The Black Triangle is located on the triangular border area between Germany's Southern Saxony; Poland's Lower Silesia and the Czech Republic's Northern Bohemia.
It is formed by a triangle shaped range of mountains: The Ore Mountains (Krušné hory), oriented from south-west to north-east rise steeply above the Most Basin on their Czech side and descent gradually on their German side. The Lazike Hory in the Giants Mountains (Karkonosze), oriented from Northwest to Southeast are steeper on the Polish than on the Czech side. These mountains form a wind barrier and microclimate situation over the Most basin, creating unfavourable conditions for the dispersion of clouds .
Coal basin at the origin of air pollution
3 May 2000, Landsat 7 ETM,
bands 3: blue, 5: red, 6: green
The brown coal belt is located along the Most Basin, in the heart of the Black Triangle and has led to the expansion of open cast lignite extraction (pink scars on the MSS image, white scars on the ETM images).
Some coal mines measure up to 5km and reach nearly 200m in depth, thus lowering the regional water table, changing the river or wetland area, and therefore reducing the evapotranspiration process over the area.
As the extracted lignite could not be shipped far, it led to the implantation of nearby coal-fired power plants, providing energy for heating and heavy industry.
These industrial activities have generated the emission of increasingly high levels of sulphur dioxide (SO2) and nitrogen dioxide (NO2) thus contaminating the air with excessive concentration of pollutants trapped over the basin during long periods when temperature inversion would lock tons of ash and gas under a roof of warm air. The wet and dry deposition of pollutants led to soil and water acidification, has deteriorated the ecological balance and caused numerous human health problems, including respiratory diseases and cancer.
Coal storage in front of Procerady Power Station
© Czech Power Company
Tisova modernised Power Station in Most Basin
© Czech Power Company
Since the middle of the 20th century, the landscape in the region has been severely affected. According to NASA EOS "Changes in Biological Cycles", approximately 30.000 hectares of forests had to be cut because of severely damaged trees, with 52% of the forest lost on the Czech side of the Krusne Hory mountains.
Coniferous forest affected by air pollution
Satellite based estimations of coniferous forest cover change in the Krusne Hory made by Ardö et al. indicate that 50% of the coniferous forest disappeared between 1972 and 1989. The most affected areas being the south and south-east facing slopes between 600 and 1000 meter above sea level.
A report produced by Kubelka et al. for the Czech
ministry of Agriculture in 1993 indicates that 56% of the spruce
stands in the Krusne Hory mountains were cut between 1970 and 1990
and that the rest were deteriorated.
Extensive clearcutting of damaged and dead areas resulted in a sharp decrease of the forested areas.
Damaged and dead spruce forest in Czech Republic and Poland (1991)
European and trilateral cooperation in favor of environment
Since June 1991 the three concerned countries have been working together to reverse the trend in air pollution and bring the plants into compliance with European standards.
Major environmental improvement have been achieved through the application of a combinaison of modern technologies and emission reduction measures such as the decommissioning of old polluting plants, the installation of desulfurisation equipment and electrostatic precipitator and the use of fuel with low sulphur and low nitrogen content.
Polluting emissions: positive trends
Emissions form non stationary sources, are still increasing.
The Common Report on Air Quality in the Black Triangle Region 2000 indicates a declining tendancy of sulphur dioxide (91%), nitrogen oxides (78%) and solid particules (96%) emissions from the major stationary sources, in the three concerned countries, since 1989.
A comparison of spectral measurements made of Norway spruce within the Krusne Hory suggests strong evidence of forest recovery between 1991 and 1995. (NASA EOS, Changes in Biological Cycles).
Some open cast pits have been filled with water or rehabilitated for agriculture thus contributing to reestablishing the functionality of the water cycle and to the stabilisation of the local microclimatic conditions needed to attempt reforest-ation successfully.
New tree plantations can be seen on the western side of the Most Basin on the ETM 2000 image.
Research conducted by: Nicole Strub, GRID-Europe