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.

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.

This paper deals with presenting a broad range of possibilities, which can be used with computer equipment by deriving, interpreting and processing forest data. Different rates of generalized data from the forest inventory can be used as a criterion in preparing different solutions. So this data strongly influences decision making processes. The paper also presents cost analysis and multi-criteria evaluation methods.

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.

This article deals with use of several bioindication methods in forest decline studies within an international TEMPUS project carried out in Slovenia. The aim of the project was to introduce and connect different bioindication methods in order to improve methods and qualify the research staff working in this research field in Slovenia. The following bioindication methods were introduced or adapted for forest decline research in Slovenia: biochemical and physiological markers of air pollution / stress impact on forest trees (Graz Univ.: photosynthetic pigments, thiols, ascorbic acid, protective enzyme systems; Cambridge Univ.: plant hormones; Munich Univ.: mineral nutrition of forest trees); epiphytic lichens as indicators of air quality on forest sites (Graz Univ., Ljubljana Univ); determination of types of ectomycorrhizae as indicators of forest soil condition (Munich Univ., Ljubljana Univ.). The significance and practical use of bioindication methods in environmental studies is also discussed.

The Forest Research Plot was chosen on a typical site for the Pokljuka plateau. It is covered by a supposedly autochthonous old Norway spruce stand with rejuvenation centres. Data on the physiological parameters can be used as representation values for a subalpine Norway spruce stand. The studies include: standard site and dendrological parameters, physiological parameters (foliar analysis, antioxidants, hormones and aminoacids in spruce needs), genetical and biochemical analysis (isoenzymes and molecular markers), microbiological activity (acid phosphatase, rate of decomposition, number and occurrence of fungal decomposers of wood and litter) and studies of symbionts and pathogens of Norway spruce (mapping of fruitbodies of mycorrhizal fungi, types of ectomycorrhizae, endophytes, epiphytes - lichens and phytopathological surveys). All physiological and ecological studies are planned to be repeated at certain time periods in order to understand better the functioning of the forest ecosystems on Pokljuka.

Mechanisms of air pollution toxicity are very complex and depend on various physiological and biochemical properties of plants. These mechanisms (including formation of free radicals) are still poorly understood. In addition, physiological responses of forest plants to air pollution stress can be modified by various biotic (e.g., insects, pathogens, mycorrhizae associations, genetic variation) and abiotic (e.g., increasing CO2 concentrations, ultraviolet-B radiation, nitrogen desposition, nutrient deficiencies, drought) factors. An example of air pollution effects on forest trees may be responses of ponderosa pine seedlings to elevated concentrations of ozone: various physiological changes in trees (lowered net photosynthesis, altered carbon allocation, deterioration of photosynthetic pigments, etc.) have led to reduced growth and biomass of plants.

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.