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Teaching aim: Factual description and characterization of the mutual dependencies of physical factors in order to establish a base for the ecological interpretation of the Central European environment (in connection with unit 2)
Keywords: Climatic factors of Central Europe, temperate zones, west-wind zone, maritime/continental climates, natural vegetation zones, soils and their characteristics, the great river basins |
The geographical location of Germany in the heart of Central Europe explains the fact that the physical features do not stop at the national boundaries. This holds particularly true for the climatic conditions [1] which must be seen embedded in a broader continental scale [2]. In general terms, Central Europe is exposed to the westerlies of the North Atlantic Drift, which means that Germany is in the path of winds that blow over the Atlantic ocean and bring relatively warm and humid air masses onto the continent. As a consequence, maritime climate influences prevail. This means that extremes in rainfall and temperatures are rare, though they may occur. It is, however, more typical to be exposed to more moderate conditions. Precipitations [3] are evenly distributed over the year, with an average rainfall of about 500 to 700 mm per year in the Northern Lowlands. In the Central Uplands they may get as much as 1000 or even 1500 mm in the higher lying areas, and in the Alps they can reach more than 2000 mm. As a general observation it can be said that precipitations diminish west to east, where the climate becomes gradually more continental.
The above general spatial pattern also holds true for temperature variations. Mean temperatures in January are generally below zero in the eastern parts of the Northern Lowlands, whereas in the western parts they stay above. Due to higher altitudes in the south, Bavaria and the alpine region have the lowest mean temperatures during the winter, but even there they will not fall much below -5 degrees Celsius. Extreme [4] drops are seldom but may occur. Cold air masses drawn from the Arctic or from Eastern Europe can bring very chilly weather of several days duration, with temperatures tumbling as low as less -30 degrees Celsius. Heat waves in the summer can skyrocket the mercury as high as +40 degrees. But these are truly exceptional situations. They are due to the influence of either polar or tropical air masses which reach Central Europe occasionally. On the average, however, the climatic changes that occur from season to season are not very pronounced. The principal distinction between summer and winter is the length of daylight available. In fact, solar day light during the summer solstice is almost twice as high as at the turn of the winter. Snow cover ranges from about 10 days in the northern parts to 60 days in the southern parts of the country, notwithstanding longer periods in the higher mountains. All this leads to a concentration of crop farming in the warmer half of the year. Many of these crops are seeded in the late fall and lie dorment in the winter, but have an early spring start. Since German agriculture has a long standing practice of raising livestock (mixed farming) it is more of a year-round occupation than in more severe climatic areas of the world.
Very much dependent on the climatic conditions is vegetation and land use [5], although it must be emphasized that the human influence has altered the natural environment over thousands of years. A surprising fact is that Germany, despite its high population density, still has 29% of its land mass covered by woods and forests. Particularly in the sandy plains within the Northern Lowlands, in substantial portions of the Central Uplands wherever poor soils prevail and generally in the higher mountain areas there are widespread forests which are a significant economic factor in these regions. The forests have always been a major resource for timber and lumber. Today they play an important role in tourist development, but also as areas of land conservation and environmental protection. The historical importance of the forests can be seen from the frequent use of the suffix -"wald" (means forest) in place-names, e.g. Schwarzwald (black forest), Bayerischer Wald (Bavarian forest), Thüringer Wald (Thuringian forest) and many others.
The largest share of Germany's forests is characterized by a mixture of broadleaf and needleleaf trees. The most common species are oaks, maple and elms in the lowland areas, whereas beeches, pines and firs predominate in higher altitudes. Pines are also very characteristic of the sandy plains in the Northern Lowlands where soil moisture is scant. Most broadleaf trees drop their leaves in the fall to retard loss of the moisture in the dormant period. As a general observation it can be said that European mixed forests have a significant smaller variety of trees than the comparable forests in North America. According to Poulsen (1997, 65), this is quite likely to have happened due to the elimination of many species during the glacial periods. Another reason is the alteration of the vegetation by human activities for more than 5,000 years. Without this influence, more than 80 % of the Central European landmass would still be covered by forests. But human expansion has retreated the margins to today's limits. Moreover, today's forests reflect selective forestry practices which have been exercised for hundreds of years. Thus some species have been reduced if not eliminated. In some areas, new species have been introduced without always matching them to the ecological environment. A major present concern is the damage to German forests [6] (only available in German) due to air pollution. Especially in the eastern parts of the country, such damage [7] has affected up to 70 % of the trees. One of the main reasons for this was the high emission of pollutants [8] from industrial plants during GDR times. After the opening of the border, immediate steps were undertaken, to reduce this environmental threat. The result has been a considerable decrease of sulphur dioxide emission.
Soils are, like vegetation, a product of the climate, but at the same time they reflect the nature of the parent rock on which they have developed. Especially in the Northern Lowlands poorly drained, podzolic soils are dominant. They are developed to the fullest in the Heath of Luneburg (Lüneburger Heide) and further east in the Mark Brandenburg (surrounding the city of Berlin). Outside the glaciated regions, soils contain greater amounts of organic materials and are less leached of minerals. Owing to these characteristics, they have been labelled as brown podzolic soils (in German Braunerde). This is the most typical soil in Germany with generally fair farming conditions because of the relatively high components of incorporated fixed nitrogen and other nutrients. By far the best soils have developed on the loess sediments of the North German "Börde" (the transition zone between the North German Lowlands and the Central German Uplands) and in most of the geological basins. Rich in organic materials and due to the moderate rainfalls they are somewhat similar to chernozem soils.
The water bodies of Germany are intimately intertwined with human occupation, be it the North and/or the Baltic Sea, or the navigable rivers [9], which have always been important trade routes and means of access to the country. Most rivers like the Rhine (Rhein), Weser, Elbe and Odra (Oder) have their watersheds drain towards the north, whereas the Danube (Donau) is one of the important rivers that drains into the Black Sea. On the way from its source in southwestern Germany to the delta, the Danube passes through or borders eight different states and is known by no less than five different names along its course. Economically by far the most important German river is the Rhine. Interconnections through canals to other important waterways [10] such as the Danube, make it even on a European scale an important factor of communication and transportation. On top of this, the Rhine valley [11] especially between Mainz and Bonn is admittedly one of the most scenic river passages of the whole continent and thus of very high tourist value.
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Questions that may be asked:
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[1] http://www.tatsachen-ueber-deutschland.de/809.99.html (27.08.2003)
[2]
http://www.wetterzentrale.de/
[3]
http://www.dwd.de/en/FundE/Klima/KLIS/prod/spezial/index.htm
[4]
http://www.dwd.de/en/FundE/Klima/KLIS/prod/spezial/index.htm
[5]
http://www.destatis.de/basis/e/geo/geonutzt.htm
[6]
http://www.sdw.de/wald/waschb03.htm
[7]
http://pro.agrar.hu-berlin.de/cdrom/bmelf/Zahlen/folien/folie25.htm
[8]
http://www.taz.de/pt/2000/07/14/a0037.nf/text
[9]
http://www.destatis.de/basis/e/geo/geoflust.htm
[10]
http://www.destatis.de/basis/e/geo/geokanat.htm
[11]
http://www.rheintal.de/index.php?id=276
[12]
http://www.sdw.de/
[13]
http://www.bml.de/index-00073B3867951EDBB60A6520C0A8E066.html
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