Natural forests health assessment in ‘Parangalitsa’ Reserve, Rila Mountain

Health status assessment and monitoring in natural forest stands were conducted in 2024 in the ‘Parangalitsa’ Reserve (Rila Mountain, Southwest Bulgaria). A series of subsequent terrain observations were performed in the protected forest area. As a result, 16 fungal pathogens and 17 insect pests were identified as causing damage to the main tree species – Norway spruce ( Picea abies ), silver fir ( Abies alba ), Scots pine ( Pinus sylvestris ), and European beech ( Fagus sylvatica ). Among the parasitic fungi, Armillaria mellea , Heterobasidion annosum , Fomitopsis pinicola , and Fomes fomentarius were identified as the most destructive. Fir broom rust Melampsorella elatina was the causal agent for perennial infections in silver fir trees. Seventeen insect species from six families and five orders were established on Abies alba , Picea abies , and Pinus sylvestris . Attacks of the European bark beetle Ips typographus formed the reserve‘s main disturbance in the Norway spruce forests. Bark beetles Ips acuminatus and Pityokteines curvidens were the most destructive xylophages on Scots pine and silver fir trees, respectively. In high population density, the three aggressive xylophages could cause severe damage and drying of the attacked stands.