Oak forests are among the most ecologically and economically significant in Europe. Due to the consequences of climate change on the environment, successful restoration of these ecosystems has been reduced in recent times. In order to increase the regeneration of oak forests, the analysis of quality parameters of one hundred and twenty pedunculate oak (Quercus robur L.) seedlings of ten different half-sib families have been carried out in the nursery of the Institute of Forestry in Belgrade (Serbia). This study showed the influence of origin (mother trees) on the morphological characteristics of pedunculate oak seedlings. A high degree of variability has been determined for root collar diameter, height, weight of aboveground part, root weight, Roller’s sturdiness coefficient and seedlings quality index. The largest variability has been determined for the height of seedlings where a large number of transitional half-sib families is noticed between the largest and the smallest values. A small number of half-sib families (33.33%) showed high quality of seedlings, based on the cluster analysis of quality parameters. There was a high degree of correlation between root weight and aboveground part weight, giving the potential for the selection of quality reproductive material with a properly formed habitus. There was a high degree of correlation between root weight and aboveground part weight, which suggests the potential for selecting quality reproductive material with a properly formed habitus. This study facilitates the selection of suitable reproductive material sources for regenerating pedunculate oak forests within this particular region of distribution.

Species complex Fusarium sambucinum was frequently isolated from ash stands in Montenegro. Previous researches revealed that it is dangerous pathogen for one-year-old seedlings. The aim of this research was to investigate the influence of temeperature on growth and morphological characteristics of morphotype isolated from one-year-old common ash (Fraxinus excelsior L.) seedlings in Montenegro. Growth of Fusarium sambucinum pure cultures on different temperatures was the fastest on 25°C while the absence of growth occurred on 32.5°C. Cultures on optimum temperature were white reddish, aerial and with a lot hyaline, curved multi septate conidia. This research covers basic ecological and morphological characteristics of Fusarium sambucinum strain responsible for high pathogenicity towards one-year-old common ash seedlings in Montenegro.

Investigation of different seed diseases of common ash has great significance due to occurrence of ash dieback across Europe caused by Hymenoscyphus fraxineus Baral, Queloz and Hosoya (T.Kowalski) and still not completely defined strategies about regeneration of this species. Species complex Diaporthe eres are familiar pathogens of common ash. During the monitoring of health condition of common ash in Montenegro Diaporthe eres was frequently isolated from common ash seeds. The aim of this research was to investigate temperature conditions that contribute to the growth of Diaporthe eres strains from Montenegro in infected seeds and histological characteristics of Diaporthe eres spread in seeds. Growth of Diaporthe eres pure cultures on tested temperatures showed the fastest growth on 25°C and the absence of growth on 35°C. Mechanical damage did not significantly contribute to occurrence of infection. Microscopic examination of heavy infected seeds showed that hyphae of D.eres were visible on outer parts of seed spreading inside the core. In this research we investigated some basic bio ecological characteristics of D. eres associated with decline of F. excelsior seed in Montenegro.

Symptoms of disease were recorded on leaves of whitebeam (Sorbus aria (L.) Crantz) seedlings in one stand in Montenegro. Analysis showed fungi Ochrospora ariae (Fuckel) Ramsb. and Septoria sorbi Lasch were present on infected trees. Species Seporia sorbi was associated with necrotic reddish and brown spots while species Ochrospora ariae was associated with necrotic reddish spots and yellow pustule of uredinia on leaves. Species were recorded both separately and simultaneously on leaves. This is the first record of Ochrospora ariae and Seporia sorbi on whitebeam (Sorbus aria) in Montenegro. Results will contribute to better knowledge of diseases and better protection of whitebeam (Sorbus aria) in early stages of growth in this part of its areal.