The ectomycorrhizal biodiversity of selected Norway spruce stands on an Alpine limestone mountain was studied by inventories of occurring fruitbodies and descriptions of new ectomycorrhizal types. Based on fruitbody surveys a total of 137 ectomycorrhizal and 48 saprophytic species was recorded. Dependent on elevations as well as microclimatic, soil, and stand conditions there were significant differences in the fungal composition and number of species between the investigated forest plots.

Cytogenetical and biochemical investigations of common oak (Quercus robur L.) were applied in order to find suitable markers in bioindication of oak populations. In cytogenetical analyses the chromosome aberration and mitotic index were recorded. Chromosome banding, B-chromosomes, location and number of nuclear organizer regions were indicated using Giemsa C-banding method, fluorescence staining and silver impregnation. In biochemical analyses SDS-electrophoresis of soluble proteins and isoelectric focusing of isoperoxidases were used.

The article presents a state of art of forest decline inventories in Slovenia. The first part deals with methodological and technological aspects of forest health inventories, while the second one describes some hints and directions of further forest inventories development.

Research was carried out in EMFT, II-G-10 (common oak and common hornbeam zone) and in main EMFT-s on the karst (pubescent oak and oriental hornbeam, and holly oak zones) in which forest fuel loads were determined too. Soil and structure elements were sampled and measured, stand vitality and quality were measured and evaluated. Chemical and physical analyses of soil samples were performed. The samples of precipitation's and plant material were chemically analyzed. It contains the data of normal and changed forest conditions (first measurement 1969-1981, second measurement 1991-1993). In second measurement the research that deals with tree breeding and fructification was added to the project. The aim of this recently introduced research is to determine the dynamics of flowering and phenotype damage degree. Cytogenetic and some biochemical analyses were carried out with the aim of determining and establishing methodology of work. The data base was built up and data search programs were developed. The relations of ecological and structural stand elements for normal and changed stand conditions were determined. The results achieved are the basis for building up the diagnostic stand models and the evaluation model of ecological-environmental ecosystem value. The main purpose is to support decision making on different management levels.

Among a variety of stress indicators for early identification of Norway spruce (Picea abies (L.) Karsten) decline the sulphur content, photosynthetic pigment content, activity of the enzyme peroxidase, watersoluble thiols and ascorbic acid in 4 age classes of 5 spruce needles were analysed. The 10 sampling sites were selected according to the degree of forest decline, sea level, distances from the Thermal Power Plant Sostanj and air pollution.

It is often difficult to predict how synergistic effects work and how dieback may be expected to spread through an area over time. On the other hand concepts and methods for compensation of acid deposition, melioration and restauration of acidified forest areas represent a major management problem. The following examples show how GIS may be used to find answers to these questions.

The evaluation of data on the forest tree condition is weak point in forest decline monitoring as it enables only a very rough estimation of the state of forest health. The paper analyses the interpretation of the forest tree defoliation data in order to estimate their relevance and applicability. Quality control results of defoliation assessment in Slovenia are presented and the state of defoliation with its changes in the year 1987, 1991, 1993, 1994 on the 16 km grid.

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.