The concentrations of potassium were determined in: (a) the last formed wood, (b) the vascular cambial zone with conductive (noncollapsed) phloem, (c) the youngest nonconductive (collapsed) phloem and the (d) oldest nonconductive phloem, by atomic absorption flame spectroscopy in three unaffected and three heavily affected silver fir (Abies alba Mill.) trees. A commercial conditiometer and own devised Tree Tester were used to determine the electrical resistance (ER). The relationship between the ER of living tissues and K content was investigated. The tissues of unaffected trees were generally characterized by a higher K content and corresponding lower ER. In all trees the K content was highest and ER lowest in the vascular cambial zone with conducting phloem, followed by nonconducting phloem and youngest xylem.

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.

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.