The paper summarizes the main results of reach on heavy metal detoxification in ectomycorrhizas of Rhizopogon roseolus, Paxillus involutus, Cenococcum geophilum and Pisolithus arrhizus formed on Pinus sylvestris roots collected from heavily polluted areas in Poland. The data were obtained by methods including electron microscopy (TEM, SEM) accompanied by EELS and EDAX, cytochemical stainings and capillary electrophoresis. All of the species described in the paper are fungi highly resistant to toxic elements. As detoxification in mycorrhizas is dependent on both partners, the phenomenon was studied in fungi and in Pinus sylvestris roots. The strongest element-filtering effect was observed in R. roseolus / P. sylvestris symbiosis. This mycorrhiza type was characterized by the accumulation of heavy metals in the fungal mantle, and a gradual decrease of these elements was observed along the Hartig net towards the inside of the root. Potentially toxic elements were localized intercellularly in crystals deposited on the mantle and hyphal surface and in pigmented layer of the cell wall of the extramatrical hyphae, and the hyphae of the outer mantle layer. They were also detected intracellularly within electron-opaque depositions in the vacuoles. Much lower levels of toxic elements were detected in plant cells. The most common place for heavy metal accumulation was the phenolic material of the cortical cells.

First studies of this kind were based on mapping of cover and frequency of crustose, foliose and fructicose epiphytic lichens on trees which were assessed also for the decline symptoms. Since 1985 epiphytic lichen vegetation has been assessed by this methods and results, expressed as a lichen map of Slovenia were used as an air quality indicator for plots of forest die-back inventory. In case studies of forest decline, in collaboration with lichenologist from Graz Univ., Austria, all epiphytic lichen species were mapped in order to obtain better measure of air quality in the area studied. Very polluted and still clean and well preserved forests were investigated. From the material collected and determined a lichen herbarium has been established on the Slovenian Forestry Inst.. Possibilites of further research and use of epiphytic lichens as air quality indicators are discussed.

The condition of silver fir (Abies alba Mill.) trees was monitored 1988-1994 by measuring electrical resistance of living tissues at breast height. Slime cells in bark and traumatic resin canals in wood were investigated as possible symptoms of silver-fir decline.

Seven ectomycorrhizae on oak (Quercus robur L.) from a Slovenian forest stand are described, five of them for the first time in detail. Four of these species could be identified (Lactarius chrysorrheus (Fr.) Fr., L. serifluus DC. ex Fr., Xerocomus subtomentosus (L. ex Fr.) Quel., X. armeniacus (Quel.) Quel., one unidentified species was given a preliminary name ("Quercirhiza squamosa"). Two identified species, already comprehensively characterized on other tree species, are presented shortly (Laccaria amethystina (Bolt ex Hooper) Murr., Cenococcum geophilum Fr.). Whereas some of the encountered species show considerable host specifity with oak (Lactarius chrysorrheus, L. serifluus and, in a lesser degree Xerocomus armeniacus), other species have a broader host range and can even grow with conifers (Xerocomus subtomentosus, Laccaria amethystina, Cenococcum geophilum). A key for all species was established. A possible use of ectomycorrhizal species as bioindicators is discussed.

In the paper authors review the complexity of the impacts on the forest ecosystem caused by road construction and logging operations and discuss research activities in that field. Interdiciplinary approach is emphasized and research priorities are suggested. The studies are needed where structural parameters of the soils are related to the plant vitality. This will help us understand the forests response on the impact and enable us to develop the practical techniques for soil and stand protection during further actions.

Because of thinning of the ozone layer, there is a continual increase of ultraviolet B (UV-B) irradiation reaching the Earth. We have followed for two and a half years the influence of an artificial source of UV-B irradiation of 17685 J/m** 2 and 28010 J/m** 2 on spruce Picea abies (L.) Karst seedlings. The controls were irradiated with only normal, 6025 J/m** 2. Results show that 3 years seedlings are sensitive to irradiation, as may be first seen from their decreased mitotic activity and in lesser needle and seedling growth in their third year.

The haploid chromosome set of Norway spruce consists of 12 chromosomes. Most of the chromosomes are very similar in their morphology (length, arm ratio, secondary constriction). For the CGBI it is necessery to recognize all chromosomes. Therefore we used different banding methods to solve this problem. We used the root meristem and the dividing cells of the macrogametophyte as test objects. We discussed morphology of chromosomes of these two different dividing tissues. The use of image analysis equipment made it possible to get in a relatively short time a great number of data for statistical analysis. Another method was, to use an expert-system for data analysis. Finally 3-D models of interphase nuclei were reconstructed.