Fine root regenerative potential of montane Norway spruce under pollution impact

Fine roots of six probably autochthonous Norway spruce stands in the Krkono se Mts. have been investigated since 1993. Fine root (roots with diameter < 1 mm) regenerative potential was estimated as the ratio between the fine r oot quantity in soil cores and fine roots ingrown into bags of silon net si eve. These bags were filled with the same humus soil substrate without root s, and installed into the same soil cores, and then harvested two years lat er. In addition, representative fine root tips were classified under dissec ting microscope into five mycorrhizal developmental stages and three classe s of vitality. Forest stands with high values of fine root quantity in soil cores (installed in 1994) had middle or low values of fine root regenerati ve potential (estimated in 1996). Root tip analysis revealed the decreasing vitality (percentage of turgid root tips) from the less developed, nonmyco rrhizal root tips to the fully developed mycorrhizae in the dying forest st and in the Mumlavska hora plot. This tendency was not found in other forest stands.