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Morphometric studies of Sideritis scardica Grsb. and S. syriaca L. in their natural populations in Bulgaria [Estudios morfométricos de Sideritis scardica Grsb. y S. syriaca L. en sus poblaciones naturales en Bulgaria]

Background. Common whitebeam, Sorbus aria (L.) Crantz is an European and Near-Eastern deciduous tree with small red fruits. However, the edible use of this forest fruit is currently not widespread. Also, its nutritional and antioxidative properties remained undiscovered. In this study, the chemical composition and antioxidant properties of common whitebeam fruit were investigated. Materials and methods. The fruit were collected from Golo Bardo Mountain in Bulgaria. The phytochemical (carotenoids, phenolic compounds, flavonoids), nutritional (moisture, ash, titrable acidity, lipids, proteins, pectin, carbohydrates) and antioxidant activity were evaluated by four assays (DPPH, ABTS, FRAP, and CUPRAC). Results. Sugar analysis demonstrated that only fructose and glucose were detected in the fruit. Pectin content did not exceed 1.30%. Moreover, the fruit had a low lipid content (0.80%). The whitebeam fruit were also characterized as a source of carotenoids (1.69 mg/100 g fresh weight, fw), phenolic compounds (32.42 mg GAE/100 g fw), and flavonoids (20.08 mg QE/100 g fw). Among phenolic acids, only 2,4-dihydrohybenzoic, caffeic, p-coumaric, and sinapic acid were detected. The antioxidant potential of the fruit was from 168.52 mM TE/100 g fw (FRAP) to 244.81 mM TE/100 g fw (CUPRAC assay). Conclusion.The current research enriched the available information about the nutritional potential and chemical composition of common whitebeam fruit and their low sugar content. The absence of sucrose, together with its high phenolic content, demonstrated the potential of this fruit for future application in food products and supplements.

This review presents a brief survey of the Bulgarian dendroflora. The country is situated in the transition zone between the continental and Mediterranean climate and,therefore, considerable habitat diversity exists on its territory. About 370 species – trees, shrubs and sub-shrubs – have been established up until today. An overview of the species'diversity, woody formations and their distribution is presented. The data show that Bulgaria is characterised by a relatively rich dendroflora that needs appropriate close-to-nature management and measures for its conservation.

Norway spruce forests are among the forests most affected by natural disturbances in Europe. One of the key aspects is the regeneration of the disturbed areas, which is decisive for later forest development. We studied the natural regeneration after two windthrows that occurred 30 (1983) and 50 years ago (1962) in an old-growth forest over 150-year-old in the Parangalitsa Reserve and a recent windthrow (2001) in a 130-year-old single cohort forest in the Bistrishko branishte Reserve in Bulgaria. We set up study plots along transects, counted regeneration and substrates, and analyzed age using tree rings. Postdisturbance regeneration made up 62-81% of all recorded trees and was more important than advance regeneration, but it strongly differed among the windthrows. Our data indicated two discrete peaks of post-disturbance regeneration. The first peak started immediately after the windthrows and was dominated by Norway spruce and rowan, while the second one started about 30 years later and was dominated by spruce. Pioneers such as Populus tremula, Salix caprea and Pinus sylvestris were less prominent than expected, contributing up to 21% of the total regeneration. Despite the fact that the highest density of initial regeneration was found on mounds from uprooted trees, the largest total number in the three studied areas was on intact forest floor, which hosted between 69 and 80% of all regeneration. The importance of coarse woody debris rose significantly two to three decades after the disturbances and was particularly important for the secondary regeneration, which consisted of Picea abies and Abies alba.