Since 1984, forest ecosystem research has been carried out ub the Tyrolean Alps (Ziller valley/Central Alps, 1984-1990; in the Achen valley/Limestone Alps, since 1990. The main investigations focussed on air pollution stress factors and the effects on forest ecosystems. Bioindication methods were developed as well as meaningful physiological parameters to describe the reaction of trees to the prevailing circumstances.

Pollutant input / Altitudinal gradients & seasonal variation

Ozone, sulfur dioxide and nitrogen compounds: air
Conc's are highest at mid-altitudes (1000m) compared to those at the valley bottom and the timberline because of local production ("Ozone belly"). [Puxbaum, Technical University Vienna]

Ozone belly

Heavy metals: rainwater, fog
Volatile organic compounds (VOC's): air, needles
Concentrations of volatile compounds in the air ranged from 5 to 51 ppb, mainly contributed by anthropogenic sources. Their contribution to ozone formation was low. [Rosenberg, Technical University Vienna] The detoxicating capacity of Glutathione S transferase is sufficient to detoxicate the existing chlorinated hydrocarbons inputs. [Schröder, GSF Munich]
Persistent organic compounds (POC's): humus layer, needles
Concentrations of persistent compounds (e.g. PCDD/F) in the humus layer and in needles of Norway spruce show an ubiquitous distribution. [Weiss, Federal Environment Agency Austria]
Local production and long-range transport

Bioindication: Application of established & development of new methods / Development of early stress parameters

Heavy metal content (spruce needles, mosses, fungi)
The concentrations of Pb, Cd, Cu and Cd in eatable mushrooms exceeded limit values for champignons. [Peintner, University of Innsbruck]
Nutrition status (spruce needles)
Early stress diagnosis
Combining several parameters (e.g. photosynthesis, nutrition status, lipids, antioxidants, pigments) an early stress diagnosis was developed. [Bolhar-Nordenkampf, University of Vienna]
Antioxidative system (spruce needles)
Antioxidants in needles (e.g. ascorbate, thiols) increase and chlorophylls decrease with altitude, indicating a protection from oxidative stress. [Tausz, University of Graz]

Altitudinal course of antioxidative components (spruce needles)

Cytogenetic bioindication (fine roots)
Photosynthesic parameters

Measurement of photosynthetic parameters on mature spruce trees

Soil microbiology
Determination of mycorrhiza by Polymerase Chain Reaction (PCR)

Modelling of Critical Loads and Levels

Critical Loads of protons and nitrogen
Exceedances of Critical Levels of ozone
Based on half hour mean ozone concs. of 120 measuring stations & on meteorological data the AOT40 was modified regarding ozone uptake for forested areas. [Loibl; Research Centre Seibersdorf]

AOT40 regarding ozone uptake

Land use potential analysis

Land use conflict potential analysis
Land use potential analysis: Integrated data were used to perform assessments on the relative potentials for timber pro-duction, hunting, grazing, nature conservation & receation [Ottitsch, University of Agriculture]
Land use concepts

Effects of forest pasture

Vegetational and root-ecological investigations
Negative effects of grazing on the formation of fine roots and the development of mycorrhiza was proved [Sobotik FIAG Gumpenstein; Göbl/BFW]

Nitrogen input, pools and fluxes

Nitrogen budget: Since 1998, nitrogen input, fluxes and pools are investigated by continuous measurements and by modelling. [Herman, Jandl, BFW]

Saturation status of the investigation site