elsewhere in amounts, with methods and at times excluding damages to the ecosystems.
Overlap (partial or complete):
1. Natural park: STRANDJA
2. Protectred zone under the Birds Directive: Strandja
It was declared a reserve back in 1933 to protect the mixed deciduous forest of oak and Oriental beech and the plants unique only to Strandja mountain which are found nowhere else in Europe. This is the first reserve in Bulgaria. It protects a valuable plant and animal wealth. It is within Natural Park Strandja. Its area is 389.6 ha.
For the first time after World War I, the Bulgarian Botanical Society made a concrete proposal for the creation of reserves, but the favorable conditions for this became available after the establishment in 1928 of the Union for Protection of the Native Nature. Silkosia reserve was declared by Decree № 8485 of 29.06.1933 of the Ministry of Agriculture and State Property as a "strictly safeguarded state forest Upper Elenitsa – Silkosia on the land of the villages of Bulgari and Kosti, Tsarevo Municipality, Burgas District , with an area of1022.6 ha. The reason in the Order for declaring it a reserve reads: "Because of the very rare and valuable forest tree species, and because of the typical bush and grass vegetation, which are extremely interesting from the point of view of dendrology, floristry, phytogeography and ecology the state forest Upper Elenitsa – Silkosia is declared a reserve, and from now on it is prohibited to use anything from the forest, to graze livestock, and to hunt, except for scientific purposes and with special prior permission from the Ministry of Agriculture and State Property." On 29.06.2003 its 70th anniversary was celebrated.
The plant wealth of Silkosia Reserve is significant, but not fully studied. So far 260 species of higher plants belonging to 63 families and 190 genera have been identified. This represents 22.6% of Strandja flora and adds great value to the protected area. There are 16 species of relict and 3 species of endemic plants. Most impressive of the forest formations are those of Sessile oak and Oriental beech and the beech forests with undergrowth of evergreen shrubs which are relatively primitive. The southern parts of the forest, where the soils are poor, drought-resistant formations of oak and tree heath (white heath) can be found.
Besides Mediterranean plant species in the reserve there grow southeuxinus and Pontic species, which contribute to the unique features of the communities, such as Pontic rhododendron, lazhnik/tanniniferous oak, twin flowered daphne, star hyacinth, medlar-tree, borage, Aaron beard, etc.
The reserve is home to more than 50 protected animals – mammals, birds, and reptiles.
It has extremely diverse avifauna. Typical of the reserve are jays, orioles, southern nightingales, Sardinian warblers and whitethroats, different kinds of woodpeckers and raptors.