Characteristics of tree bark as an indicator in high-immission areas

Abstract

In the immission area of Frankfurt a.M. measurements of pH value, sulfur content and concentrations of Ca, K and Na of tree bark have been made. In the case of the deciduous trees Fraxinus excelsior, Acer platanoides and Tilia spp. all parameters can be used as an indicator for the degree of immissions. Even in the "desert of lichens" a division into four different zones of load is possible. Because in the Rhein-Main area winds from the southwest predominate, the size of zones of greatest air pollution depends on the distribution of winds. Correlations between the sulfur content of bark and the arithmetical mean value of SO in the air have been found. The sulfur values of bark range from 50 to 270 μg/cm, the SO values from 0.08 to 0.13 mg/m. A correlation between electric conductivity and Ca values in the bark suspension was also found. With distance from the immission center the Ca content of bark is decreasing. In the immission area of Frankfurt a.M. pH value and sulfur content of bark of deciduous trees must be regarded as indicators for air quality and the Ca values as indicators for dust immissions.

The Ecology of Lobarion Pulmonariae and Parmelion Caperatae in Quercus Dominated Forests in South-West Norway

“…The significance of the soil for the epiphytic vegetation is frequently stressed (Olsen 1917, Ochsner 1928, Waldheim 1944, Barkman 1958, Kalb 1972), although wind is often assumed to carry dust upon the bark. Cacontent of the bark has even been regarded as an indicator for dust (Lotschert & Kohm 1979). This seems unlikely in an old forest with a dense cover of ground vegetation, far away from cultivated areas and roads.…”

Variations in bark acidity and conductivity over the trunk length of silver fir and Norway spruce

“…Härtel and Grill (1972) introduced a measure of general air pollution by using conductivity of bark. Bark is revealed to be an excellent material for determining the degree of environmental acidity due to gaseous sulphur dioxide pollution (Grodzinska 1971(Grodzinska , 1982Härtel and Grill 1972;Lötschert and Köhm 1977). Some authors found that bark pH is more acid in coniferous trees than in deciduous trees under unpolluted conditions (Johnsen and Sochting 1973;Swieboda et al 1979).…”

Pine (Pinus Eldarica Medw.) needles as indicator for heavy metals pollution

“…Numerous different bio-indicators are used in monitoring air pollution, such as mosses, lichens, vascular plants, woody plants, etc. Both the broadleaves and coniferous trees are used in air pollution studies (Löstschert and Köhm, 1978;Grodzinka, 1982;Huhn et al, 1995;Lippo et al, 1995;Adeniyi, 1996). The aim of this work is to determine the pollution levels (concentrations) of Pb, Cu, Zn, Ni and Cr in the atmosphere of Tehran city using pine tree (Pinus Eldarica Medw.)…”