Bulgaria

Alexander Alexandrov *, Ivan Iliew**

*Forest Research Institute, **University of Forestry, Sofia

Multi-centuries and thousand-year old trees represent a valuable genetic resource having survived many unfavourable climatic conditions - wind and snow storms, droughts and floods, high air temperatures and hard frosts, virus attacks, bacteriological and fungous diseases, and pests.

Pinus heldreichii Christ has been described by Konrad Christ in 1863 and as Pinus leucodermis Ant. by F. Antoine in 1864. It occurs in the Balkan Mountains in Albania, Bosnia and Herzegovina, Montenegro, Serbia, North Macedonia, Bulgaria, Greece and in the Apennines (Calabria - Pollino National Park). With the common name Heldreich's or Bosnian pine, it usually grows on steep, sunny, dry rocky slopes on carbonate Cambisols from 900-1,000 m to 2,500 m above sea level, reaching the alpine tree line. As a pioneer species, it is capable of recolonization under extreme environmental conditions.

In Bulgaria this species is distributed in Slavyanka Biosphere reserve and Pirin National Park where probably grows the oldest known living coniferous tree in Europe - Baikushev's pine or Baikusheva mura at age over 1,300 years. This Heldreich's pine was found by the Bulgarian forester Konstantin Baikushev in 1897 on Pirin Mountain at an altitude of 1930 m. Its dimensions are: height - 25 m, diameter at breast height - 2.5 m and 7.8 m in circumference (Fig. 1). The health status of this tree is quite good for the age and most likely it can survive many decades more.

In situ genetic conservation of Pinus heldreichii Christ in Bulgaria amounts to 180 stands on 1,116.9 ha (1,107.1 ha of reserves and 9.8 ha of native permanent seed production stands).