National park Rila: Flora
There are 4 vegetation belts (beech, coniferous, subalpine and alpine) in the Rila NP. Tree, shrub and herbaceous phytocoenoses are included in their composition. The forest vegetation is represented mainly by phytocoenoses of coniferous species. Forests` dominant age is 90 years and the average thickness – 0,65. The forest reserve is 6 000 000 cubic meters. The coniferous thickets are the main primary vegetation of the subalpine belt and are widely distributed in it. The short shrub phytocoenoses of Juniperus Sybirica and the herbaceous phytocoenoses, many of which are primary, are considerable components of the vegetation cover in this belt. The alpine belt comprises herbaceous phytocoenoses and short shrubs as Arctostaphylles uva-ursi and Salix herbacea that are of restricted distribution.
The park`s vegetation is related to the Rila-Rhodope subregion of the Illyrian province belonging to the European deciduous region.
At present the park`s vegetation diversity is represented by more than 12 classes, 12 orders, 17 unions, 92 associations and 28 subassociations. All classes, of which the phytocoenoses are distributed in the park are common to the classes of the European mountains` vegetation. The order Seslerietalia comosae Simon 1958 is endemic for the Balkan peninsula. The rest are also common to the Central European mountains. 6 of the unions are regional Balkan, 3 are Carpatho-Balkan, the rest 8 are European. With little exceptions the associations are either Bulgarian or distributed in Rila Mountains only, i.е. endemic for the Bulgarian and Rila vegetation.
Characterization of the forest fund
The forest fund (FF) in the NP comprises 53481,0 hа, which are 66% of the National park`s territory. This is about 1,3% of the Forest fund of Bulgaria.
The afforested area comprises 42560,6 hа (1,1% of the country`s afforested area). This means that 52,5% of the park are territories covered with forests.
The whole afforested area consists of:
- wild plantations – 24 965,8 hа (58,7%);
- dwarf-pine – 15 359,5 ha (36,1%);
- artificial plantations – 2 235,3 hа (5,2%).
About 75% of the afforested area are situated at altitude range from 1 500 to 2 200 m a.s.l. The average altitude of the park`s FF is 1 790 m a.s.l., which is the middle of the subzone of alpine spruce forests in our country and involves optimal conditions for the development of coniferous tree species.
The tree species forming the forests in the NP, which have been subjected to economic valuation, are 33. 4 species of them are found in crops only – Pinus nigra, Pseudotsuga douglasii, Larix eurpaea, Pinus strobus. 40 194,2 ha (94,4%) of the forest area in the park is covered with coniferous tree species: spruce – 11 180,5 ha (26,3%), white pine –6 341,8 ha (14,9%), white fir – 4 951,6 ha (11,6%), fir-tree – 1 896,5 ha (4,5%), others – 15 823,7 ha (37,1%). The deciduous species cover 2 366,4 ha: beech – 1 016,1 ha (2,4%), durmast – 214,5 ha (0,5%), aspen – 161,9 ha (0,4%), birch – 134,0 ha (0,3%), hornbeam – 114,6 ha (0,3%), sycamore – 64,8 ha (0,1%), others – 660,5 ha (1,6%).
The average forest productivity is 2,9, which shows favourable environmental conditions for the tree species` development. The spruce (2,7), fir-tree (2,8) and white-fir (2,9) species have the highest productivity. The white-pine forests (3,2) have lower productivity.
The average age of NP forests is 90 years – 91 years of the coniferous and 74 of the deciduous forests. The forests that are over 100 years old comprise 13 514,6 ha (31,8%) of the afforested area.
The total forest reserve in the NP is 6 228 861 m3. The spruce (48%) is dominant in the forest biomass. The white pine forms 20%, white white fir 18% and the fir-tree – 10%. The beech reserve is the biggest among the deciduous reserves – 223 125 м3 (4%). The average reserve per hectare is 233 м3 and the average increase – 2,82 м3 per hectare.
The sanitary forests` status according to the R damage index is: healthy (R=0 – 30%) – 83%, ill (R=30 – 60%) – 15%, dying (R>60%) – 2%. This shows that a great part of the tree vegetation has a good sanitary status and the variations observed are of local and temporary character. The white pine and after that the white fir have the lowest damage index. The sanitary status of the spruce and fir-tree is lower.
About 1400 vascular plants are established within the park borders. Some of them are of utmost biological and scientific importance. 51 of them are protected by law and 13 are included in the European list of rare, endangered and endemic plants. 98 rare and endangered species are listed in the Red Data book of Bulgaria. Alchemilla pyrenaica, Aquilegia aurea, Armeria alpina, Empetrum nigrum, Cystopteris regia, Leontodon rilaensis, Primula halleri are rare species. Gentiana lutea and Gentiana punctata are endangered. There are 57 endemic species in Rila – 36 Balkan, 18 Bulgarian and 3 local endemics that are not found anywhere but in Rila: Primula deorum, Rheum rhaponticum and Alchemilla pawlowskii. This small part of scientifically important species called endemics or species that are found on a certain territory form the main part of the vegetation. The bryoflora is represented by 274 bryophyte species, 233 fungi species and 130 species of fresh water algae.