Antioxidative and photoprotective responses of trees at high elevations

In the beginning of the nineties of the last century, it has been observed that trees at higher elevated plots accumulate higher concentrations of protective substances - antioxidants and photoprotective carotenoids - in leaf tissues (Fig. 11.3). Spruce needles from trees at timberline plots often contain higher concentrations of ascorbate, glutathione, tocopherol, or carote-noids (Polle et al. 1992 Polle and Rennenberg 1992 Tausz et al. 1998 Table 11.1), potentially conferring better...

Specific pedogenetic factors at the timberline

Due to the geological heterogeneity of the European Alps, a large diversity of parent materials is the basis for pedogenesis in the timberline ecotone. The Eastern Alps consist of a central mass of crystalline and schistose rocks flanked on each side by a zone of Mesozoic beds consisting largely of limestone with minor shares of sandstones and marls. Glaciations has altered the original rock structure and shape of the landscape, leaving glacial deposits as soil parent material in many places....

Water Transport

Trees evolved complex water transport systems to span the distance between the mesophyll and the roots. These transport systems are characterized by their hydraulic efficiency and safety, whereby a trade-off between these aspects is often observed (e.g. Tyree et al. 1994). The lower the resistance in the xylem the higher is its hydraulic efficiency, but a low resistance often corresponds to an increased risk of embolism induced by drought or freeze-thaw events (e.g. Zimmermann 1983 Tyree et al....

Effects of the needle rust Chrysomyxa on Norway spruce

Chrysomyxa rhododendri is a needle rust requiring a host shift between Rhododendron species (telio-host) and Norway spruce (intermediate aecio-host) for completion of its life cycle (De Bary 1879). Infection of spruce is therefore restricted to subalpine regions where trees are within the reach of the airborne basidiospores formed on Rhododendron leaves in late spring. Basidiospores only penetrate into developing current-year needles of spruce. During early summer, infected needles show a...

Soil types and humus forms

Soil formation at timberline is usually slow and lasted for only 12000 years or less. Steep slopes are shaped by erosion, especially if stabilising vegetation is absent. So, many soils are in a constant process of rejuvenation. As a result, poorly developed soils are omnipresent in high mountain areas. Although soil forming processes depend at least partially on the altitud-inal change of climatic conditions, no single soil type can be considered typical for the timberline ecotone. On a...